,transcriber's ,notes ,text printed in italics has been transcribed between underscores1 bold face printed text between equal signs4 ,small capitals have been replaced with ,,all ,,capitals4 ,literature references are numbered and listed per chapter at the end of the chapter1 footnotes 7indicated by letters in square brackets7 will be found directly underneath the paragraph1 table or illustration to which they refer4 ,more ,transcriber's ,notes may be found at the end of this text4 ,,lead ,,poisoning ,,and ,,lead ,,absorption ,,international ,,medical ,,monographs ,general ,editors ,,leonard ,,hill1 ,m4,b41 ,f4,r4,s4 ,,william ,,bulloch1 ,m4,d4 ,,the ,,volumes ,,already ,,published ,,or ,,in ,,preparation ,,are3 ,,the ,,mechanical ,,factors ,,of ,,digestion4 ,by ,,walter ,b4 ,,cannon1 ,a4,m41 ,m4,d41 ,george ,higginson ,professor of ,physiology1 ,harvard ,university4 ,ready4 ,,syphilis3 ,,from ,,the ,,modern ,,standpoint4 ,by ,,james ,,macintosh1 ,m4,d41 ,grocers' ,research ,scholar2 and ,,paul ,,fildes1 ,m4,d41 ,b4,c41 ,assistant ,bacteriologist to the ,london ,hospital4 ,ready4 ,,blood-,,vessel ,,surgery ,,and ,,its ,,applications4 ,by ,,charles ,,claude ,,guthrie1 ,m4,d41 ,ph4,d41 ,professor of ,physiology and ,pharmacology1 ,university of ,pittsburgh1 etc4 ,ready4 ,,caisson ,,sickness ,,and ,,the ,,physiology ,,of ,,work in ,compressed ,air4 ,by ,,leonard ,,hill1 ,m4,b41 ,f4,r4,s41 ,lecturer on ,physiology1 ,london ,hospital4 ,ready4 ,,lead ,,poisoning ,,and ,,lead ,,absorption4 ,by ,,thomas ,,legge1 ,m4,d41 ,d4,p4,h41 ,h4,m4 ,medical ,inspector of ,factories1 etc42 and ,,kenneth ,w4 ,,goadby1 ,d4,p4,h41 ,pathologist and ,lecturer on ,bacteriology1 ,national ,dental ,hospital4 ,,the ,,protein ,,element ,,in ,,nutrition4 ,by ,major ,d4 ,,mccay1 ,m4,b41 ,b4,ch41 ,b4,a4,o41 ,m4,r4,c4,p41 ,i4,m4,s41 ,professor of ,physiology1 ,medical ,college1 ,calcutta1 etc4 ,,shock3 ,the ,pathological ,physiology of ,some ,modes of ,dying4 ,by ,,yandell ,,henderson1 ,ph4,d41 ,professor of ,physiology1 ,yale ,university4 ,,the ,,carrier ,,problem ,,in ,,infectious ,,disease4 ,by ,j4 ,c4 ,,ledingham1 ,d4,sc41 ,m4,b41 ,m4,a41 ,chief ,bacteriologist1 ,lister ,institute of ,preventive ,medicine1 ,london2 and ,j4 ,a4 ,,arkwright1 ,m4,a41 ,m4,d41 ,m4,r4,c4,p41 ,lister ,institute of ,preventive ,medicine1 ,london4 ,,diabetes4 ,by ,j4 ,j4 ,,macleod1 ,professor of ,physiology1 ,western ,reserve ,medical ,college1 ,cleveland1 ,u4,s4,a4 ,a ,descriptive ,circular of the ,series will be sent free on application to the ,publishers3 ,,london3 ,,edward ,,arnold ,,new ,,york3 ,,longmans1 ,,green ,,co4 ,,international ,,medical ,,monographs ,general ,editors ,,leonard ,,hill1 ,m4,b41 ,f4,r4,s4 ,,william ,,bulloch1 ,m4,d4 ,,lead ,,poisoning ,,and ,,lead ,,absorption ,,the ,,symptoms1 ,,pathology ,,and ,,prevention1 ,,with ,,special ,,reference ,,to ,,their ,,industrial ,,origin ,,and ,,an ,,account ,,of ,,the ,,principal ,,processes ,,involving ,,risk ,,by ,,thomas ,m4 ,,legge1 ,m4,d4 ,,oxon41 ,d4,p4,h4 ,,cantab4 ,h4,m4 ,,medical ,,inspector ,,of ,,factories2 ,,lecturer ,,on ,,factory ,,hygiene ,,university ,,of ,,manchester ,,and ,,kenneth ,w4 ,,goadby1 ,m4,r4,c4,s41 ,d4,p4,h4 ,,cantab4 ,,pathologist ,,and ,,lecturer ,,on ,,bacteriology1 ,,national ,,dental ,,hospital ,,appointed ,,surgeon ,,to ,,certain ,,smelting ,,and ,,white ,,lead ,,factories ,,in ,,east ,,london ,,london ,,edward ,,arnold ,,new ,,york3 ,,longmans1 ,,green ,,co4 #aiab ,all rights reserved ,,general ,,editors' ,,preface ,the ,editors hope to issue in this series of ,international ,medical ,monographs contributions to the domain of the ,medical ,sciences on subjects of immediate interest1 made by first-hand authorities who have been engaged in extending the confines of knowledge4 ,readers who seek to follow the rapid progress made in some new phase of investigation will find therein accurate information acquired from the consultation of the leading authorities of ,europe and ,america1 and illuminated by the researches and considered opinions of the authors4 ,amidst the press and rush of modern research1 and the multitude of papers published in many tongues1 it is necessary to find men of proved merit and ripe experience1 who will winnow the wheat from the chaff1 and give us the present knowledge of their own subjects in a duly balanced1 concise1 and accurate form4 ,this volume deals with a subject of wide interest1 for lead is dealt with in so many important processes of manufacture--in the making of white lead2 pottery glazing2 glass polishing2 handling of printing type2 litho-making2 house1 coach1 and motor painting2 manufacture of paints and colour2 file-making2 tinning of metals2 harness-making2 manufacture of accumulators1 etc4 ,the authors bring forward convincing evidence1 experimental and statistical1 in favour of the causation of lead poisoning by the inhalation of dust4 ,this makes prevention a comparatively simple matter1 and the methods of prevention are effective1 and will contribute greatly to the health of the workers and the prevention of phthisis1 which is so prevalent among lead-workers4 ,exhaust fans and hoods1 or vacuum cleaners1 for carrying away the dust formed in the various processes--these are the simple means by which the dust can be removed and the workers' health assured4 ,,leonard ,,hill4 ,,william ,,bulloch4 ,september1 #aiab4 ,,authors' ,,preface ,progress in the knowledge of the use of lead1 the pathology of lead poisoning1 and the means of preventing or mitigating the risk from it1 has been rapid of late years1 and has led to much legislative action in all civilized countries4 ,the present is a fitting time1 therefore1 to take stock of the general position4 ,we have both1 in different ways1 been occupied with the subject for several years past1 the one administratively1 and the other experimentally1 in addition to the practical knowledge gained by examining weekly over two hundred lead-workers4 ,the present treatise takes account mainly of our own persona experience1 and of work done in this country1 especially by members of the ,factory ,department of the ,home ,office1 and certifying and appointed surgeons carrying out periodical medical examinations in lead factories4 ,the book1 however1 has no official sanction4 ,we are familiar with the immense field of ,continental literature bearing on legislation against lead poisoning1 but have considered any detailed reference to this outside the scope of our book1 except in regard to the medical aspects of the disease4 ,most of the preventive measures mentioned are enforced under regulations or special rules applying to the various industries or under powers conferred by the ,factory and ,workshops ,act1 #aija4 ,occasionally1 however1 where1 in the present state of knowledge1 particular processes are not amenable to the measures ordinarily applied1 we have suggested other possible lines on which the dangers may be met4 ,we have not reprinted these regulations and special rules1 as anyone consulting this book is sure to have access to them in the various works published on the ,factory ,acts4 ,the practical value of the experimental inquiry described in ,chapter ,,vi41 and the light it seems to throw on much that has been difficult to understand in the causation of lead poisoning1 has led us to give the results in detail4 ,one of us 7,k4 ,w4 ,g47 is responsible for ,chapters ,i41 ,,iii41 and ,v4 to ,,xi41 and the other 7,t4 ,m4 ,l47 for ,chapters ,,ii4 and ,,xii4 to ,,xvii42 but the subject-matter in all 7except ,chapter ,,vi41 which is the work entirely of ,k4 ,w4 ,g47 has been worked upon by both4 ,our thanks are due to the ,sturtevant ,engineering ,co41 ,ltd41 ,london2 ,messrs4 ,davidson and ,co41 ,ltd41 ,belfast2 the ,zephyr ,ventilating ,co41 ,bristol2 and ,messrs4 ,enthoven and ,sons1 ,ltd41 ,limehouse1 for kindly supplying us with drawings and photographs4 ,september1 #aiab4 ,,contents ,,chapter ,,page ,i4 ,,historical--,,chemistry ,,of ,,lead #a ,,ii4 ,,tiology #g ,,iii4 ,,susceptibility ,,and ,,immunity #bg ,,iv4 ,,statistics ,,of ,,plumbism #dd ,v4 ,,pathology #fb ,,vi4 ,,pathology--,continued #ha ,,vii4 ,,symptomatology ,,and ,,diagnosis #aaj ,,viii4 ,,excretion ,,of ,,lead #abg ,,ix4 ,,the ,,nervous ,,system #adj ,x4 ,,chemical ,,investigations #afe ,,xi4 ,,treatment #ahd ,,xii4 ,,preventive ,,measures ,,against ,,lead ,,poisoning #aii ,,xiii4 ,,preventive ,,measures ,,against ,,lead ,,poisoning--,continued #bba ,,xiv4 ,,preventive ,,measures ,,against ,,lead ,,poisoning--,continued #bcj ,,xv4 ,,description ,,of ,,processes #bdb ,,xvi4 ,,description ,,of ,,processes--,continued #bfe ,,xvii4 ,,description ,,of ,,processes--,continued #bhh ,,index #cje ,,list ,,of ,,plates ,,facing ,,page ,,plate ,i4 #ib ,,plate ,,ii4 #ic ,,plate ,,iii4 #ie ,,plate ,,iv4 #bgf ,,lead ,,poisoning ,,and ,,lead ,,absorption ,,chapter ,i ,,historical--,,chemistry ,,of ,,lead ,the use of lead for various industrial processes and for painting was well known to the ancients4 ,pliny#a speaks of white lead1 and a method of corroding lead in earthen pots with vinegar1 sunk into a heap of dung1 as the means by which white lead was made for paint4 ,agricola mentions three forms of lead--white lead1 a compound which was probably bismuth1 and metallic lead itself4 ,the alchemists were acquainted with the metal under the name of 8saturn10 the term signifying the ease with which the nobler metals1 silver and gold1 disappear when added to molten lead4 ,colic caused by lead was also known in ancient times1 and is described by ,pliny2 many other writers refer to it1 and ,hippocrates was apparently acquainted with lead colic4 ,not until ,stockhusen#b1 however1 in #afef1 ascribed the colic of lead-miners and smelters to the fumes given off from the molten liquid was the definite co-relation between lead and so-called 8metallic colic0 properly understood1 and the symptoms directly traced to poisoning from the metal and its compounds4 thius1 in the early part of the sixteenth century1 gave a description of a type of colic called 8bellon10 frequently associated with the drinking of certain wines4 ,tronchin#c1 in #ageg1 discovered that many of these wines were able to dissolve the glaze of the earthenware vessels in which they were stored1 the glaze being compounded with litharge4 ,in our own country1 ,john ,hunter#d describes the frequent incidence of 8dry bellyache0 in the garrison of ,jamaica1 caused by the consumption of rum which had become contaminated with lead4 ,many other writers in ancient and historical books on medicine have written on the causation of colic1 palsy1 and other symptoms1 following the ingestion of salts of lead2 and as the compounds of lead1 mainly the acetate or sugar of lead1 were freely used medicinally1 often in large doses1 opportunities constantly occurred for observing the symptoms produced in susceptible persons4 ,it is not to the present purpose to examine the historical side of the question of lead poisoning1 but those interested will find several valuable references in ,meillre's work 8,le ,saturnisme0#e4 ,lead was used in the seventeenth and eighteenth centuries particularly1 and in the earlier part of the nineteenth1 for its action upon the blood4 ,in view of experimental evidence of the action of lead on the tissues1 particularly the blood1 this empirical use has interest4 ,salts of lead were found to be hmostatic1 and were therefore used for the treatment of ulcers because of the power1 notably of lead acetate1 of coagulating albuminous tissue4 ,it was also used in the treatment of fevers1 where again it is quite possible that the administration of a lead salt1 such as an acetate1 produced increase in the coagulability of the blood4 ,at the same time spasms of colic and other accidents followed its use4 ,there is practically no disease to which the human body is subject which was not treated by lead in some form or another4 ,lead1 with the addition of arsenic1 was given for malaria1 while its use in phthisis was also common4 ,the present use of diachylon plaster is an instance of the continuous use of a salt of lead medicinally1 as also is the lotion of the ,british ,pharmacopia containing opium and lead4 ,,the ,,chemistry ,,of ,,lead4 ,physical ,properties4--,lead belongs to the group of heavy metals1 and occupies a position between bismuth and thorium in the list of the atomic weights1 the atomic weight being #bjfd1 and density #aahe4 ,it is blue-grey in colour1 and its softness and facility to form a mark upon paper are well known4 ,lead melts at a temperature of #cbe ,c41 and at this temperature a certain 7if negligible7 amount of volatilization takes place1 which vapour becomes reprecipitated in the form of an oxide4 ,use is made of the volatility of the metal at the higher temperatures1 #eej ,c4 and upwards1 in the oxidation of lead from a mixture of lead1 silver1 and gold2 the oxide of lead1 or litharge1 is partially collected and absorbed by the crucible1 but the greater part is mainly removed from the surface of the liquid metal as it is formed1 while the richer metal is left in the crucible4 ,chemically speaking lead is a tetrad1 and forms a number of organic derivatives1 especially through the intervention of a particular oxide1 minium4 ,lead forms metallic alkalies and alkaline earths1 resembling silver in this direction1 and also metallic compounds with zinc and copper2 in this point it is very similar to silver4 ,small quantities of lead present in other metals--as1 for instance1 a small trace in gold--alter its physical qualities to a great extent2 whilst the addition of minute traces of other metals to lead--as1 for instance1 antimony--cause it to become hard1 a fact made use of in the manufacture of shot4 ,a number of oxides of the metal are known3 two varieties of protoxides 7massicot and litharge71 protoxide hydrate1 and bioxide4 ,sulphide1 or galena1 represents the chief form in which lead is found in ,nature1 and from which the actual metal is produced by metallurgical processes4 ,the salts of lead may be divided as follows3 #a4 ,the carbonates or hydrated carbonates employed in a large number of industrial and other processes1 which are the cause of much lead poisoning4 #b4 ,the acetates1 both normal and basic1 which are particularly concerned in the production of white lead--at any rate in the process of converting metallic lead into the hydrated carbonate through the medium of acetic acid and steam4 #c4 ,chromate of lead1 which is used as a pigment1 and also in dyeing yarns1 etc4 #d4 ,the nitrates and chlorides2 the chloride particularly is used as an oxidizing agent 7plumbing1 soldering1 tinning of metals74 #e4 ,the silicates1 silico-borates1 silico-fluoborates1 which constitute the many varieties of glass and crystals used in optical instruments1 and the various glazes and enamel colours used in the potteries4 ,there are a large number of other derivatives1 but these are not of special interest to the subject in hand4 ,the ,action of ,water upon ,lead4--,the action of water on lead was known even to the ancients1 ,pliny and ,galen having written on the subject4 ,at times1 and under certain conditions1 as much as #bj milligrammes per litre have been found1 as in the ,bacup epidemic1 and #ad milligrammes per litre in the epidemic at ,claremont4 ,bisserie#f in #aijj made an exhaustive inquiry into the action of water upon lead2 he gives the following conclusions3 #a4 ,water and saline solutions attack lead more or less readily when it is in combination with another metal1 such as solder1 copper1 bronze1 iron1 or nickel1 the result being a hydrated oxide4 #b4 ,the maximum effect is produced with water slightly acid and with solutions of chlorides or nitrates4 ,with these it is not necessary to have other metals present1 and if the water is thoroughly aerated the pure metal is attacked4 #c4 ,bicarbonates and carbonic acid exercise by themselves an action on wet lead1 but the carbonate of lead formed in the process adheres firmly to the surface of the metal1 and prevents any further action4 #d4 ,sulphates act in the same way1 but in less degree4 #e4 ,this protective action is much diminished when the water is even slightly charged with nitrates or organic material4 ,pouchet has pointed out that lead branch-pipes fixed to iron water-pipes1 thus producing an 8iron-lead couple10 set up definite electro-chemical changes1 and tend to increase the rate at which solution of lead in the pipe water takes place4 ,houston#g1 in an extensive and very full report on the effect of water upon lead1 especially undertaken for the purpose of inquiry into the contamination of supplies of drinking water by means of lead1 distinguishes two species of action--namely1 plumbo-solvency1 which is brought about by the acidity of the water in contact with lead2 and a second kind of action1 erosion1 determined to some extent by the dissolved air in the water4 ,he came to the conclusion that the plumbo-solvency and erosive action of water on metallic lead differed considerably1 and that the protective layer or plumbo-protective substance did not always protect lead pipes from the solvent action of water4 ,chemical ,characters of ,lead ,salts4--,a short summary of the chemistry of lead salts may not be out of place4 ,a soluble salt of lead1 such as the acetate or nitrate1 is precipitated by 7#a7 hydrogen sulphide or alkaline sulphide as a brown or black precipitate1 which is insoluble in ammonium sulphide4 ,in dilute solutions this sulphide is1 however1 appreciably soluble in mineral acids1 and may introduce errors in analysis1 especially as the solubility is distinctly increased by the presence of certain earthy salts4 ,the sulphide produced through the action of alkaline sulphide on a soluble salt of lead is less soluble than is the corresponding acid sulphide4 ,soluble salts of lead are at once precipitated by albumin or peptone2 the resulting precipitate has no stable composition4 ,under certain conditions definite colloidal precipitates are formed1 particularly in the presence of sulphide of copper or mercury4 7#b7 ,sulphuric acid or soluble sulphates produce a precipitate of lead sulphate insoluble in excess of the precipitating salt or sulphuric acid1 and only slightly soluble in alkaline solutions4 ,this method is the one generally adopted for gravimetric determination of a lead salt4 7#c7 ,potassium chromate produces a precipitate of chromate of lead very little soluble in acid1 but soluble in caustic alkali4 7#d7 ,potassium iodide produces a yellow lead iodide1 soluble on heating1 and reprecipitating and crystallizing on cooling4 7#e7 ,alkaline chlorides and hydrochloric acid produce needle-like crystals of lead chloride soluble on heating1 and reprecipitating on cooling4 7#f7 ,potassium nitrate in conjunction with a copper salt 7copper acetate7 produces a precipitate of a triple copper1 lead1 and potassium nitrate1 crystallizing in characteristic violet-black cubes4 ,this reaction is one made use of in the qualitative determination of small quantities of lead in organic fluids 7see p4 #afg74 ,all the precipitates of lead salts1 with the exception of the sulphide1 are soluble in fixed alkalies1 in ammonium acetate1 ammonium tartrate1 and ammonium citrate4 ,it is possible to determine the presence of lead in a large volume without evaporating down the whole bulk of fluid4 ,by this means liquid containing lead is treated with sulphide of copper1 sulphide of mercury1 or baryta-water4 ,meillre states that he has detected the presence of as small a quantity as #a milligramme of lead in #a1jjj c4c4 of water in this manner without evaporating the liquid4 ,where lead is in organic combination1 as is the case in the urine of persons suffering from lead poisoning1 it is not decomposed by hydrogen sulphide1 and the method is therefore not applicable in such cases1 but is useful in water examination4 ,electrolytic ,reactions4--,solutions of lead are easily electrolyzed1 and give a precipitate of lead at the cathode2 simultaneously the peroxide is produced at the anode1 and the reaction is acid4 ,in nitric acid solutions ,riche pointed out that the whole of the lead is carried to the anode1 and this is the reaction made use of in the determination of lead present in the urine 7see p4 #agb74 ,the presence of copper in an electrolyte regulates the precipitation of lead oxide1 copper alone being deposited at the cathode1 and at the same time the presence of a small quantity of copper promotes the destruction of organic materials4 ,,references4 #a ,,pliny3 lxxxiii41 #aa1 ,n4c4v4 #b ,,stockhusen3 ,de ,litharg4 ,fumo1 etc4 ,goslar1 #afef4 #c ,,tronchin3 ,de ,colica ,pictonum4 #ageh4 #d ,,john ,,hunter3 ,observations of ,diseases of the ,army in ,jamaica4 ,london1 #aghh4 #e ,,meill,,re1 ,g43 ,le ,saturnisme4 ,paris1 #aijc4 #f ,,bisserie3 ,bull4 ,soc4 ,pharmacol4 ,may1 #aijj4 #g ,,houston3 ,local ,government ,board ,annual ,report1 #aija-jb1 supplement1 vol4 ii4 ,,chapter ,,ii ,,tiology ,lead poisoning of industrial origin rarely occurs in the acute form4 ,practically all cases coming under the notice of either appointed surgeons1 certifying surgeons1 or even in the wards of general hospitals1 are of the subacute or chronic type4 ,there is no reason to suppose that lead compounds are used more frequently by the workers in lead industries as abortifacients than by other persons4 ,the compounds of lead which are responsible for poisoning in industrial processes are for the most part the hydrated carbonate1 or white lead1 and the oxides of lead1 whilst a comparatively small number of cases owe their origin to compounds1 such as chromates and chlorides4 ,the poisonous nature of any lead compound from an industrial point of view is proportional to 7#a7 the size of the ultimate particles of the substance manufactured1 and therefore the ease with which such particles are capable of dissemination in the air2 and 7#b7 the solubility of the particles in the normal fluids of the body1 such as the saliva1 pharyngeal and tracheal and bronchial mucus1 etc41 and the fluids of the stomach and intestine4 ,an instance of the variation in size of the particles of lead compounds used industrially is the difference between ground lead silicate 7fritted lead7 used in the potteries1 and the size of the particles of ordinary white or 8raw0 lead4 ,by micrometric measurements one of us ,k4 ,w4 ,g4#a found the average size of the particles of fritt to be ten times that of the white lead particles4 ,further1 direct experiment made with equal masses of the two compounds in such a manner that the rate of settling of the dust arising could be directly compared in a beam of parallel light showed presence of dust in the white lead chamber fifteen minutes after the fritt chamber was entirely clear4 ,it is found as a matter of practice that where dust is especially created1 and where it is difficult to remove such dust by exhaust fans1 the greatest incidence of lead poisoning occurs4 ,the association of dusty processes and incidence of lead poisoning is discussed in relation to the various trades in ,chapters ,,xv4 to ,,xvii4 ,fume and vapour given off from the molten metal or compounds1 such as chlorides 7tinning71 are only a special case of dust4 ,the channels through which lead or its compounds may gain entrance to the animal body are theoretically three in number3 #a4 ,respiratory tract4 #b4 ,gastro-intestinal4 #c4 ,cutaneous4 ,for many years most authorities have held that industrial poisoning by means of compounds of lead takes place directly through the alimentary canal1 and that the poison is conveyed to the mouth mainly by unwashed hands1 by food contaminated with lead dust1 and by lead dust suspended in the air becoming deposited upon the mucous membrane of the mouth and pharynx1 and then swallowed4 ,as evidence that lead dust is swallowed1 the classical symptom of colic in lead poisoning has been adduced1 on the supposition1 in the absence of any experimental proof1 that the lead swallowed acted as an irritant on the gastro-intestinal canal1 thus causing colic1 and1 on absorption from the canal1 setting up other general symptoms4 ,much of the early treatment of lead poisoning is based upon this assumption1 and the administration of sulphuric acid lemonade and the exhibition of sulphate of magnesia and other similar compounds as treatment is further evidence of the view that the poisoning was considered primarily intestinal4 ,one of the chief objections to this view1 apart from the experimental evidence1 is that in those trades where metallic lead is handled1 particularly lead rolling1 very few hygienic precautions have ever been taken in regard to washing before meals1 smoking1 etc4 ,although in these trades the hands become coated with a lead compound 7oleate71 and the workers frequently eat their food with unwashed hands1 thus affording every opportunity for the ingestion of lead1 the incidence of poisoning is by no means as high or so pronounced in these occupations as in those giving rise to lead dust1 such as the white lead industry1 where special precautions are taken1 and where the incidence of poisoning is always related to the dust breathed4 ,respiratory ,tract4--,in a report on the incidence of lead poisoning in the manufacture of paints and colours1 one of us ,t4 ,m4 ,l4#b in #aijb laid stress on the marked incidence of poisoning in the specially dusty lead processes4 ,following on that report special attention was given to the removal of dust by means of exhaust ventilation4 ,with the introduction of precautionary measures1 the incidence of poisoning underwent a marked decrease1 this decrease being most definite in those industries where efficient exhaust ventilation could be maintained 7see p4 #dg74 ,experience shows that cases of poisoning in any given trade or manufacturing process are always referable to the operations which cause the greatest amount of dust1 and where1 therefore1 the opportunity of inhaling lead dust is greatest4 ,the investigations of ,duckering#c1 referred to on p4 #bjc1 show the amount of dust present in the air in certain dangerous processes4 ,his results clinch the deductions made from general observation1 that dusty processes are those especially related to incidence of industrial poisoning4 tiologically1 therefore1 the relationship of dust-contaminated air and poisoning is undeniable1 and in not a few instances on record persons residing at a distance from a lead factory have developed poisoning1 although not employed in any occupation involving contact with lead1 aerial infection through dust remaining the only explanation4 ,the actual channel through which the lead dust suspended in the air gains entrance to the body is1 therefore1 of especial importance2 one of two channels is open--gastro-intestinal and respiratory4 ,the investigations of one of us 7,k4 ,w4 ,g47 on the experimental production of lead poisoning in animals has shown conclusively that the dust inhaled was far more dangerous1 and produced symptoms far earlier than did the direct ingestion of a very much larger quantity of the same compound by way of the mouth and gastro-intestinal canal4 ,there is no doubt whatever that the chief agent in causing lead poisoning is dust or fume suspended in the air4 ,that a certain amount finds its way into the stomach direct is not denied1 but from experimental evidence we consider the lung rather than the stomach to be the chief channel through which absorption takes place 7see p4 #ha74 ,the following table gives a specific instance of the incidence of lead poisoning in a white lead factory1 and demonstrates clearly the tiological importance of dust4 ,the increase in reported cases1 as well as in symptoms of lead absorption not sufficiently severe to prevent the individual from following his usual occupation1 was associated with the rebuilding of a portion of the factory in which the packing of dry white lead had been carried on for a large number of years4 ,the alterations necessitated the removal of several floors1 all of which were thoroughly impregnated with lead dust4 ,before the alterations were undertaken it was recognized that considerable danger would arise2 stringent precautions were therefore taken1 and the hands engaged in the alterations kept under special observation4 ,notwithstanding this there was an increase in the number of reported cases1 which were all mild cases of colic2 all recovered1 and were able to return to their work in a short time4 ,,table ,i4--,,lead ,,poisoning ,,in ,a ,,white ,,lead ,,factory4 ,the figures refer to the weekly examination of the whole of the men4 ,for example1 if a man was returned as suffering from anmia on three occasions1 he appears as three cases in ,column #g4 ---------------------------------------- ------------------ ,total ,total ,cases ,cases ,number ,cases in in of of ,dusty ,other ,cases ,cases ,cases ,exami-,poison- ,pro- ,pro- of ,sus- of of ,blue ,year nations ing cessescessespension,anmia,tremor ,line ---------------------------------------- ------------------ 7#a7 7#b7 7#c7 7#d7 7#e7 7#f7 7#g7 7#h7 7#i7 #aije #e1dfd #i #h #a #bj #gh;,b#bdi;,b#caa;,b #aijf;,a #e1jif #ah #af #b #i #bef #bae #ecb #aijg #d1cjc #d #c #a #f #fb #ha #ch #aijh #c1ife #d #c #a #e #dj #be #aa ---------------------------------------- ------------------ ,a ,structural alterations in progress1 including cutting up 8lead floor10 saturated with white lead dust4 ,b ,these numbers for the half-year only1 the inspection being taken over in ,june1 #aije4 ,meillre#d goes to considerable trouble to show that absorption of lead dust by the lung is hypothetical2 that it may take place1 but that it is not a channel of absorption of practical importance4 ,he cites a number of opinions and experiments by various observers on the absorption of lead through the mucous membrane of the mouth1 alimentary canal1 conjunctiva1 etc41 and he regards the absorption of lead as one peculiarly confined1 in the majority of instances1 to the intestinal canal4 ,the usual view is that1 in the passage of the respired dust-laden air through the nose1 the larger particles of dust are deposited first of all upon the mucous membrane in the interior chambers of the nose2 further1 a second deposit takes place on the posterior wall of the pharynx and in the throat1 where the eddies produced by the current of air inhaled through the nostrils allow the finer particles to become more easily deposited4 ,finally1 should a small trace gain access to the larynx1 it is said to be deposited there upon the mucous membrane1 to be subsequently ejected1 and only a very small proportion of the total may ever find its way into the lung4 ,in all arduous labour1 directly the respiration rate rises through extra calls made upon the muscles of the body1 an increase in the depth of respiration takes place2 yet even under these circumstances ,meillre and others incline to the view that the dust is deposited on the mucous surfaces of the mouth and swallowed4 ,experimental evidence is entirely opposed to these suppositions4 ,in the first place1 unless particles of dust readily find their way into the lung1 it is difficult to understand how the lung itself becomes the site of so much deposit of carbon1 and of flinty material in stonegrinder's pneumokoniosis4 ,the staining of the lung by means of carbon particles1 particularly in dwellers in cities1 is too well known to warrant more than a passing reference4 ,moreover1 experimental work has shown that fine powders suspended in the air easily reach the lung4 ,armit#e has shown that the nickel in nickel carbonyl poisoning gains direct access to the lung1 and becomes deposited there1 the metallic particles being readily demonstrated in the lung tissue itself4 ,further1 the experiments 7see p4 #hd7 demonstrate that white lead dust and other forms of lead dust definitely gain access to the lung1 and thus inhaled produce all the symptoms of lead poisoning in animals subjected to the inhalation4 ,white lead1 litharge1 or red lead1 are not easily suspended in water1 and long-continued mixing is necessary to make a suspension4 ,great difficulty is found in 8laying0 lead dust by water1 as the following experiment demonstrates3 ,five wash-bottles are arranged in series2 in the first ground dry white lead is placed1 and the other three bottles are filled with water1 and a tube laid under the surface of the water in such a way that the air from the first bottle must pass the whole of the water seals in each subsequent bottle4 ,in the last bottle is dilute nitric acid saturated with sulphuretted hydrogen4 ,if the series is now attached to an aspirating jar1 and air drawn slowly over at the rate of ordinary respiration1 the white lead powder in the first bottle being at the same time shaken so that the air is fully charged with finely powdered dust1 lead is quickly detected in the air passing through the last bottle of the series1 by the darkening of the solution4 ,in this way the presence of lead dust has been demonstrated after passing through four #b-;inch water seals and #h feet of -inch wet rubber tubing4 ,such an experiment negatives the theory that all1 or even a large quantity1 of a finely divided powder becomes deposited on the upper portion of the respiratory tract4 ,particles of lead present in the air in industrial processes are exceedingly minute1 and even in ground white lead the average size of the particle is under #a 4 ,finally1 ,tanquerel#f and ,stanski#g succeeded in producing lead poisoning experimentally by blowing lead dust through a tube inserted in a tracheotomy opening4 ,there remains1 therefore1 no room for doubt that the lung is the pre-eminent portal for lead absorption1 particularly in industrial processes2 from which it follows1 as has been extensively shown in actual practice1 that the diminution of dust in workshops and factories by means of exhaust ventilation is invariably followed by a diminution in the number of cases of plumbism4 ,gastro-,intestinal4--,we have dealt with absorption by way of the lung1 and have insisted that such inhalation of dust is of greater importance in giving rise to industrial lead poisoning than gastro-intestinal absorption4 ,gastro-intestinal absorption can take place1 and is by no means negligible1 in ordinary industrial conditions4 ,one of the most interesting and important confirmatory evidences of the absorption of lead by the gastro-intestinal canal is to be found in the large outbreaks of poisoning in which water-supplies have been contaminated1 either at their source or locally4 ,we have already seen that electrolysis may play an important part in the solution of lead in water1 and also learnt from ,gautier#h that the carbon dioxide content of water is not necessarily the sole predisposing element in the solution of lead4 ,in this connection an important case is described by ,thresh#i1 where water by no means soft1 but holding some #cj degrees of hardness1 produced lead poisoning in an isolated family4 ,the water in question was distinctly acid to litmus-paper1 and contained a very high percentage of nitrates2 the compound or salt of lead present was therefore one easily absorbed from the alimentary canal 7see p4 #hf74 ,in all instances of water-borne lead poisoning the amount of lead present in the water was small2 but as such lead would not be removed by boiling1 the amount of water consumed per person from the contaminated source was probably large4 ,as the signs of poisoning did not appear until a considerable time had elapsed1 a much larger quantity of lead was probably absorbed than would appear from the simple statement that the water contained grain per gallon4 ,a number of cases have been reported from use of diachylon as an abortifacient1 and the symptoms in these cases are invariably those which occur in other severe forms of poisoning such as are met with in industrial processes4 ,in nearly every case colic was the first symptom1 followed later by paresis of various types--amaurosis1 albuminuria1 albuminuric retinitis1 melancholia1 encephalopathy--and not a few of the persons succumbed4 ,in most of the reported cases abortion was produced1 but in some1 particularly in one#aj1 three dozen pills containing diachylon were taken in a month1 producing acute lead poisoning1 colic1 and paresis1 but not abortion4 ,in fifteen recorded cases of the use of diachylon1 fourteen showed a lead line1 in many cases distinct and broad4 ,this point has considerable interest1 as such a line cannot have been produced by oral contact4 ,the drug in the form of pills would be rapidly swallowed1 and little opportunity afforded for particles to remain in the mouth4 ,its presence1 therefore1 suggests excretion from circulating blood of lead which has been absorbed in the intestine4 ,the blue line will be referred to again later 7see p4 #abb74 ,practically all cases of water poisoning and of swallowing of lead compounds have developed colic4 ,further1 colic is cited in all the early recorded cases1 even in the very earliest cases referred to in the historical note1 of lead poisoning2 and as poisoning in those cases had invariably taken place by swallowing the drug1 it may be presumed from this association has arisen the belief that lead must be swallowed to produce gastro-intestinal symptoms4 ,no attention has been paid to the fact that a few cases of definite cutaneous absorption of lead from the use of hair lotions have been followed by colic4 ,gastro-intestinal symptoms1 therefore1 can be produced without the direct ingestion of the drug1 and colic is a symptom of generalized blood-infection rather than a localized irritative action on the intestinal mucosa4 ,this question1 again1 is more related to pathology than tiology1 and is dealt with in that section4 ,but mention may be made here of the fact that a number of observers1 more lately ,meillre1 have laid it down as an axiom that experimental production of lead poisoning in animals gives no criterion or evidence of lead poisoning produced in man industrially4 ,very grave exception must be taken at once to such a statement4 ,in the majority of experiments quoted by ,meillre the quantity of lead given for experimental purposes has been large--much larger1 indeed1 than is necessary to produce small and characteristic effects--and instead of chronic poisoning an acute lead poisoning has generally been set up2 and even where chronic poisoning has supervened1 the condition has as a rule been masked by the severer initial symptoms4 ,on the other hand1 the evidence to be derived from comparison of the various observations from animal experiments brings out with remarkable unanimity the similarity of the symptoms to those produced in man1 and1 as will be seen later in the section devoted to ,pathology1 experiments by one of us 7,k4 ,w4 ,g47 have so far confirmed this surmise2 in fact1 a description of a case of encephalopathy coming on after lead poisoning of a chronic nature1 described by ,mott1 agrees in practically every particular with the train of symptoms as observed in these experimental animals4 ,certain slight differences as to the muscles first affected are observed1 but it is practically always the homologous muscle 7the physiological action of which more nearly resembles the human muscle7 which is the one to be affected in the animal1 not the anatomical homologue4 ,thus1 for instance1 in the cat the spinal muscles1 and particularly the quadriceps extensor1 is the muscle which is first affected through the medium of the anterior crural nerve4 ,this extensor muscle is one which only performs a slight amount of work in extending the knee-joint1 the amount of work being1 however1 disproportionate to the size of the muscle4 ,the extensors of the fore-feet ultimately do become weakened1 but it is the hind-limb upon which the stress first falls4 ,attention has been given to the solubility of lead salts in gastric juices1 the majority of such experiments having been performed with artificial gastric juice4 ,the method at present in use1 prescribed by the amended rules of ,august1 #aijj1 for earthenware and china factories1 is based on some1 if slight1 consideration of the physiology of digestion4 ,the method described by ,rule ,,ii4 states that the estimation of the quantity of lead present in the lead fritt shall be performed as follows3 ,a weighed quantity of dry material is to be continuously shaken for one hour at room temperature with one thousand times its weight of an aqueous solution of hydrochloric acid1 containing #jbe per cent4 of ,h,cl4 ,this solution is thereafter to be allowed to stand for one hour1 and to be passed through a filter4 ,the lead salt contained in a portion of the clear filter is then to be precipitated as lead sulphide1 and weighed as lead sulphate4 ,this method has been adopted on the supposition that the solubility of a lead salt in the gastric juices is the chief source of the lead poisoning in the ,potteries1 and that the hydrochloric acid content of the solution determines1 for practical purposes1 the quantity of lead dissolved out of a given sample4 ,the temperature1 however1 at which this estimation is made--namely1 room temperature--is one considerably lower than that of the body1 and the quantity of lead taken up into solution at this temperature is less than that which occurs at the ordinary temperature of the body--#cg ,c4 ,practically twice as much lead is dissolved out of fritt at #cg ,c4 for an hour as is rendered soluble at the ordinary temperature of the room--about #ae ,c4 ,thomason#aa1 who made some experiments in this direction1 gives a figure of #bce lead oxide dissolved at #ae ,c4 and #ded at #cg ,c4 ,in another estimation--a matter1 too1 of some considerable importance--it was found that acetic acid dissolved #aig per cent1 at #ae ,c41 and #cbg at #cg ,c4 ,in lactic acid the figure was #bbh at #ae ,c41 and #cec at #cg ,c4 ,it is therefore a low estimation of the solubility of any substance by the gastric juices if the substance is operated on at a temperature below that of the body4 ,the question of the solubility of a lead salt in the gastric contents is important in view of the small quantities of dust swallowed2 and in addition to hydrochloric acid1 other substances are also present in the gastric juice1 which is by no means a simple aqueous solution of the mineral acid4 ,further1 the gastric juice1 except in cases of pathological type1 is not acid in periods of gastric rest1 unless such acidity may be represented by the presence of fermentative acids--acetic1 lactic1 and butyric4 ,the activity of the gastric juice on lead is directly caused by the quantity of organic acids present in addition to the hydrochloric acid1 and by the presence of foodstuffs--7#a7 in the undigested and 7#b7 in the semidigested condition4 ,in considering the absorption of lead products from the gastro-intestinal canal1 the normal digestive processes should not be lost sight of--that is1 the sequence of events which occur during digestion of food4 ,on swallowing food1 no definite acidity is present in the stomach for fifteen to twenty minutes1 and even after that time the hydrochloric acid is only commencing to be secreted4 ,as digestion proceeds1 and the whole mass becomes partially dissolved1 such portions as are in a soluble condition are passed through the pyloric opening at intervals1 and the whole contents of the stomach do not pass straight through the pyloric opening as through an ordinary straight drain-pipe4 ,as each mass of food passes onwards through the pylorus1 it comes into contact in the duodenum with pancreatic juice1 and with the bile1 these alkaline fluids rapidly change the reaction1 and allow the other ferments1 trypsin1 etc41 to become active4 ,as the mass proceeds onwards through the intestine1 the succus entericus also exerts its function4 ,finally the fluid contents of the intestine are passed onwards through the ileo-ccal valve4 ,during the passage from the pylorus to the ileo-ccal valve1 the reaction of the intestinal contents undergoes variations1 from an alkaline in the duodenum or upper parts of the jejunum1 to acid at the ileo-ccal valve4 ,practically no absorption takes place from the stomach itself2 a small quantity of water and such highly volatile fluids as alcohol may be absorbed1 but the main absorption is not commenced until the food has left the stomach2 in fact1 the stomach contains no mechanism for food absorption4 ,the work of absorption of the products of digestion is carried on actively through the small intestine until finally the materials have reached the large intestine through the ileo-ccal valve2 water is then mainly absorbed1 and albuminous fluids and substances in solution to some extent1 but the amount of absorption which takes place is infinitesimal as compared with that of the small intestine4 ,these points in the physiology of digestion require to be taken into account when discussing the absorption of lead salts in the gastro-intestinal canal4 ,when human gastric juice is obtained direct from the stomach in man1 and lead is submitted to its action1 definite quantities of lead pass into solution2 and1 curiously enough1 in the normal gastric juice lead sulphate is as soluble as both white lead and litharge4 ,the following two tables give the results of the estimation of the direct action of human gastric juice upon lead4 ,the particular point is that the juice was obtained by the stomach tube from persons who had been given a simple test meal preceded by a twelve hours' fast2 the juice was therefore in a normal condition4 ,the tests gave the following results in the normal stomach3 ,lead sulphate #jjhj per cent4 ,white lead #jjdh ,litharge #jjdj ,in the second digestion1 in which the analysis of the contents showed the patient to be suffering from the condition known as 8hyperhydrochloridia10 the results were-- ,lead sulphate #jjdf per cent4 ,white lead #jjdb ,litharge #jcdj ,a very large number of experiments have also been performed for the purpose of determining the solubility of raw lead glaze1 and white lead1 in artificial digestions1 the digestions having been made up in such a way that they resembled as far as possible in every particular the ordinary stomach contents4 ,the type of digestion used was as follows3 ,dry breadcrumbs #adj grammes4 ,hydrochloric acid #e c4c4 ,lactic acid #ja c4c4 ,acetic acid #ja c4c4 ,pepsin #ab grammes4 ,milk #a1bjj c4c4 ,digestions were performed with this mixture1 and in every case the digest was divided into two portions2 each portion was retained at body temperature1 with agitation for a couple of hours1 and at the end of that time one portion was submitted to analysis4 ,the second portion was neutralized1 sodium carbonate and pancreatic ferment added1 and digestion carried on for another two and a half hours at body temperature4 ,at the end of this time the pancreatic digest was examined4 ,thirty-five digestions were performed4 ,when #a gramme of white lead was used--that is1 #jja per cent41 containing #jge per cent4 of lead oxide--the quantity of lead found as lead oxide in the acid digest varied from #b to #c per cent41 whilst the amount found in the pancreatic digest varied from #d to #fe per cent4 of the added salt4 ,on increasing the amount to #ab grammes--that is1 #a per cent4--the quantity returned in the digest only increased from #ae to #b per cent4 ,in other words1 in the addition of larger quantities of material the ratio of solubility did not rise in proportion to the quantity added4 ,where a direct pancreatic digestion was performed without the preliminary digest of the gastric contents1 the amount of lead present in the digest was only about #jb per cent4 of the quantity added2 indeed1 it was very much smaller than the amount dissolved out after preliminary acid digestion--that is1 if the normal sequence of digestion is followed1 the solubility progresses after the gastric digest has been neutralized and pancreatic ferment has been added1 whereas very slow action indeed occurs as the result of action of the pancreatic digest alone4 ,some experiments described by ,thomason#ab1 although carried out without special regard to the physiological question of the progressive nature of digestion1 distinctly confirm the point raised4 ,thus1 in a digest of gastric juice1 milk1 and bread1 #ej per cent4 of lead was dissolved1 whereas when pancreatic juice alone was used only #jd per cent4 was found to be dissolved1 a remarkable confirmation of the point under discussion4 ,the difficulty of estimating lead present in these gastric digestions is a very real one1 as1 owing to the precipitation of lead by various fluids of an albuminoid nature1 it is difficult to determine the amount of lead present in a given quantity of digest2 moreover1 in making such a digest1 much of the material may become entangled among the clot of the milk in a purely mechanical fashion1 and1 in attempting to separate the fluid from the other portion of the digest1 filtration no doubt removes any lead which has been rendered soluble first of all1 and reprecipitated as an albuminate4 ,an albuminate of lead may be formed with great ease in the following way3 ,a #e per cent4 solution of albumin in normal saline is taken1 #jjb per cent4 of hydrochloric acid is added1 and #aj per cent4 solution of lead chloride added as long as a precipitate is formed4 ,the precipitate is then filtered off1 and washed in a dialyser with acidulated water until no further trace of lead is found in the washings4 ,a portion of this substance taken up in distilled water forms a solution of an opalescent nature1 which readily passes through the filter and gives the reaction of protein with ,millon's reagent1 and the lead reaction by means of caustic potash and sulphuretted hydrogen1 but very large quantities of mineral acid are required to produce any colour with hydrogen sulphide4 ,lead which gains access to the stomach1 either dissolved in water or swallowed as fine dust1 becomes in all probability converted first into a soluble substance1 chloride1 acetate1 or lactate1 which compound is then precipitated either by the mucin present in the stomach1 or by the protein constituents of the food1 or by the partially digested food 7peptonate of lead may be formed in the same way as the albuminate described above74 ,in this form1 or as an albuminate or other organic compound1 it passes the pylorus1 and becomes reprecipitated and redigested through the action of the pancreatic juice4 ,a consideration of the action of artificial gastric juices and the properly combined experiments of gastric and pancreatic digestions suggest that the form in which lead becomes absorbed is not a chloride1 but an organic compound first formed and gradually decomposed during the normal process of digestion1 and absorbed in this manner from the intestine along with the ordinary constituents of food4 ,dixon ,mann#ac has shown that about two-thirds of the lead administered by the mouth is discharged in the fces1 and that the remaining one-third is also slowly but only partially eliminated4 ,this point is of very considerable importance in relation to industrial poisoning of presumably gastro-intestinal origin1 and consideration of the experiments quoted suggests that the digestion of albuminate or peptonate may to some extent be the basis which determines the excretion of so much of the lead via the fces4 ,this alteration of solubility has no doubt a bearing on the immunity exhibited by many animals when fed with lead1 and probably explains the fact that many of the experimental animals fed with lead over long periods exhibited no symptoms of poisoning 7see p4 #he71 whereas control animals1 given a far smaller quantity of lead by other means and through the lung1 rapidly developed symptoms of poisoning4 ,a diversity of opinion exists as to the effect of pepsin upon the solubility of lead4 ,oliver#ad considers that the pepsin has a retarding influence on the solubility of lead in the gastric juice1 and ,thomason's experiments also support this view1 although it is difficult to see why the action of pepsin alone should be of such extreme importance4 ,there is also the complicating fact that other added substances in the food may mask any direct pepsin factor that may be present4 ,albumose and peptone rather than pepsin are to be regarded as the more important substance physiologically in their reaction with lead1 and it is interesting to note that ,schicksal#ae found that by exposing lead in the form of white lead in a #a per mille solution of hydrochloric acid in the presence of peptone produced a greater solvent effect on white lead than did the diluted acid alone1 and the same effect was also seen on metallic lead4 ,,table ,,ii4--,,schicksal',s ,,table4 ---------------------------------------- ------------------------ ,amount dissolved returned as ,metallic ,solution4 ,substance4 ,time4 ,lead4 ---------------------------------------- ------------------------ 7a7 #aj per cent4 peptone#ajj ,white lead1 #c days#jadga grm4 #ja per cent4 ,h,cl c4c4#aj grms4 at #cg ,c4 7b7 #aj per cent4 peptone#ajj ,metallic lead1 #jjccj #ja per cent4 ,h,cl c4c4#d grms4 7c7 #ja per cent4 ,h,cl1 #ajj ,white lead1 #jjihc c4c4#aj grms4 7d7 #ja per cent4 ,h,cl1 #ajj ,metallic lead1 #jjaid c4c4#d grms4 7e7 #jc per cent4 ,na,,co ,metallic lead1 ,none #d grms4 7f7 #jc per cent4 ,na,,co ,white lead 7g7 #jc per cent4 ,na,,co ,white lead #je per cent4 ,na,cl 7h7 #jc per cent4 ,na,,co ,metallic lead #je per cent4 ,na,cl ---------------------------------------- ------------------------ ,the experiments referred to on p4 #ah undoubtedly agree with those of ,schicksal4 ,in addition to the presence of peptones1 the effect of carbonic acid must be also considered1 as increase in solubility in gastric and pancreatic digestions was produced when carbonic acid gas was bubbled through the digest during the period of action4 ,the whole question of solubility of many materials in the fluids of the stomach and intestinal canal requires entire revision1 not only as regards lead1 but as regards a number of other metals1 including arsenic4 ,the ,mechanism of ,lead ,absorption4--,the final method of absorption of lead particles or lead solution into the animal body remains to be considered4 ,experimental phagocytosis of lead particles--as1 indeed1 of any minute particles of substance--suspended in an isotonic solution1 may be observed directly under the microscope4 ,lead particles show no exception to the rule1 and white blood-corpuscles in a hanging-drop preparation1 made by suspending them in an isotonic salt solution and serum1 may be watched englobing particles of lead1 and by appropriate means the ingested lead may be afterwards demonstrated4 ,in such an experiment1 much of the lead absorbed by the individual corpuscles rapidly loses its property of giving a black precipitate with sulphuretted hydrogen1 and has apparently become converted into an organic compound1 peptonate or albuminate4 ,in the section devoted to the ,chemistry of ,lead1 it has been noted that the colloidal solutions of lead are not precipitated by sulphuretted hydrogen1 and that albuminates and peptonates of lead are presumably of colloidal form4 ,there seems evidence1 therefore1 that the direct absorption of lead takes place by means of the phagocytes of the body1 and that in them it becomes converted into a colloidal form1 in which it is probably eliminated through the kidney and intestine1 mainly the latter4 ,further evidence of the englobement of lead particles by ambic cells may be gained if sections of the intestines of experimental animals are examined2 in the lymphoid glands particles of lead may be seen situated in the interior of the walls1 and even in the cells4 ,it does not by any means follow that these particles of lead sulphide present in the cells have been formed in situ2 more probably the lead has been converted into a sulphide in the intestinal lumen itself1 and subsequently taken up by the ambic cells situated in its periphery4 ,another solution is possible--namely1 that the particles seen in the intestinal wall are particles of lead in process of excretion into the intestine itself1 and that the pigmentation of the vessel walls and cells is caused by the staining of the particles of lead passing from the blood into the lumen of the tube1 which have been converted into a sulphide during their passage4 ,the localization of the staining in the large intestine1 especially in the region of the appendix in animals 7cats71 tends to support this theory4 ,the large bowel near the ileo-ccal valve1 the appendix1 and even the glands in the immediate neighbourhood1 are found to be discoloured1 and to contain lead in larger quantities than any other portion of the intestine4 ,in extreme cases the whole of the large intestine may be stained a greyish-blue4 ,the bloodvessels in the mesentery in this region are also engorged4 ,when1 however1 a salt of lead1 such as lead carbonate or lead oxide1 gains access to the stomach1 it may be easily converted into chloride by the free hydrochloric acid present in the stomach2 and1 in addition1 should there be any chronic acid-dyspepsia 7hyperchlorhydria71 particularly of the fermentative type1 in which free lactic acid and other organic acids are to be found within the viscus1 small quantities of lead swallowed as dust undergo solution and conversion into chloride or lactate4 ,the pouring out of acid gastric juice from the stomach glands does not take place immediately after the first bolus of food is swallowed1 and it may be twenty minutes or half an hour before the gastric contents have an acid reaction4 ,during this time any lead salts previously swallowed may become incorporated with the bolus of food and escape absorption4 ,lead in solution or suspension in the stomach which becomes mixed up with the food1 and at the same time subjected to the action of various albuminous constituents of the food in addition to acids1 causes an albuminate or peptonate of lead to be easily formed1 and as such can never be absorbed from the stomach direct2 practically no absorption takes place in the stomach1 and the presence of food containing albuminate precipitates any lead in solution as an organic insoluble salt4 ,the bolus of food impregnated with small quantities of lead passes onwards to the intestine1 where further digestion takes place4 ,as the mass passes through the intestine the action gradually results in the reappearance of acidity1 but at the same time a certain quantity of sulphuretted hydrogen is produced1 some of it from the degradation of the sulphur-containing moiety of the protein molecule by ordinary hydrolytic process and intestinal ferments1 quite apart from any bacterial action4 ,a portion of the lead present in the chyme may be set free again for absorption4 ,the bile is said to assist in the solution of lead in vitro4 ,in experiments made by one of us1 which are quoted later1 it has been shown that an isolated loop of intestine allows the absorption of a soluble lead salt 7chloride7 when there is no food present in the loop4 ,as the food mass proceeds through the length of the intestine more and more sulphur is set free1 and an opportunity arises for the fixation of the lead as a sulphide1 but even as a sulphide it is slightly soluble4 ,probably1 however1 most of the lead becomes absorbed long before it reaches the stage at which free sulphur or sulphuretted hydrogen exists for the formation of sulphide4 ,it is highly probable that lead1 in common with a number of other heavy metals1 including arsenic1 is absorbed gradually in the upper part of the intestine1 and re-excreted in the lower4 ,such an hypothesis is undoubtedly strongly supported by the remarkable staining of the large intestine and the ileo-ccal valve4 ,the exact mechanism of the absorption of lead from its compound with albumin or peptone as a lead peptonate or albuminate is very difficult to state at present2 lead albuminate is undoubtedly insoluble in water or normal saline and in albumin4 ,the process of absorption1 then1 of the metal lead from the gastro-intestinal canal is very closely related to the absorption of other heavy metals1 and the fact that animals after very large doses of lead salts administered via the mouth show hmorrhages in the intestinal wall1 in addition to hmorrhages in other parts of the body1 with occasional distinct ulceration1 suggests a localized coagulative action on the vessels in the wall of the intestine as the probable origin of the ulceration4 ,a consideration of this problem of lead absorption from the intestine--probably only the minutest quantity of lead1 if any1 is absorbed from the stomach direct--is one of considerable importance in the prevention of such lead poisoning as is attributable to swallowing lead4 ,no work in a lead factory should be commenced in the morning without partaking of food1 because if food be present the opportunities for absorption of lead are greatly diminished1 and of all foods the one to be recommended as the most efficient is milk1 or cocoa made with milk4 ,the absorption of dust through the lung is probably an exceedingly complicated reaction1 and ,armit's experiments with nickel carbonyl probably give the clue4 ,he found that in nickel carbonyl poisoning the volatile product was split up on the surface of the lung cells1 the metallic portion passing onwards into the lung itself1 to be eventually absorbed by the serum4 ,from the pathological and histological investigations described on p4 #ha1 and from the fact that particles of lead are very readily taken up by white blood-corpuscles1 we can conclude that absorption of the finer lead particles gaining access to the lung takes place through the medium of these phagocyte cells1 as such cells are well known to exist within the alveoli of the lung4 ,the stored-up carbon particles found in the lungs in dwellers in cities show that such transference of particles from the alveoli to the inner portions of the lung trabecul is a constant phenomenon1 and it is therefore easily understood how rapidly any fine particles not of themselves irritant may be easily taken up by the tissues4 ,once having gained access to the interior of the cells1 the particles subjected to the action of the serum of the blood in the ordinary process of bathing the tissues by the exuding lymph--nay1 more1 actual particles of lead--may thus be actually transferred bodily into the finer blood-spaces1 and so be carried forward to the general circulation4 ,such particles as remain fixed in the lung will undergo gradual absorption1 and the constant presence of carbonic acid in the circulating blood brought to the lung undoubtedly largely contributes to their solution1 and there is no need to presuppose the necessity of some recondite interaction of organic acid for the solution of the inhaled lead in the lungs4 ,in the absorption of the substance from the intestine1 it may go direct into the blood-stream in a similar fashion through the lacteals along the lymph channels1 and so into the thoracic duct1 and finally into the general circulation4 ,on the other hand1 a certain amount1 probably not an inconsiderable portion1 is taken up by the portal circulation and transferred direct to the liver itself4 ,chemical analysis of the liver supports this view1 as does also the considerable amount of stress thrown upon the liver when poisoning has taken place from the intestinal canal on administration of massive doses of a highly soluble lead compound4 ,according to ,steinberg#af1 excretion of lead takes place partly from the liver by the bile4 ,this is probable1 but there is no experimental evidence at the present time to support the view4 ,if such an excretion does take place1 the form in which the lead is excreted is probably one in which it is no longer soluble by digestive action4 ,on the other hand1 it may be in so soluble a form as to become reabsorbed from the intestine1 thus setting up a constant cycle4 ,but such a theory is one that would require a considerable amount of experimental evidence to support it before it could be relied on4 ,there is no doubt that1 however absorbed1 lead remains stored up in the body in minute quantities in many places1 and the close analogy to arsenic is met with in the curious elimination of the metal by the fces4 ,cloetta#ag1 quoted by ,dixon ,mann1 discovered that1 although dogs were unable to take a larger dose of arsenic than #jjjce gramme per day without exhibiting toxic results1 they could nevertheless take arsenic in much larger doses if it were given in the solid form1 and he was able to increase the dose to as much as #b grammes per diem without showing any toxic symptoms4 ,examination of the urine and fces showed that as the amount of urinary excretion of arsenic diminished1 so that in the fces increased1 and in lead poisoning1 even in massive doses swallowed in error1 the amount of lead excreted by the urine rapidly diminishes in quantity1 although the patient may be still suffering from the effects of lead poisoning4 ,the experiments1 also1 quoted on p4 #ajj constantly pointed to the elimination of lead by way of the intestine1 and in practically all the animals that had suffered from chronic poisoning well-marked dark staining of the upper part of the ccum due to lead was invariably present4 ,this staining and excretion of lead of the large intestine undoubtedly takes place in man4 ,in a case described by ,little#ah1 where diachylon had been administered1 the administration of a large enema containing sulphate of magnesium came away black4 ,a more detailed result of the experiments and a consideration of the elimination of lead are reserved for another chapter1 but it is impossible to consider the tiology of the disease without some reference to the general histological channels of absorption and excretion4 ,cutaneous ,absorption of ,lead4--,a considerable amount of controversy has centred on the question of the absorption of lead through the unbroken skin4 ,it has been shown that such drugs as belladonna applied to the skin alone may produce dilatation of the pupil2 an ointment containing salicylic acid spread upon the skin and thoroughly rubbed in is followed by the appearance of derivatives of salicylic acid in the urine2 mercury may be applied to the skin1 and rubbed in1 in sufficient quantities to produce salivation2 and a very large number of other drugs may be cited1 all of which when applied to the unbroken epidermis with friction produce the physiological action of the drug4 ,there is no reason to exclude lead from the category of drugs which may be absorbed through the medium of the skin1 and1 as several observers have shown1 animals may be poisoned by lead on applying a plaster of lead acetate to the skin4 ,amongst these experiments may be quoted those of ,canuet#ai and ,drouet#bj on rabbits4 ,some observers1 among whom may be mentioned ,manouvrier#ba1 have attempted to prove that paralysis of the hands occurs more often in the right hand in right-handed people1 in the left hand with left-handed people1 and from the various experiments showing absorption of lead through the unbroken skin they seek to connect the lesion of the nerve with absorption direct through the skin of the hands4 ,many objections can be urged against acceptance of this theory4 ,lead workers who are constantly manipulating lead in a state of solution with bare hands do not appear as a class to be more subject to wrist-drop than do persons who are exposed to inhalation of fumes or dust of lead2 in fact1 incidence of paralysis and of nerve lesions generally is more severe among persons exposed to prolonged inhalation of minute quantities of lead through the respiratory tract4 ,the greater the exposure to dust1 the greater the number of cases of anmia and colic1 whilst in other industries1 as has already been stated1 where lead exists as an oleate on the hands of the workers day in and day out for many years1 paralysis and even colic are of rare occurrence2 in other words1 persons especially exposed to the absorption of lead through their hands show a much smaller incidence of lead poisoning of all types than do those exposed to lead dust4 ,further1 the pathology of wrist-drop and similar forms of paresis tends to show that the nerve supplying the affected muscles is not affected primarily1 but that the initial cause is hmorrhage into the sheath of the nerve1 producing ultimate degenerative change4 ,the hmorrhage1 however1 is the primary lesion4 ,,references4 #a ,,goadby1 ,k4 ,w43 ,a ,note on ,experimental ,lead ,poisoning4 ,journal of ,hygiene1 vol4 ix41 ,no4 #a1 ,april1 #aiji4 #b ,,legge1 ,t4 ,m43 ,report on the ,manufacture of ,paints and ,colours containing ,lead 7,cd4 #bdff74 #aije4 #c ,,duckering1 ,g4 ,e43 ,journal of ,hygiene1 vol4 viii41 ,no4 #d1 ,september4 #d ,,meill,,re1 ,g43 ,le ,saturnisme1 chap4 iv4 ,paris1 #aijc4 #e ,,armit1 ,h4 ,w43 ,journal of ,hygiene1 vol4 viii41 ,no4 #e1 ,november1 #aijh4 #f ,,tanquerel ,,des ,,planches3 ,trait des ,maladies de ,plomb1 ou ,saturnines4 ,paris1 #ahci4 #g ,,stanski3 ,loc4 cit4 #h ,,gautier3 ,intoxication ,saturnine1 etc4 ,acadmie de ,mdecine1 viii41 ,november1 #ahhc4 #i ,,thresh1 ,j4 ,c43 ,the ,lancet1 p4 #ajcc1 ,october #g1 #aije4 #aj ,ibid41 ,january #e1 #aiji4 #aa ,,thomason3 ,report of the ,departmental ,committee on ,lead ,manufacture3 ,earthenware1 ,china1 vol4 ii41 appendices1 p4 #fa4 #aiaj4 #ab ,ibid4 #ac ,,dixon ,,mann3 ,forensic ,medicine and ,toxicology1 p4 #die4 #aijh4 #ad ,,oliver1 ,,sir ,t43 ,lead ,poisoning 7,goulstonian lectures74 #ahia4 #ae ,,schicksal3 ,die ,bekmpfung der ,bleigefahr in der ,industrie1 p4 #ch4 #aijh4 #af ,,steinberg3 ,international ,congress of ,industrial ,hygiene4 ,brussels1 #aiaj4 #ag ,,cloetta3 ,dixon ,mann's ,forensic ,medicine and ,toxicology1 p4 #dfc4 #ah ,,little3 ,the ,lancet1 ,march #c1 #aijf4 #ai ,,canuet1 ,t43 ,thse1 ,paris1 #ahbe1 ,no4 #bjb4 ,essai sur le ,plomb4 #bj ,,drouet3 ,thse1 ,paris1 #ahge4 ,recherches ,experimentales sur le ,rle de l',absorption ,cutane dans la ,paralysie ,saturnine4 #ba ,,manouvrier1 ,a43 ,thse1 ,paris1 #ahgc1 ,no4 #dga4 ,intoxication par ,absorption ,cutane4 ,,chapter ,,iii ,,susceptibility ,,and ,,immunity ,a large number of poisonous substances1 among which lead may be included1 are not equally poisonous in the same dose for all persons4 ,it is customary to speak of those persons who show a diminished resistance1 or whose tissues show little power of resisting the poisonous effects of such substances1 as susceptible4 ,on the other hand1 it is possible1 but not scientifically correct1 to speak of immunity to such poisonous substances4 ,persons1 particularly1 who resist lead poisoning to a greater degree than their fellows are better spoken of as tolerant of the poisonous effects than as being partially immune4 ,the degree of resistance exhibited by any given population towards the poisonous influence of lead shows considerable variation4 ,thus1 in a community using a water-supply contaminated with lead1 only a small proportion of the persons drinking the water becomes poisoned4 ,there are1 of course1 other factors than that of individual idiosyncrasy which may determine the effect of the poison1 as1 for example1 the drawing of the water first thing in the morning which has been standing in a particular pipe4 ,but even if all disturbing factors are eliminated in water-borne lead poisoning1 differing degrees of susceptibility are always to be observed among the persons using the water4 ,lead does not differ1 therefore1 from any other drugs to which persons show marked idiosyncrasies4 ,thus1 very small doses of arsenic may produce symptoms of colic in susceptible persons2 a limited number of individuals are highly susceptible to some drugs1 such as cannabis indica1 while others are able to ingest large doses without exhibiting any sign of poisoning2 and it is well known that even in susceptible persons the quantity of a particular drug which first produces symptoms of poisoning may be gradually increased1 if the dosage be continued over long periods in quantities insufficient to produce marked symptoms of poisoning4 ,in this direction a number of experiments have been performed with arsenic1 particularly those of ,cloetta#a1 who found that the dose of arsenic for dogs could be gradually raised1 if given by the mouth1 to many times the ordinary fatal dose1 but that if at this point a subminimal fatal dose was injected beneath the skin acute symptoms of arsenic poisoning followed4 ,we show in a later chapter that the excretion of lead in persons tolerant of the metal takes place through the medium of the bowel1 and that probably those individuals who are engaged in what are recognized as dangerous processes in lead industries1 and yet show no signs of illness1 have established a kind of balance between the intake of the poison and its excretion by the bowel4 ,it is rarely possible in such persons to find any lead excreted through the kidney4 ,occasionally1 however1 such persons1 after working a considerable time in a dangerous lead process1 become suddenly poisoned1 and inquiry frequently discloses the fact that some disturbing factor1 either intercurrent illness1 alcoholic excess1 etc41 has occurred1 or that the breathing of a big dose of dust has precipitated the symptoms of general lead poisoning4 ,on the other hand1 the experience of all persons engaged in the routine examination of lead workers is that1 although a worker may show signs of lead absorption as distinguished from definite lead poisoning during the earlier period of his employment1 he later shows less and less signs of the influence of the poisonous substance2 even a mild degree of definite poisoning in the early stages of work in a lead process does not seriously militate against this gradually acquired tolerance1 whilst careful treatment during such a time as the man is acquiring tolerance to the poison frequently tides him over the period1 and enables him to withstand the ordinary dangers attached to his work4 ,the earliest symptom of lead absorption is anmia4 ,the anmia is not very profound1 and the diminution in the red blood-cells rarely reaches as low as #b1jjj1jjj per c4c41 the hmoglobin remaining somewhere between #ge and #hj per cent4 ,some loss of orbital fat1 as well as fat in the other parts of the body1 occurs1 but beyond this no obvious clinical signs of poisoning exist4 ,should such persons possess unhealthy gums1 a blue line rapidly makes its appearance1 but where the gums are healthy it is unusual to see any sign of deposit in this prodromal stage4 ,persons who gradually acquire tolerance go through the stage of anmia without exhibiting any symptoms of colic or paresis1 and without any treatment the hmoglobin and the number of red cells gradually pass back to a more or less normal condition4 ,during this period--that is1 whilst the blood shows signs of a diminution in its corpuscular and colour content--basophile granules may always be found if sought for1 but disappear as a rule when the blood-count has returned to about #d1jjj1jjj per c4c4 and an #hj per cent4 hmoglobin4 ,such a man has now developed tolerance to the poisonous influence of lead1 a tolerance which may be described as a partial immunity produced by recurrent subminimal toxic doses4 ,on the other hand1 in a number of persons who show definite susceptibility1 the blood-changes are progressive1 and do not show signs of automatic regeneration4 ,in such persons1 even after so short time as four to six weeks' exposure to lead absorption1 definite symptoms of colic may make their appearance4 ,the removal of such an individual from the poisonous influence of lead generally clears up the symptoms in a short time1 but the symptoms may occasionally continue for several months after removal from the influence of the poison4 ,an individual of this type is to be looked upon as showing peculiar susceptibility1 and should not be employed in any lead process where there is risk4 ,such statistics as are available on this point show that an increased tolerance to the poisonous influence of lead is gradually acquired during periods of work1 in that the number of attacks of poisoning diminish in frequency very considerably in relation to the number of years worked4 ,as will be seen on reference to the chapter dealing with the statistics of lead poisoning 7p4 #df71 the greatest number of cases occur in persons who have only worked a short time in lead4 ,on the other hand1 the sequel of lead poisoning only make their appearance1 as a rule1 after long-continued exposure4 ,it is important to bear in mind that the various forms of paresis rarely make their appearance unless the subject has been exposed to long-continued absorption of lead1 and1 further1 that the blood of such persons will as a rule show1 on careful examination1 evidences of the long-continued intoxication4 ,if measures1 therefore1 were taken to determine the presence of such continued intoxication1 and to diminish the amount of poison absorbed 7subjecting the individual at the same time to a proper course of treatment71 a large number of the cases of paralysis1 encephalopathy1 and death1 incidental to the handling and manufacture of lead1 could be eliminated4 ,susceptibility may at times be shown by several members of one family4 ,oliver#b says that he has known many members of one family suffer from and die of lead poisoning4 ,in our experience several instances of this susceptibility have been noticed4 ,in one case two brothers1 working in one shift of men1 developed poisoning1 although no other persons in that shift showed any signs of it4 ,a third brother1 who came into the works after the other two had left1 and who was placed under special supervision on account of the susceptibility exhibited by his two brothers1 although given work which exposed him to the minimal degree of lead absorption1 developed signs of poisoning six weeks after his entrance into the factory4 ,in another factory1 three sons1 two daughters1 and the father1 all suffered from lead poisoning within a period of four years3 the father had three attacks of colic1 ultimately wrist-drop in both hands2 one daughter had one attack of colic1 and the other three attacks2 whilst the three brothers all suffered from colic and anmia1 and one had early signs of weakness of the wrist4 ,there was no evidence at all to show that these persons were more careless1 or had been more exposed to lead dust1 than any other of the persons with whom they worked1 or that the work they were engaged upon was more likely to have caused illness to them than to other workers4 ,persons with a fresh complexion and red hair have been noted to be more susceptible to lead poisoning than dark-haired persons4 ,in one factory with which we are familiar1 a number of ,italian workmen are employed2 these show considerably less susceptibility to lead poisoning than do their ,english comrades as long as they adhere to their own national diet4 ,when1 however1 they give this up1 and particularly if they become addicted to alcohol1 they rapidly show diminished resistance2 in fact1 all the cases of plumbism occurring among the ,italians in this factory during the last ten years have been complicated with alcohol4 ,it is possible that the relatively large quantity of vegetables in the diet of these ,italians influences the elimination of absorbed lead4 ,there is some reason to suppose1 however1 that there may be racial immunity to lead poisoning4 ,the following case in the same factory illustrates a point already mentioned--namely1 the gradually acquired tolerance to poisoning1 and the unstable equilibrium existing4 ,the individual was a man of twenty years of age4 ,he commenced work on ,august #b1 #aije4 ,six weeks later he was under treatment for seven weeks1 for lead absorption1 and had a peculiarly deep blue line round his gums1 and a diminished hmoglobin of #ge per cent4 ,the symptoms disappeared with ordinary routine treatment1 and his work was shifted to a position in the factory where he was exposed to the minimum amount of lead absorption1 at which work he continued during the rest of the time he remained in the factory4 ,he continued quite well until ,june1 #aijf1 when he was again under treatment for two weeks1 with the same blue line and anmia1 and his blood showed the presence of basophile granules4 ,he was under treatment again in ,january and ,february1 #aiji1 for five weeks1 had again a deep blue line and basophile staining of his blood4 ,on ,november #g1 #aiaa1 having had no anmia and no blue line1 he had a slight attack of colic4 ,during this period of work his blood had been examined on eight occasions1 and on each occasion it had shown basophile granules4 ,the attack of colic was an exceedingly mild one4 ,there is no reason to suppose that he had indulged in alcoholic excess1 but there was some reason to think that for about a month he had been subjected to increased lung absorption4 ,no other persons working in the same shift at the same work developed poisoning during the whole of this period4 ,this case illustrates initial susceptibility1 partial tolerance1 and ultimate breaking down of such partially established tolerance4 ,during the experimental inquiry on lead poisoning by one of us ,k4 ,w4 ,g4#c1 the question of the subminimal toxic dose and the minimal toxic dose was under consideration4 ,animals subjected to inhalation of lead dust invariably succumbed to the effects of the poison when the dose given represented from #jjjja to #jjjjc gramme per litre of air inhaled1 the period of inhalation being half an hour three times a week4 ,on the other hand1 when the lead content of the air was as low as #jjjjja gramme per litre1 the symptoms of poisoning were long delayed1 and in more than one instance1 after an early diminution in weight1 recovery of the lost weight took place1 and the animals1 whilst showing apparent symptoms of absorption1 had no definite symptoms of paresis4 ,these observations tend to confirm such clinically observed facts as are given in the case cited above1 but they1 of course1 do not form a criterion as to the amount of lead dust which may be regarded as innocuous to man4 ,lead is peculiarly a cumulative poison1 and post-mortem analyses of viscera show that it may be stored up in certain parts of the body1 more especially in the bone and red bone marrow and brain1 and to some extent in the liver1 spleen1 and kidneys4 ,any circumstance1 therefore1 that temporarily interferes with the ordinary channels through which lead is excreted may determine the presence of a much larger quantity than usual of the metal in circulation in the body2 and if in addition an increased quantity of the poison be inhaled1 more or less acute symptoms follow4 ,the localization of the deposit of lead is therefore of some importance4 ,meillre and ,richer#d give an analysis of various organs of the body1 but their results are not in accord with the majority of other observers4 ,they found that the hair particularly contains a large quantity of lead4 ,they do not seem to have examined the bones4 ,next to the hair1 the liver seems to have contained the largest amount4 ,wynter ,blyth#e found #aaga milligrammes of lead in the brain of a person who died of encephalopathy4 ,in another case he found #jf gramme in the liver1 #jjjc in the kidney1 and #jjgb in the brain4 ,hougounencq#f examined the organs of a person who died from lead poisoning1 and found the largest amount of lead in the large intestine4 ,large intestine #jbaej gramme4 ,small intestine #jjdcj ,liver #jjjej ,brain #jjjjh ,in the lung1 stomach1 kidney1 and heart1 only traces were found4 ,dixon ,mann#g describes some experiments in which potassium iodide was given in cases of chronic poisoning1 and during the whole of the experiments the fces and urine were analyzed three times a week4 ,he found by this means that a considerable amount of lead was being eliminated by the intestine4 ,he therefore administered #b grammes of lead acetate three times a day for five days to a patient1 and he found that the fces contained #jagfb gramme the first day1 #jagdaa gramme the second day2 the fourth day it had fallen to #jjjec gramme1 and on the sixth day to #jjjjf gramme4 ,the largest amount at any one time in a day obtained from the urine was only just over #jjja gramme2 the average amount found in the case of chronic poisoning was about #c milligrammes1 whereas the greatest amount at any one time in the urine was only #ji milligramme4 ,the quantity of lead present in the brain necessary to determine acute poisoning is not known1 and it is probable that an extremely minute quantity will produce very serious effects2 and in support of this may be quoted a number of observations in which search has been made for the metal in persons who have died of diseases affecting the brain associated with other symptoms of poisoning1 and yet post-mortem examination of the brain by chemical methods has not revealed the presence of any lead whatever4 ,in the case reported by ,mott 7see p4 #ga71 no lead at all was recognized in the brain4 ,there are no reasons1 therefore1 for supposing that the immunity to lead poisoning depends on the fixation and storing up of the poisonous metal in a non-poisonous form in some special situation in the body1 and1 further1 the particular situation in the body richest in lead in any given case of poisoning will depend rather on 7#a7 the type of compound causing the poisoning1 and 7#b7 the portal through which such poisoning occurs4 ,the question of the detection of lead in the body is referred to in the chapter dealing with ,chemical ,examination4 ,it is as well to point out in this connection that chemical investigation of the amount of lead present in the organs of persons dying from lead poisoning should1 if possible1 always be made where there is any doubt as to the diagnosis4 ,certain observers--amongst them ,gautier#h--;are of opinion that traces of lead may be found in normal persons4 ,thus1 in a rat 7,mus decumanus7 ,gautier found #b milligrammes of lead in #fj grammes of liver4 ,he considers that in many persons at least #je milligramme of lead may be swallowed daily incorporated with the food1 as a number of foods are liable to contamination by lead4 ,tinned foods1 particularly those which are soldered up after the materials have been placed in the tin1 certain tinned fruits with acid juices1 often contain small masses of solder loose in the tins2 in the case particularly of fruits the natural acid may slowly dissolve the lead from the solder4 ,the amount of so-called 8normal0 lead1 if it is to be found at all1 must be very small1 and would certainly be much smaller in the case of a normal person than in one who had been subject to definite lead poisoning4 ,such experimental evidence as is forthcoming supports the clinical observations that persons exposed to small doses of lead eventually develop tolerance of the metal1 so that they may ultimately withstand many times the dose sufficient in the first instance to produce poisoning4 ,such circumstances are the natural factors in the prevention of poisoning1 and if due care be given to their significance1 the surgeon in charge of any lead works may by judicious treatment and alternation of employment so assist and strengthen the natural defensive forces that susceptibility may be diminished1 and the degree of tolerance increased to a very considerable extent4 ,we do not imply that efficiency in the exhaust ventilation can be in any way relaxed2 all we desire to emphasize is that certain natural defensive forces of the body do undoubtedly exist by which susceptible persons ultimately become less susceptible1 and that by appropriate means these defensive forces may be augmented4 ,susceptibility and immunity to poisoning by lead may be considered1 according to the type of lead compound absorbed1 further in its relation to age and sex4 ,all compounds of lead are not poisonous in the same degree2 the more easily soluble compounds are more poisonous than the less soluble4 ,on the other hand1 compounds which appear at first sight unlikely to produce poisoning may do so2 for instance1 fritted lead or lead silicate1 a substance largely used in the potteries as a glaze1 and manufactured by fusing together litharge and a silicate1 would appear at first sight to be quite an innocuous substance4 ,owing to its method of preparation1 however1 it is not a pure compound of lead and silica1 but contains lead oxide1 metallic lead1 etc41 entangled in its meshes1 and experimentally one of us 7,k4 ,w4 ,g47 has demonstrated that such a compound may be acted on by the tissues of the body1 both when injected subcutaneously and even when inhaled1 and so gradually produce definite symptoms of lead poisoning1 but at a much slower rate than the more poisonous lead compounds4 ,the fineness of division in which the compound of lead exists is another factor affecting its poisonous nature2 the more finely divided particles find their way into the lung more easily than the coarser particles4 ,various subsidiary matters may also determine the susceptibility in a given individual1 and of these a certain number require mention1 as they probably act as definite predisposing factors4 ,age and sex may be regarded as predisposing factors to lead poisoning1 and certain diseases also4 ,age4--,young persons are regarded as more liable to lead poisoning than adults1 although it is difficult to obtain definite figures on the point1 the duration of employment acting as a disturbing factor in estimating the susceptibility of young persons4 ,they may have worked in a lead works for a year or more without showing any signs of poisoning1 but develop them later in adult life1 although it is very likely that absorption had taken place during the earlier period4 ,in the ,report of the ,departmental ,committee on the ,use of ,lead in the ,potteries 7,appendix ,,xii471 the attack rate for the period #ahii to #aiji for young persons is #aic per #a1jjj1 and for adults #ahh for the same period1 but the figures upon which these attack rates are based are too small to build any conclusion4 ,the general clinical conclusions of appointed surgeons and certifying surgeons in the various lead factories would be1 we believe1 that the susceptibility of young persons is at least twice that of adults1 and there is some ground for supposing that the tissues of an adult when growth has ceased more readily adapt themselves to deal with the absorption and elimination of poisonous doses of lead than do the tissues of a young person4 ,sex4--,women are more susceptible to poisoning by lead than men1 and in lead poisoning from drinking water the proportion of women 7especially pregnant women7 and children attacked is stated to be higher than in men1 and one such epidemic is quoted by ,oliver where the rise in the number of miscarriages and premature births led to the discovery of the fact that the water-supply was contaminated with lead4 ,the close relationship of lead poisoning to miscarriage has been repeatedly made out1 especially by ,oliver1 in the white lead industry as carried on twenty years ago4 ,oliver also quotes the effect upon rabbits#i1 ,glibert upon guinea-pigs#aj1 and in the experiments of one of us 7,k4 ,w4 ,g471 referred to on p4 #ii1 all the animals to which lead was given during pregnancy aborted2 and1 further1 with one exception out of eight animals1 all died of lead poisoning1 not as the result of the abortion1 but some time later1 although no further administration of lead was made4 ,this confirms the well-known abortifacient effect of diachylon1 and there is no doubt that the lead circulating in the maternal blood determines the abortion4 ,further1 observers who have examined the ftus in such cases have demonstrated the presence of lead in the ftus itself4 ,oliver#aa found that eggs painted with lead nitrate did not hatch out1 and on opening the eggs the embryos were found to have reached only a limited stage of development1 and to have then died1 whereas control eggs painted with lime produced live chicks4 ,from what is stated later with regard to the curious action of lead upon the blood1 the mechanism of abortion is easily understood2 it is probable that placental hmorrhages are produced1 as in other organs of the body4 ,but the effect of lead on the female is not only apparent during pregnancy4 ,a considerable number of women working in lead processes suffer from amenorrha1 and often from periods of menorrhagia and dysmenorrha1 which as a rule is the more striking symptom4 ,the effect of lead on the uterine functions1 however1 only exists so long as the constant intake of the poison is taking place1 and many cases are recorded where women1 after having had successive abortions while working in lead factories1 have ultimately gone through a normal pregnancy and given birth to a living child4 ,this circumstance bears a strong analogy to the similar train of events in syphilis4 ,in the ,report of the ,committee on the ,use of ,lead in the ,potteries1 some inquiry was made with regard to the possible association of lead absorption on the male side as a predisposing cause of infant mortality and premature birth4 ,the tables given are not very conclusive1 and from our own observations there seems to be very little evidence for supposing that a male lead worker is less likely to beget children1 or that his children are more likely to be unhealthy than those of men working in any other industrial process4 ,we are here speaking of the effect of lead under the conditions of its general use in this country now4 ,in the absence of any precautions whatever as to daily absorption of dangerous dust1 the effect on the offspring1 even in the case of male lead workers1 may well be evident1 as has been shown by ,chyzer#ab in the manufacture of pottery as a home industry in ,hungary4 ,one greatly disturbing factor in estimating the greater susceptibility of the female than the male in many lead industries is that the more dangerous work is performed by the women1 such1 for instance1 in the ,potteries1 as the process of colour-blowing and ware-cleaning4 ,predisposing ,causes of ,lead ,poisoning4--,in lead poisoning1 as in many other diseases1 a number of predisposing and contributory causes may be cited which tend to lower the susceptibility of the individual to the poisonous effect of the metal and its compounds1 or to so modify the functions of the body that a smaller dose of poison may produce more profound changes than would otherwise be the case4 ,certain diseases may be regarded as predisposing causes by lowering the general resistance of the body tissues to the influence of lead1 and a consideration of the chapter on ,pathology will at once demonstrate how seriously certain diseases may contribute in this way4 ,the peculiar effect of lead is upon the blood and the walls of the bloodvessels1 and it will therefore follow that any disease which may affect the intima of the bloodvessels may predispose to lead poisoning2 and1 further1 as the elimination of lead takes place to a certain extent through the kidney1 any disease which affects either the renal epithelium or the general maintenance of the excretory function of the kidney may predispose that organ to the irritative effects of the lead circulating in the blood4 ,in the same way1 the condition of lead absorption in which the balance of absorption and elimination of lead remains in such a ratio that no definite symptoms of lead poisoning appear may have that delicate balance easily upset by the introduction of some secondary cause1 which1 when operating in association with lead absorption1 may precipitate symptoms attributable to poisoning by that metal4 ,chronic alcoholism especially1 producing as it does definite changes in the kidney of itself--changes which it is impossible to distinguish by the naked eye from the effects of lead poisoning--must clearly act as a predisposing1 if not even an exciting1 cause of lead kidney infection4 ,in experiments upon animals1 it was found that the addition of alcohol to the diet of an animal which was the subject of chronic lead absorption precipitated the attack of definite poisoning2 in other words1 the latent period of lead poisoning--that is to say1 the resistance exhibited by the tissues to the toxic influence of lead--was considerably diminished by this addition of a second irritant1 alcohol4 ,in several experiments1 also1 where the form of lead experimented with was one of the least toxic of the lead compounds1 the animals subjected to such a compound alone did not become poisoned1 but succumbed if alcohol were added to their diet4 ,this experimental work is amply borne out by the clinical evidence of all persons who have had experience of industrial lead poisoning1 as cases of colic and wrist-drop are frequently observed in lead workers shortly after alcoholic excesses4 ,individuals1 therefore1 who are suspected of the alcoholic habit should not be employed in any process where they are likely to run risk of absorption of lead dust4 ,such diseases as syphilis and gout1 by causing a heightened arterial tension or definite disease of the intima of the bloodvessels themselves1 tend to weaken the arteries in much the same manner as does lead circulating in the blood1 and must on that account act as predisposing causes4 ,in persons employed in lead trades some species of tolerance is generally developed1 and if the functions of the body progress in the normal way the balance of elimination and absorption are equal1 and1 as will be seen later1 the chief channel for the elimination of lead from the body is through the bowel4 ,it follows1 therefore1 that any disease which tends to produce constipation or chronic inactivity of the normal intestinal functions will also tend to lower the resistance of the individual to lead poisoning4 ,of the various types of intestinal disease of a chronic nature--such1 for instance1 as chronic dysentery1 colitis1 and the like--little need be said2 but the predisposing effect of diseased conditions of the upper portion of the alimentary canal must not be overlooked1 more particularly affections of the oral cavity itself4 ,this special type of infection1 often included under the term of 8oral sepsis10 besides producing anmia1 is also a constant cause of intestinal disturbance1 and as such operates as a particular predisposing cause of lead poisoning4 ,with regard to gout the evidence is not so clear4 ,it was pointed out by ,garrod#ac that gout was common among house-painters1 and it has been generally stated that lead poisoning predisposes to this complaint4 ,in the opinion of a considerable number of observers1 however1 gout is by no means common among persons working in white lead factories or lead-smelting works1 but there seems to be some reason to suppose that it is somewhat common among those persons employed in the painting trades1 but not among those employed in the manufacture of paints and colours4 ,from the experiments carried out by one of us ,k4 ,w4 ,g4#ac4 it seems probable that the occurrence of gout among painters may be associated with the use of turpentine1 largely employed in the ordinary processes of painting1 as this substance in particular is not one that is used by workers in other lead trades1 and1 from experiments performed on animals1 the inhalation of turpentine vapour was found to produce very definite changes both in the kidney and the general metabolism of the body4 ,malnutrition4--,malnutrition is recognized as a predisposing cause of practically all forms of disease1 and with a chronic intoxication1 such as lead poisoning1 malnutrition and starvation1 with its attendant depression of all the vital forces of the body1 is essentially a predisposing cause of poisoning1 so much so that even the fact of commencing work without previously partaking of food may operate directly as a cause of poisoning4 ,it has been found1 moreover1 experimentally by one of us ,k4 ,w4 ,g4#ad that an animal fed with milk containing lead nitrate did not develop poisoning1 though the control animal developed well-marked symptoms of poisoning with a much smaller dose given in water4 ,anmia4--,anmia has already been referred to as occurring with great frequency in persons who are absorbing lead1 and it usually forms one of the chief factors in the symptom-complex of lead cachexia4 ,as the action of lead is particularly upon the blood and the hmopoietic organs1 diminishing the number of red cells and the amount of hmoglobin1 and impairing the organs from which fresh blood-cells are produced1 a disease or state associated with anmia other than of lead origin acts as a definite predisposing cause in the development of toxic symptoms in a worker in an industrial lead process4 ,among the anmias1 two particular types may be referred to as of chief importance4 ,in the first place1 chlorosis1 the anmia occurring particularly in young women1 is often associated with intestinal stasis4 ,lead anmia occurring in a chlorotic person is always more severe than simple lead anmia4 ,young persons suffering from chlorosis1 therefore1 should not be employed in a dangerous lead process until the anmia has been treated4 ,the second type of anmia1 which1 from its frequency1 may be also regarded as a predisposing cause of lead poisoning1 is chronic secondary septic anmia4 ,anmias of this type1 as was pointed out by ,william ,hunter#ae1 resemble in many points the original idiopathic or ,addisonian anmia1 often termed 8pernicious anmia10 and one of us has had occasion to inquire into the curious type of secondary anmia associated with septic affections of the upper respiratory tract1 particularly those related to chronic suppurative affections of the accessory sinuses of the nose1 of the gums1 of the mucous membrane of the mouth and the throat4 ,the commonest forms of this secondary anmia are those due to chronic post-nasal discharge1 and to chronic infections of the gums and alveolus of the jaws1 the latter often classed together under the term 8pyorrha alveolaris40 ,this term is an exceedingly clumsy one1 indicating a discharge of pus from the gum edges and sockets of the teeth1 which are often loose4 ,the disease commences as an infective gingivitis along the edges of the gum1 and progresses to rarefying osteitis of the alveolar process1 and often of the body of the bone4 ,the affection rarely gives rise to pain1 and as a rule the individual is entirely unaware that any chronic suppuration is present1 and little or no notice is therefore taken of the disease4 ,progressive anmia may thus be set up without any knowledge of its cause1 partly by absorption of the actual bacteria and their products through the alveolar bloodvessels1 and partly by the fact of the constant swallowing of pus and bacterial products1 which set up various forms of chronic gastro-intestinal incompetence4 ,from the discharges of the mouth1 and issuing from the gum edges1 numerous bacteria have been isolated1 and in more recent work one of us ,k4 ,w4 ,g4#af has succeeded in isolating and identifying certain bacteria as a direct cause of arthritis deformans1 a malady occasionally1 but without sufficient grounds1 ascribed to lead poisoning4 ,arthritis of various types may occur in persons engaged in lead trades1 but in all such cases we have had the opportunity of examining there has been some obvious source of septic infection1 and no evidence that the arthritis was due to the action of lead4 ,it is most important to draw the attention of those engaged in the protection of lead workers from the dangers of their occupation to these chronic septic conditions of the mouth1 and it may be taken as a general rule that1 wherever the blue line makes its appearance along the gums1 such gums are in a state of chronic infection1 and the appearance of the blue line is merely a secondary effect4 ,it is exceedingly rare to find the blue line in persons with intact gums and clean teeth2 and although attention is frequently drawn to the fact that a lead line exists in a person whose teeth are normal1 little or no notice is taken of the presence or absence of a suppurative condition of the gum margins4 ,moreover1 such a suppurative condition does not always result in obvious inflammation of the gum edges1 and very considerable destruction of the alveolus and the interdental bone may exist without any obvious signs of its presence1 unless the case be examined carefully with a fine probe4 ,this particular point has been the subject of experiment by one of us4 ,animals exposed to the influence of air laden with lead dust never develop a blue line1 although all the usual symptoms of lead poisoning make their appearance4 ,when1 however1 some slight suppurative lesion of the gums was produced by an inoculation into the gum tissue of organisms isolated from a case of infective gingivitis in a human being1 the site of inoculation and any suppurative lesion that resulted locally at once allowed the development of a blue line1 and it was only in animals so treated that it was possible to produce experimentally the ,burtonian line4 ,there is no doubt that any chronic septic infection may predispose to lead poisoning through the production of a secondary anmia1 and it is therefore inadvisable to pass for work in a lead process of a dangerous nature any persons suffering from an infected condition of the mouth4 ,it follows also that the care of the mouth and gums should be rigorously enforced upon all persons employed in lead trades1 as the mere mechanical facilities for the accumulation of dbris around the individual teeth tends to increase the quantity of lead dust that may be retained in the mouth4 ,this is gradually rendered soluble and absorbed1 through the action of the bacterial acids which are always produced along the gum margins when any entangled food is retained in the interdental spaces4 ,one further point of importance attaches to the infections of the upper respiratory tract--namely1 the constant ingestion of bacteria of a fermentative type4 ,by this means the contents of the stomach may be maintained in a state of hyperacidity1 and any small quantities of lead which become swallowed are thereby at once rendered soluble in the intermeal periods4 ,of the other types of anmia which may act as predisposing causes of lead poisoning1 little need be said1 as they are either associated with other grave symptoms or are rare in this country4 ,but as all forms of anmia1 particularly septic anmia1 malarial fever1 etc41 are associated with destruction of the blood-cells1 the presence of basophile staining granules in the red corpuscles of such persons is a constant feature1 and must not be confounded with the basophile staining owing its origin to the effect of lead4 ,in addition to the diseases mentioned which may be said to predispose to lead poisoning1 certain other diseases have been stated to be predisposed to by the action of lead4 ,it is no doubt a fact that where chronic anmia1 wasting1 loss of subcutaneous fat1 decreased muscular power1 and general lowering of the metabolic activity of the body1 are produced1 an individual so affected may be supposed to be more susceptible to certain infectious diseases1 and among these stress has been laid on the alleged association of phthisis with lead absorption4 ,this point is discussed in the next chapter4 ,in summing up the difficult question of predisposition to lead poisoning1 together with the correlated questions of susceptibility and immunity1 certain facts may at any rate be clearly stated3 #a4 ,undoubted individual susceptibility and immunity exist with regard to lead poisoning in exactly the same way as individual susceptibility and immunity may be shown to exist towards poisoning by many other metals and drugs4 ,therefore1 given the same opportunities for infection1 a person showing early signs of lead absorption may be regarded as susceptible4 #b4 ,females are at least twice1 and probably three times1 as susceptible to lead poisoning as are males4 ,much of this susceptibility is determined by the extra stress thrown upon the female generative organs4 #c4 ,certain diseases predispose to lead poisoning mainly by nature of the alterations in metabolism produced--chiefly anmia4 #d4 ,many persons engaged in lead industries become gradually tolerant of the absorption of lead1 and in time resist much larger doses than would have been possible at the commencement of exposure1 but in such persons the balance between absorption and excretion upon which that tolerance depends may become easily disturbed by intercurrent disease or sudden increase in absorption4 ,,references4 #a ,,cloetta3 ,dixon ,mann's ,forensic ,medicine and ,toxicology1 p4 #dfc4 #b ,,oliver1 ,,sir ,t43 ,diseases of ,occupation1 p4 #adb4 #c ,,goadby1 ,k4 ,w43 ,departmental ,committee on ,lead ,poisoning1 etc41 in ,china and ,earthenware ,manufacture1 ,appendix ,no4 ,,xxv4 #d ,,meill,,re ,,and ,,richer3 ,meillre's ,le ,saturnisme4 ,paris1 #aijc4 #e ,,blyth3 ,abstract of ,proc4 ,chem4 ,soc41 #ahhg-hh4 #f ,,hougounencq3 ,meillre's ,le ,saturnisme1 p4 #gc4 #g ,,dixon ,,mann3 ,british ,medical ,journal1 #ahic4 #h ,,gautier3 ,socit de ,biologie1 ,april1 #aijc4 #i ,,oliver1 ,,sir ,t43 ,british ,medical ,journal1 ,may #ac1 #aiaa1 p4 #ajif4 #aj ,,glibert1 ,d4 ,j43 ,le ,saturnisme ,exprimental4 ,extrait des ,rapports ,annuels de l',inspection du ,travail4 ,bruxelles1 #aijf4 #aa ,,oliver1 ,,sir ,t43 ,diseases of ,occupation1 p4 #aci4 #ab ,,chyzer1 ,a43 ,des ,intoxications par le ,plomb se prsentant dans la ,cramique en ,hongrie4 ,budapest1 #aijh4 #ac ,,garrod3 ,the ,lancet1 #ahgj4 #ad ,,goadby1 ,k4 ,w43 ,departmental ,committee on ,lead ,poisoning1 etc41 in ,china and ,earthenware ,manufacture1 ,appendix ,,xxv4 #ae ,,hunter1 ,,william3 ,severest ,anmias4 #af ,,goadby1 ,k4 ,w43 ,the ,lancet1 ,march #aa1 #aiaa4 ,,chapter ,,iv ,,statistics ,,of ,,plumbism,a ,a ,based mainly on reports received from certifying factory surgeons during the ten years #aijj-aiji4 ,classification of notified cases of lead poisoning was carried out on practically the same lines between the years #aijj and #aiji1 and comparison of the data so collected has interest1 in view of their large number--nearly #g1jjj--;in respect of 7#a7 increase or decrease in recorded amount in each one of eighteen classes of industries2 7#b7 severity and number of attack--i4e41 whether first1 second1 third1 or chronic2 and 7#c7 main symptoms4 ,notification was first enjoined by ,section #bi of the ,factory and ,workshop ,act1 #ahie1 which subsequently1 on consolidation of the ,factory ,acts1 became ,section #gc of the ,act of #aija4 ,this enactment requires every medical practitioner1 attending on1 or called in to visit1 a patient whom he believes to be suffering from lead poisoning contracted in a factory or workshop1 to notify the case forthwith to the ,chief ,inspector of ,factories at the ,home ,office2 and a similar obligation is imposed on the occupier of a factory or workshop to send written notice of every such case to the certifying surgeon and inspector of factories for the district4 ,in form there is close similarity between this section and that requiring notification under the ,infectious ,diseases 7,notification7 ,act2 but whereas the symptoms of these diseases are1 within well-recognized limits1 precise1 in lead poisoning the differential diagnosis has not infrequently to be made from a variety of common ailments--headache1 anmia1 rheumatism1 abdominal pain2 and there is no precise standard of what constitutes lead poisoning4 ,the notification of the practitioner as a rule gives no information beyond the belief that the case is one of lead poisoning4 ,as a matter of routine the notification is followed up by an inquiry by the certifying surgeon and inspector to see whether regulations already in force have been infringed in the particular work-place or not1 and as to how far there may have been contributory negligence on the part of the sufferer4 ,the data supplied on the surgeon's report form the basis of the tabulation#a4 ,brief explanation is wanted of the method adopted in classification4 ,cases represent all attacks reported within a year1 and not previously reported within the preceding twelve months1 so as to make the number of persons and cases in a year the same4 ,where the interval between two reports on the same person was more than twelve months1 the fresh attack was again included4 ,the number of such second reports on persons already included in a return numbered #bhd 7#db per cent471 and a portion of these certainly1 probably not more than #ajj1 have been included twice or thrice in the total #f1fch cases4 ,cases in which there was obvious error in diagnosis1 or in which the opinion of the certifying surgeon was very strongly against the diagnosis 7especially when the report had been made in the first instance by the occupier alone1 and not by a medical practitioner71 were excluded from the return4 ,these numbered #deh 7#fh per cent474 ,others1 again1 where there was a strong element of doubt1 but not to be regarded as more than a difference of opinion between two medical men1 were marked doubtful and included4 ,of these there were #dbd 7#fc per cent474 ,the classification of industries was designed to represent the way in which the poisoning may be supposed to originate from 7a7 lead fumes 7#a to #d71 7b7 handling metallic lead 7#e and #f71 7c7 dust from lead compounds 7#g to #ad71 and 7d7 lead paint 7#ae to #ag74 ,we attach now only slight importance to this attempt to define causation1 as it will appear from our survey that we regard almost all cases as the result of inhalation either of fumes or dust4 ,the reports describe not only the particular attack1 but also the general condition of the patient at the time of the attack4 ,very frequently a combination of symptoms--colic1 anmia1 and varying degree of paralysis--are described as present1 and when this is the case each one of them has been entered under the appropriate heading4 ,the total number of symptoms1 therefore1 greatly exceeds the number of cases1 but this does not affect the correctness of the estimate of each one as a proportion on the total number reported4 ,the reports do not give detailed information such as can be gained from hospital records4 ,especially is this the case with the symptoms of paralysis and encephalopathy4 ,table ,,iii4 shows the number of reported cases included in returns for each of the years #aijj to #aiji4 ,on the total figures there has been a reduction of #dgg per cent4 ,in the several industries the salient feature is that the considerable diminution achieved is limited to industries--notably white lead1 earthenware and china1 litho-transfers1 and paints and colours--in which1 under regulations or special rules1 locally applied exhaust ventilation for the removal of dust1 and periodical medical examination of the workers1 have been required4 ,where1 owing to the nature of the processes carried on1 it has been found impracticable1 in the present state of knowledge1 to apply local exhaust ventilation1 and where periodical examination of the workers is lacking1 as in smelting of metals,a and industries using paint1 there has been tendency to increase in the number of cases4 ,in coach-building the increase is in part due to activity in the motor-car industry4 ,a ,this is now required by the regulations dated ,august #ab1 #aiaa4 ,,table ,,iii4--,,notification ,,of ,,poisoning ,,by ,,lead 7,,under ,s4 #gc1 #aija71 #aijj-aiji4 ---------------------------------------- ------------------------- ,reported --------------------------------- ,total ,industry4 #aijj-ji4aiji4aijh4aijg4aijf4aije4 ---------------------------------------- ------------------- 7#a7 7#b7 7#c7 7#d7 7#e7 7#f7 7#g7 ,,lead ,,poisoning #f1gfbeecfdfeghfcbeib #a4 ,smelting of metals #dab #ff #gj #bh #ch #bd #b4 ,brass works #ge #e #f #i #aa #e #c4 ,sheet lead and lead piping #aji #i #ad #f #g #i #d4 ,plumbing and soldering #bag #bh #bg #bj #af #bd #e4 ,printing #bjj #ba #cj #bf #af #ai #f4 ,file-cutting #baa #h #i #aj #ae #ab #g4 ,tinning and enamelling #ach #ba #aj #be #ah #ad #h4 ,white lead #a1bie #cb #gi #ga #ajh #ij #i4 ,red lead #ajh #aj #ab #g #f #aj #aj4 ,china and earthenware #a1jfe #eh #aagajc #ajg #hd #aj;a4 ,litho-transfers #dh #a #b #aj #e #e #aa4 ,glass cutting and polishing #dh #d #c #d #d #c #ab4 ,enamelling iron plates #eb #c #g #f #d #b #ac4 ,electric accumulators #bhe #bg #be #ba #bf #bg #ad4 ,paints and colours #dbb #ci #be #ce #cg #eg #ae4 ,coach-building #fig #ie #gj #gj #he #ef #af4 ,ship-building #bfi #bg #ae #bb #bf #cb #ag4 ,paint used in other industries #deb #db #dg #di #cg #di #ah4 ,other industries #fei #eg #gh #ef #ff #gj ---------------------------------------- ------------------- ---------------------------------------- ----------------- ,cases4 --------------------------- ,industry4 #aijd4aijc4aijb4aija4 #aijj4 ---------------------------------------- ------------- 7#a7 7#h7 7#i7 7#aj7 7#aa7 7#ab7 ,,lead ,,poisoning #eigfadfbihfca1jeh #a4 ,smelting of metals #cc #cg #bh #ed #cd #b4 ,brass works #aj #ae #e #f #c #c4 ,sheet lead and lead piping #g #aa #ab #ag #ag #d4 ,plumbing and soldering #ba #bf #bc #bc #i #e4 ,printing #ae #ac #ai #bc #ah #f4 ,file-cutting #bj #bd #bg #df #dj #g4 ,tinning and enamelling #aj #ad #aa #aj #e #h4 ,white lead #aaf #aji #adc #ahi #ceh #i4 ,red lead #aa #f #ac #ad #ai #aj4 ,china and earthenware #ajf #ig #hg #ajf #bjj #aj;a4 ,litho-transfers #c #c #b #g #aj #aa4 ,glass cutting and polishing -- #d #h #aa #g #ab4 ,enamelling iron plates #c #d #c #i #aa #ac4 ,electric accumulators #cc #bh #af #di #cc #ad4 ,paints and colours #cb #ci #df #ef #ef #ae4 ,coach-building #di #gd #fc #fe #gj #af4 ,ship-building #dh #bd #ae #bh #cb #ag4 ,paint used in other industries #bg #df #dd #fa #ej #ah4 ,other industries #ec #dj #fd #hi #hf ---------------------------------------- ------------- ,the principal figures are those of the cases1 fatal and non-fatal2 the small figures relate to fatal cases only4 ,for the sake of completeness the figures for the years #aiaj and #aiaa are given below4 ,the grand totals are comparable with those for each of the years #aijj to #aiji1 but not the total for all of the several groups of industries4 ,thus1 the name of heading ,no4 #g is altered to 8,tinning of metals10 and ,no4 #ab to 8,vitreous enamelling10 because of regulations widening their scope1 and now including cases which previously figured in ,no4 #ah1 8,other industries40 ---------------------------------------- ---- ,industry4 #aiaa4aiaj4 ---------------------------------------- ---- ,,lead ,,poisoning #ffieje ,smelting of metals #dh #cd ,brass works #i #g ,sheet lead and lead piping #ab #d ,plumbing and soldering #cg #be ,printing #cb #cc ,file-cutting #ah #i ,tinning of metals #ac #ag ,vitreous enamelling #ai #ag ,white lead #da #cd ,red lead #ac #aj ,china and earthenware #ib #gg ,litho-transfers #a #a ,glass cutting and polishing #e -- ,electric accumulators #bd #ca ,paints and colours #ba #ag ,coach and car painting #ajd #gj ,ship-building #cf #ba ,use of paint in other industries #ef #ea ,other industries #hh #dg ---------------------------------------- ---- ,,table ,,iv4--,,analysis ,,of ,,reports ,,on ,,lead ,,poisoning ,,by ,,certifying ,,surgeons ,,from ,,january #a1 #aijj1 ,,to ,,december #ca1 #aiji4 ---------------------------------------- ---------------------- ,severity of ,symptoms4 ---------------------------------------- -------------------- ,no4 ,occupation4 ,total4 ,severe4 ,moderate4 ,slight4 ---------------------------------------- -------------------- 7#a7 7#b7 7#c7 7#d7 7#e7 7#f7 ---------------------------------------- ---------------- ,m4 ,f4 ,m4 ,f4 ,m4 ,f4 ,m4 ,f4 #a ,smelting of metals3 ,cases #daa -- #ajd -- #aje -- #aig -- ,per cent4 #ajj -- #bec -- #bef -- #dgi -- #b ,brass works3 ,cases #gj #d #bf #b #bj #a #bb #a ,per cent4 #ajj -- #cga -- #bhf -- #cae -- #c ,sheet lead and lead piping3 ,cases #ajb #d #be #a #bi #a #dg #b ,per cent4 #ajj -- #bde -- #bhd -- #dfa -- #d ,plumbing and soldering3 ,cases #ahf #cj #fe #f #di #f #fe #af ,per cent4 #ajj #ajj #cdibjj #bfcbjj #cdiecc #e ,printing3 ,cases #aij #f #ee -- #dc #a #hb #e ,per cent4 #ajj -- #bhi -- #bbf -- #dcb -- #f ,file-cutting3 ,cases #agd #cd #he #h #cd #e #dh #ba ,per cent4 #ajj #ajj #dhibce #aieadg #bgffah #g ,tinning and enamelling of hollow-ware3 ,cases #hd #ec #bf #ac #bg #af #ca #bd ,per cent4 #ajj #ajj #cajbde #cbacjb #cfidec #h ,white lead3 ,cases #a1afg #gf #cag #bg #bce #aa #eic #cc ,per cent4 #ajj #ajj #bgbcee #bjaade #ejhdcd #i ,red lead3 ,cases #ajh -- #cj -- #ca -- #de -- ,per cent4 #ajj -- #bgh -- #bhg -- #dag -- #aj ,china and earthenware3 ,cases #dij #egb #ajb #hf #aeh #aha #baf #bhf ,per cent4 #ajj #ajj #bjhaej #cbbcaf #ddaejj #aj;a,litho- transferers3 ,cases #bj #bh #b #e #b #h #ae #ae ,per cent4 #ajj #ajj #ajjagi #ajjbhf #gejecf #aa ,glass cutting and polishing3 ,cases #dg -- #bj -- #aa -- #af -- ,per cent4 #ajj -- #dbe -- #bcd -- #cdj -- #ab ,enamelling of iron plates3 ,cases #ch #ad #f #f #ai #d #ac #c ,per cent4 #ajj #ajj #aehdbi #ejjbhf #cdbbad #ac ,electric accumulators3 ,cases #bha -- #eh -- #gj -- #aea -- ,per cent4 #ajj -- #bjf -- #bdi -- #ecg -- #ad ,paint and colour works3 ,cases #cig #ba #aaa #b #ajd #d #agf #ae ,per cent4 #ajj #ajj #bgi #ie #bfbaij #dddgae #ae ,coach-making3 ,cases #fgh #c #agf -- #ahg #b #bic #a ,per cent4 #ajj -- #bfj -- #bgf -- #dcb -- #af ,ship-building3 ,cases #bfa -- #ic -- #ea -- #ajh -- ,per cent4 #ajj -- #cef -- #aie -- #dad -- #ag ,paints used in other industries3 ,cases #dje #db #abg #aa #ig #g #agd #bb ,per cent4 #ajj #ajj #cadbfb #bciafg #dcjebd #ah ,other industries3 ,cases #ebh #aad #afj #cg #aag #bb #bcj #eb ,per cent4 #ajj #ajj #cjccbe #bbbaic #dcfdef ,total cases #e1fcga1jjaa1ehh #bjda1chi #bfib1ebb #dif per cent4 #ajj #ajj #bhbbjd #bdgbfi #ddgdie ---------------------------------------- ---------------- ---------------------------------------- --------- ,number of ,attack4 ---------------------------------------- ------- ,third1 or ,no4 ,occupation4 ,first4 ,second4 ,chronic4 ---------------------------------------- ------- 7#a7 7#b7 7#g7 7#h7 7#i7 ---------------------------------------- ---- ,m4 ,f4 ,m4 ,f4 ,m4 ,f4 #a ,smelting of metals3 ,cases #bgf -- #fe -- #fd -- ,per cent4 #fgb -- #afh -- #aef -- #b ,brass works3 ,cases #dj #c #aa #a #ag -- ,per cent4 #ega -- #aeg -- #bdc -- #c ,sheet lead and lead piping3 ,cases #gb #c #ag -- #aa #a ,per cent4 #gjf -- #afg -- #ajh -- #d ,plumbing and soldering3 ,cases #aad #bb #cj #a #cb #c ,per cent4 #facgccafa #ccagbajj #e ,printing3 ,cases #aah #f #bi -- #cc -- ,per cent4 #fba -- #aec -- #agd -- #f ,file-cutting3 ,cases #di #bd #ci #d #gh #f ,per cent4 #bhbgjfbbdaahddhagf #g ,tinning and enamelling of hollow-ware3 ,cases #ej #ca #ah #af #ae #f ,per cent4 #eieehebadcjbagiaac #h ,white lead3 ,cases #ifa #ef #ajh #i #di #c ,per cent4 #hbdgcg #icaah #db #ci #i ,red lead3 ,cases #ij -- #h -- #h -- ,per cent4 #hcc -- #gd -- #gd -- #aj ,china and earthenware3 ,cases #big #dfi #ia #fe #hg #ag ,per cent4 #fjfhbjahfaadagg #cj #aj;a,litho- transferers3 ,cases #ag #bg #b -- -- #a ,per cent4 #hejifdajj -- -- #cf #aa ,glass cutting and polishing3 ,cases #ba -- #i -- #ag -- ,per cent4 #ddg -- #aia -- #cfb -- #ab ,enamelling of iron plates3 ,cases #ca #aa #g #b -- -- ,per cent4 #hafghfahdadc -- -- #ac ,electric accumulators3 ,cases #bbb -- #dj -- #ac -- ,per cent4 #gij -- #adb -- #df -- #ad ,paint and colour works3 ,cases #bij #af #fa #c #ci #b ,per cent4 #gcagfbaedadc #ih #ie #ae ,coach-making3 ,cases #dje #b #abg -- #aad #a ,per cent4 #eih -- #ahg -- #afh -- #af ,ship-building3 ,cases #aha -- #da -- #bd -- ,per cent4 #fij -- #aeg -- #ib -- #ag ,paints used in other industries3 ,cases #bch #cf #hc #d #ga #a ,per cent4 #ehhhegbje #ieage #bd #ah ,other industries3 ,cases #cbi #ic #he #ad #hf #e ,per cent4 #fbchafafaabcafc #dd ,total cases #c1hjj #gii #hga #aai #geh #df per cent4 #fgdgihaeeaaiacd #df ---------------------------------------- ---- ---------------------------------------- --------------------- ,main ,symptoms4 ---------------------------------------- ------------------ ,no4 ,occupation4 ,gastric4 ,anmia4 ,headache4 ,paretic4 ---------------------------------------- ------------------ 7#a7 7#b7 7#aj7 7#aa7 7#ab7 7#ac7 ---------------------------------------- -------------- ,m4 ,f4 ,m4 ,f4 ,m4 ,f4 ,m4 ,f4 #a ,smelting of metals3 ,cases #cbe -- #ii -- #ah -- #ii -- ,per cent4 #gia -- #bda -- #dd -- #bda -- #b ,brass works3 ,cases #eg #d #bh #c #af #c #bh #b ,per cent4 #had -- #djj -- #bbi -- #djj -- #c ,sheet lead and lead piping3 ,cases #hb #b #bh #a #i #a #bf #b ,per cent4 #hjd -- #bge -- #hh -- #bee -- #d ,plumbing and soldering3 ,cases #adf #be #eh #ad #bc #aj #df #g ,per cent4 #ghehcc #cabdfgabdccc #bdgbcc #e ,printing3 ,cases #add #f #da #c #bb #a #cf -- ,per cent4 #geh -- #baf -- #aaf -- #ahi -- #f ,file-cutting3 ,cases #ajd #bc #ej #ag #ae #b #hj #c ,per cent4 #eihfgg #bhgejj #hf #ei #dfj #hh #g ,tinning and enamelling of hollow-ware3 ,cases #fe #di #cc #ab #i #c #ai #ac ,per cent4 #ggdibe #cicbbfajg #eg #bbfbde #h ,white lead3 ,cases #a1jjc #ei #bhf #h #ea #e #abj #g ,per cent4 #heiggf #beaje #dd #ff #ajc #ib #i ,red lead3 ,cases #hg -- #bh -- #h -- #ad -- ,per cent4 #hjf -- #bei -- #gd -- #acj -- #aj ,china and earthenware3 ,cases #cah #dcj #ic #ahc #gh #aha #adg #gi ,per cent4 #fdigeb #aijcbjaeicaf #cjjach #aj;a,litho- transferers3 ,cases #af #be #b #h #f #ad #a #h ,per cent4 #hjjhic #ajjbhfcjjejj #ejbhf #aa ,glass cutting and polishing3 ,cases #bh -- #i -- #b -- #ad -- ,per cent4 #eif -- #aia -- #db -- #bih -- #ab ,enamelling of iron plates3 ,cases #cg #h #c #e #b #b #c #c ,per cent4 #igdega #giceg #ecadc #gibad #ac ,electric accumulators3 ,cases #bee -- #gj -- #aj -- #cd -- ,per cent4 #ijh -- #bdi -- #cf -- #aba -- #ad ,paint and colour works3 ,cases #cdd #ai #aba #h #cf #b #ha #a ,per cent4 #hfgije #cjecha #ia #ie #bjd #dh #ae ,coach-making3 ,cases #ecg #b #agh -- #aji -- #aeg #a ,per cent4 #gib -- #bfc -- #afa -- #bcb -- #af ,ship-building3 ,cases #bjg -- #gg -- #bg -- #ed -- ,per cent4 #gic -- #bie -- #ajc -- #bjg -- #ag ,paints used in other industries3 ,cases #cbi #cf #ajh #ba #dj #ac #aaj #ab ,per cent4 #habheg #bfgejj #iicaj #bgbbhf #ah ,other industries3 ,cases #dbh #ia #afa #db #eh #ah #aba #ae ,per cent4 #haagih #cjecfhaajaeh #bbiacb ,total cases #d1eab #ggia1dgc #cbe #eci #beea1aij #aec per cent4 #hjjggh #bfacbe #ifbee #baaaec ---------------------------------------- -------------- ---------------------------------------- -------- ---------------------------------------- ------ ,encephalo- ,rheumat- ,no4 ,occupation4 pathic4 ic4 ,other4 ---------------------------------------- ------ 7#a7 7#b7 7#ad7 7#ae7 7#af7 ---------------------------------------- --- ,m4 ,f4 ,m4 ,f4 ,m4 ,f4 #a ,smelting of metals3 ,cases #i -- #ff -- #aa-- ,per cent4 #bb -- #afa -- #bg-- #b ,brass works3 ,cases -- -- #i #a #c-- ,per cent4 -- -- #abi -- #dc-- #c ,sheet lead and lead piping3 ,cases #b -- #aa #a #a #a ,per cent4 #bj -- #ajh -- #aj-- #d ,plumbing and soldering3 ,cases #aj -- #ba #d #h-- ,per cent4 #ed -- #aacacc #dc-- #e ,printing3 ,cases #h -- #ah -- #h-- ,per cent4 #db -- #ie -- #db-- #f ,file-cutting3 ,cases #g -- #af -- #bj #c ,per cent4 #dj -- #ib -- #aaehh #g ,tinning and enamelling of hollow-ware3 ,cases #d #b #h #d #a-- ,per cent4 #dh #ch #ie #ge #ab-- #h ,white lead3 ,cases #ei #f #ih #g #ad #b ,per cent4 #ea #gi #hd #ib #abbf #i ,red lead3 ,cases #i -- #ac -- #c-- ,per cent4 #hc -- #abj -- #bh-- #aj ,china and earthenware3 ,cases #bf #dc #eb #fg #ci #h ,per cent4 #ec #ge #ajfaag #hjad #aj;a,litho- transferers3 ,cases -- #b #e #b -- #a ,per cent4 -- #ga #bej #ga -- #cf #aa ,glass cutting and polishing3 ,cases #b -- #d -- #i-- ,per cent4 #db -- #he -- #aia-- #ab ,enamelling of iron plates3 ,cases -- #a #f #a -- -- ,per cent4 -- #ga #aeh #ga -- -- #ac ,electric accumulators3 ,cases #e -- #ab -- #b-- ,per cent4 #ah -- #dc -- #jg-- #ad ,paint and colour works3 ,cases #h #a #dc #b #g-- ,per cent4 #bj #dh #ajh #ie #ah-- #ae ,coach-making3 ,cases #af -- #gi -- #bc-- ,per cent4 #bd -- #aag -- #cd-- #af ,ship-building3 ,cases #h -- #bc -- #d-- ,per cent4 #ca -- #hh -- #ae-- #ag ,paints used in other industries3 ,cases #aj #a #da #c #h #a ,per cent4 #be #bd #aja #ga #bjbd #ah ,other industries3 ,cases #ag #f #dc #ae #ae-- ,per cent4 #cb #ec #haacb #bh-- ,total cases #bjj #fb #efh #ajg #agf #af per cent4 #ce #fb #ajcajg #caaf ---------------------------------------- --- ,to reduce the size of the table1 columns showing the number in each occupation in which 7a7 the severity of attack1 and 7b7 the number of attack were not stated1 have been omitted4 ,of the former there were #agj1 and of the latter #bde4 ,the total figures1 however1 in ,column #c include them4 ,table ,,iv4 shows the severity of the attacks as stated by the surgeon1 the number of attack1 and the main symptoms4 ,the personal element enters into the character of the reports1 and symptoms which one surgeon might describe as slight another might regard as moderate1 or even severe4 ,in general1 however1 8slight0 includes cases of 7#a7 colic without complication1 and of comparatively short duration2 7#b7 anmia in adolescence aggravated by employment2 and 7#c7 either of the above with tendency to weakness of the extensors4 8,moderate0 includes 7#a7 a combination of colic with anmia2 7#b7 profound anmia2 7#c7 partial paralysis2 and 7#d7 cases in which there is constitutional debility4 8,severe0 includes 7#a7 marked paralysis2 7#b7 encephalopathic conditions--convulsions1 optic neuritis1 and mental affections2 7#c7 grave undermining of the constitution associated with paralysis1 renal disease1 and arterio-sclerosis4 ,the reports are made during the attack1 and information is not received of the sequel which may supervene1 except in the event of a later report as the result of fresh exposure to lead4 ,number of attack has reference to definite occurrence of disability4 ,transient attacks which have preceded the disabling condition have been usually disregarded4 ,it was necessary to limit the number of attacks which might be regarded as indicating chronic plumbism1 and all those included in ,column #aj are either third attacks or cases of chronic lead poisoning4 ,among the main symptoms1 the headings 8,gastric10 8,paretic10 8,encephalopathic10 and 8,rheumatic or ,arthralgic10 represent fairly accurately the relative incidence of these in cases of lead poisoning in this country2 those under the headings 8,anmia0 and 8,headache0 are useful in comparing relative incidence on the two sexes1 but they occur1 probably1 much more frequently than the figures would indicate2 those under 8,tremor0 and 8,other0 are less valuable4 ,under 8,other0 are included 8,gout10 8,nephritis10 or 8,cerebral ,hmorrhage10 so that entry under this head indicates chronic1 rather than mild1 lead poisoning4 ,the conclusions from the table are easy to draw1 as1 in general1 the feature which causes severity of symptoms to be prominent leaves its mark also on 8,number of ,attack0 and 8,main ,symptoms40 ,thus1 in the industries in which severe cases exceed the average 7brass1 plumbing1 printing1 file-cutting1 tinning1 glass-cutting1 ship-building1 paints used in other industries1 and other industries71 the chronic nature of the plumbism is markedly above the average1 and some severe symptom1 usually paralysis1 is also above the average4 ,an exception to this rule is china and earthenware1 where severity is considerably below the average1 but where1 among men1 the figures for chronic lead poisoning and paralysis are distinctly high4 ,it will be seen1 however1 that the proportion of slight cases even in this industry is below the average4 ,on the other hand1 severity is below the average in smelting1 white lead1 red lead1 litho-transfers1 enamelling1 electric accumulators1 paints and colours1 and coach-painting1 and the symptoms in these industries are1 in general1 colic rather than high degree of paralysis2 but in them a severe symptom which is above the average1 in general1 is encephalopathy4 ,the explanation of these differences depends1 we believe1 on two factors3 7#a7 ,duration of employment1 with which1 naturally1 the age of the worker is associated2 7#b7 opportunity of inhaling lead dust4 ,the longer the employment1 the more likely1 naturally1 if absorption goes on1 is the plumbism to become chronic1 and to be associated with paralysis1 its prominent sign4 ,duration of employment among males in file-cutting and china and earthenware1 as contrasted1 for instance1 with that in white lead1 is very much longer1 and the same could be shown of comparatively new industries1 such as electric accumulators and litho-transfers4 ,thus1 in one year the age distribution and duration of employment of those attacked in three of these industries was as follows3 ---------------------------------------- ------------------- ,duration of ,age ,distribution4 ,employment4 ,industry4 ------------------------------------ ,under ,over ,under #cj4 ,over #cj4 #e ,years4 #e ,years4 ---------------------------------------- ----------------- ,per ,cent4,per ,cent4,per ,cent4,per ,cent4 ,china and earthenware #eid #djf #ebb #dgh ,white lead #deg #edc #hfh #acb ,file-cutting #bbi #gga -- #ajjj ---------------------------------------- ----------------- ,persons employed in the manufacture of white and red lead1 electric accumulators1 paints and colours1 and the others named1 are exposed essentially to dust from salts of lead1 which are readily absorbed4 ,poisoning1 therefore1 if precautions are inadequate1 will quickly show itself1 causing certain workers to seek other employment after one attack4 ,poisoning thus produced is more likely to induce colic1 or1 if the dose has been large or the individual markedly susceptible1 encephalopathic symptoms1 than paralysis4 ,on the other hand1 the slowness of the onset of symptoms in the case of brass workers1 plumbers1 printers1 file-cutters1 and tinners1 is more the result of inhalation of fumes or of dust of metallic lead than of salts of lead2 or if the inhalation be of salts of lead1 then of these in less amount and over a long period1 with1 as a result1 gradual undermining of the constitution1 showing itself in paralysis1 arterio-sclerosis1 and renal disease4 ,the two factors indicated obviously account for the differences in severity and number of attack between males and females4 ,if second and third attacks are comparatively fewer in females than in males1 it follows that1 in general1 the attack will be less severe also1 and this is brought out in the figures4 ,cerebral symptoms--encephalopathy1 to which headache may be added--are more than twice as frequent in females as males4 ,this may be due to idiosyncrasy1 but it may very possibly be simply the result of short duration of employment of young workers in processes where dust of salts of lead is incidental4 ,attacks generally are most frequent in the first or second year of employment4 ,thus1 of #b1aie attacks reported in the four years #aijd to #aijg1 as to which sufficient data are given1 #hih occurred in the first two years of employment1 and of these #fgb occurred in the first year--that is1 three-sevenths of all the cases were reported during the first two years1 and four-sevenths in the whole of the remaining years of employment4 ,it is1 unfortunately1 impossible to say what is the proportion of attacks among those employed for any given age period4 ,in some factories--as1 for example1 lead smelting works--the average duration of employment is about thirteen years4 ,the length of employment preceding an attack was made out from reports on cases which occurred in the white lead industry in #ahih--;a time when a number of new workers were taken on to replace the female labour abolished in ,june of that year1 and conditions as regards removal of dust were entirely different from what they are now4 ,the figures1 therefore1 can only be considered to have bearing upon incidence under almost the worst possible circumstances4 ,of #aee attacks1 duration of employment was stated to have been less than #a week in #c1 from #a week to #a month in #h1 from #a to #c months in #fb1 from #c to #f months in #dd1 from #f to #ab months in #ab1 and #a year and over in #bf4 ,attempt has been made to discredit the value of ,section #gc of the ,factory ,act1 #aija1 on the ground that the proportion of cases in which some degree of paralysis is present is very high as compared with the extent found by other observers4 ,the points we have laid stress on--7#a7 duration of employment1 7#b7 varying kinds and amounts of lead dust and fumes--are1 we believe1 quite sufficient to account for1 and give value to1 the figures dealt with4 ,to them should be added another factor1 though one of less account--namely1 the extent to which particular muscles are used4 ,in the case of file-cutters1 for instance1 there is no doubt that the cramped position of the left hand holding the chisel1 and the work thrown on the right in holding the heavy mallet1 determine the direction of the paralysis1 especially on to the muscles of the thenar and hyperthenar eminences and of the fingers4 ,there is1 however1 difficulty in deciding whether such entries on reports as 8weakness of arms and legs10 8weakness of arms10 8muscular weakness10 etc41 should be interpreted as incipient paralysis4,a ,with a disease like lead poisoning showing marked tendency to affect the muscles supplied by the musculo-spiral and other nerves1 the only safe course was to include all these terms as equivalent to partial paralysis4 ,table ,v4 on p4 #ed shows close parallelism for the six years4 ,a ,during the years #aiaj and #aiaa cases were classified so as to distinguish definite paralysis1 as far as possible1 from the more indefinite terms referred to1 with the result tabulated opposite4 ,we have little doubt that in most of the cases included in columns 7#c7 and 7#f7 some slight degree of paresis was present4 ---------------------------------------- -------------------------- #aiaj4 #aiaa4 ---------------------------------------- -- ,weakness ,weakness of ,arms of ,arms ,paral- or ,loss ,paral- or ,loss ,form of ,paralysis4 ysis4of ,power4,total4 ysis4of ,power4,total4 ---------------------------------------- ---------------------- 7#a7 7#b7 7#c7 7#d7 7#e7 7#f7 7#g7 ,arms and complete -- -- -- #b -- #b legs partial #d #f #aj #a #d #e ,legs complete -- -- -- -- -- -- partial #d #d #h -- #f #f ,both complete #ae -- #ae #bg -- #bg forearms partial #ai #cj #di #bj #dd #fd ,right complete #h -- #h #e -- #e forearm partial #f #d #aj #d #g #aa ,left complete #c -- #c #b -- #b forearm partial #b #a #c #a #g #h ,fingers #c -- #c #g -- #g ,neuritis 7including numbness of hands or arms7 #e -- #e #e -- #e ,other 7including paralysis of deltoid1 muscles of speech1 locomotor ataxy1 and general paralysis7 #a -- #a #d #b #f ---------------------------------------- -- #gj #de #aae #gh #gj #adh ---------------------------------------- ---------------------- ,if it is difficult to distinguish rightly all the cases classed as 8paralysis10 it is even more difficult to determine what should be included under the term 8encephalopathy40 ,we have limited it to epileptiform seizures1 optic neuritis 7uncomplicated by epilepsy71 and various forms of insanity4 ,table ,,vi4 on p4 #ed is interesting as showing how fairly constant the numbers are from one year to another4 ,except in the one industry of earthenware and china1 in which a return of the number of persons employed according to process and kind of ware has been made on three separate occasions1 and in which the reports of the certifying surgeons enable the cases of poisoning to be classified in the same way1 it is difficult to determine accurately the attack rate of lead poisoning4 ,even in the earthenware and china trade many things have to be borne in mind4 ,the poisoning which occurs is not distributed evenly over all the factories4 ,thus1 among the #eej potteries1 in the years #aijd to #aijh1 five potteries were responsible for #ge cases1 and #agc for the total number of cases 7#eag71 leaving #cgg factories from which no cases were reported4 ,,table ,v4--,,forms ,,of ,,paralysis3 #aijd-aiji4 ---------------------------------------- --------------------- ,form of ,paralysis4 ,total4#aiji4aijh4aijg4aijf4aije4aijd4 ---------------------------------------- --------------------- 7#a7 7#b7 7#c7 7#d7 7#e7 7#f7 7#g7 7#h7 ,arms and legs complete #ab #b #b #a #b #a #d partial #fb #ac #g #i #ac #i #aa ,legs complete #c -- -- #a -- #a #a partial #be #e #g #a #c #e #d ,both forearms complete #afb #bi #cc #bi #bh #bd #ai partial #ccd #ei #gj #ef #ef #dc #ej ,right forearm complete #ci #aa #f #g #d #h #c partial #fb #i #ag #ad #aa #e #f ,left forearm complete #ad #b #b #d #a #c #b partial #bb #d #a #d #f #d #c ,fingers #cf #c #c #g #aj #f #g ,neuritis 7including numbness of hands or arms7 #cb #g #h #c #c #e #f ,other 7including paralysis of deltoid1 muscles of speech1 locomotor ataxy7 #aj #c #a #c #a -- #b ---------------------------------------- --------------------- #gih #adg #aeg #aci #ach #aad #aah ---------------------------------------- --------------------- ,,table ,,vi4--,,encephalopathy4 ---------------------------------------- -------------- ,symptom4 #aiaa4aiaj4aiji4aijh4aijg4aijf4aije4aijd 4 ---------------------------------------- -------------- ,epilepsy #f #af #ab #ae #ad #aa #ab #ae ,optic neuritis #b #c #c #b #c #g #e #d ,mental defect #e #b #b #a #f #c #a #b ---------------------------------------- -------------- ,total #ac #ba #ag #ah #bc #ba #ah #ba ---------------------------------------- -------------- ,the same state of things is found in all the other industries4 ,particular factories1 owing to special method of manufacture or special manner of working1 may have an incidence out of all proportion to that prevailing in the trade generally4 ,and it is1 of course1 control of these more obvious sources of danger by the efforts of manufacturers and the factory inspectors that has led to the notable reduction recorded--e4g41 in white lead works and the pottery industry4 ,returns of occupiers do not lend themselves readily to exact estimate of the number of persons exposed to risk of lead poisoning1 as they do not differentiate the processes1 and in nearly all factories in which lead is used some of those returned will not come into contact with it4 ,in industries1 however1 in which there is periodic medical examination of persons employed in lead processes an attack rate can be made out4 ,it must be regarded as approximate only1 as in the manufacture of electric accumulators1 for instance1 medical examination is limited to persons employed in pasting1 casting1 lead-burning1 or any work involving contact with dry compounds of lead1 whereas the reported attacks include a few persons engaged in processes other than those named4 ,,table ,,vii4--,,attack ,,rate ,,from ,,lead ,,poisoning ,,in ,,the ,,year #aiaj ,,in ,,certain ,,industries4 ---------------------------------------- ------------------------ ,probable ,number of,number of,attack ,rate ,number of ,persons ,reported per ,industry4 ,examinations4 employed4 ,cases4 ,thousand4 ---------------------------------------- ------------------------ ,white lead #gg1geb #a1die #cd #bb ,red lead #h1jif #fge #aj #ae ,vitreous enamelling #c1jfd #gff #ag #bb ,tinning of metals #a1dge #dib #ag #cd ,electric accumulators #ac1jfe #a1jhi #ca #bh ,paints and colours #ai1jha #a1eij #ag #aa ,earthenware and china #gh1efj #f1edg #gg #ab ---------------------------------------- ------------------------ ,as has been mentioned above1 the accurate information we have of the numbers employed in the several processes in the earthenware and china industry enable us to use the figures for that industry to illustrate1 what is certainly true of all other lead industries also1 the fact of the relative greater degree of risk in one process than another4 ,the fall in the number of fatal cases attributed to lead poisoning1 as is perhaps to be expected1 seeing that the great majority are deaths from chronic lead poisoning1 does not run parallel with the diminution in the number of cases4 ,thus1 in the five years #aije to #aiji the deaths numbered #add1 as compared with #aca in the previous five years1 although the cases fell from #c1gfa to #c1jja4 ,we believe this is due to an increasing inclination to attribute chronic nephritis1 and even 7without sufficient justification in our opinion7 phthisis and pneumonia1 to lead poisoning on the death certificates of lead workers4 ,copies of all death certificates on which lead poisoning is entered as directly or indirectly a cause are received by the ,chief ,inspector of ,factories4 ,all of industrial origin are included in the return4 ,of a total of #bfd which could be followed up1 encephalopathic symptoms appeared on the death certificate in #ch 7#ajf per cent472 ,bright's disease1 cerebral hmorrhage1 paralysis1 or chronic lead poisoning either alone or as a combination of symptoms closely connected1 in #ahh 7#gab per cent472 phthisis in #ac 7#ej per cent472 and other diseases1 such as pneumonia1 etc41 in #be 7#id per cent474 ,table ,,ix4 brings out the relative frequency in the several groups of industries1 and1 as is to be anticipated1 the different average age at death when due to acute and chronic lead poisoning4 ,,table ,,viii4--,,lead ,,poisoning ,,in ,,earthenware ,,and ,,china ,,works 7,,china1 ,,earthenware1 ,,tiles1 ,,majolica1 ,,jet ,,and ,,rockingham1 ,,china ,,furniture ,,and ,,electrical ,,fittings1 ,,sanitary ,,ware74 ---------------------------------------- ------------------------- ,attack-,rate per ,per- ,cases ,reported3 ,thousand sons ,average employed3 ,processes4 em- per ,year4 ,average per ,year4 ployed------------------------------ in #aijg-aijc-ahii-aijg-aijc-ahii- #aijg4aiaj4aijf4aijb4aiaj4aijf4aijb4 ,a ,b ,c ---------------------------------------- --------------------- ,in dipping-house3 ,dippers ,m4 #ghf #ag #ah #bf #bb #bc #cd ,f4 #aej #f #d #g #dj #cj #fh ,dippers' assistants ,m4 #dfc #c #c #g #g #g #ae ,f4 #cig #ac #ah #ag #cc #df #de ,ware-cleaners ,m4 #aae #a #b #c #i #bj #cj ,f4 #dfa #ae #ah #cj #cc #da #fe ---------------------------------------- --------------------- ,total ,m4 #a1cdf #ba #bc #cf #ae #ag #bg ,f4 #a1jjh #cd #dj #ed #cd #db #eh ---------------------------------------- --------------------- ,glost-placers ,m4 #b1bia #af #ab #cc #g #e #ad ,f4 #abj #a #a #a #h #aj #ad ,majolica-painters ,m4 #bh -- -- -- -- -- -- ,f4 #ceh #f #h #aj #ac #ad #bj ,ground-layers ,m4 #eh #a -- #a #ag -- #ag ,f4 #aeg #a #a #d #f #e #ac ,colour and litho ,m4 #ad -- -- -- -- -- -- dusters ,f4 #adc -- #a #d -- #g #cc ,enamel colour and ,m4 #ea -- -- #a -- -- #cf glaze blowers ,f4 #bhh #c #c #b #aj #ad #ab ,colour-makers and ,m4 #cga #e #e #f #ac #ac #ag millers and mixers of ,f4 #ee #a #a #a #ah #dh #aad glaze or colour ,other persons in ,m4 #cbg #b #a #b #f #e #aa contact with lead ,f4 #acb #a #b #d #h #ba #ge ---------------------------------------- --------------------- ,m4 #d1ejd #dd #da #hj #aj #i #ai ,grand total ,f4 #b1cfa #de #eg #hj #ai #be #cg ------------------------------------ 7,m4 and ,f47 #f1hfe #hi #ih #afj #ac #ae #be ---------------------------------------- --------------------- ,a ,calculated on return of employment for #aijg4 ,b ,calculated on return of employment for #aijd4 ,c ,calculated on return of employment for #aijj4 ,the statistical evidence from death certificates published in the decennial supplements of the ,superintendent of ,statistics#b is of significance1 not only in enabling comparison to be made between one industry and another1 in regard to mortality from lead poisoning1 but also in determining the other causes of death most frequently entered on death certificates of lead workers1 and therefore1 if they are in high excess1 as compared with male workers generally1 they are to be ascribed with some degree of certainty to deleterious effects of lead on some of the principal organs4 ,thus1 in ,table ,x4 a list of occupations is given in which the mortality from plumbism in the years #aijj to #aijb was double or more than double the standard4 ,it represents the mortality which would occur if the male population in the particular industry had exactly the same age population as that of 8all males40 ,further1 the annual mortality among 8all males0 is taken as #a1jjj1 and that of males engaged in the several industries is stated as a proportion of this4 ,this 8mortality figure0 of #a1jjj is made up of the mortality from various causes 7of which only those considered to bear upon lead poisoning are given in the table7 in the proportion stated4 ,the contention that1 because lead workers die from certain diseases more frequently than 8all males10 such diseases must be the sequel of lead poisoning is untenable unless other recognized causes of the diseases in question have been excluded4 ,for excess of deaths from phthisis and respiratory diseases the conditions of work and exposure to inhalation of mineral and metallic dust or vitiation of atmosphere1 in pottery1 spelter1 printing works1 and file-cutting workshops1 sufficiently account4 ,the figures1 indeed1 take no account of this1 and their value1 in some at any rate1 is still further diminished by the very large number of occupations 7several involving no contact at all with lead7 included in the headings4 ,with exception of the strikingly greater proportion of deaths among lead-workers from ,bright's disease1 the figures are too contradictory to draw deductions from as to what are 8sequel0 of lead poisoning4 ,but this figure--#afj1 as compared with #ce for all males--is confirmatory evidence1 if any were needed1 that chronic ,bright's disease is a sequela4 ,and1 from the pathology of lead poisoning1 we believe that the granular condition of the kidney is due to the sclerotic change brought about in its substance by microscopic hmorrhages4 ,we have very little evidence indeed in man that this interstitial change is set up or preceded by an acute tubal nephritis4 ,while we do not deny that there may be some parenchymatous change associated with lead poisoning1 we do not believe that it is of the kind which gives rise to the large white kidney1 and we should therefore exclude such disease as a sequela4 ,but if chronic ,bright's disease is admitted1 the train of symptoms associated with it--notably arterio-sclerotic changes resulting in cerebral hmorrhage and albuminuric retinitis--must be admitted also4 ,unless it were established that granular nephritis were present in a lead-worker before commencement of lead employment1 we think it would be useless to endeavour to prove that the condition was independent of lead1 despite its comparative frequency as a cause of death apart from employment4 ,,table ,,ix4--,,main ,,symptoms ,,appearing ,,as ,,the ,,cause ,,in #bfd ,,death ,,certificates ,,of ,,lead ,,poisoning4 ---------------------------------------- ------------------- ,industry4 ,cere- bral ,encepha-,bright's,hmor-,paral- lopathy4,disease4rhage4 ysis4 ---------------------------------------- ------------------- 7#a7 7#b7 7#c7 7#d7 7#e7 ,smelting of metals #a #f -- #c ,brass works -- #c -- #a ,sheet lead and lead piping -- #a -- -- ,plumbing and soldering #b #c -- #a ,printing #c #c -- #b ,file-cutting #a #aa #b #b ,tinning and enamelling -- #a -- -- ,white lead #ac #b #b #d ,china and earthenware #h #bd #ad #c ,glass-cutting #a #f -- -- ,electric accumulators #b #a -- #a ,paints and colours #d #a -- -- ,coach-making #a #h #e #f ,ship-building #a #d #a -- ,paints used in other industries -- #c #a #d ,other industries #a #b #a -- ---------------------------------------- ------------------- ,total #ch #gi #bf #bg ---------------------------------------- ------------------- ,average at death #cb #dc #dg #dc ---------------------------------------- ------------------- ---------------------------------------- ---------------- ,pneu- monia1 ,bron- chitis1 ,heart ,failure1 ,industry4 ,lead ,colic1 ,poi- ,hernia1 son-,phthi- and ing4 sis4 ,aneurism4,total4 ---------------------------------------- ---------------- 7#a7 7#f7 7#g7 7#h7 7#i7 ,smelting of metals #e #a #a #ag ,brass works #a -- #a #f ,sheet lead and lead piping #a -- #a #c ,plumbing and soldering #b #a #b #aa ,printing #e #a #c #ag ,file-cutting #b #a -- #ai ,tinning and enamelling #a -- -- #b ,white lead #b #a #c #bg ,china and earthenware #f #b -- #eg ,glass-cutting #a -- #a #i ,electric accumulators -- -- #b #f ,paints and colours #b #a #c #aa ,coach-making #aj #c #d #cg ,ship-building #a #a -- #h ,paints used in other industries #f #a #b #ag ,other industries #aa -- #b #ag ---------------------------------------- ---------------- ,total #ef #ac #be #bfd ---------------------------------------- ---------------- ,average at death #dd #ch #dj -- ---------------------------------------- ---------------- ,,table ,x4--,,comparative ,,mortality ,,from ,,specified ,,causes ,,among ,,males ,,engaged ,,in ,,certain ,,occupations3 #aijj-aijb4 ---------------------------------------- --------------------------- ,causes of ,death4 ---------------------------------------- - ,dis- ,dis- ,dis- easeseases eases of of of the the the ,cir- ,res- ,ner- cula-pira- vous tory tory ,all ,alco- ,phthi- ,sys- ,sys- ,sys- ,occupation4 ,causes4holism4,gout4 sis4 tem4 tem4 tem4 ---------------------------------------- -------------------- 7#a7 7#b7 7#c7 7#d7 7#e7 7#f7 7#g7 7#h7 ,all males #a1jjj #af #b #ahf #aje #ade #agd ,printer #iid #h #c #cjj #aaa #abe #aca ,file-maker #a1gjj #ad -- #chg #bbe #aih #cbe ,copper-worker #a1jij #g #c #afb #ajd #aci #ceg ,lead-worker #a1djh #ch -- #afe #acd #bbb #cji ,coach-maker #hbd #d #d #abi #aac #abi #aej ,earthenware #a1dic #h -- #bhe #aca #bai #dgc ,glass #a1bfj #g #d #bhc #aca #agg #bfh ,painter and plumber #a1aad #ac #h #bac #acc #aje #afh ---------------------------------------- -------------------- ---------------------------------------- ------------ ----------------------------- ,other ,dis- ,dis- eases eases of of the the ,diges- ,uri- tive nary ,sys- ,bright's ,sys-,plum-,acci- ,occupation4 tem4 ,disease4 tem4bism4dent4 ---------------------------------------- -------- 7#a7 7#i7 7#aj7 7#aa7 7#ab7 7#ac7 ,all males #eg #ce #ag #a #ei ,printer #ee #db #ae #b #ba ,file-maker #gh #acd #bf #ef #df ,copper-worker #de #bd #ba #c #ea ,lead-worker #ad #afj -- #ajb #eb ,coach-maker #df #ci #ad #h #bi ,earthenware #eg #cc #bj #aj #cc ,glass #ed #eh #af #h #ca ,painter and plumber #ca #gd #bj #bc #ej ---------------------------------------- -------- ,other conditions which might readily be admitted as sequel are optic neuritis1 following on an attack of encephalopathy4 ,no general statement can be made in regard to mental and nervous diseases1 gout1 pernicious anmia1 as sequel1 as each must be considered in relation to the evidence adduced in the particular case1 and after exclusion1 in the first two1 of syphilis as a cause4 ,the distinction between causation and association has to be borne in mind before admitting as sequel of lead poisoning diseases of bacterial origin1 such as phthisis or pneumonia1 or any disease to which the affected person may be thought to have been rendered more prone by reason of lead employment4 ,the contention that a person may have been debilitated by lead poisoning is no proof that the enfeeblement of the constitution was the cause either of the bacillus gaining entrance into the lung or of the ultimate fatal issue from the engrafted disease4 ,such assertion in every case must rest on supposition4 ,evidence that lead employment predisposes to phthisis is not necessarily made stronger1 in our opinion1 by existence during life of clinical symptoms1 or1 in their absence1 of detection of lead in the tissues post mortem4 ,in classifying causes of death1 the general rule should be to select1 from the several diseases mentioned in the certificate1 the disease of the longest duration4 ,exceptions to this rule are that definite diseases ordinarily known as constitutional diseases should have preference over the other diseases mentioned4 ,after thirty-five years of age1 certificates of death from lead poisoning are almost always filled in in association with other diseases which are the usual causes which lead to mortality generally4 ,but neither phthisis1 nor pneumonia1 nor any acute disease of the heart or lungs1 nor valvular disease of the heart1 nor1 indeed1 any acute febrile condition1 can have direct relation with--i4e41 be a sequela of--lead poisoning4 ,,references4 #a ,annual ,reports of the ,chief ,inspector of ,factories since #ahih1 especially for #aiji1 p4 #ai4 #b ,supplement to the ,sixty-fifth ,annual ,report of the ,registrar-,general on the ,mortality in ,certain ,occupations in the ,three ,years #aijj1 #aija1 #aijb1 by ,dr4 ,john ,tatham1 pp4 cxix-cxxii1 ,cd4 #bfai4 ,,chapter ,v ,,pathology ,the pathology of lead poisoning has formed the subject of scientific inquiry from the time that the association of certain pathological symptoms was definitely correlated with poisoning by means of the metal or its salts4 ,acute poisoning1 due to accidental swallowing of large doses of lead salts or to use of lead salts criminally1 generally produces a train of symptoms different from those met with in chronic industrial poisoning4 ,but it is difficult to understand why so many writers upon the subject of lead poisoning should have attempted to draw a hard-and-fast line between the pathological symptoms in acute and chronic poisoning4 ,this is especially the case when the after-history of cases of acute poisoning is traced1 for in a large number of instances a case of acute poisoning drifts on into a subacute1 and finally a chronic1 stage4 ,all the symptoms of paralysis1 encephalopathy1 and even kidney degeneration1 have been described in persons who were first of all the subjects of acute poisoning4 ,the direct effect of a lead salt1 such as the acetate1 upon the mucous membrane of the stomach1 is a caustic one1 and the attention of observers seems to have been focussed on what is really a secondary effect of the lead salt1 and not one intrinsically associated with actual poisoning by the metal itself4 ,a good deal of experimental work has also been performed in one way or another--mainly by feeding with1 or inoculation of1 considerable quantities of soluble lead salts--but1 with one or two notable exceptions1 such experiments have not carried the knowledge of the true pathology of lead poisoning very much farther4 ,the statement is not uncommonly made that no definite correlation exists between the symptoms observed in animals and those observed in man1 the reason being that the massive doses given to animals cannot be similar to1 nor can they produce results comparable with1 the slow intoxication taking place in man2 although the after-history of the majority of cases of acute poisoning shows that the symptoms suffered are generally identical with the severer symptoms seen in cases of chronic poisoning of industrial origin4 ,one of the chief reasons explaining this remarkable point of view arises from the fact that the tissues which come into the hands of the pathologist for post-mortem and histological examination are as a rule derived from cases of chronic poisoning1 cases in which the acute symptoms have drifted into the subacute or chronic stage1 when any minute changes existing in the initial stages of the poisoning have long since disappeared1 or their significance has been so far obscured by secondary changes that the primary lesions are lost sight of4 ,a critical examination of the very large amount of literature published on lead poisoning negatives the idea that acute and chronic poisoning differ fundamentally in their pathology1 and observers are found describing identical pathological lesions resulting from acute or chronic industrial poisoning4 ,it is impossible to review the whole of the existing literature4 ,kobert#a1 in summing up the general effect of lead upon the animal body1 makes the following general statement3 8,lead affects especially the striped and unstriped muscles1 the epithelium of the excretory glands1 the neuroglia of the central nervous system1 and is essentially a protoplasmic poison40 ,we base our knowledge on definite experiments1 so arranged that the method of exposure was in every way similar to that in lead industries4 ,the only point of difference that can be urged against them is one of degree2 but as the train of symptoms produced was in every way comparable with those suffered by man1 this objection cannot be sustained4 ,the fact that the symptoms develop in a shorter time than they do in industrial processes is merely a function of the intensity of the poisoning4 ,an attempt will be made first to summarize the literature on the pathology of lead poisoning1 and1 as such literature covers an immense amount of ground1 to group the pathological findings of various observers1 as far as possible1 under four main headings--namely3 ,gastro-intestinal system4 ,nervous system4 ,excretory system4 ,circulatory system4 ,gastro-,intestinal4--,as the chief early symptom of all types of chronic poisoning is abdominal colic1 early investigators turned their attention to the pathology in this region1 and ascribed the colic to various causes4 ,oliver#b noted that1 in animals poisoned with lead1 the intestine was found to be irregularly contracted1 and ascribed the pain in abdominal colic to the irregular contraction of the intestines themselves1 supposing that the effect of lead was on the muscular tissues4 ,he also noted the presence in the intestine1 both large and small1 of staining due to lead1 and the considerable amount of lead to be found in the large intestine4 ,we have only met with staining by lead in the large intestine4 ,dixon ,mann#c pointed out that the fces contain two-thirds of the amount of lead taken by the mouth in experimental cases1 and considered that the lead was re-excreted into the intestine2 and a number of other observers hold this view4 ,recent work confirms the supposition1 and there is no doubt that lead is eliminated in this way4 ,stockvis#d has occasionally seen small ulcers or abrasions in the small intestine2 these he thinks may be due to small hmorrhages4 ,mntrier#e1 quoted by ,meillre1 describes a form of glandular atrophy of the stomach which is met with in chronic lead poisoning4 ,he states that the alcoholic gastritis generally present in persons the subject of saturnine gastritis renders the differentiation exceedingly difficult4 ,this observer is also in complete agreement with many others who associate much of the chronic lead poisoning to association with alcoholic intemperance4 ,the particular type of gastric degeneration ,mntrier regards as due to the effect of lead is 8une sclrose regulire1 inter-tubulaire1 se recontrant d'une manire diffuse et gnrale dans le muqueuse gastrique40 ,he further considers that this gastric sclerosis occurs earlier than the disease of the kidneys4 ,kussmaul and ,meyer#f describe a chronic intestinal catarrh with chronic degenerative changes in the intestinal mucosa very similar to the changes described by ,mntrier4 ,tanquerel#g inclined to the view that the colic was not associated with spasm of the intestines1 and states that no clinical evidence could be found of intestinal spasm by rectal examination during a spasm of colic4 ,but1 as ,bernard#h points out1 intestinal spasm may occur with 8ballonment0 of the rectum4 ,another cause of colic is suggested by ,bokai#i--namely1 hypersensibility of the intestinal nerves--and he cites as evidence the diminution in pain produced by the administration of morphine2 and it is not improbable that some hypersensibility of the nervous system of the intestine goes hand in hand with the vaso-constriction that has been shown to exist1 while1 in addition1 many observers have found degenerative and even subacute inflammatory changes in the sympathetic nervous system of the abdomen1 mainly in the splanchnic area and the solar ganglion4 ,the action of vaso-dilator drugs on the pain of colic demonstrates the close association of vaso-motor changes with the acute paroxysmal pain4 ,riegels#aj investigated the cause of colic in #bjj cases4 ,he found that in every instance there was reason to suppose that toxic vaso-constriction of the vessels in the splanchnic area1 due to irritation in the vaso-constrictor nerves1 was brought about by the action of lead4 ,definite gastritis has also been described in some way simulating that caused by arsenic1 with thickening in the submucosa of the stomach and intestine4 ,associated with this enteritis is endarteritis1 atrophy of the glands1 and ,lieberkhn's follicles4 ,in the colon as well as the ileum was a well-marked enteritis involving the muscular lesions of the gut4 ,various other authors describe degenerative processes with cirrhotic changes in the gastro-intestinal tract4 ,amongst these1 ,galvini#aa describes1 in a case of death from very chronic lead poisoning1 extreme cachexia1 perihepatitis1 perisplenitis1 atrophy of the stomach1 liver1 and spleen1 and chronic sclerosing peritonitis 7saturnine peritonitis74 ,associated with general changes in the abdominal cavity1 marked inflammation and sclerosis was found in the solar plexus4 ,there is said to be a very considerable correspondence between the condition of the peritoneal cavity and its contents in lead poisoning and barium poisoning4 ,in some of the animals referred to in the description of the experiments1 marked inflammatory conditions of the small intestines and colon were found1 and in not a few instances definite ulceration and signs of recent hmorrhages were found scattered along the intestinal tract4 ,no sclerosis was found1 however1 in the peritoneal cavity1 though a common symptom of all the animals1 whether poisoned by inhalation1 inoculation1 or feeding1 was the absence of practically all fat from the peritoneal cavity1 the omentum being represented by an exceedingly thin membrane without any traces of fat whatever4 ,nervous ,system4--,perhaps the oldest classical symptom of lead poisoning is the potter's palsy or wrist-drop due to interference with the nerve-supply of the extensor muscles of the hand1 leading to inability to extend the wrist or the fingers on the arm1 wasting of the affected extensor muscles1 and finally a claw-shaped hand due to contractions produced by the pull of the unopposed flexor groups4 ,the origin of this extensor paralysis has been the subject of much controversy4 ,one party regards the lesion as of central origin1 affecting the upper motor neurons or their connections in the spinal cord2 the other takes the view that paralysis is mainly of a peripheral type4 ,tanquerel#ab1 whose classical work on lead poisoning still contains one of the best descriptions of the disease from the clinical standpoint1 describes an associated affection of the peripheral sensory nerves resulting in definite ansthesia and hypersthesia1 and there is no doubt that sensory nerve affection1 although not very common in lead poisoning1 does occur occasionally1 and is due to peripheral affection of the nerves4 ,occasionally generalized peripheral neuritis is to be met with1 but even this is much less common than in alcoholism or other toxic forms of peripheral neuritis4 ,in the opinion of most of the observers who regard the neuritis as of peripheral origin1 the ultimate interference with the motor nerves is due to an ascending neuritis of the peripheral nerves affecting the spinal ganglia1 and ,pal and ,mannaberg#ac have described polyneuritis2 whilst ,westphal#ad1 ,dejerine#ae1 ,eichhorst#af1 ,ramond#ag1 and others1 support particularly the primary lesion of the peripheral nerves as the cause of the disease4 ,marie and ,babinski#ah in #ahid evolved the central theory1 and supported it by reference to the apparent bilateral occurrence of the paresis and the analogy with many examples of polymyelitis4 ,vulpian and ,steiglitz#ai1 examining cords of animals poisoned by lead1 described vacuolation of the cells in the anterior cornua of the cord4 ,the original suggestion of the spinal origin of the disease was enunciated by ,erb#bj1 who1 without particular reference to either the electrical or histological changes to be found in lead poisoning1 based his theory on the similarity of the lesions to polymyelitis4 ,a few cords of persons who have died of lead poisoning do show slight changes in the anterior cornua4 ,one other theory of the nerve affections in plumbism is that advanced first of all by ,hitzig#ba1 and later by ,boerwinkel#bb and ,eichhorst#bc1 who regard the initial disease as one related to the circulation1 and not necessarily to the nerve lesions themselves4 ,potain#bd1 basing his observations on the anatomical distribution of the blood vessels1 points out that the flexor muscles1 excluding the supinator longus1 are drained by the median cephalic vein1 whilst the extensors are drained by the interosseous--a peculiarity of considerable importance1 as the supinator longus escapes paralysis in the majority of cases of wrist-drop4 ,the presence of paralysis in the muscles and the association of nerve lesions to muscular paralysis led investigators to examine the nervous system1 and probably more attention has been paid to the pathology of poisoning in this direction than in any other4 ,many records of isolated cases are to be found in the literature of the subject1 and the examination of the spinal cord has been carried out in many instances2 several have been cases of generalized paralysis or dementia1 with involvement of the trunk muscles as well as those of the extremities in the paresis4 ,many observers who have made histological examinations in such cases have found nuclear changes in the anterior columns of the cord suggesting polymyelitis4 ,a small number only of the total cases of paresis1 however1 come under this heading4 ,vulpian#be1 ,oppenheimer#bf1 ,oeller#bg1 and others1 described degenerative and proliferative changes in the grey matter of the cord4 ,steiglitz#bh by animal experiments produced inflammatory processes in the anterior grey substance1 vacuolations in the ganglion cells1 and degeneration in the anterior root ganglia4 ,in the paralyzed muscles the changes of degeneration are found3 the muscle nuclei become spindle-shaped1 the interstitial tissue undergoes degeneration1 the muscle becomes atrophied1 takes the stain badly1 shows irregular striation1 and the muscle bundles become ill-defined and fused4 ,scarcely any two observers are agreed as to the exact nerve lesions which are to be found1 and so at variance are the various theories based upon the pathological findings that it is by no means uncommon to find two sets of observers quoting the same electrical reactions and histological appearances as proving in the one case peripheral1 and in the other the central1 origin of the paralysis4 ,on the other hand1 in the quite early observations of ,hitzig#bi particular attention was called to the bloodvessels and their possible association with the disease4 ,moreover1 as has been already cited1 ancient physicians were in the habit of making use of lead as a styptic and hmostatic because of its peculiar action on the blood4 ,probably as a result of improved histological methods of examining the nervous tissue1 renewed attention was given to the nerve fibres and nerve cells1 with the result that1 in the very large number of observations recorded1 many different nerve lesions are described as the sequel of lead intoxication4 ,on the other hand1 ,hitzig's observations on the associated inflammation of the bloodvessels has received confirmation by several independent workers4 ,westphal#cj cites a case of chronic lead poisoning resulting in death from encephalopathy1 and describes degeneration and dema of the brain following a process of chronic inflammation in the smallest and minute bloodvessels1 and also associated with degeneration of the ganglion cells in the vicinity4 ,chvostek#ca also publishes a similar case where cerebral degeneration and some dema had occurred4 ,kolisko#cb1 in examining the brain of a girl who had died of encephalopathy1 found chronic dema of the brain and spinal cord1 the condition closely resembling that described by ,hitzig as chronic cerebral hypertrophy4 ,quensel#cc1 in a man who had died of encephalopathy1 found leptomeningitis1 atrophy of the cortex with degeneration of the parenchymatous elements of the cells and nerve fibres1 degenerative changes in the vessels1 nuclear destruction and pigmentation of the cells1 and dema4 ,nissl#cd described granules1 which bear his name1 present in the ganglion cells in the cortex1 with parenchymatous degeneration4 ,these cases were not associated with paralysis1 nor is encephalopathy by any means always complicated with paralysis of muscles4 ,berchthold#ce describes a case of typical spastic paraplegia due to lead1 and states that the cortical neurons were but little damaged1 the weight of the poison having fallen upon the peripheral segments4 ,sorgo#cf describes a case of progressive spinal muscular atrophy traced to lead1 in which degeneration of the spinal cord was a marked feature4 ,steiglitz#cg1 in describing the inflammatory processes produced in animals poisoned by lead1 makes special mention of a distinct minute inflammatory change in the grey matter of the brain1 with vacuolation occurring in the ganglion cells in the anterior horns of the spinal cord4 ,prvost and ,binet#ch1 on the other hand1 describe an inflammation of the peripheral nerves occurring after administration of lead to rabbits for one month4 ,they produced what they describe as 8a lead polyneuritis10 with primary affection of the motor nerves4 ,with the brain1 as with other parts of the body1 various writers describe widely differing changes4 ,experimentally1 when the doses have been massive and the animals rapidly poisoned1 very little has been found1 and some regard this as evidence against the central origin of lead paresis4 ,on the other hand1 in cases of chronic poisoning 7mainly chronic industrial poisoning71 where an opportunity of post-mortem examination has been afforded1 marked atrophic changes have been discovered both in the brain and spinal cord1 in the motor nerves supplying the affected muscles1 and throughout the nervous system generally1 so much so that anterior polymyelitis of old origin is described1 vacuolation and degeneration of the ganglion cells1 and various other pathological changes associated with nerve degeneration4 ,on reviewing the literature1 it becomes practically certain that in the old and advanced cases of poisoning lesions are invariably found in the central nervous system1 while in the less advanced cases the most marked change has been found in the peripheral nerves4 ,in only a very few instances have any observers noted the fact of hmorrhages occurring in the nervous tissues1 and one of the most important observations on this point is the careful description by ,mott#ci1 of a fatal case of lead poisoning in an asylum1 in which distinct yielding of the vessel walls with minute hmorrhages was present in the cerebral cortex4 ,this case is quoted in full on p4 #ga4 ,in the record of the experiments by one of us 7,k4 ,w4 ,g47 on p4 #ie are described the hmorrhages occurring in the anterior crural nerves of cats poisoned by lead4 ,these animals showed most distinct loss of power in their hind-limbs1 as was evidenced by their inability to jump1 and other symptoms homologous to wrist-drop in man4 ,in these animals no nerve degeneration or alteration in the spinal cord was found sufficiently gross to account for the paralysis1 whereas the amount of pressure produced by the yielding of the vessel walls on the nerve bundles and the associated exudation was evidently sufficient to cause compression1 and thereby loss of function in the nerve in question4 ,now1 the pathological changes described by numerous observers1 such as parenchymatous and interstitial changes in the brain1 destruction of the anterior grey matter1 and1 finally1 the degenerative changes in the muscle groups1 the macroscopical and microscopical atrophy of the muscle bundles with the fibrillation and other changes1 are none of them opposed to the view that hmorrhage and exudation are the earliest and initial change2 in fact1 in experimental animals minute hmorrhages could always be traced in the earliest stages of poisoning1 frequently before definite symptoms appeared4 ,confirmation of this theory is seen in the work of ,glibert#dj1 and the drawings he gives showing fibrous changes in the lungs1 hyperplasia1 congestion1 and emphysema1 cirrhotic conditions of the liver1 and1 as he describes it1 blood-stasis caused by elongation and dilatation of the capillaries1 are all of them highly confirmatory of the hmorrhage theory4 ,further confirmation is also afforded by the observations on the action of lead salts upon the blood itself4 ,from the earliest days lead has been used as a styptic1 and its empirical use has been shown by later observation to be due to its power of readily coagulating albumin and peptone4 ,further1 in chronic lead poisoning there is a marked increase in the coagulation time of the blood4 ,glibert1 in the work already referred to1 points out the increased ductility of the red blood-cells in lead poisoning4 ,quite apart from this1 there is no doubt that definite alterations in the red blood-cells occur2 a species of icterus is common in lead poisoning1 the anmia of lead poisoning is of a destructive type1 increased urobilin may occur in the urine1 and in some instances hmatoporphyrin is present in considerable quantities4 ,the bone-marrow in cases of lead poisoning undergoes distinct inflammatory change1 and may possibly be the cause of some of the curious aching arthralgias often noted as a clinical symptom4 ,all the pathological evidence that can be adduced points unmistakably to the blood as suffering the initial stress in lead poisoning1 and it is therefore by no means surprising that the blood vessels should be the next in order to undergo degenerative changes4 ,it is probably this degenerative change1 particularly associated with the increased coagulability1 alteration in viscosity1 the destruction of the blood-cells themselves1 and the permeation of the vessel walls by definite1 if exceedingly minute1 quantities of lead salts1 that determines the yielding of the smaller and generally the weaker bloodvessels4 ,in the histological examination of the experimental animals there was considerable evidence that the venules1 rather than the arterioles1 are the first to yield4 ,the following case of chronic lead encephalitis1 with the examination of the nervous system described by ,mott#da1 is a case that has a large bearing on the general pathology of lead poisoning1 and has the merit of being so carefully described that we cite it at length1 as bringing out some of the special features connected with the pathology of lead poisoning4 ,the patient was a coach-painter1 aged forty-four4 ,family history of no particular interest4 ,had been a painter since a boy4 ,no specific history4 ,treated for enlargement of liver at one time4 ,married4 ,no children4 ,his wife a widow2 four children before married to him4 ,before the attack of encephalitis1 which ultimately resulted in his death1 he suffered from colic and obstinate constipation4 ,the commencement of the final attack of lead infection was associated with an epileptiform fit1 from which he recovered and resumed his work1 but from this time onwards he suffered from progressive weakness and progressive inability to perform his ordinary work4 ,constant indulgence in alcohol did not pull him together as before2 and although previously he had been able to indulge in large quantities of alcohol1 a very little now affected him adversely4 ,the first epileptiform attack was in ,july1 and in ,november he commenced to have delusions1 was restless1 suspicious4 ,on admission to the asylum he showed marked cachexia4 ,weight1 #h stone #g pounds2 height1 #e feet #i inches4 ,there was present well-marked oral sepsis and blue line4 ,mental ,condition4--,restlessness2 disorientation2 remitting delirious state2 periods of shouting coincident with colic1 worse at night2 auditory hallucinations4 ,physical ,condition4--,bilateral wrist-drop2 extensor paralysis of the fingers2 hand-grip and gait impaired2 reaction of degeneration of paralyzed muscles2 coarse tremors2 fibrillary twitching2 staccato articulation4 ,sensory4--,no definite change4 ,reflexes4--,pupils normal4 ,sluggish reaction to light and accommodation4 ,organic4--,deglutition difficult4 ,micturition and defcation not under control4 ,vaso-motor4--,tche crbrale marked4 ,eye neuro-retinitis4 ,unequal amaurosis4 ,heart4--,increased action1 variable2 alteration during exacerbations of colic4 ,second sound in aortic area accentuated4 ,high pressure1 variable4 ,majority of arteries thickened4 ,he suffered gradual mental change2 the whole of the mental symptoms increased in severity until the patient looked like the final stages of a case of general paralysis4 ,he died on ,december #a4 ,colic was present at intervals during the whole time4 ,post-mortem made the next day4 ,septic bronchitis4 ,hmorrhage at the base of epiglottis and left vocal cord4 ,lungs4--,septic broncho-pneumonia4 ,pericardium4--,small amount of fluid4 ,heart4--,striated1 bluish4 ,weight #aa ounces4 ,ventricles4--,slight hypertrophy of left ventricle4 ,valves4--,competent4 ,aorta4--,atheroma near its bifurcation4 ,arteries4--,all more or less thickened4 ,peritoneum4--,retroperitoneal hmorrhage in region outside pancreas4 ,mesenteric glands enlarged1 indurated1 bluish on section4 ,stomach4--,normal4 ,intestines4--,vessels congested4 ,large bowel constricted at irregular intervals4 ,ccum4--,mucosa slate-coloured4 ,colon4--,dark-greenish mass4 ,liver4--,blue on section2 pale yellow areas2 soft in consistency4 ,weight1 #dg ounces4 ,spleen4--,normal4 ,kidneys4--,no fat4 ,cirrhotic1 adherent1 atrophic cortex1 granular4 ,muscles4--,generally dark in colour2 wasted4 ,a very complete histological examination was made of the brain and spinal cord1 and throughout the particular changes noticed were proliferation of the glia1 hyaline thickening of the walls of the vessels1 both arteries and veins1 and presence of congestion2 and here and there rupture of the smallest vessels1 causing miliary microscopic hmorrhages into the perivascular sheaths and the substance of the brain4 ,there was no infiltration with lymphocytes and plasma cells1 as is found in general paralysis4 ,the neuroglia showed a formative hyperplasia resulting from chronic irritation4 ,in the cortex there was neuroglia proliferation in the polymorpho layer and the molecular layer4 ,changes were seen in the ,betz cells1 particularly in the ,nissl substance1 with perinuclear chromatolysis1 such as is generally found in chronic peripheral neuritis1 whether due to lead1 alcohol1 or other toxic causes4 ,there was no coarse atrophy or degeneration of the fibres of the cortex4 ,neither the cerebellum nor the spinal cord at any of the levels examined showed fibre atrophy or degeneration1 except possibly a slight diffuse sclerosis in the crossed pyramidal tracts of the lumbar region4 ,microscopical examination was made of the heart1 spleen1 kidney1 liver1 lung1 and suprarenal gland4 ,there was a general condition of angiosclerosis2 in the liver a fibrotic overgrowth around the vessels2 in the kidneys well-marked interstitial fibrosis4 ,a chemical examination of the brain was also conducted by the copper potassium nitrite method1 but no lead was found4 ,excretory ,system4--,a large number of observers have shown that great stress is thrown on the kidney in the excretion of lead4 ,discussion has taken place as to whether the effect is a primary interstitial or a parenchymatous nephritis4 ,most observers are agreed that the histological changes found in the kidneys of lead workers have very little by which they may be differentiated from the effects of alcohol4 ,although the kidney suffers directly from the effect of circulating lead1 the amount of lead excreted by the kidney in chronic cases is usually small1 variable in quantity1 and very rarely exceeds more than #e milligrammes in the twenty-four hours4 ,the chemical estimations of the quantity of lead found in the kidney of persons who have died of lead poisoning given by different observers1 vary exceedingly4 ,even in cases of definite lead poisoning1 where there can be no reasonable doubt as to the diagnosis1 many cases are on record where no lead at all has been discovered in the kidney4 ,it is not acute nephritis which is seen in lead poisoning1 but the chronic cirrhotic variety4 ,this probably takes a very long time to develop2 indeed1 animals kept under the influence of lead for two years show very little kidney destruction4 ,it is quite possible that in the kidney disease met with in lead-workers the combined effect of alcohol with lead is really the causative factor4 ,there is not sufficient statistical evidence to make a definite statement on this point1 and it would only be possible by comparing the records of the autopsies of a number of persons working in lead who do not die from lead poisoning1 and who were non-alcoholic1 with a similar number of persons who1 in addition to their lead absorption1 were alcoholic subjects4 ,it is unusual to find blood in the urine1 and the condition of the kidney does not suggest that it would be present4 ,gull and ,sutton#db have described arterio-capillary fibrosis in which the intima of the larger vessels became greatly hypertrophied1 and many of the smaller vessels are practically destroyed by obliterative arteritis4 ,the production of arterio-sclerosis1 with attendant thickening of the vessel walls and with the various symptoms commonly associated with arterio-sclerosis1 were regarded as secondary symptoms of lead poisoning4 ,the action of lead on the vessel walls themselves thus independently proved by a large number of observers working at different aspects of the problem suggests the pathological change in the vessels as the common element in the cause of these diverse symptoms of lead poisoning--colic1 paralysis1 mania4 ,generally speaking1 however1 the attention of most has been rather focussed on the kidney and the degenerative changes occurring in that organ due to the irritative action of lead in the process of excretion than on the vessels themselves4 ,lead in the urine is by no means so common nor so definite a symptom of lead poisoning as might be supposed1 considering the extreme manner in which the kidneys suffer in old-standing cases4 ,of particular importance in this respect is the case referred to by ,zinn#dc1 where a woman aged thirty-three received #bj grammes of lead acetate in error4 ,after the first acute symptoms had passed off1 the case drifted on to one of chronic poisoning1 with the usual symptoms of colic1 anmia1 and cachexia4 ,during the whole period of the disease1 both acute and chronic stages1 examinations of the urine for lead were made1 using the method of ,fresenius ,babo#dd2 yet lead was only detected in the urine during the early stages1 and directly the acute symptoms had passed off no further lead could be detected4 ,this point is of some importance1 particularly when taken together with the experiments quoted by ,blum#de1 who1 injecting animals with lead iodide1 was unable to recover lead from the urine4 ,the iodide only passed through the kidney1 the lead being retained in the body4 ,jaksch#df states very definitely that lead is not found in the urine in chronic cases1 but only in the acute cases1 and then quite early4 ,with regard to the kidney two views are held--the one regarding the disease of the kidney as primarily affecting the bloodvessels1 and the other as an initial parenchymatous change causing secondary obstruction and alteration in the vessels themselves4 ,there is therefore much evidence to show that1 whether the bloodvessels be primarily or secondarily affected1 almost all observers are in accord in the opinion that at one time or another1 either sooner or later1 the bloodvessels become affected through the action of lead4 ,kobert#dg points out that in no case was distinct cirrhosis of the kidney produced in experimental lead poisoning in animals2 inflammation certainly was to be seen1 either interstitial or parenchymatous1 but apparently the poisoning had not progressed a sufficient length of time for definite cirrhosis to be produced4 ,on the other hand1 kidney changes have been found of various types1 all of which may be the precursors of the ultimate cirrhotic and fibroid change occurring in the kidneys seen in chronic poisoning by lead as well as in chronic alcoholism4 ,particular stress must be laid on the fact that cirrhotic kidneys are so frequently the direct result of long-continued alcoholic excess1 and1 from what has been demonstrated in the experimental researches on predisposition to lead caused by alcohol1 the condition of cirrhosis of the kidney in a lead-worker is by no means indicative of lead poisoning1 as it may be an old alcoholic effect long antedating that due to lead4 ,oliver#dh1 ,charcot#di1 ,gombault#ej1 ,hoffer#ea1 and others1 found a certain amount of parenchymatous degeneration4 ,von ,leyden#eb1 however1 was able to produce a granular condition of the kidney with glomeruli shrunken and an arterio-capillary fibrosis4 ,gayler#ec1 on the other hand1 thinks that the arteritis of the smallest arteries is the preliminary effect upon the kidney1 whereas more recently ,glibert#ed published plates of the kidney showing definite sclerosis as well as interstitial nephritis4 ,cornil#ee and ,brault#ef think the vessels are affected only secondarily1 and that parenchymatous changes are the primary lesion4 ,hoffer#eg1 by feeding guinea-pigs with lead1 produced very definite obliterative arteritis4 ,klemperer#eh claims to have produced inflammation and definite necrosis of portions of the kidney substance4 ,the whole of the kidney is not necessarily affected4 ,only portions of it may show changes1 while ,kleinenberger#ei notes that in chronic lead poisoning1 at the time of acute exacerbation of the disease1 granular casts as well as red blood-cells are found2 and1 further1 that in cutting through them crystallized masses are occasionally found1 consisting of urates1 and sometimes containing lead4 ,gayler#fj considers that the effect on the kidney commences in the muscular coats of the smaller vessels1 in which endarteritis followed by obliterative arteritis is set up4 ,practically all observers1 therefore1 are in agreement that the kidney suffers to a very considerable extent in chronic poisoning1 and the majority of observers are also in agreement that the bloodvessels themselves are the primary seat of the change4 ,further1 the presence of blood in the urine is exceedingly rare in chronic lead poisoning1 despite ,kleinenberger's#fa statement to the contrary4 ,it certainly may occur during a very acute attack1 but we have never seen this symptom4 ,circulatory ,system4--,arterio-sclerosis occurring in lead-workers has been known for some time1 and the anmia of saturnism has been known for an even longer period4 ,for some time no definite type of anmia was associated with lead cachexia1 and the anmia was generally regarded as one arising from general malnutrition4 ,here and there through the literature of the pathology of lead poisoning are to be found remarks which suggest that the action upon the bloodvessels may be a primary instead of a secondary effect4 ,obliterative arteritis is described by ,uhthoff#fb1 ,pflueger#fc1 ,oeller#fd1 and ,pal#fe1 and in other cases obliterative retinitis has been considered to be associated with the action of the lead upon the vessel walls4 ,heubel#ff1 and later ,rosenstein#fg1 found that1 in dogs poisoned with lead1 definite cerebral anmia was produced1 due to vaso-constriction1 and consider it to be due to the direct action of lead upon the intima of the vessel walls4 ,associated with such poisoning were symptoms of eclampsia and urmia1 and the latter author considers that the urmia is due to vaso-constriction of the kidney vessels4 ,oliver#fh and others have also pointed out the alteration in the pulse-rate associated with exacerbations of colic1 and a number of observers have noted that certain drugs1 such as atropin and amyl nitrite1 which are known vaso-dilators1 have a distinctly calming effect upon the paroxysms of pain4 ,one or two other observers have actually noted the presence of hmorrhages in the lesions2 thus1 in the case quoted by ,mott#fi definite yielding of the vessel walls and signs of old hmorrhage are described amongst other lesions in the brain4 ,seifert#gj also describes the presence of hmorrhages amongst the ganglion cells in the anterior columns of the cord1 both in the case of persons who have died of lead poisoning and animals to which lead had been given experimentally4 ,in addition1 ,sajous#ga describes a case of paralysis of the superior laryngeal nerve1 associated with hmorrhages1 in the region of the abductor muscles of the larynx4 ,mott's case also showed this laryngeal hmorrhage4 ,more recently ,elschnig#gb1 in his observations upon the eye1 has determined a close association between vaso-motor affections1 constrictions1 and dilatations1 and various eye lesions1 such as amaurosis and amblyopia1 occurring in lead poisoning4 ,rambousek#gc1 in summing up ,elschnig's work1 points out how much his observations tend to bridge over the gap between the action of lead upon the blood1 the bloodvessels1 and the nerves4 ,he points out that the eye is a peculiarly favourable organ for watching the effect of a poison so insidious as lead4 ,the bloodvessels1 the nerves1 and the muscles1 are all open to inspection and actual observation to a degree not to be found in any other part of the body4 ,elschnig#gd1 in a typical case of sudden lead amaurosis associated with acute lead colic1 found that very definite motor spasm of the vessels of the eye1 conjunctiva1 and the retina1 were associated with the amaurosis4 ,he argues from this that the action of lead is probably directly upon the unstriped muscular fibre of the vessel walls2 that such an action may1 and does1 extend to the vessels of the eye muscles1 producing paralysis of the muscles of accommodation1 and a dilatation of the pupil1 which may be observed in a large number of persons employed in conditions subjecting them to lead absorption4 ,elschnig further considers that the transitory amaurosis which is often associated with lead poisoning may be due to vaso-motor disturbances in the brain itself1 as well as in the eye4 ,still more recently1 and due1 no doubt1 to a great extent to the work of ,elschnig1 further attention has been drawn to the vascular system in lead poisoning4 ,elschnig's work has carried the question another stage forward by showing the association of vaso-motor disturbances with eye disease1 whilst in this country ,oliver#ge pointed out the effect upon the pulse of abdominal colic4 ,at the beginning of the researches on this point described in the next chapter1 this clue running through the whole of the pathology of lead poisoning was not appreciated4 ,at the commencement of the investigations there seemed to be no main general line of symptoms or histological findings that could be adduced as characteristic of lead poisoning2 in fact1 the initial experiments were performed1 with the object of examining the association of lung-absorbed lead compounds as a possible cause of lead poisoning1 as against the entrance of lead by the alimentary canal2 but as the experiments proceeded it became clear that the stress of the initial intoxication was undoubtedly falling upon the bloodvessels1 and more particularly upon the minuter bloodvessels1 and less on the arterial side of the capillaries 7although the capillaries were to a large extent associated with the process7 than upon the venous radicles4 ,a general consideration of the pathology shows that lead causes changes in the nervous system affecting both upper and lower segments1 degeneration of the ganglion cells in the cord and in the brain1 interstitial inflammation of the neuroglia1 cortical degeneration1 distinct neuritis1 both axial and peri-axial1 of the peripheral nerves1 and also signs of change in the sympathetic nervous system in chronic lead poisoning4 ,later work has1 however1 all tended to point out that the chief and first effect of lead is upon the blood4 ,moritz#gf first pointed out the presence of basophile granules in the red blood-cells4 ,the work was followed up by ,emden#gg1 ,gravitz#gh1 ,zinn#gi1 ,otto#hj1 ,silbert#ha1 and by ,escherich#hb4 ,all these authors found basophilic erythrocytes in the blood associated with blood-destruction1 and ,escherich in addition describes early changes taking place in the intima of the bloodvessels associated with vaso-constriction4 ,the ,italian author ,mattirolo#hc1 as well as ,marchet#hd and ,jores#he1 came to a similar conclusion4 ,glibert of ,brussels#hf1 carrying the observations somewhat farther1 and although working with guinea-pigs1 which normally show basophilic staining in their blood-cells1 was able to demonstrate one further point of considerable value--namely1 the increase in the viscosity of the blood1 with blood-corpuscles of greater toughness1 elasticity1 and power to resist destruction when making films1 than in normal blood4 ,there is thus very striking continuity in the observations of all the various observers1 despite the fact that at first sight their descriptions may appear discordant4 ,there seems no doubt that practically all authors who have given attention to the subject are agreed that the circulatory system1 and primarily the blood circulating in the vessels1 is affected by lead1 and1 further1 that the vessels themselves undergo degeneration of various types1 many of the cases examined showing complete obliterative arteritis as the result of long-standing irritation4 ,others describe no obliterative changes of this type in the vessels1 because attention was given mainly to the nervous system1 where the cells were found degenerated and showing chromatolysis4 ,but1 on the other hand1 careful observers1 such as ,mott1 have noted the presence1 in passing1 of these apparent yieldings of the vessels here and there in the region of the degenerated nervous tissue4 ,again1 even the histological action of a drug such as amyl nitrite points to involvement of the vaso-motor system4 ,perhaps this curious association through all the described pathology and bloodvessel infection would not appear so clear but for the more recent investigations described in the following chapter4 ,,references4 #a ,,kobert3 ,lehrbuch der ,intoxikationen1 #bte ,aufl41 #aijf1 p4 #cfa4 #b ,,oliver1 ,,sir ,t43 ,lead ,poisoning4 #ahia4 #c ,,dixon ,,mann3 ,forensic ,medicine and ,toxicology1 p4 #die4 #d ,,stockvis3 ,international ,congress of ,industrial ,hygiene4 ,brussels1 #aiaj4 #e ,m,n,,trier3 ,meillre's ,le ,saturnisme1 pp4 #aca-acf4 #f ,,kussmaul ,,and ,,meyer3 ,deutsches ,archiv fr ,klin4 ,med41 ix41 p4 #bhc4 #g ,,tanquerel3 ,trait des ,maladies de ,plomb1 ou ,saturnines4 ,paris1 #ahci4 #h ,,bernard3 ,meillre's ,le ,saturnisme1 p4 #aee4 #i ,,bokai3 ,trib4 ,med41 ,june #aa1 #ahia4 #aj ,,riegels3 ,kobert's ,lehrbuch der ,intoxikationen1 p4 #cfc4 #aa ,,galvini3 ,rivista ,clinica1 fasc4 iii41 #ahhd4 #ab ,,tanquerel3 ,ibid4 #ac ,,pal ,,and ,,mannaberg3 ,revue ,gnrale de ,villaret1 ,gaz4 des ,hp41 ,fv4 #af and #ai1 #aijc4 #ad ,,westphal3 ,archiv f4 ,phys4 u4 ,nervenkr41 #ahgd4 #ae ,,dejerine3 ,mm4 de la ,soc4 de ,biologie1 #ahgi1 et ,expos de ,titres1 p4 #eh1 #ahid4 #af ,,eichhorst3 ,ueber ,bleilhmung4 ,virchow's ,archiv1 #ahij1 p4 #bag4 #ag ,,ramond3 ,maladies du ,systme ,nerveux1 t4 xi4 #ahie1 #ahif4 #ah ,,marie ,,and ,,babinski3 ,meillre's ,le ,saturnisme1 p4 #aic4 #ai ,,vulpian ,,and ,,steiglitz3 ,archiv fr ,psych41 #ahib1 xxiv41 p4 #a4 #bj ,,erb3 ,berl4 ,klin4 ,woch41 #ahhd1 p4 #aaj4 #ba ,,hitzig3 ,studien ber ,bleiverg4 ,berlin1 #ahfh4 #bb ,,boerwinkel3 ,virchow's ,archiv1 ,bd4 cxx41 #ahij4 #bc ,,eichhorst3 ,ibid4 #bd ,,potain3 ,bull4 ,med41 #ahhg4 #be ,,vulpian3 ,maladies du ,systme ,nerveux4 #ahgi4 #bf ,,oppenheimer3 ,zur ,kennt4 der ,exp4 ,bleiverg4 ,berlin1 #ahih4 #bg ,,oeller3 ,path4 ,anatom4 der ,bleilhmung4 ,mnchen1 #ahhc4 #bh ,,steiglitz3 ,archiv fr ,psychiatrie1 ,bd4 xxiv41 #ahib4 #bi ,,hitzig3 ,ibid4 #cj ,,westphal3 ,archiv fr ,psychiatrie1 ,bd4 xix41 #ahhh4 #ca ,,chvostek3 ,neurol4 ,centralblatt1 #ahig4 #cb ,,kolisko3 ,die ,bekmpfung der ,bleigefahr in der ,industrie1 von ,leymann1 p4 #ba4 #aijh4 #cc ,,quensel3 ,archiv fr ,psychiatrie1 ,bd4 xxxv41 #aijb4 #cd ,,nissl3 ,allgemeine ,zeitschrift fr ,psychiatrie1 ,bd4 xlv41 #ahib2 ,bd4 iv4 #ahig4 #ce ,,berchthold3 ,die ,bekmpfung der ,bleigefahr in der ,industrie1 von ,leymann1 p4 #bc4 #aijh4 #cf ,,sorgo3 ,wien4 ,med4 ,woch41 #aijj4 #cg ,,steiglitz3 ,archiv fr ,psychiatrie1 ,bd4 xxiv41 #ahib4 #ch ,,pr,,vost ,,and ,,binet3 ,revue ,mdicale de la ,suisse ,romande1 ii41 #ahhi4 #ci ,,mott3 ,archives of ,neurology and ,psychiatry1 vol4 iv41 p4 #aag4 #dj ,,glibert3 ,le ,saturnisme ,exprimental3 ,extrait des ,rapports ,ann4 de l',insp4 du ,travail1 #aijf4 #da ,,mott3 ,ibid4 #db ,,gull ,,and ,,sutton3 ,kobert's ,lehrbuch der ,intoxikationen1 #bte ,aufl41 #aijf1 p4 #cgj4 #dc ,,zinn3 ,berl4 ,med4 ,woch41 #ahii4 #dd ,,fresenius ,,babo3 ,liebig's ,annalen1 vol4 xlix41 p4 #bhg4 #ahdd4 #de ,,blum3 ,wien4 ,med4 ,woch41 ,no4 #ac1 #aijd4 #df ,,jaksch3 ,klinische ,diagnostik4 #dg ,,kobert3 ,ibid41 p4 #cfi1 and general ,literature1 p4 #cgf4 #dh ,,oliver1 ,,sir ,t43 ,lead ,poisoning4 #ahia4 #di ,,charcot3 ,leons sur les ,maladies du ,foie et des ,reins4 ,paris1 #ahhb4 #ej ,,gombault3 ,archiv fr ,physiologie1 #ahha4 #ea ,,hoffer3 ,dissertation1 ,freiburg1 #ahhc4 #eb ,,von ,,leyden3 ,zeit4 fr ,klin4 ,med41 #ahhc4 #ec ,,gayler3 ,ziegler's ,beitr41 ii41 #ahhh4 #ed ,,glibert3 ,ibid4 #ee ,,cornil3 ,journal de l'anat4 et physiol41 ,no4 #b1 #ahhc4 #ef ,,brault3 ,loc4 cit4 #eg ,,hoffer3 ,loc4 cit4 #eh ,,klemperer3 ,kobert's ,lehrbuch der ,intoxikationen1 #bte ,aufl41 #aijf1 p4 #cgj4 #ei ,,kleinenberger3 ,mnch4 ,med4 ,woch41 ,no4 #h1 #aijd4 #fj ,,gayler3 ,loc4 cit4 #fa ,,kleinenberger3 ,loc4 cit4 #fb ,,uhthoff3 ,handbuch der ,aug4 ,lief4 ,leipzig1 #aija4 #fc ,,pflueger3 ,die ,bekmpfung der ,bleigefahr in der ,industrie1 von ,leymann1 p4 #ba4 #aijh4 #fd ,,oeller3 ,ibid4 #fe ,,pal3 ,zentralbl4 f4 innere ,med4 ,leipzig1 #aijc4 #ff ,,heubel3 ,path4 und ,symp4 ,chron4 ,bleiverg4 ,berlin1 #ahga4 #fg ,,rosenstein3 ,virchow's ,archiv4 #ahig4 #fh ,,oliver1 ,,sir ,t43 ,lead ,poisoning4 #ahia4 #fi ,,mott3 ,ibid4 #gj ,,seifert3 ,berl4 ,klin4 ,woch41 #ahhd4 #ga ,,sajous3 ,archiv fr ,laryng41 iii41 #ahhb4 #gb ,,elschnig3 ,wien4 ,med4 ,woch41 #ahih4 #gc ,,rambousek3 ,die ,bekmpfung der ,bleigefahr1 von ,leymann1 p4 #ae4 #aijh4 #gd ,,elschnig3 ,loc4 cit4 #ge ,,oliver1 ,,sir ,t43 ,lead ,poisoning4 #ahia4 #gf ,,moritz3 ,st4 ,petersb4 ,med4 ,woch41 #aija4 #gg ,,emden3 ,die ,bekmpfung der ,bleigefahr1 von ,leymann1 p4 #ai4 #gh ,,gravitz3 ,deutsche ,med4 ,woch41 ,no4 #cf4 #ahii4 #gi ,,zinn3 ,berl4 ,klin4 ,woch41 #ahii4 #hj ,,otto3 ,revue ,md41 #ahib4 #ha ,,silbert3 ,ibid4 #hb ,,escherich3 ,die ,bekmpfung der ,bleigefahr1 von ,leymann1 p4 #ah4 #hc ,,mattirolo3 ,ibid41 p4 #ai4 #hd ,,marchet3 ,ibid41 p4 #ai4 #he ,,jores3 ,ziegler's ,beitr41 ,bd4 xxxi41 #aijb4 #hf ,,glibert3 ,ibid4 ,,chapter ,,vi ,,pathology--,continued,a ,a ,this chapter is the work entirely of one of us 7,k4 ,w4 ,g47 ,it was thought that some light might be thrown on chronic intoxication produced by lead salts if direct experiment were made upon animals1 resembling in the arrangement of such experiments1 as far as possible1 the industrial conditions under which human beings contract lead poisoning4 ,the animals chosen for the experiments were cats1 as it is a fact of common knowledge that it is impossible to keep cats in lead works1 particularly white-lead1 because they rapidly become poisoned if allowed to stray about the works4 ,the same holds good in the case of dogs4 ,from the statistics already given in ,chapter ,,iv41 and from the remarks in the chapter on tiology1 there was no doubt whatever that dust played a most important rle in the production of industrial lead poisoning4 ,in attempting1 therefore1 to copy the industrial conditions1 it is essential to submit the animals experimented upon to infection by means of air in which lead dust is suspended4 ,a large number of experiments have been carried out in the first place1 by myself#a1 and later in conjunction with ,dr4 ,goodbody#b1 and another series of experiments were also undertaken by myself#c4 ,further experiments are still in progress in this and other directions4 ,the methods of experiment adopted were as follows3 #a4 ,breathing ,experiments--,first ,series4--,a4 ,the animals experimented upon were placed in a large closed chamber at one end of which an electric fan was fitted in such a way that the air was kept in constant motion4 ,the lead dust was introduced by means of a funnel through the roof in a definite quantity during timed intervals4 ,by means of an aspirating jar and a tube inserted into the side1 samples of air were withdrawn from time to time during the experiments1 and submitted to chemical analysis to determine the quantity of lead circulating in the air4 ,these samples were drawn off at the level of the animals' heads4 ,great care was taken to eliminate any swallowing of dust by the animals during the experiments1 by protecting their coats from the dust and carefully brushing them at the conclusion of each exposure4 ,second ,series4--,b4 ,in other experiments a chamber containing two separate compartments was constructed1 and lead dust suspended in air was blown into the two compartments by means of an electric fan situated outside4 ,the apparatus was so arranged that the draught of air from the fan passed through two separate boxes1 in which the lead compound under experiment was kept agitated by means of small fans situated in the boxes and driven by a second electric motor4 ,in this way two different samples of lead were experimented on at one and the same time1 the air current driving in the dust through the two boxes being equal on the two sides2 the quantity of dust was therefore directly proportional to the compound used4 ,samples of the dusty air were aspirated off and subjected to analysis1 as in the first series4 ,in this series of experiments the animals were so arranged that only their heads projected into the dust chamber during exposure4 #b4 ,feeding ,experiments4--,feeding experiments were carried out by mixing a weighed dose of the lead compound experimented with1 and adding this to a small portion of the animal's first feed in the morning4 ,it was found that unless the lead was well incorporated with the animal's food it would not take the lead in the dry form2 and in dealing with white lead and other dust1 it was necessary to give the compound in a similar form to that in which a man would obtain it under industrial conditions1 which of course precluded the use of a solution4 ,the amount of lead given by the mouth as a control to the inhalation experiments was from seven to ten times the dose which could be taken by the animal during its exposure in the cage1 and the dose was given daily1 and not every third day as in the inhalation experiments4 ,all the compounds used in the inhalation experiments were given to animals by the mouth1 the animals' weights being carefully noted4 ,in a further series of feeding experiments a soluble salt of lead was added to the animals' food 7water or milk71 the salt in this case being the nitrate4 ,the quantity added was much smaller than in the dust experiments4 #ja gramme was given daily4 #c4 ,inoculation ,experiments4--,as a further control to both the breathing and feeding experiments1 the various lead compounds similar to those used in the other experiments were inoculated into animals4 ,the insoluble salts gave some difficulty in the technique of injection1 but by using a large needle1 and making the suspension of the material in the syringe1 the difficulty was overcome4 ,the quantity of material inoculated varied2 it was calculated in fractions of a gramme per kilogramme body weight1 the quantity of fluid used being the same in all cases--namely1 #aj c4c4--and inoculations were made subcutaneously and intramuscularly in the muscles of the back after previous shaving4 ,in only one case was localized inflammation produced1 and this was when the acetate was the salt employed4 ,none of the animals exhibited any signs of discomfort during the experiments from the presence of lead dust in the air2 once or twice sneezing was noticed1 but this was an uncommon occurrence4 ,this point is of practical importance1 as the lead dust contained in the air in white-lead and other factories is not of itself irritating to the mucous membrane of the lung4 ,the animals subjected to this form of experiment were no doubt absorbing much larger doses of lead than are persons engaged in the manufacture of lead compounds4 ,the only ascertainable difference in the ultimate pathological lesions produced in animals1 whether inhaling large quantities or minimal quantities of dust1 was the rate at which the poisoning took place4 ,in certain experiments it was found that the animals maintained a kind of equilibrium1 much as do workmen engaged in dusty lead processes4 ,it was found1 moreover1 that some animals showed a certain amount of tolerance to the effect of lead dust1 in that their weights remained almost constant1 but an increase in the quantity of lead present in the air immediately produced progressive diminution in the body weight2 and as this diminution in the body weight approached to one-third of the animal's initial weight1 so symptoms of chronic poisoning supervened4 ,in addition to the animals inhaling lead dust over prolonged periods1 certain other inhalation experiments were made for the determination of lead dust in the lung as opposed to the stomach4 ,in the inhalation experiments proper1 where the animals were exposed to inhalation every other day or every third day1 for only an hour at a time1 the quantity of lead present in the air was not very large1 and it was thought essential to determine if1 in exceedingly dusty atmospheres1 any appreciable amount of lead could be found in the stomach4 ,ten animals were submitted to the inhalation of air heavily charged with various types of lead dust4 ,the animal was exposed to the dust for an hour and a half to two hours2 at the end of this time it was ansthetized1 and when the respirations had ceased1 and the animal was dead1 sulphuretted hydrogen was blown into the lung and into the stomach4 ,the animal was then rapidly dissected and staining looked for4 ,the tissues were further treated with acid and re-exposed to sulphuretted hydrogen gas4 ,in one animal only out of the ten was any staining noticed in the stomach4 ,in none of the others was any such staining found1 but very definite blackening was found in the larynx1 trachea1 and macroscopically even in some of the bronchioles4 ,sections of the lung were further submitted to histological examination1 and by means of micro-chemical tests with chromic acid and with iodine1 and also by comparing sections of the experimental animals and animals which had not been subjected to lead dust inhalations1 a very much larger quantity of material was found present in the lungs of the inhalation animals than in the normal animal4 ,the dust was situated in the alveoli and the alveolar cells1 and often in the lymphatics4 ,on examining microscopically sections of the lungs of those animals exposed to graduated inhalation over extensive periods1 a far larger number of blackened granules1 dust1 pigment1 and other substances1 was found than in similar sections of animals which were under normal conditions and had not been exposed to lead dust1 although it is true such animals show a very fair proportion of carbon particles taken up by the lung tissue4 ,a further important fact was noticeable in animals ,nos4 #ba and #bb 7see p4 #aja71 which had been exposed to a low solubility glaze such as is used in the ,potteries4 ,low solubility glaze is compounded with lead frit--that is to say1 a lead glaze 7or lead silicate7 which has been finely ground4 ,the particles of this substance are much larger than those of ordinary white lead1 and in addition they are much more angular4 ,of three animals exposed to this glaze1 one actually died of pneumonia 7acute71 and the other two suffered from some bronchial trouble1 both of them showing distinct signs of pneumonic patches and old and chronic inflammation when examined histologically2 whereas in none of the other animals exposed to white lead dust or to the high solubility glaze1 which contained white lead as opposed to lead frit1 no such pneumonic or fibroid changes were found4 ,this point is of some pathological importance4 ,the inhalation experiments also throw some light on the quantity of lead necessary to produce poisoning4 ,the animals in the inhalation experiments were exposed for varying periods1 and constant estimations made of the lead present in the air4 ,in a number of instances samples were taken from the cage air during the whole of the experiment1 as rapidly as possible4 ,the quantity of lead floating in the air was found to increase as the experiment progressed1 although a large amount of the lead introduced was caught on the side of the cage and deposited on the floor4 ,in the later experiments the method of taking the samples continuously during the experiment was abandoned1 and four samples only were taken1 and the average recorded4 ,a simple calculation will give the quantity of lead dust it would be possible for an animal to inhale during the whole of this period of exposure4 ,the utmost tidal air in the case of a cat would be taken at #ej c4c4 ,taking the average1 about #jbg gramme of lead was inhaled during the half-hour of exposure4 ,feeding ,experiments4--,twelve feeding experiments of various types are recorded4 ,the method of experiment was as follows3 ,the compound under investigation was carefully weighed out each day 7#je to #aj gramme71 the substance being some of the same compound that was being made use of for inhalation experiments4 ,in the case of the white lead it was found essential to mix it with the animals' food2 they were given white lead in a small amount of their food1 and no further food was given for some little time after the dose of lead had been swallowed4 ,low and high solubility glazes were also made use of for feeding1 and as a further experiment alcohol was given to the animals in addition to the previous course of lead inhalation or feeding1 and the exposure to lead continued after the alcohol was given4 ,in addition to high solubility glazes1 white lead1 and flue dust1 a soluble salt of lead was also used1 in one series the salt being the nitrate4 #ja gramme was given daily2 and it is these two nitrate animals 7#df and #dg7 which showed distinct differences from the white lead and other feeding experiments4 ,in one case the lead was given mixed with water1 in the other mixed with milk4 ,the animal which was fed with the nitrate dissolved in water developed encephalopathy1 whereas the one in which the substance was mixed in milk exhibited no signs1 though fed for a similar period4 ,both the animals increased in weight1 which is an unusual effect in experimental lead poisoning4 ,the question of the addition of milk1 which apparently prevented the absorption of lead1 is of very considerable importance1 as it is highly probable1 as has been pointed out with regard to the precipitation of lead by means of organic substances1 that the albuminoid substances in the milk precipitate the nitrate already in a state of solution2 and it may be argued from these experiments that mixing the white lead with the food would tend to prevent the lead having a toxic or deleterious effect1 but even when the lead was given in the form of pills between meals no poisonous effect was noticed4 ,further1 the quantity of white lead given was considerable1 and it is highly questionable whether the quantity of lead so taken would be dissolved by the gastric juice excreted under normal circumstances in its entirety1 as a very considerable quantity would pass onwards through the pylorus undissolved4 ,until the lead compound has become soluble it cannot react with the albuminoid constituent of the food4 ,ordinary dry white lead or litharge does not combine directly with albumin4 ,the majority of the experimental animals showed alteration in weight4 ,the most important point which is brought out by these experiments1 considering them from the point of view of inhalation1 is the enormous quantity of white lead the 8feeding0 animals swallowed without producing any apparent symptoms4 ,the quantities cited are the amounts given per diem1 whereas in the inhalation experiments the animals were rarely exposed more than three days a week for an hour at a time 7see table1 p4 #aja74 ,the quantity of lead1 therefore1 given by the gastro-intestinal canal was at least ten times as much1 in many cases fifteen or twenty times as much1 as could be taken by the other animals via the lung during inhalation1 and yet these animals showed little or no susceptibility to poisoning when fed with white lead or other lead compounds1 unless alcohol was given in addition4 ,an examination of the stomach after death showed1 in the case of the alcoholic animals1 distinct evidence of gastritis1 and there is some reason to suppose that in such animals a degree of hyperacidity may have existed1 thereby promoting the rate of solution of the lead4 ,the increased susceptibility to lead poisoning through the agency of alcohol is interesting4 ,no4 #f received1 in addition to its inhalations or period of exposure in the dusty air1 #ej c4c4 of port wine per diem4 ,symptoms of lead poisoning appeared a day sooner than in any other animal1 and if we eliminate this experiment1 as the dust 7flue dust from blast-furnace7 contained also arsenic and antimony1 three days sooner than the litharge animal1 and twenty-five days sooner than the other animals exposed to white lead dust4 ,in addition1 this animal was the only one which actually died during the period of experiment2 all the other animals were killed at the end of two months and submitted to histological examination2 but the animal which had received alcohol died with symptoms closely simulating lead encephalopathy in man4 ,the predisposing action of alcohol is still further emphasized by the subsequent experiments with three animals exposed to white lead dust2 one was exposed thirty-seven and the other thirty days before symptoms appeared1 whereas when alcohol was given poisoning was apparent within twelve days1 and after only four inhalations4 ,in the case of animals fed with white lead1 one after eight months1 and the other a year and a half1 showed no signs of lead poisoning at all1 while the weights remained constant4 ,at the end of this time alcohol 7#ej c4c4 of port wine7 was added to the animals' diet1 and one month after the addition of alcohol to the diet1 the dose of white lead being continued constant1 encephalopathy ensued4 ,in a second case the animal was started on alcohol in addition to the white lead4 ,in a month it was showing signs of slight paresis4 ,again1 an animal fed on a low-solubility frit consisting of ground-up lead silicate1 showed no ill-effects after receiving a daily dose of this compound4 ,at the end of this time alcohol was added to its diet1 and six months later the animal developed symptoms of cerebral involvement1 which continued at intervals until a fatal attack of encephalopathy at the end of a year4 ,there is thus definite evidence to show that the addition of alcohol to the animal's diet undoubtedly hastened and determined the appearance of lead poisoning1 and this1 taken in conjunction with the inhalation experiments previously cited1 is very strong evidence of the increased susceptibility to lead poisoning produced by alcohol4 ,this supersensitiveness to lead through the medium of alcohol is a matter of clinical experience to most persons who have had experience of industrial lead poisoning1 particularly those who have been engaged in the routine examination of persons working in factories4 ,inoculation ,experiments4--,in order to control both the feeding and the inhalation experiments1 and more particularly to obtain direct information of the effect of lead upon the body tissues1 resource was had to the inoculation of the various lead compounds tested--namely3 7#a7 ,white lead1 7#b7 litharge1 7#c7 lead frit4 ,these three compounds are the three types of lead salt which are used in the ,potteries1 whilst white lead and litharge are the compounds causing industrial poisoning in the largest proportion of cases in other industries4 ,as a further control1 the more soluble lead salts were also made use of--namely1 acetate1 nitrate1 and chloride--mainly for the purpose of establishing some standard of poisoning both in rate and dose4 ,several rather unexpected results were derived from the inoculation experiments1 which will be referred to4 ,the method of inoculation was to suspend the lead compound to be tested in normal saline solution or distilled water4 ,the animal was then shaved1 and the lead compound inoculated into the muscles of the back4 ,the corrosive action of these lead salts was avoided by using a considerable quantity of diluent4 ,lead frit is a constituent of low-solubility glaze--that is to say1 a glaze which has not more than #e per cent4 soluble lead when subjected to the standard test of exposing #a gramme of the glaze to a litre of #jjd per cent4 hydrochloric acid for an hour at room temperature4 ,the frit which was the constituent of this glaze is produced by heating together litharge or lead and silica1 the production being a yellow1 hard1 glaze-like material looking very much like sugar-candy4 ,it is not by any means a compound of lead and silica of simple composition1 as different samples show a wide variation in their lead content2 whilst1 in addition1 the mode of its formation closely resembles that of an alloy or amalgam1 and allows of the formation of a eutectic entangling in its meshes both of the constituents of which it is formed1 so that a certain amount of free lead1 in addition to the silicates of various descriptions1 are present4 ,at the same time the compound is highly resistant to the action of mineral acids1 and1 of course1 much more insoluble and refractory than white lead1 litharge1 or other lead oxides4 ,the body fluids1 however1 particularly the fluids in the subcutaneous and muscular tissue1 definitely exert some action upon this fritted lead1 and it was found experimentally that symptoms of poisoning could be produced in the experimental animals when even small doses were administered4 ,a gramme of frit was inoculated1 and in all but one case the animals showed definite signs of lead poisoning1 and in two instances actually died with symptoms of encephalitis4 ,by washing the frit with distilled water1 a slight diminution in the poisonousness was found1 but by washing the frit with two or three changes of dilute acetic acid 7#c per cent471 and then with distilled water1 no pathological results followed inoculation4 ,water-washing frit alone definitely reduces the poisonous effect1 but not to the same extent as the preliminary washing with acetic acid4 ,on the other hand1 washing with hot water had a much greater effect than cold-water washing4 ,further evidence given by the inoculation experiments shows the relationship between the more soluble and the insoluble lead salts4 ,the dose of acetate required to kill an animal was about #ja gramme of acetate per kilogramme body weight4 ,on the other hand1 #ja gramme of white lead produced no ill-effects1 #je gramme per kilogramme body weight produced death in about two months4 ,in addition1 those animals suffering from the more acute forms of poisoning developed definite eye changes and retinal hmorrhages4 ,tortuosity and increased size of the retinal vessels were observed in several instances4 ,besides controlling the experiments of feeding and inhalation1 the inoculation experiments play a still more important part1 as they furnish the correlation1 necessarily1 of the histological changes found as the result of poisoning by means of lead4 ,in all the animals which have died of poisoning1 certain definite trains of symptoms made their appearance4 ,these symptoms were in practically all particulars similar to those observed in industrial lead poisoning in man1 the onset of the affection and its clinical course corresponding to the symptom-complex in man1 including those of cortical involvement1 and often similar to the classical ,jacksonian variety4 ,throughout these experiments the animals exhibited no signs of irritation1 and during the initial period1 even1 when loss of weight was a noticeable feature1 their appetites remained exceedingly good2 they were quite friendly1 and purred loudly when stroked2 but when symptoms of poisoning became manifest1 particularly the onset of paralysis1 a definite change in mental phenomena took place3 the animals became quarrelsome1 highly apprehensive of danger without cause1 morose and lethargic by turns4 ,at this stage1 in more than one instance1 acute encephalopathy supervened4 ,the mental change was peculiarly striking in reference to ,mott's case1 quoted on p4 #ga1 as in all respects it was exactly analogous with the train of symptoms recorded in that case4 ,to sum up1 the symptoms produced in the experimental animals by the lead compounds inoculated and respired1 no matter what the particular compound of lead experimented was1 were as follows3 #a4 ,slight preliminary rise in weight at the commencement of the experiment1 lasting from one to two weeks4 #b4 ,progressive loss of weight1 mainly due to the disappearance of all fat1 subcutaneous1 kidney1 mesenteric1 etc41 with associated anmia1 and the curious sunken and pinched faces commonly associated with saturnine cachexia4 #c4 ,paresis of various types4 ,in the cat the muscles first affected are those of the back and the quadriceps extensor of the hind-limbs4 ,the onset of the paralysis is slow and insidious1 but may be acute2 as a rule weakness in the muscles of the lumbar region and the spine are the first symptoms2 secondly1 inability to jump1 owing to the weakness of the quadriceps extensor1 while the animal tends to fall over when turning round quickly4 ,encephalitis occurs1 and is frequently fatal4 ,as a rule the affection is unilateral2 complete loss of consciousness may occur1 followed by slow but complete recovery4 ,the animals gave no evidence of suffering pain1 and1 when recovered from an attack of encephalopathy1 would at once take milk1 but seemed dazed and uncertain in their movements4 ,when the animals reached the stage of paralysis1 they were destroyed under ansthetics1 and subjected to post-mortem examination4 ,the post-mortem findings of a typical case were as follows3 ,the animal was emaciated1 the fur easily pulled out1 and the muscles were exceedingly flaccid4 ,rigor mortis was slow in making its appearance2 the blood remained fluid for a considerable time4 ,practically no fat was to be found in the whole of the mesentery1 and the omentum was devoid of fat and shrivelled4 ,the fat around the kidneys had entirely disappeared4 ,there was little orbital fat4 ,the peritoneum was thin and glistening1 and very frail4 ,the whole of the mesenteric vessels1 particularly in the region of the large intestine and the ileo-ccal valve1 were engorged with blood2 whilst in the lower part of the small intestine1 and often in the duodenum1 occasionally in the whole of the jejunum and ileum1 traces of minute hmorrhages were found along the intestinal wall4 ,the liver was engorged with blood1 as was the spleen4 ,the kidney capsule stripped easily1 but was occasionally adherent here and there4 ,the whole of the cortical vessels were injected with blood1 the branching showing most distinctly4 ,a good deal of serous fluid was at times found underneath the kidney capsule4 ,on section the cortex appeared engorged with blood1 and showed here and there1 even to the naked eye1 small hmorrhages4 ,in the region of the appendix a few large mesenteric glands were invariably found1 whilst a few glands might also be found in the wasted mesentery of the small intestine4 ,in the region of the appendix the glands were frequently dark in colour4 ,on opening the gut1 minute hmorrhages and ulcerated patches were to be found in the lower part of the ileum2 the ileo-ccal valve1 and the whole of the large intestine1 extending right up to the end of the appendix1 was covered with a dark slate-blue slime1 in which lead could be easily recognized by chemical processes4 ,ulceration of the gastric mucous is uncommon1 and only on one occasion were any hmorrhages found4 ,in the thoracic cavity the lungs were generally found to be emphysematous1 and particularly in those animals subjected to inhalation of lead frit containing angular particles of lead glaze broncho-pneumonia was found4 ,the heart was flabby1 and occasionally distinct roughening and thickening of the valves was seen4 ,nervous ,system4--,on opening the skull1 hmorrhages were frequently found at the base of the brain1 occasionally situated over the surface of the cerebrum4 ,minute hmorrhages were found often underneath the arachnoid membrane1 but the largest hmorrhages were always found at the base of the brain1 and spreading down into the spinal canal along the medulla4 ,on removing the cord1 minute hmorrhages were found along the surface1 irregular in distribution1 and never very large4 ,on section the brain and cord appeared normal4 ,histology4--,a large number of sections were prepared from the animals developing symptoms of poisoning2 the various tissues are described seriatim3 ,muscles4--,these appear to have undergone general fatty degeneration4 ,the individual muscle fibres are indistinct in outline1 and show irregular areas stained by hmatoxylin4 ,some infiltration may be seen here and there between the muscle fibres1 and minute hmorrhages are occasionally detected1 the chief appearance being that of general atrophy4 ,the heart muscle shows similar degeneration1 and the tendency of the sarcolemma to break down and stain irregularly is apparent4 ,in many areas the muscle fibres stain poorly1 if at all4 ,occasionally minute hmorrhages are found1 passing between the muscle fibres4 ,liver4--,the hepatic cells show varied degeneration2 the vessels passing between the cells are engorged with blood1 the cells being frequently much distorted from their general arrangement1 and here and there completely obliterated by small areas of exudation as well as actual hmorrhages4 ,spleen4--,the parenchyma shows masses of irregular spaces filled with recently-shed blood2 the individual cells show a granular degeneration1 with occasional basophile staining1 the general appearance being one of chronic congestion4 ,here and there cloudy swelling may be seen4 ,intestine4--,sections across the small intestine show atrophy of the intestinal wall1 slight degeneration of the muscular coats1 with infiltration and minute hmorrhages4 ,large ,intestine4--,here similar minute hmorrhages are found1 in no case large enough to be seen by the naked eye4 ,areas of necrotic tissue are also seen in which considerable quantities of lead sulphide particles are found4 ,,plate ,i ,illustration3 ,,fig4 #a4--,,section ,,of ,,large ,,intestine ,,of ,,animal ,,poisoned ,,by ,,inhalation ,,of ,,white ,,lead1 ,,showing ,,excretion ,,of ,,lead ,,by ,,tissues4 7,,stained ,,eosin ,,and ,h,,matoxylin47 #bej4 ,the whole of the large intestine was stained black1 the staining commencing at the ileo-ccal valve4 ,no staining is observable in the small intestine2 the line of demarcation is sharp4 ,illustration3 ,,fig4 #b4--;,,intestinal ,,ulceration ,,in ,,turpentine ,,poisoning4 7,,stained ,,eosin ,,and ,h,,matoxylin47 #bej4 ,illustration3 ,,fig4 #c4--,,section ,,of ,,anterior ,,crural ,,nerve ,,from ,,animal ,,poisoned ,,by ,,inhalation ,,of ,,white ,,lead ,,dust1 ,,showing ,h,,morrhage ,,in ,,nerve4 7,,stained ,h,,matoxylin ,,and ,,eosin47 #bej4 ,there was paralysis of the quadriceps extensor on the right side2 the left leg was unaffected and the left anterior crural nerve was unaffected4 ,,plate ,,ii ,illustration3 ,,fig4 #a4--,,section ,,of ,,lung ,,of ,,animal ,,exposed ,,to ,,inhalation ,,of ,,white ,,lead ,,dust1 ,,showing ,,mass ,,of ,,lead ,,in ,,the ,,lung ,,substance4 7,,stained ,h,,matoxylin ,,and ,,eosin1 ,,and ,,treated ,,with ,h,s47 #bej4 ,illustration3 ,,fig4 #b4--,,lung ,,of ,,animal ,,exposed ,,to ,,turpentine ,,vapour4 7,,stained ,h,,matoxylin ,,and ,,eosin47 #bej4 ,illustration3 ,,fig4 #c4--,,lung ,,of ,,animal ,,exposed ,,to ,,inhalation ,,of ,,white ,,lead ,,dust1 ,,showing ,,chronic ,,inflammation ,,with ,,exudation ,,and ,,capillary ,,leakage ,,and ,h,,morrhage4 7,,stained ,h,,matoxylin ,,and ,,eosin47 #bej4 ,lung4--,red or grey hepatization may be found1 or a general appearance of broncho-pneumonia1 where the dust used contained angular or insoluble substances4 ,in animals subjected to prolonged inhalation1 particles of lead could be demonstrated in the alveolar cells1 and in the tissue beyond1 either by staining with chromic acid or by means of iodine4 ,staining by sulphuretted hydrogen is not very satisfactory1 as most animals resident in a large city show masses of carbon situated in various parts of the alveolar cells4 ,if1 however1 a section be treated by means of iodine or chromic acid1 and watched under the microscope during the process1 the particles of carbon are easily differentiated from those of lead compounds4 ,nervous ,system4--,sections of the brain and spinal cord1 and of the nerve supplying the paralyzed muscles1 all exhibited the same phenomena of minute hmorrhages4 ,in later cases some change in the cells is found1 but as a rule1 beyond a slight increase of the intracellular substance1 little or no change is found in the cellular elements of the brain2 but in the region of the surface minute hmorrhages may be constantly traced1 spreading over the surface of the cortex4 ,in the cord1 sections made in various situations failed to show any very definite degeneration1 and little or no hmorrhage was observed amongst the cells of the cord4 ,hmorrhages could occasionally be seen on the surface4 ,in a number of animals the anterior crural nerves supplying the paralyzed quadriceps extensor muscles were examined carefully both for degeneration and for hmorrhages4 ,very few degenerated nerve fibres were found1 not more than would be accounted for by the minute hmorrhages1 which were found passing in between the nerve bundles1 and here and there producing pressure on the nerve bundles themselves4 ,kidney4--,in the kidneys minute microscopical hmorrhages1 some of them quite large1 were found in the cortex4 ,the hmorrhages are diffuse and irregular1 and apparently due here1 as in other situations in the body1 to the breaking down of minute venioles rather than arterioles4 ,in many cases the change is capillary4 ,parenchymatous nephritis may be seen1 probably resulting from the transudation taking place from the vessel walls4 ,the chief view brought out in the histological examination of the various organs is one of capillary hmorrhage4 ,this phenomenon is not peculiar to lead poisoning1 but1 from the work of ,moore of ,liverpool#d1 it would seem that all heavy metals1 such as bismuth1 mercury1 not excepting iron1 tend to produce a curious generalized yielding of the minuter vessel walls4 ,armit#e has demonstrated a similar effect with nickel4 ,the phenomena is1 however1 typically associated with lead poisoning1 and may1 we think1 be regarded as the definite factor of chronic lead poisoning4 ,for the purposes of controlling the experiments of inhalation1 two other series of experiments were undertaken4 ,in one instance an animal was fed for two years on white lead2 the animal was given #ja gramme per day1 and this was increased up to #je gramme1 and ultimately #a gramme4 ,this animal exhibited no symptoms whatever of lead poisoning1 and when it was killed1 at the end of the time of experiment1 showed no apparent lesion1 with the exception of very marked staining of the colon and vermiform appendix4 ,this staining of the large intestine and the appendix1 the engorgement of the vessels1 particularly of the omentum and mesentery1 the enlargement of the lymphatic glands in the neighbourhood of the colon1 ileo-ccal valve1 and appendix1 suggest the absorption of lead in the upper part of the intestine1 and its discharge or elimination into the large intestine4 ,that lead is absorbed into the upper part of the intestine was demonstrated in the following manner3 ,an animal was ansthetized1 an incision made1 and a loop of intestine pulled up and clamped off1 a solution of lead chloride being run into the loop by means of a hypodermic syringe4 ,the mesenteric vein passing from this loop of intestine was then carefully secured1 a small opening made in it1 and the blood collected drop by drop until some #dj c4c4 had been collected1 the time occupied being about three-quarters of an hour4 ,the blood thus collected was submitted to chemical examination1 and lead was demonstrated to be present4 ,lead therefore passes direct from the intestine into the portal circulation4 ,in only one of the feeding experiments with solid compounds of lead was any definite symptom of lead poisoning produced1 and in this instance the compound used was dust collected from the flues of a blast-furnace4 ,this dust was afterwards found to contain a considerable quantity of arsenic4 ,the experiment cannot therefore be regarded as conclusive4 ,with the more soluble salts of lead1 however1 such as the acetate1 lead poisoning may be set up by means of lead administered via the intestinal canal3 #a gramme of lead acetate administered by means of a hypodermic syringe through a catheter passed into the stomach of a cat produced abortion in ten days1 and death in three weeks4 ,four grammes of acetate produced a similar effect in a dog in four weeks4 ,,plate ,,iii ,illustration3 ,,fig4 #a4--,,kidney ,,of ,,animal ,,poisoned ,,with ,,white ,,lead 7,,inhalation71 ,,showing ,,microscopical ,h,,morrhages4 7,,stained ,h,,matoxylin ,,and ,,eosin47 #bej4 ,illustration3 ,,fig4 #b4--,,kidney ,,of ,,man ,,dying ,,of ,,chronic ,,lead ,,poisoning4 7,,stained ,h,,matoxylin ,,and ,,eosin47 #bej4 ,illustration3 ,,fig4 #c4--;,,brain ,,of ,,young ,,woman ,,dying ,,of ,,acute ,,lead ,,encephalopathy1 ,,showing ,,small ,,cerebral ,h,,morrhages4 7,,stained ,h,,matoxylin ,,and ,,eosin47 #bej4 ,the two following cases1 in which both chemical and histological examination has been carried out on the tissues of persons who had been employed in occupations which rendered them exposed to absorption of lead1 and who died with symptoms directly suggestive of lead poisoning1 may be added1 as they confirm the experimental results given above in all particulars3 ,,case #a4--;,a woman aged twenty-one1 employed in a litho-transfer works1 who died after a short illness during which the chief symptoms were headache and mental clouding4 ,at the post-mortem examination no pathological lesions were discoverable with the exception of a small gland which had become calcareous1 situated near the right bronchus4 ,the brain was injected over the left cerebral hemisphere1 but no hmorrhages were to be seen with the naked eye4 ,there were no other pathological signs4 ,a portion of the brain showing the injection and congestion were submitted to histological and chemical analysis4 ,histologically the brain tissue was found to be normal1 with the exception of slight chromatolysis of some of the larger cells2 but interspersed about the whole section in the slides examined1 but more particularly in the area of the cortex1 minute microscopical hmorrhages were found 7see ,fig4 #c74 ,here and there these hmorrhages were seen related to the expanded capillaries1 all of which showed considerable engorgement with blood4 ,the arteries and veins themselves were1 in addition1 considerably distended4 ,there was no interstitial degeneration of the neuroglia noticed4 ,a few patches were found which apparently represented old hmorrhages undergoing gradual fibroid degeneration4 ,in no case were the hmorrhages of a size that could be detected by the naked eye4 ,two hundred and fifty grammes of the injected area of the brain were submitted to chemical examination by the moist process described in the chapter on ,chemical ,analysis4 ,the nitric acid filtrate from the electrolytic deposition gave a well-marked precipitate with sulphuretted hydrogen1 which was filtered off and recognized as lead4 ,there was only the merest trace of iron present4 ,by colorimetric estimation the quantity of lead found present in the brain estimated as ,pb was #jjadc gramme4 ,the quantity found in #bej grammes of brain substance examined from the injected area was #jjjda gramme4 ,,case #b4--;,a man who had been employed in an electrical accumulator works for a considerable time1 and who had had a history of several attacks of lead colic and one of lead paresis affecting both hands4 ,the man's work in connection with lead ceased from the time of the paresis1 but some three years subsequently he died with cerebral hmorrhage4 ,portions of the organs1 brain1 kidney1 liver1 and spleen1 were examined histologically1 stained in the ordinary way with hmatoxylin and eosin4 ,in the brain the same marked microscopical hmorrhages were observed as described in the previous case1 and in addition many more areas of old fibroid scars1 very minute1 but apparently corresponding to earlier minute hmorrhages4 ,the kidney showed definite interstitial hmorrhage 7see ,plate ,,iii41 ,fig4 #b71 as did the liver and spleen4 ,a portion of the brain was further submitted to chemical examination1 and #jjjad gramme of lead was determined as present4 ,the importance of this confirmatory evidence is undoubted1 as the presence of the capillary hmorrhage existing in the tissues of a person dying under suspicious circumstances when employed in a lead process is confirmed by the chemical determination of lead in the tissues4 ,the following tables1 arranged under three headings1 give some of the experimental results obtained by submitting animals to the effect of compounds of lead4 ,table ,,xi4 gives the inoculation experiments4 ,the materials used in these experiments were those used in the inhalation and feeding experiments4 ,the experiments are also arranged in such a manner that each series is a control one of the other4 ,the amount of substance used for the inoculation gives some rough idea of the dose required to produce poisoning in an animal2 but even this question of dose in absolute quantities1 administered hypodermically1 shows considerable variation in the degree of poisonous effect4 ,the first animal in ,table ,,xi4 was inoculated with acetate1 this being one of the more soluble lead compounds1 and was given it in three small doses4 ,the animal received #jc gramme per kilogramme of body weight1 whereas in ,no4 #ce #b grammes of washed frit--that is to say1 lead glaze formed by fusing together litharge and silica--actually did produce symptoms1 but of a mild nature4 ,animal ,no4 #cc only had #jaf gramme1 being #jje gramme per kilogramme of body weight2 and this caused acute symptoms4 #jce gramme of white lead in a #cejj kilogramme animal 7,no4 #ca7 produced no symptoms at all4 ,in the list of the inoculation experiments1 three animals only exhibited no symptoms--one of these 7,no4 #ca7 which was given white lead hypodermically1 and ,nos4 #da and #db1 which were inoculated with lead silicate or lead frit1 which had been previously treated with acetic acid or water4 ,several practical points arise from these experiments1 notably with regard to the frits1 as it is seen that a considerable amount of the toxic properties contained in frit are removed by washing--most by washing with acetic acid and water1 but also to some extent by washing with hot water alone1 showing that in the ordinary production of lead frit for pottery purposes a certain amount of lead in a soluble condition as regards the body tissues was still present4 ,this is no doubt entangled in the true silicates in the forms of oxides1 or even as carbonate4 ,further1 the toxicity of the lead compounds used may certainly be arranged in the order of their solubility with regard to the animal tissues1 the acetate being the most poisonous1 and the frit1 when washed1 the least2 but unwashed frit1 even in relatively small doses1 may produce poisoning4 ,this point is still further emphasized in ,table ,,xiii4 ,animal ,no4 #db1 four months after previous inoculation1 showed no signs of poisoning4 ,lead nitrate in water was therefore given in quantities of #jja gramme per diem2 one month later this animal developed poisoning4 ,table ,,xii4 deals with the feeding experiments4 ,in these experiments acetate was given in one case only1 and then in the form of pills coated with keratin4 ,it is impossible to say1 however1 whether the animal ever received any soluble lead1 as on one or two occasions the keratin pills passed right through the animal without dissolving4 ,on the other hand1 feeding with nitrate of lead in water produced symptoms1 but when the nitrate was given in milk no symptoms appeared4 ,it will be noticed it took a cat four months to show any signs of poisoning taking #ja gramme per day2 whereas the animal receiving subcutaneous doses of #jaf gramme of acetate showed paralysis in fifteen days1 and in twenty-two days was so ill that it had to be destroyed under an ansthetic4 ,the same relationship in time also obtains in the case of the animals fed on dry white lead4 ,in practically no instance did definite or severe poisoning follow the feeding on dry white lead alone1 even when quite large quantities were taken4 ,on reference to the inoculation experiments of ,table ,,xi41 it will be seen that the inoculation of #b grammes of dry white lead produced definite symptoms1 although the feeding cats had an amount very largely in excess of this4 ,the only animals fed on white lead or frit exhibiting signs of lead poisoning were those which were given alcohol in addition to the lead compound4 ,a comparison of the results given in ,tables ,,xi4 and ,,xii4 shows that animals which received lead compounds subcutaneously suffered much more than the animals which received the lead via the gastro-intestinal canal1 even when the doses given via the mouth were exceedingly large4 ,it will follow1 then1 that the actual contact with the more intimate fluids of the body1 rather than the digestive juices1 determines the solubility and general distribution of the lead compound in the body4 ,this is confirmed by a recent paper by ,straub#f4 ,the animals experimented upon by feeding were kept in the laboratory under the same conditions as the inhalation animals1 but were so placed that under no circumstance could they obtain any lead dust by inhalation4 ,these animals were used as control to the breathing experiments1 the substance fed to the animals being in all cases the same substance as was used for the various inhalation experiments2 but in addition a certain number of the animals were given alcohol1 which are referred to in ,table ,,xii4 ,alcohol was also given to animal ,no4 #f in the inhalation series4 ,the animals fed with lead were fed with the same compound which was used for the inhalation experiments1 #jd to #a gramme being given daily2 so that during the period these animals were exposed to lead dust the other animals were taking the same compound via the intestinal canal1 but in much larger quantities1 and yet they exhibited no signs of lead poisoning4 ,,table ,,xi4--,,inoculation4 ---------------------------------------- ---------------------- ,no4 of ,ani- mal4,weight4,total ,compound used and ,quantity4 ---------------------------------------- ---------------------- ,kgs4 #af #cbjj #jia grm4 lead acetate3 7#a7 #jaf2 7#b7 #je2 7#c7 #jbe #be #ccej ,fritted lead3 7#a7 #jf2 7#b7 #bj #bf grms4 #bh #cjej #b grms4 white lead #ca #cdej #jce grm4 white lead #cb #bijj #jc grm4 frit #cc #caej #jaf grm4 ,pb,o as acetate #ce #cgej #bj grms4 water-washed frit #dj #cjej #aj grm4 unwashed frit #da #cjjj #aj grm4 acetic acid and water-washed frit #db #bhjj #aj grm4 water-washed frit #dc #bijj ,lead nitrate in water3 #jja grm4 per diem ---------------------------------------- ---------------------- ---------------------------------------- ----------------------- ,no4 ,number of of ,ani- ,inocu- mal4lations4,date of ,first ,symptoms4 ---------------------------------------- ----------------------- #af #c ,forty-fifth day encephalopathy #be #b ,twenty-sixth day slight paralysis of left hind-limb #bh #a ,fourth day aborted #ca -- ,no symptoms #cb #a ,eleventh day stiff joint2 stepping not normal #cc #a ,fifteenth day paralysis #ce #a ,ninth day aborted #dj #a ,forty-seventh day some muscular weakness #da #a ,no symptoms #db #a ,no symptoms #dc -- ,thirtieth day encephalopathy ---------------------------------------- ----------------------- ---------------------------------------- ------------ ,no4 of ,ani-,duration4 ,result4 ,final mal4 ,weight4 ---------------------------------------- ------------ ,kgs4 #af #dg days ,died #agej #be #bf days ,killed #cbjj #bh #bc days ,died ,weight not affected #ca #a year ,recovered #ccjj #cb #bh days ,paralysis2 died #bdjj #cc #bb days ,paralysis2 killed #baej #ce #a year ,recovered1 but thin#bijj #dj #eh days ,died #bbej #da #e months,recovered #bijj #db #d months,recovered #biej #dc #e months,died #bajj ---------------------------------------- ------------ ,,table ,,xii4--,,feeding ,,experiments4 ---------------------------------------- ------------------------ ,no4 ,first of ,other ,appearance ,ani- ,sub- of ,poisoning mal4,weight4 ,compound of ,pb used4 stance4 ,symptoms4 ---------------------------------------- ------------------------ ,kgs4 #b #bgej #je to #ja grm4 flue dust ,none ,vomited fifth day2 7#ee per cent4 ,pb,o7 from no other symptoms blast-furnace flue #i;a #cejj #je grm4 dry white lead ,none ,vomited fifth day2 no other symptoms #aa;a #chej #jh grm4 ,none ,none #cijj ,after #h months given #ej c4c4#a month alcohol alcohol 7port wine7 #ab #chjj #jh grm4 dry white lead #ej c4c4#a month slight port paralysis wine #ac #cdjj #jh grm4 dry white lead ,none ,none #ad #cfej #jd grm4 low-solubility ,none ,none frit #cgcj #jd grm4 low-solubility #ej c4c4#f months en- frit and alcohol port cephalopathy wine #bc #dajj #a grm4 high-solubility ,none ,none glaze #dfjj ,given lead nitrate1 #jja to,none ,none #ja grm4 #bd #bijj #a grm4 high-solubility ,none ,none glaze #df #baej #ja grm4 lead nitrate in ,none #d months opistho- water tonus #dg #bajj #ja grm4 lead nitrate in ,none ,none milk #di #bejj #b grs4 acetate in keratin ,none ,none pill #ae #biej ,control no lead ,none ,none ---------------------------------------- ------------------------ ---------------------------------------- ------------------- ,no4 ,total of ,duration ,ani-of ,exper- ,final mal4 iment4 ,result4 ,weight4 ---------------------------------------- ------------------- ,kgs4 #b #b months ,recovered #bjjj #i;a#b months -- #ccej #aa;a#h months -- #cijj #b months ,died 7encephalopathy7 #aejj #ab #ch days ,died 7encephalopathy7 #bbej #ac #ah months,recovered #biej #ad #h months ,given port wine #cgej #a year ,died cerebral symptoms #bfjj #bc #a year ,no symptoms #d #fjj #e months ,no symptoms except loss of weight #cdej #bd #f months ,recovered #dcej #df #d months ,died cerebral symptoms #cbjj #dg #d months ,recovered,a #bijj #di #c months ,recovered,a #bfej #ae #a year ,no symptoms due to confinement in cage #cajj ---------------------------------------- ------------------- ,a ,increased in weight4 ,,table ,,xiii4--,,inhalation ,,experiments4 ---------------------------------------- ------------------------ ,no4 of ,compound of ,lead ,ani- in ,dust and ,average ,number of mal4,weight4,quantity in ,air during ,experiment4,method4,inhalations4 ---------------------------------------- ------------------------ ,kgs4 #a #cjjj #jjjg to #jja grm4 flue dust from ,a #aa of #a hour blast-furnace flue #b #cehj #jjjg to #jja grm4 litharge dust ,a #ab #d #dajj #jjja to #jjjg grm4 white lead ,a #ab dust #f #ebjj #jjja to #jjjg grm4 white lead ,a #ab 7alcohol3 #ej c4c4 port wine daily in milk7 #g #cjjj #jjja to #jjjg grm4 white lead2 ,a #aa no alcohol #aj #dejj #jjjja to #jjja grm4 white lead ,b #dj of #bj minutes #aa #cgej #jjjja to #jjja grm4 white lead ,b #dj of #bj minutes #ba #cijj #jjja to #jji grm4 low-solubility ,b #ad of #a hour glaze #bb #cijj #jjja to #jji grm4 low-solubility ,b #bf glaze #cj #cejj #jjja to #jji grm4 low-solubility ,b #ad glaze ---------------------------------------- ------------------------ ---------------------------------------- -------------- ,no4 of ,day of ,dura- ,ani- ,first tion of ,final mal4 ,symptoms4 ,series4 ,result4 ,weight4 ---------------------------------------- -------------- ,kgs4 #a #ac days 7#d #b months,lead poisoning 7stopped #bbjj inhalations7 experiment7 #b #ae days 7#e #b months,lead poisoning 7stopped #cjjj inhalations7 experiment7 #d #cg days 7#ab #b months,lead poisoning 7stopped #cjcj inhalations7 experiment7 #f #ab days 7#d #b months,paralysis2 died #cfej inhalations7 #g #cj days 7#i #b months,paralyzed2 killed #agjj inhalations7 #aj #abj days 7#cjadd days,paralyzed2 killed #cbjj inhalations7 #aa #abj days 7#cjadd days,paralyzed2 killed #bgej inhalations7 #ba #db days 7#ad #db days ,acute pneumonia #bgjj inhalations7 #bb #fj #hj days ,killed2 old pneumonia #bejj #cj #de #de days ,killed #bdej ---------------------------------------- -------------- ,the experiments definitely bring out one all-important fact--namely1 that lead dust circulating in the air is many times more dangerous than lead actually swallowed2 for even if the animals which were exposed to the inhalation of dust swallowed the whole of the quantity contained in the respired air1 they would only obtain one-tenth of the amount the other fed animals were getting4 ,it is1 of course1 impossible to suppose that the whole of the lead contained in the inhaled air reached the lung4 ,it can only have been the smaller particles which did so4 ,therefore the ratio is many more than ten times between the fed and the inhaling animal2 in all probability only one-tenth of the contained lead in the respired air reaches the lung4 ,under these circumstances the ratio of poisoning via the lung to poisoning via the intestinal canal is as #ajj 3 #a4 ,table ,,xiii4 deals with the question of inhalation4 ,every care was taken during these experiments to avoid any vitiation of such experiments by the actual swallowing of lead dust by the animals exposed to breathing4 ,moreover1 all the animals were carefully controlled1 in that an animal of somewhat similar weight at the same time was subjected to the ingestion of the same lead compound1 but in much bigger quantities1 via the mouth4 ,it will be seen immediately1 on comparing ,tables ,,xi4 and ,,xii4 with ,table ,,xiii41 that the rate of poisoning by means of dust is greatly in excess of the rate of poisoning by feeding1 even where poisoning by feeding actually occurred4 ,also that the amount of dust present in the air inhaled shows a marked correlation with the date of appearance of the first symptoms of poisoning1 and that where the quantity of dust is very much reduced the poisoning was delayed longer than might have been expected1 and that when poisoning did appear the symptoms were much less pronounced than with the more dusty atmospheres2 and this although the quantity of lead obtained would be relatively the same over the range of time the animals were exposed4 ,the knowledge gained in dealing with industrial poisoning clinically receives very strong corroboration from these inhalation experiments1 for it is a well-known fact that many persons engaged in dusty trades exhibit a species of immunity to lead poisoning4 ,it is true that some susceptible persons1 as has already been pointed out1 very rapidly show signs of poisoning1 even with a dosage producing no effect in other persons working under similar conditions2 and it is highly probable that these persons have arrived at a species of equilibrium by which they are able to excrete the lead ingested1 and so prevent any accumulation and general damage to their tissues4 ,directly1 however1 the dosage is increased1 signs of poisoning come on1 as in the case of animals ,nos4 #aj and #aa4 ,for some seventy to eighty days little or no sign of poisoning was seen with the small dosage commenced with4 ,at the end of this time1 as no symptoms appeared1 the quantity of lead in the air was increased1 with the result that poisoning rapidly became manifest4 ,we have also in these inhalation experiments1 in ,cases #ba and #bb1 definite evidence that a low-solubility glaze--that is to say1 glaze containing fritted lead--is capable of setting up lead poisoning when taken via the lung1 as when such glaze is inoculated1 although it produces no such symptoms when given via the mouth1 except1 perhaps1 when it is complicated by excessive alcohol4 ,symptoms exhibited by ,experimental ,animals4--,the cat is peculiarly susceptible to lead poisoning4 ,in lead works it is impossible to keep a cat any length of time1 as it rapidly dies of poisoning4 ,all the animals subjected to lead absorption1 and definitely suffering from symptoms of lead poisoning1 exhibited the following symptoms3 #a4 ,slight increase of weight over the first period of poisoning1 lasting from one to three weeks4 #b4 ,a progressive diminution in weight1 progressing until the animal exhibited definite signs of poisoning4 #c4 ,wasting1 especially of the spinal muscles 7the erector spin and in the lumbar region71 out of proportion to the determined loss of weight2 pinched facies1 with frequent exhibition of running from the eyes and nose1 even when not exposed to the action of lead dust1 merely by inoculation4 #d4 ,various types of paralysis1 particularly in the cat2 the muscles of the back and of the quadriceps extensor of the hind-legs show signs of paralysis4 ,in the cat the quadriceps extensor is paralyzed sooner than the extensor communis digitorum in man4 ,the cats show loss of power in the hind-limbs by inability to jump4 ,the reflexes1 particularly the knee-jerks and elbow-jerks1 are first of all increased1 and latterly become lost4 ,the chief and main sign which was noted in the histological examination of the animals inoculated was one of minute microscopical hmorrhages 7this has already been referred to72 these hmorrhages were not confined to any particular position in the body nor to any one organ4 ,in the animals which showed symptoms of epilepsy1 occasionally thickening of the pia mater was found1 but invariably in such cases small hmorrhages were found immediately under the arachnoid1 not covering any great area1 but apparently causing pressure upon small areas of the cortex4 ,in others1 again1 the hmorrhages were found lower down in the brain1 and a few in the spinal cord4 ,at times a large amount of hmorrhage was to be found present at the base of the brain1 spreading downwards from the medulla into the spinal canal1 but this only occurred in such animals as died with encephalopathic symptoms4 ,in animals which had signs of more chronic poisoning--that is to say1 gradual loss of body weight1 emaciation1 constipation1 contraction of the abdomen1 and paresis1 particularly of the hind-limbs and the muscles of the back--hmorrhages were found in the muscles1 liver1 spleen1 lung1 heart1 various positions in the abdomen1 in the spinal cord1 in the nerve-supply of the affected muscle1 and even in the brain1 none of them large enough to produce absolute destruction of more than a very minute portion of the organ in which they were situated4 ,now1 all these symptoms1 and1 more important still1 the phenomena of hmorrhage1 were found in all the animals which exhibited similar symptoms1 whether they were poisoned by inhalation of dusty lead compounds or fed upon lead compounds associated with alcohol2 but even in some of the animals which were fed upon lead compounds--particularly white lead--and which had exhibited no definite symptoms of paralysis1 or1 for that matter1 any symptom referable to poisoning1 here and there slight histological changes which were referable to minute hmorrhages4 ,the experimental work therefore carries us very considerably forward in correlating the symptomatology and pathology of lead poisoning4 ,the symptoms produced in susceptible animals by the actual inoculation of a lead compound differ only in degree and rapidity of onset from those produced in animals submitted to inhalation with similar compounds4 ,feeding1 on the other hand--that is1 ingestion by way of the gastro-intestinal canal--even in large quantities1 did not produce poisoning to any great extent1 except when some material such as alcohol was added1 thereby breaking down the animal's resistance4 ,another interesting fact is given--that if lead is taken by the mouth in addition to milk a great deal of the poisonous effect is got rid of2 thus of two animals--,nos4 #df and #dg--which received lead nitrate in their food1 the one in water and the other in milk1 the one which received it in milk showed no effects even after four months' experiment1 whereas at the end of four months the animal which was receiving the compound in its water died4 ,this brings out a point already insisted upon--namely1 that in all lead factories it is highly important that no work should be undertaken first thing in the morning1 before the workers have had a proper meal1 and that in the absence of a proper meal milk is the best substitute4 ,it is highly probable that the soluble lead salt becomes united in some form of albuminate which is dealt with later1 and perhaps turned into a sulphide and excreted without absorption4 ,there is no possible doubt1 from the large series of experiments which ,i have performed1 that lead inhaled is far more poisonous than when absorbed in any other way2 further1 that the amount of poisoning produced differs somewhat according to the type of compound inhaled1 and the experiments1 moreover1 give some suggestion as to the dose which is likely to produce poisoning4 ,it is seen1 where the animal is inoculated with white lead1 the dose required to produce symptoms is below #a gramme per kilogramme of body weight1 but above #jb gramme per kilogramme of body weight4 ,in feeding1 #jh gramme1 and even #a gramme1 per diem for eighteen months produces no effect1 although the same quantity plus an excess of alcohol rapidly produces the disease4 ,on the other hand1 as small a dose as #ja gramme of nitrate of lead given in water for four months produced death4 ,turning to the inhalation experiments1 the quantity of dust breathed when as high as #jjjjg gramme per litre produced symptoms after only twelve inhalations for a period of about thirty-seven days2 whereas when the dose was reduced to #jjjja gramme per diem the time required to produce symptoms of poisoning was #abj days2 in fact1 this last dose 7#jjjja7 for the animal under experiment was almost the lower limit1 as this animal showed an almost steady line of weight for a considerable time1 the weight remaining up for the first hundred days1 a slight variation taking place from week to week until a progressive diminution set in4 ,practically all the animals poisoned manifested a very distinct diminution in body weight2 in four only other symptoms of poisoning appeared first4 ,this is a fact that is often to be noted amongst lead-workers1 and if a progressive diminution in weight takes place1 there is strong reason for supposing that a considerable alteration in the metabolism of the body has taken place2 but it does not follow that microscopical hmorrhages or other definite effects of poisoning are present1 although such is probable4 ,finally1 in summing up the conclusions to be drawn from the above experiments1 it has been suggested that such experiments as inoculation1 experimental inhalation1 or even feeding1 are no criterion of the circumstances under which industrial workers become infected with lead4 ,it is perhaps hardly necessary to refer to this point1 but for the fact that it is possible this book may be made use of by those who are not in the habit of dealing with experimental pathology4 ,one of the first and most important matters in dealing with any form of poisoning is to obtain knowledge of the actual symptoms both clinically and physiologically1 as well as pathologically1 of the effects of any drug1 and to determine if the symptoms so produced in an experimental animal conform to the symptoms as seen in man4 ,for the purpose1 therefore1 an animal is required which is susceptible to the poison1 and therefore cats were used in the foregoing experiments1 as it is absolutely impossible to keep a domesticated cat in any white lead works1 for the animals invariably become poisoned by lead4 ,the second point in prosecuting an inquiry into the pathology of any disease is to determine the train of poisoning when definite dosage1 both in quantity and compound1 is made use of4 ,by feeding an animal with a compound only1 the absorption through the gastro-intestinal canal could be studied2 whereas by inoculating some of the compound--in suspension if it be insoluble1 or in solution if it be soluble--into the subcutaneous or muscular tissue1 the direct action of the body fluids on the compound may be studied2 and1 furthermore1 its absorption by the membranes--that is1 the cell membranes and the animal tissues--are determined4 ,it is necessary to give at first a dose big enough to produce definite symptoms1 and then to gradually decrease the dose to find the minimum amount producing symptoms within a reasonable amount of time4 ,inoculation experiments therefore give an answer to a number of these questions1 and are the basis upon which further inquiry is conducted2 they form a criterion from which it is possible to judge the effect of inhalation1 and the same remarks which have been made with regard to inoculation refer to inhalation experiments4 ,it is essential first of all1 in the experimental animals1 to subject them to rigorous enough conditions to obtain definite symptoms1 and then1 by varying the experiments1 to study the amount1 entrance1 and general behaviour1 of the poison1 correlating the evidence so obtained from the definite knowledge already gained with the previous experiments4 ,it is hoped that this brief note on experimental evidence will assist in the elucidation of the foregoing experiments to those who are not conversant with the application of experimental evidence4 ,further ,experiments relating to ,lead ,poisoning amongst ,painters4--,a series of further experiments were made1 with particular reference to lead poisoning exhibited by painters2 and as these experiments and their results could not have been undertaken without the previous knowledge gained of the pathology of lead poisoning due to the inhalation of particles of dust floating in the air1 their discussion has been reserved until the previous section had been dealt with4 ,it has been supposed by some that surfaces painted with lead paint give off certain emanations containing the metal lead as an organic compound4 ,as the incidence of lead poisoning amongst painters is exceedingly high1 as far as any statistical evidence can be obtained 7see p4 #dh71 it would seem that the painter is peculiarly exposed to infection by lead dust2 and if1 in addition1 organic compounds of lead were given off1 he would be still more liable to lead poisoning4 ,two methods of experiment were used3 #a4 ,the exposure of animals to the fumes given off from freshly painted surfaces1 the paints used being compounded with white lead1 lead sulphate1 zinc sulphide1 and zinc oxide4 ,animals were exposed in a cage similar to that used in the inhalation experiments previously described1 but1 instead of blowing in the contaminated air1 the cages were so arranged that boards freshly painted with the special paint under experiment were introduced into the cage daily1 the animals remaining the whole time in the chamber4 ,special precautions were taken with regard to ventilation4 #b4 ,an animal was placed in a chamber1 and the compound to be tested was heated electrically by means of a coil surrounding the glass tube in which the compound was placed4 ,the current was regulated by means of resistances1 so that the thermo-couple and galvanometer gave a constant reading of #ei ,c4 ,air was constantly passed through the tube over the heated substance and into the animal's cage1 which was efficiently ventilated4 ,in this way any emanations which were given off from the normal room temperature or up to #ei ,c4 were carried over into the animal's cage1 and there breathed4 ,the apparatus was so arranged that the heating coil extended close to the point of delivery into the cage4 ,the result of these experiments showed that the animals confined in cages and exposed to freshly painted surfaces1 where the paint used was white lead1 zinc oxide1 or lead sulphate1 very soon showed signs of poisoning1 and they became emaciated and suffered from recurrent attacks of salivation4 ,the animals exposed in the cages in which air was passed over either white lead paste1 zinc paste1 or lead sulphate paste1 showed no signs of illness1 although kept in the cage and subjected to the inhalation of any fumes which might be given off for three months1 spending the whole of the day in the cage1 but being removed during the night to separate cages4 ,it therefore seemed clear that1 whatever illness was produced in the animals exposed to fresh paint1 they were not suffering from absorption of lead1 but of some other compound of which the paint was made4 ,various constituents of the paint were therefore tried--namely1 the metallic bases1 lead or zinc1 and linseed-oil1 with turpentine and lead acetate mixed with turpentine4 ,the animal exposed to the turpentine alone very rapidly showed signs of disease--salivation1 a tendency to diarrha1 strabismus1 but the latter only after a two-hour exposure1 whilst the quantity of turpentine present in the cage air did not exceed #aj milligrammes per litre4 ,the animal exposed to turpentine and lead acetate exhibited few symptoms1 but the same in kind as the animal exposed to turpentine alone4 ,the linseed-oil animal showed no signs of disease whatever4 ,the animals exposed to the metallic bases of the paint--namely1 zinc oxide or white lead--showed no signs of poisoning as long as the compound itself was not thrown into the air in the form of dust2 but when lead dust was present in the air the animal rapidly showed the ordinary signs of lead poisoning4 ,the animal exposed to zinc oxide dust showed very little sign of discomfort1 but by prolonged exposure early kidney disease was produced1 and signs of chronic inflammation were detectable in the lung4 ,it is interesting to note in this connection that ,lehmann#g describes symptoms produced in cats when exposed to the vapour of turpentine4 ,the animals which ,i exposed to turpentine vapour exhibited the same symptoms as those described by ,lehmann4 ,he gave no result of the histological inquiry of the animals so exposed1 but in no case1 apparently1 was the animal killed after exposure4 ,in my animals exposed to the vapour of turpentine very definite disease of the kidney was produced1 the inflammation tending rather to the tubular than the interstitial variety of nephritis4 ,the tubules were found blocked with dbris1 their contour irregular and destroyed1 and their substance pale and almost hyaline2 whilst areas of cloudy swelling1 together with small hmorrhages1 were to be found scattered about the kidney4 ,the heart muscle was flabby1 and the heart tending to dilatation2 whilst microscopically hmorrhages could be found throughout the organ of a minute capillary nature1 and passing between and disturbing the muscle bundles4 ,no changes of any sort were found in the tissues of the animals exposed to the emanations given off from white lead paste4 ,by analyses these emanations were found to contain no lead1 but traces of aldehyde1 formic acid1 and ,,co4 ,it follows1 therefore1 that the effect of turpentine when inhaled by the painter must be to act as a contributory cause of lead poisoning1 and it is interesting in this connection to recall the fact noted on p4 #ch1 that ,garrod has described gout as occurring constantly among painters4 ,the statement already quoted1 that gout is not common among workers in white lead factories1 where the exposure to lead is very much greater than among painters1 points to turpentine as the cause of the increased incidence of gout among house-painters rather than lead absorption4 ,the importance of dust containing lead as a source of illness and lead poisoning in painters must not be minimized1 as in sand-papering1 etc4 7see p4 #acg74 ,the importance of lead dust inhaled in this way is perfectly understood4 ,it is1 however1 highly probable that the combined action of the turpentine with the lead accounts for the fact that headache is a common symptom of early disease in painters1 which is not the case among white-lead workers4 ,,references4 #a ,,goadby1 ,k4 ,w43 ,journal of ,hygiene1 vol4 ix41 ,no4 #a1 #aiji4 #b ,,goadby1 ,k4 ,w41 ,,and ,,goodbody3 ,the ,lancet1 vol4 ii41 p4 #ihh1 #aiji4 #c ,,goadby1 ,k4 ,w43 ,report of the ,committee on ,lead1 etc41 in ,potteries1 vol4 iii41 p4 #dgh1 #aiaj4 #d ,,moore3 ,private communication4 #e ,,armit3 ,journal of ,hygiene1 vol4 viii41 ,no4 #e1 #aijh4 #f ,,straub3 ,berl4 ,med4 ,woch41 p4 #adfi1 #aiaa4 #g ,,lehmann3 ,archiv fr ,hygiene1 vol4 xxxiv41 p4 #cba1 #ahii4 ,,chapter ,,vii ,,symptomatology ,,and ,,diagnosis ,acute ,poisoning4--,acute poisoning by lead is not common4 ,industrially it hardly ever occurs4 ,zinn#a states that1 out of #bjj cases of industrial lead poisoning in his clinic in ,berlin1 only one was to be regarded as an acute case4 ,in most instances the poisoning is due to swallowing some compound of lead1 either as an abortifacient or to commit suicide4 ,the pathology and symptoms of such acute lead poisoning depend in the first place upon the nature of the salt of lead swallowed1 as1 for instance1 after swallowing sugar of lead a burning taste is complained of1 with acute gastric pain1 generally coming on within an hour of taking the poison1 salivation1 metallic taste in the mouth1 acute hiccough1 and griping pain in the abdomen4 ,the mouth is stained a whitish-grey4 ,later there is a great fall in blood-pressure1 the skin becomes moist1 or a cold sweat may appear4 ,the respiration and pulse drop2 finally comes vertigo1 acute headache1 coldness of the extremities1 ansthesia1 and death in one or two days1 or the case passes on to one of chronic poisoning4 ,if the patient survives for the first two or three days1 retinal changes frequently make their appearance1 and occasionally acute fever may supervene4 ,various paralyses also appear1 and the case then becomes one of subacute or chronic poisoning4 ,the lethal dose for healthy adults is probably as large as #ej grammes for lead acetate1 for lead carbonate #be grammes2 these doses are1 of course1 only approximate4 ,post mortem in a case of acute lead poisoning by ingestion1 the mouth and stomach show the presence of a lead salt in the mucous exudation1 together with corrosive gastritis and considerable swelling and dema of the mucous membrane4 ,the large intestine is generally stained darkly1 from a light brown to a deepish black2 this staining may not appear until quite low down in the intestine4 ,there is hypermia of the liver1 much engorgement of the vessels in the mesentery1 the kidney1 and the brain4 ,the rest of the intestinal viscera show signs of engorgement4 ,fluid may be present in the peritoneal cavity1 and occasionally in the other serous cavities4 ,the histological examination of the various organs exhibits the same microscopical hmorrhages as are found in the cases of chronic poisoning to be described later4 ,although acute lead poisoning is rare in industrial experience1 it may occur from time to time4 ,several cases are on record where a workman developed an acute attack of poisoning as a result of immersion in a white lead beck2 another case is described which followed immersion in a tank of solution of lead acetate4 ,an accident of this description may conceivably occur2 the treatment of such a case should be energetic1 as the poisoning is chiefly due to lead swallowed4 ,an emetic should be given1 followed by sublimed sulphur1 or1 better still1 the stomach washed out with dilute hydrogen sulphide water slightly acidulated with sulphuric acid1 so as to change any lead present in the stomach into the least soluble form4 ,a brisk purge should be given1 and the patient encouraged to drink considerable quantities of lemonade containing sodium or potassium citrate4 ,alcohol1 even during collapse1 should be avoided2 a hypodermic injection of strychnine is preferable4 ,it must be borne in mind that lead is absorbed in the upper part of the intestine1 and only in a minute degree1 if at all1 from the stomach2 it is re-excreted mainly by the large bowel and by the urine2 to some extent also by the sweat and saliva4 ,treatment is therefore directed towards 7a7 forming an insoluble compound as far as possible2 7b7 promoting the elimination of the poison2 7c7 placing as little work as possible upon the tissues most affected4 ,only milk should be given as food for two to three days4 ,the diagnosis of lead poisoning is not in itself of any great difficulty where any one of the classical symptoms of lead poisoning is present1 such as lead colic1 paresis1 or the characteristic lead anmia or cachexia4 ,on the other hand1 the premonitory symptoms of poisoning1 as seen by a club doctor1 particularly in persons engaged in industrial processes1 are more difficult to determine2 but for the appointed surgeon1 who has an opportunity of watching them from week to week1 the gradual development of anmia1 extensor weakness1 and other early symptoms1 should give no difficulty4 ,the clinical diagnosis requires to be made earlier by the appointed surgeon than by the general practitioner2 for the appointed surgeon's duty in a white lead works is not only to treat lead poisoning when it is once established1 but1 by carefully noting premonitory signs1 to avoid the development of actual symptoms in susceptible persons4 ,it is convenient1 therefore1 to divide the diagnosis of lead poisoning1 from the clinical standpoint1 into two divisions--incipient and pronounced4 ,such incipient changes are for the most part noticed amongst lead-workers1 and in many cases are more strictly signs of lead absorption than signs of lead poisoning4 ,the earliest symptoms of poisoning are found in the vascular system1 and the curious pallor of the face in persons who have worked in lead for a considerable period is often pronounced1 although the conjunctiva may not show such a diminution in colour as might be expected from the facial change1 while the actual determination of hmoglobin may be almost normal4 ,in addition to this1 a person of fresh colour working in lead1 if susceptible1 very quickly loses his florid appearance1 often heightened by the colour of the face only remaining on the cheek-bones as a hectic flush4 ,such a person will also show diminution in the colour of the conjunctival vessels1 and invariably a distinct yellowish appearance of his sclerotics1 due to the pigmentation of that tissue by broken-down blood-pigment4 ,the yellow colour of the eyes is definite evidence that blood-destruction is in progress4 ,following on the anmia1 or1 more strictly speaking1 the pallor of the face1 a well-marked wasting of the subcutaneous fat takes place4 ,in animals poisoned with lead in small or large doses--particularly in small doses given over a considerable period--this wasting of all subcutaneous and other fat is a very marked feature1 so much so that practically no kidney1 mesenteric or abdominal fat is to be found4 ,the fat is lost in a greater proportion than other body tissues4 ,in man the infra-orbital fat1 together with the fat about the buccinator muscle1 suffers early1 and a curious facial contour is produced1 two well-marked folds being seen--one the ordinary naso-labial fold1 and the other situated at the anterior margin of the masseter4 ,this1 together with the loss of the orbital fat1 gives the face a curious pinched appearance4 ,such a pinched appearance is also to be found in animals 7cats7 poisoned by lead4 ,the wasting frequently precedes any other symptoms1 and it is no uncommon thing to find that a man who has been working in a lead process exposing him to inhalation of dust for a year is losing weight4 ,in one case a man of #aj stone #g pounds was reduced in weight to #i stone #b pounds in fourteen months1 during the whole of which time he showed no signs at all of lead poisoning1 and only towards the latter end of the time did he exhibit any blue line on his gums2 there were no symptoms referable to lead poisoning4 ,such a case is typically one of lead absorption1 which1 if continued1 would ultimately result in pronounced anmia with either colic or paralysis1 probably the former4 ,the man in question was not engaged in any lead process1 but was an electrician attending to the electric light and motors in a smelting works4 ,his occupation necessitated work above the general ground-level1 and therefore he inhaled the fumes and finer dust particles detached especially from the arc lamps which required adjustment4 ,in many persons who have worked in lead for long periods1 wasting does not progress beyond a certain point1 and these persons may be regarded as having established a certain degree of immunity4 ,men are met with who have worked in white lead factories and in smelting works for periods of from twenty to1 in one case1 forty-three years1 a considerable portion of such period being antecedent to the time at which the regulations in force for dust removal and general protection of the workers were established1 and they must have been exposed to much lead dust4 ,nevertheless they were less emaciated than many who have only worked a year or two years in a factory under modern hygienic conditions and special regulations4 ,such persons are either immune from the commencement1 or they have established a certain degree of tolerance towards the metal2 the latter supposition is the more probable1 as there is reason to think several of them suffered from a mild degree of poisoning during the earlier years of their employment4 ,the rate of development of pallor and wasting are the important facts in incipient poisoning4 ,anmia1 together with the presence of basophile granules in the red cells1 in a previously healthy person1 and diminution in the hmoglobin to #ge per cent41 is definite evidence that absorption is leading on to poisoning--that is1 blood-destruction--and coincidently insidious damage to the finer bloodvessels and their nerve-supply 7see ,chapter ,v474 ,such a person may at any moment develop a sudden attack of colic or paresis4 ,associated with the wasting and pallor comes wasting of the muscles themselves1 quite apart from any nerve lesions1 and with it a certain degree of mental lethargy1 slowness in comprehension1 and loss of power over individual muscles or groups of muscles1 more usually the latter4 ,the mental lethargy shows itself in many ways--amongst others1 heaviness and drowsiness--and careful examination should be made of any man who1 previously a good time-keeper1 commences somewhat suddenly to be late in the morning4 ,the muscles of the hands and the arms1 may show no definite wasting as compared one with another2 but early loss of power1 particularly of the extensors of the wrist or fingers1 may be present for six months to a year before definite wrist-drop makes its appearance4 ,in two cases under our own observation1 loss of power of the extensor muscles of the wrist was present--in the one case for eight1 and in the other case eleven1 months before definite paresis occurred4 ,in the one case the first symptom of paralysis was inability to extend the little fingers of both hands2 the case was at once suspended from work1 and was given treatment4 ,within forty-eight hours both wrists were so far affected that they could not be extended4 ,in the second case the first symptom of paresis other than the loss of extensor power was the inability to oppose the thumb to the first index-finger of the left hand2 within seven days complete wrist-drop of the left hand1 partial drop of the right hand1 including the middle and ring fingers1 occurred4 ,both cases made a complete recovery4 ,by no means all wrists which show weakness of the extensor muscles ultimately develop paralysis2 for1 on looking through the records of the examination of three factories1 only #d per cent4 of persons whose wrists were noted as showing loss of extensor power ultimately developed definite paralysis4 ,in the extended position of the hands1 when the surgeon is examining for extensor weakness1 note should be made of any tremor1 as fine tremor is frequently an early symptom of ensuing paralysis4 ,the tremor is generally fine1 increased on attempting to perform concerted acts 7intention tremor72 some loss of co-ordination may be found4 ,where the nerve supplying the muscle has suffered alteration in its conductivity1 as by the occurrence of a small hmorrhage in its sheath1 gradual diminution in the nutrition of the muscle takes place2 but whether or not this is sufficient explanation for the chronic wasting which is seen in the hands is not yet definitely proved4 ,in examining the hands outstretched for tremor and loss of muscular power1 wasting of the interossei may be seen before any definite evidence of paralysis supervenes4 ,on the palm of the hand both the thenar and the hypothenar eminences may show flattening1 and attention should always be paid to this portion of the hand1 as an early flattening of the hypothenar eminence particularly is one of the earlier symptoms of wrist paralysis4 ,constipation4--,constipation is a well-known precursor of colic in lead poisoning cases1 but is by no means an invariable rule4 ,about #ae per cent4 of cases of lead colic suffer from intermittent diarrha4 ,a number of cases 7see the table on p4 #di7 show that 8rheumatic0 symptoms are amongst those associated with lead poisoning4 ,some of these rheumatic symptoms1 as has been explained1 may be due to minute hmorrhages1 in the muscle or elsewhere1 setting up the pains of a rheumatic nature in the part affected4 ,one other symptom occurs with considerable frequency both as a precursor of colic and as an associated symptom in constipation1 and even in diarrha associated with lead poisoning1 and often regarded as of rheumatic origin--namely1 lumbago4 ,complaints of lumbago in lead-workers should always be regarded seriously1 as they may be a guide in discovering an early intoxication4 ,from what has been said of the excretion of lead into the large intestine in poisoned animals1 the symptom of lumbago often complained of by lead-workers may1 in some instances at any rate1 owe its origin to overloading of the large intestine1 due to the inhibitory action of lead on the intestinal muscles4 ,it has been seen that excretion of lead into the large intestine is the normal method of excretion of the metal1 and that concomitant congestion of the vessels in the corresponding mesenteric area is an associated symptom in poisoned animals4 ,local vasomotor spasm may also contribute4 ,the ,pulse4--,the pulse in lead poisoning in the incipient stage is perhaps not so important as when poisoning has become pronounced4 ,considerable variation exists amongst different observers with regard to the blood-pressure of lead-workers4 ,our experience is1 on the whole1 that it tends to be high1 and pressures of #aej to #agj mm4 ,hg are common4 ,in an average of #ajj cases we found the highest pressure to be #agh1 and the lowest #aae1 the mean #aej4 ,collis#b1 in a special report on smelting of materials containing lead1 gives the average blood-pressure of #ada smelters as #adhb1 and of #ch white lead-workers as #aefe4 ,increase of tension undoubtedly takes place as lead absorption becomes more established1 and the well-known high arterial tension of arterio-sclerosis is to be found in most workers employed in lead for any considerable period4 ,even in the cases quoted above showing no signs of lead poisoning1 notwithstanding long duration of employment in lead factories1 there was a distinct increase of arterial tension1 not necessarily attributable to lead alone1 but possibly also to such incidental causes as gout1 alcoholism1 syphilis1 etc4 ,when colic is present1 marked diminution in the pulse-rate may be noticed during the spasms1 and even without the presence of colic a diminution in the pulse-rate1 with a definite increase of tension1 as estimated by the finger1 is a matter of practical importance in the diagnosis of absorption4 ,in quite early stages the pulse may be increased1 and a small1 rapid pulse should be regarded as a suspicious sign4 ,only in the later stages of the disease do alterations in the heart-sounds take place4 ,sphygmograph tracings of the pulse of lead-poisoned persons shows the well-marked high tension type4 ,lead ,colic4--,probably the commonest symptom1 and the one for which first and foremost relief is sought1 is abdominal colic4 ,the colic of lead poisoning1 when once seen1 is rarely mistaken a second time4 ,the pain is generally referred to the lower portion of the abdomen1 low down1 and often the sufferer points to a position immediately above the pubes2 pain may often be referred also to the right iliac fossa1 and on this account the possibility of appendicitis1 or even perityphlitis or chronic colitis1 must not be forgotten4 ,colic1 as shown in the statistics on p4 #di1 is the chief symptom complained of4 ,no doubt1 as has been previously suggested1 the fact that colic is so common a symptom induced earlier pathologists to regard the entrance of lead through the gastro-intestinal canal as being the portal of lead infection4 ,we have1 however1 demonstrated in the chapter on ,pathology that the absorption of lead1 particularly in industrial processes1 is mainly by way of the lung1 and in the rsum of the literature it has already been pointed out that strong evidence exists for regarding colic and other abdominal symptoms associated with pain as due to vaso-motor disturbances in the splanchnic and mesenteric areas4 ,lead colic is usually irregular1 with marked exacerbations and remissions1 and in the acute form the legs are drawn upwards towards the abdomen1 the body is flexed at the hips1 the face anxious and drawn1 whilst the body is covered with a cold sweat1 the eyes are staring1 and convulsive movements of the limbs occur4 ,the sufferer often finds relief from firm pressure upon the abdomen1 a point of considerable importance in diagnosis2 the pain is not increased1 but distinctly relieved1 by firm pressure4 ,if the abdomen be digitally examined during a paroxysm of pain1 the intestines will be found contracted under the fingers1 often in an irregular fashion4 ,in an animal acutely poisoned with lead the intestines are found irregularly contracted during a very large portion of their length1 and when removed from the body have the appearance of a string of sausages4 ,there is evidence that spasmodic contraction of the circular fibres of the muscles of the mucosa has taken place1 and the wave of peristalsis1 moving forward1 meets with a block at these points of constriction1 thereby causing pain4 ,the colic affecting the lower part of the abdomen may possibly be related to the excretion of lead into the large intestine1 and the affection of the bloodvessels in the mesentery1 and in animals poisoned by means of lead the vessels in the mesentery1 particularly in the region of the ileo-ccal valve and the large intestine1 are engorged with blood4 ,during a paroxysm the patient frequently screams in agony and rolls about upon the bed or the floor4 ,temporary relief may be obtained by leaning upon a pillow placed upon the back of a chair4 ,the relief afforded by such procedure is also strongly in favour of the vaso-motor origin of the pain4 ,during the spasm the abdomen is retracted1 and fibrillary twitching of the abdominal parietes may often be seen2 a constant desire to go to stool is generally present1 but only results in straining and1 perhaps1 the passage of a little mucus and blood4 ,vomiting is often associated with this stage1 and the patient frequently vomits a considerable amount of thick1 tenacious mucus4 ,the vomit is not uncommonly regarded by the patient as composed of white lead1 if he has been working in that industry4 ,tanquerel in #a1bag cases noted vomiting #djj times1 and marked retraction of the abdomen #fdi times4 ,occasionally the patient complains of a sense of great weight in the abdomen1 particularly in the intervals between the spasms of pain4 ,during the exacerbations of colic very marked diminution in the pulse-rate takes place1 a fact that has already been referred to in the section dealing with vaso-motor disturbances4 ,the pulse may be as low as #bj beats per minute1 but it varies generally between #dj and #ej per minute4 ,very occasionally the first stage of colic is associated with a slight rise of temperature4 ,this must be regarded as an intercurrent affection rather than as one definitely associated with lead poisoning4 ,probably in such circumstances a gastritis other than the lead vaso-motor colic is the reason for the elevation of temperature1 but it may confuse the diagnosis1 suggesting rather an acute gastritis than lead colic4 ,under normal conditions the temperature falls during the colic1 the extremities are cold1 and the body is covered with a moist perspiration1 the temperature dropping to #if1 and even lower4 ,on palpating the abdomen during these acute exacerbations1 it is found that not only the gastric region1 but the whole of the abdomen1 is affected4 ,occasionally the acute pain is referred to the navel1 but generally to the lower region of the abdomen2 and very frequently the pain is described as running down into the scrotum1 whilst there may also be pain complained of as far as the knee-joint1 but this last is unusual4 ,there may or may not be well-marked peristalsis taking place1 but quite commonly large hardened tumours can be felt in various situations in the abdomen1 corresponding to the contracted intestinal walls4 ,shifting tumours1 then1 may be regarded rather as a diagnostic sign of the acute forms of lead colic4 ,the colic rarely commences without some slight prodromal symptoms of dyspepsia or gastric discomfort2 generally for two or three days preceding the attack there is loss of appetite1 with a distaste for food1 and obstinate constipation1 particularly a general feeling of languor associated with an unpleasant taste in the mouth4 ,tanquerel1 and later ,grissolle#c1 among others1 described a form of stomatitis which they thought was a prodromal symptom of an attack of lead colic4 ,our own experience1 however1 does not at all coincide with these statements4 ,very occasionally the sufferer from acute colic may die during a paroxysm due to heart failure1 but we have had no experience of such a fatality1 although such an occurrence has been recorded on more than one occasion4 ,after the first acute attack of colic1 which generally commences suddenly1 often without previous warning1 but is as a rule ushered in by irregular and finally complete constipation1 or with diarrha alternating with constipation1 the colic still occurs at irregular intervals2 and although the constipation be relieved by enemata or the use of strong purgatives1 paroxysmal pain will recur for days1 and even weeks4 ,in one particular case colic recurred at intervals for eight weeks1 although the bowels were open each day and the patient had been under regular treatment1 whilst the anmia and other general symptoms of poisoning had disappeared4 ,according to the researches of ,meillre#d and others1 lead is stored up in the body in various situations1 and is gradually eliminated1 such elimination taking place mainly through the fces1 and only to a limited extent through the urine4 ,probably the elimination of lead through the lower part of the intestine accounts for the recurrent attacks of colic4 ,amino#e1 ,chatin#f1 and ,harnack#g1 regard this colic as due to vaso-constriction taking place in the splanchnic area1 and the rapid action of such drugs as atropin1 chloroform1 and nitroglycerine1 support this view4 ,in fact1 ,mayer#h in #ahha demonstrated that in lead colic the splanchnic vessels undergo well-marked minute inflammatory changes4 ,others1 from investigations carried on in persons who had died of lead poisoning1 regard the acute pain as set up by irritation of the sympathetic nervous system1 particularly of the solar plexus1 irritation of the nerves in this region presumably setting up reflex colic4 ,the inhalation of amyl nitrite during an attack of colic will often entirely relieve it1 and the pulse will immediately rise to the normal rate4 ,it is difficult1 however1 in observing a case of colic1 to determine whether the colic is preceded by slowing of the pulse and the rise of blood-pressure1 or whether the colic is the immediate exciting cause of the constriction of the vessels and the alteration of the pulse-rate4 ,chronic ,colic4--,the acute form of lead colic frequently passes on to a chronic condition2 the attacks become much less intense1 and may at times only amount to general discomfort in the abdomen1 but the symptoms may last for several weeks1 and even months1 with no abdominal discomfort for a period of a week or ten days1 then recurrence of pain1 gradually increasing until it has attained a considerable degree of intensity1 and then passing away1 only to reappear in two or three days' time4 ,in such cases of prolonged colic after an interval of two or three weeks1 small doses of strychnine or tincture of nux vomica will determine the onset of an attack of colic1 showing that the intestinal muscular tissue remains in a state of hypersensibility long after the attack appears to have passed away4 ,a particular form of colic of long duration with exacerbations and remissions has been known for many years in the ,french navy1 called 8seamen's colic40 ,before this time outbreaks had occurred in various parts of the world1 and ,john ,hunter#i described a form of dry bellyache occasioned by drinking certain ,west ,indian wines1 the wines in question having been stored in contact with lead--in fact1 the vigorous ,saxon of ,john ,hunter peculiarly describes this chronic form of lead colic4 ,although the prodromal stages of malaise1 lassitude1 loss of appetite1 nausea1 etc41 generally precede both the acute and the chronic forms1 colic often commences suddenly4 ,men may be examined in the factory in the morning1 when the ordinary routine examination has elicited no symptoms1 and yet cases of acute colic have occurred later in the same day in the very men examined4 ,the chief points associated with lead colic are-- #a4 ,the intermittent character4 #b4 ,the relation of the colic mainly to the lower part of the abdomen4 #c4 ,the slowing of the pulse4 #d4 ,the relief afforded by firm pressure on the abdomen4 ,to which may be added the action of amyl nitrite and other drugs of a similar physiological action4 ,headache4--,persistent headache is another of the symptoms associated with lead poisoning1 but it is not common as an early symptom4 ,the headache complained of by painters is probably not due to lead poisoning1 but1 as has been suggested1 to turpentine4 ,the headache of lead poisoning is invariably a later symptom1 and frequently follows an attack of colic a week or more after the abdominal pain has ceased4 ,the position of the headache varies2 it may be of the vertex type1 almost entirely confined to the vertex and occipital regions4 ,on the other hand1 it is frequently irregular1 and neuralgic in type2 but in this type1 frontal and temporal1 more particularly temporal1 the patient describes the pain as if a blunt instrument were being pushed through his head from both temporal regions at the same time4 ,earache1 or pain in the region of the petrous portion of the temporal bone1 may at times suggest ear disease1 but this situation is not so common as suboccipital or temporal pain4 ,the headache in these situations is no doubt associated with the meningeal artery in the temporal region1 and with the sinuses in the occipital region4 ,the headache1 not unlike the colic1 undergoes remissions and exacerbations4 ,with the exacerbations vertigo is common1 and on more than one occasion in our experience a person suffering from persistent lead headache and vertigo has been arrested as suspect of alcoholism4 ,headache and vertigo without either colic or paresis is by no means uncommon1 and may be associated with pains in the arms and legs4 ,these pains are generally referred to by the patient as rheumatic1 and it is a little interesting to call to mind the number of instances in which rheumatic symptoms are returned as associated with lead poisoning in the statistics given on p4 #dh4 ,it is probable that these pains are neither muscular nor purely nervous in origin1 but are primarily due to small lesions of the bloodvessels1 as described in the chapter on ,pathology1 occurring in various parts of the body1 and thereby setting up localized irritation1 too minute to form an area which can be discovered by palpation1 but sufficiently pronounced to produce irritation and reflex pain1 in some respects similar to 8bends0 in compressed air disease4 ,this special type of rheumatic pain differs1 of course1 from the lumbago associated with constipation4 ,persistent headache is an exceedingly grave feature1 and although it may at times disappear quickly on treatment1 mental clouding and alteration of the higher functions is always to be feared2 not infrequently persistent headache ushers in a final and fatal encephalopathy4 ,in such a case the headache persists1 becomes more and more excruciating1 the patient rapidly shows loss of mental power1 and may gradually sink into a condition of delirium4 ,on the other hand1 an attack of acute delirium may suddenly supervene1 commencing with sudden loss of consciousness1 followed by irregular movements of all the limbs1 frothing at the mouth and nose1 and finally mania4 ,recovery is by no means uncommon1 and after a sudden attack of this description the patients are entirely ignorant of the whole circumstance2 they may occasionally recover powers of locomotion1 and wander to long distances1 unable to give an account of themselves or to remember their names1 and only after a considerable time recover consciousness of their identity2 but this type of case is comparatively rare4 ,the case quoted by ,mott#aj gives a typical history of mental affection due1 no doubt1 to lead1 but partially complicated by alcohol4 ,the ,burtonian ,line4--,much controversy has raged around the significance of the blue line on the gums to be seen in certain persons working in lead1 as to whether this particularly well-marked sign is to be regarded as a diagnostic symptom of lead poisoning or not4 ,for a long time it was regarded1 and by many is still regarded1 as sufficient evidence in itself to determine that a person is suffering from lead poisoning4 ,on the other hand1 those who have had considerable experience of industrial lead poisoning1 particularly in the routine examination of workmen occupied in various lead industries1 do not regard the occurrence of the ,burtonian line as of more value than that the person showing such pigmented gums has been exposed to lead absorption4 ,there are two kinds of ,burtonian line3 #a4 ,a fine bluish line is seen around the gingival margins1 more pronounced on the interdental papill of the gum1 and always more marked around such teeth as are coated with a deposit of tartar than around teeth which are clean4 ,this line is undoubtedly due to the decomposition of the lead salts which have gained access to the mouth1 by the sulphuretted hydrogen produced by the decomposition and putrefaction of food1 epithelial dbris1 and other materials1 which have accumulated around the edges of the teeth and in the interdental spaces4 ,peculiar evidence of this may often be seen in the mouths of certain persons whose parotid glands are discharging saliva which promotes deposits of calculus4 ,thus1 one may often find merely the two first upper molar teeth on both sides of the upper jaw coated with tartar1 no other teeth in the upper jaw being similarly affected4 ,this deposit of calcium phosphate and carbonate is exceedingly porous1 and becomes saturated with the products of decomposition1 evolving sulphuretted hydrogen in fairly large quantities4 ,in the mouths of such persons working in lead factories a dark bluish staining of the cheek in apposition to the filthy tooth may be frequently seen1 and where the rest of the teeth are free from deposit no such staining is observable4 ,viewed with a hand-lens1 the blue line is seen to be made up of a large number of minute granules of dark colour which are deposited1 often deeply1 in the tissue4 ,it is a matter of importance to note that a blue line is rarely seen in the mouths of those persons who pay attention to dental hygiene2 where the teeth are clean1 the gums closely adherent to the teeth1 and entire absence of pus and freedom from deposit we have never seen a ,burtonian line produced4 ,many of the so-called healthy mouths with perfect teeth have yet infected gums4 ,on examining sections of such a line1 it is interesting to note that at first sight the particles appear to be situated deeply in the tissue1 and mainly in relation to the bloodvessels supplying the gum4 ,a little closer attention shows that the particles are really aggregated1 particularly in the deficiencies between the epithelial cells which are constantly thrown off from the surface of the gum1 a process which has its origin in an inflammatory condition1 the whole gum becoming hypertrophied1 with numerous small areas of ulceration4 ,in these positions a certain amount of direct absorption of dust and fine particles takes place from the ulcerated surface1 and becomes converted into lead sulphide by the sulphuretted hydrogen produced locally from the decomposing tissue4 ,a certain amount of pigmentation is also referable to the mucous glands4 ,it is well known that1 in infections of the mouth of the type of pyorrha alveolaris or of rarefaction of the alveolar process1 a good deal of infection coexists in the mucous glands of the buccal membrane1 especially along the gum margins themselves1 and the lead dust also becomes deposited in these glands1 and later forms a sulphide4 ,it is possible that some blue lines are due to excretion of lead from the blood4 ,some little care is required to differentiate between the early lead ,burtonian line and the curious bluish-grey appearance of the gum edges in cases of pyorrha alveolaris2 when once the two conditions have been studied1 little difficulty exists1 but the use of a hand-lens will at once settle the matter4 ,the bluish appearance of the gum in many cases of gum disease is due to local cyanosis4 ,a few other forms of pigmentation of the gum edges exist1 such as an occasional blue line seen in workers with mercury1 a black line in coal-miners1 and so on1 but these hardly call for discussion in the present instance4 ,any pigmentation of the nature discussed above is to be regarded as a sign that the worker has been subjected to the inhalation of lead dust1 and is therefore suspect of lead absorption1 in whom definite symptoms of lead poisoning may be expected to occur if the exposure to the harmful influence be long-continued4 #b4 ,in the second variety of blue line the pigmentation is not confined to the gum edge or to a band rarely exceeding a millimetre in width1 as is the ordinary common blue line4 ,in this case the whole of the gingival mucous membrane from the edges of the teeth1 and extending some way into the buccal sulcus1 five or six millimetres or even a centimetre wide1 may be seen4 ,when this phenomenon is present1 it is always associated with a marked degree of pyorrha alveolaris1 the gums are soft1 dematous1 and pus oozes from their edges1 the teeth are frequently loose1 and the other symptoms of disease of the os marginum are present4 ,sections made from such a case suggest still more that some excretion of lead has taken place from the bloodvessels1 as the lead particles may be seen closely related to the capillaries2 but here again there is little doubt that it is due to absorption from the externally inflamed surfaces of the gum rather than excretion of the vessels themselves4 ,it is interesting to note that1 in all the experimental animals1 in no instance has any ,burtonian line been observed1 although the animals 7cats and dogs7 have been fed upon cat's meat1 which readily undergoes putrefaction1 and organisms capable of producing sulphuretted hydrogen are invariably present in the mouths of such animals4 ,notwithstanding this1 the blue line has not been observed1 because the animals' gums were entirely free from infection or pathological changes4 ,by causing an artificial inflammation around the canine teeth of an animal exposed to lead infection1 a definite blue line was produced in two weeks4 ,this line had all the characteristics of the common ,burtonian line4 ,this form of blue line with a deep pigmentation of the whole of the gums1 although in itself not to be regarded as diagnostic of lead poisoning alone1 rarely occurs unless the person has been subjected to such long-continued poisoning that other symptoms have already made their appearance4 ,the blue line1 then1 whichever type is observed1 cannot in our opinion be regarded as a diagnostic sign of lead poisoning1 but is merely an indication that the person who exhibits the phenomenon has been at some time or other subjected to lead absorption4 ,there is no evidence to show that lead is excreted by the salivary glands4 ,a number of cases of poisoning certainly complain of a metallic taste in the mouth1 and1 judging from the analogy of mercury1 it is possible that excretion of small quantities of lead may take place through the saliva2 but such a point is merely of scientific interest1 and has no practical bearing on the question of lead poisoning4 ,pigmentation in the salivary glands suggesting excretion of lead has not been observed1 notwithstanding the constant presence of potassium sulphocyanide in the parotid saliva4 ,the blue line of ,burton may occasionally be observed1 in other regions of the body4 ,from time to time the intestine is found stained with a bluish-black deposit of lead sulphide1 and in a case of acute poisoning following the ingestion of a large quantity of lead acetate1 and in the cases described by ,oliver of the ingestion of lead oxide 7litharge71 black staining of the intestines was peculiarly well marked4 ,in all the animals referred to it forms a constant feature in the large intestine1 and in the chapter on ,pathology this blue staining of the large intestine is more minutely described4 ,we have met with it once in the post-mortem examination of a man who died of lead poisoning1 and when found it may1 we think1 be regarded as a diagnostic sign4 ,macroscopical evidence is not sufficient2 it is necessary to make a histological examination of the tissues1 when the stained areas are seen to be associated with the lymphoid tissue in the intestinal wall1 and not only interstitial portions1 but actually the interior of the cells themselves1 are found to be packed with small bluish granules4 ,such a histological finding would be highly characteristic of an extreme case of lead poisoning4 ,where considerable quantities of lead have been taken into the gastro-intestinal canal1 a blue ring has occasionally been described surrounding the anus4 ,about #he per cent4 of cases of lead poisoning with colic show obstinate constipation as a leading symptom4 ,the constipation generally exists for several days preceding the onset of the colic1 and may persist for as long as twelve to fourteen days1 while six to seven days is a common period4 ,there is very little that is characteristic about the constipation other than its intractability2 indeed1 it is frequently of the greatest difficulty to relieve this symptom4 ,no doubt the direct origin is due to the excretion of lead into the large intestine 7see p4 #id74 ,palpation of the colon often shows distension1 with a good deal of pain on pressure at both the hepatic and splanchnic flexures1 more particularly the latter4 ,distinctly painful spots may be found in the length of the intestine1 due to small ulcers1 or more probably to the minute hmorrhages which we have elsewhere described as associated with lead poisoning4 ,the remaining #ae per cent4 of cases have as a prodromal symptom diarrha4 ,further1 diarrha is not uncommon amongst persons who are working in a lead factory1 and who do not show other signs of poisoning2 and as lead taken into the body in various ways is excreted through the fces in common with other heavy metals1 such as iron1 bismuth1 nickel1 as well as arsenic1 the occurrence of diarrha should suggest to the surgeon the possibility of considerable lead absorption having taken place4 ,,references4 #a ,,zinn3 ,berl4 ,klin4 ,woch41 ,no4 #ej1 #ahii4 #b ,,collis1 ,e4 ,l43 ,special ,report on ,dangerous or ,injurious ,processes in the ,smelting of ,materials containing ,lead1 p4 #f4 #aiaj4 #c ,,grissolle3 ,thse1 ,paris1 #ahce4 #d ,,meill,,re1 ,g43 ,le ,saturnisme1 p4 #abb4 ,paris1 #aijc4 #e ,,amino3 ,archiv4 ,ital4 di ,clin4 ,med41 #ahic4 #f ,,chatin3 ,province ,md41 ,lyon1 ,no4 #d1 #ahib4 #g ,,harnack3 ,deutsch4 ,med4 ,woch41 #ahig4 #h ,,mayer3 ,virchow's ,archiv1 #ahha4 #i ,,hunter1 ,,john3 ,observations of the ,diseases of the ,army in ,jamaica4 ,london1 #aghh4 #aj ,,mott1 ,f43 ,archives of ,neurology and ,psychiatry1 vol4 iv41 p4 #aag4 ,,chapter ,,viii ,,excretion ,,of ,,lead ,symptomatology and ,diagnosis 7,continued7--,excretion of ,lead4--,the two chief channels for excretion of lead are the urine and the fces1 while some include the saliva and the sweat4 ,in the case of the sweat there is not much evidence1 but a few observers1 mainly ,french1 claim to have discovered traces of lead in the skin of lead-workers4 ,in such a case1 however1 it is exceedingly difficult to eliminate the question of surface contamination2 and although brisk peripheral circulation and transudation may possibly carry off a certain amount of lead1 the chance of this is highly improbable4 ,there seems rather more evidence that the salivary glands may eliminate lead1 as a number of other substances are undoubtedly passed in this way4 ,mercury certainly undergoes excretion through the salivary glands and the mucous glands of the mouth1 and it is therefore not improbable that a metal so closely related in its chemical1 and perhaps physiological1 relations may be excreted in a similar fashion4 ,meillre#a cites three instances of parotitis which were considered to be of lead origin1 and further quotes an instance where1 in chemical examination of the salivary glands after death1 lead was found in small quantities4 ,chronic parotitis is not infrequently cited as a symptom in cases of reported industrial lead poisoning1 and may owe its origin to impairment of the salivary gland by the passage of the metal4 ,chronic parotitis1 or even tenderness of the parotid glands1 does not occur frequently among lead-workers with symptoms of lead absorption4 ,excretion1 however1 of lead through the salivary glands is not of great importance1 except from the occasional complaint of a metallic taste in the mouth in chronic lead poisoning1 and in such instances possibly definite excretion of lead is taking place through the parotid glands4 ,a case may be cited which rather supports the view that lead may be excreted through the salivary glands4 ,a certain worker engaged in a dangerous lead process from time to time1 but never as a constant symptom1 showed distinct pigmentation in the internal surfaces of both cheeks in the region of the buccal papill of the parotid duct4 ,the pigmentation was intermittent2 at times a large patch of deep blue-black pigmentation was found in the situation on both sides1 with no staining of the cheeks around or of the gum margins1 although his teeth in these regions were coated with foul tartar4 ,if the lead in this instance gained access through the mouth1 why should it have been deposited merely upon the cheek in this one situation1 despite the fact that several other situations in the mouth exhibited the same conditions of bacterial decomposition for the production of sulphuretted hydrogen8 ,we have not observed this pigmentation in the neighbourhood of the ducts of the submaxillary and sublingual glands1 but only in the parotid4 ,by far the most important organ in the excretion of lead1 from the point of view of symptomatology and diagnosis1 is the kidney4 ,lead is not uncommonly found in the urine of lead-workers and in the urine of those suffering from lead poisoning4 ,the quantity present is usually small and in a form in which it is exceedingly difficult to detect4 ,yet very pronounced changes in the kidneys may take place1 with little evidence in the urine itself that pathological changes are taking place4 ,the urine of workers in lead factories is frequently high-coloured2 in fact1 as a general rule the degree of pigmentation is greater than is normal1 and in those persons who show some degree of icterus1 with the curious yellowish-brown colour of the conjunctiv1 hmatoporphyrin may be detected on applying suitable tests4 ,in well-established cases of chronic poisoning1 albuminuria as a rule is found1 together with certain alterations in the other constituents of the urine1 such alteration frequently making its appearance before the definite onset of albuminuria4 ,further1 the changes in the eye1 referred to under a special heading1 have been frequently described as albuminuric retinitis of lead origin1 it being true that eye changes are often associated with chronic changes in the kidney4 ,in acute poisoning lead is generally found in the urine1 but in chronic poisoning it is by no means a common occurrence4 ,from time to time small quantities are excreted1 and in the chemical analysis made of the kidneys in cases of fatal lead poisoning a certain amount of lead has frequently been noted4 ,wynter ,blyth#b found in the kidneys of two white lead workers a total of #jjjc gramme4 ,peyrusson and ,pillault#c1 quoted by ,meillre1 found a similar quantity1 #jjjc gramme1 while in experimental animals ,meillre himself found considerably less1 only #jjjja gramme2 ,stevenson1 in a case reported by ,newton ,pitt#d1 #jjjhf per cent4 of lead in the ccum and colon4 ,notwithstanding a small quantity of lead which may be determined by chemical methods as present in the urine or the kidney1 very definite nephritis is set up in these organs1 obviously due to the irritative effect of the metallic poison4 ,the ,kidneys4--,kidney disease of several types has been described as associated with poisoning by lead1 particularly with chronic lead poisoning1 where large quantities of a soluble lead salt have been ingested4 ,very considerable strain is thrown upon the kidney1 with the result that the lead salts themselves are passed through2 but1 as has been pointed out when dealing with acute poisoning1 the passage of lead through the kidneys does not continue for any considerable time1 and in lead poisoning of an industrial and chronic nature no lead at all has been found in the urine in undoubted cases4 ,even when present1 it may be difficult to detect unless the electrolytic method is used 7see p4 #agd74 ,at the same time kidney disease undoubtedly does occur in a very large number of workers4 ,all heavy metals1 of which silver1 mercury1 iron1 zinc1 and finally lead1 may be quoted as examples1 appear to be eliminated by the kidney when they are present in the body in toxic doses1 and often when in small non-toxic doses1 but in the latter case to a greater extent through the bowel than through the kidney4 ,the lead circulating in the blood1 in common with other heavy metals1 may be found chemically in the kidney1 but the quantity recovered is not as large as one would expect from the considerable amount of inflammation often present4 ,in the experiments on animals1 subjected to poisoning over considerable periods1 the condition of the kidney in every instance showed distinct histological changes2 and the longer such animals had been subjected to the poisonous effects of the metal1 the more advanced were the signs of degeneration in its structure4 ,in the earliest cases the disease partook much more of the nature of an interstitial nephritis1 and it was in the later and more chronic stages only that changes in the glomeruli and fibroid degeneration were to be found1 but in even these earliest cases of poisoning definite minute interstitial hmorrhages were to be found scattered about the kidney4 ,these minute hmorrhages did not cause symptoms of hmaturia1 as in none of the experimental animals was bloody urine observed4 ,on the other hand1 besides definite small areas of hmorrhage1 patches were discoverable1 indicative of hmorrhage which had undergone fibroid change4 ,even in the illustrations given by ,glibert#e1 there appears to be evidence that hmorrhage had taken place and had undergone fibroid degeneration1 and there is very little doubt that in cases of kidney disease1 the preliminary action of the poison determines small local yieldings of the vessel walls1 with leakage1 often hardly amounting to true hmorrhage1 at such spots4 ,there is nothing opposed to the theory in the findings of other observers2 in fact1 if the preliminary gross effect be leakage of the description given1 all the other lesions described by various observers follow as a corollary4 ,in the kidney1 as in the other regions of the body1 the venioles rather than the arterioles appear to be the preliminary site of destruction1 and microscopical observation of the sections leads to the view that the intima of the vessels and not the media or the muscular coat is the one affected in the first place4 ,capillary hmorrhages under these conditions are easier to understand than if the arterioles themselves or their muscular or middle coats were primarily affected4 ,as degenerative changes progress1 the whole of the vessel--external and middle coats and intima--undergoes change1 ultimately resulting in the extreme narrowing and consequent blocking of the vessels themselves4 ,further shrinkage taking place in this area produces the shrunken sclerosed kidney4 ,zinc in the form of oxide behaves in very much the same way upon the kidney as does lead4 ,an experimental animal1 which was given #jb gramme of zinc oxide per kilogramme body weight by hypodermic injection in the muscles of the back1 died in fifteen days1 and the kidneys showed extensive hmorrhages--not merely the minute and capillary hmorrhages found in lead poisoning1 but hmorrhages extending right through from the cortex4 ,clinically1 kidney disease1 unless albumin be detected in the urine1 is not a prominent symptom during the progress of an attack of chronic lead poisoning1 and is to be regarded as a late symptom1 developing as the result of long-continued irritation4 ,the difficulty of eliminating alcoholic complication has been discussed1 and there are no specific symptoms or post-mortem signs which enable one to distinguish alcoholic nephritis from the nephritis of lead poisoning4 ,in the chapter on ,pathology1 the effect of alcohol on the kidney was cited as a common predisposing cause of kidney disease in lead-workers1 and the effect of alcoholic excess in the case of a person who is already the subject of chronic lead absorption may determine the change from absorption to definite poisoning1 because of alteration in the excreting-power of the kidney4 ,so long as the ratio between ingestion and excretion is maintained the balance is kept up1 and1 although the tissues of the body may show signs of a certain amount of degeneration1 no definite disease is produced2 but the gastric irritation and the work thrown upon the kidney in removing from the blood large quantities of alcohol may be sufficient to alter this absorption-excretory balance and determine the attack of poisoning4 ,acute nephritis is rare1 and cannot be regarded as a sequela of chronic lead poisoning4 ,acute nephritis occurring in a lead-worker1 with the associated symptoms of general dema of the face1 eyes1 hands1 feet1 is of the gravest possible moment1 and such a sudden appearance of nephritis is almost invariably fatal4 ,in chronic nephritis1 to which most of the lead cases belong1 the usual signs are to be found in the urine4 ,pain is rarely a symptom2 and although pain in the back is often complained of by lead-workers1 examination rarely suggests that the backache is of kidney origin1 but rather the lumbago type associated with chronic constipation4 ,care1 however1 must be taken1 when backache is complained of1 in eliminating kidney disease as a possible origin of the pain4 ,a quantitative examination of the urine1 with reference to the total acidity and phosphate excretion1 may assist2 and although this is not possible in a routine examination of cases of lead absorption1 it may be useful in cases of suspected poisoning1 especially where there are evidences of a good deal of blood-destruction4 ,for convenience of description1 it is better to consider the action of lead upon the blood under two headings3 #a4 ,that of the corpuscular and other changes4 #b4 ,the action on the vessel walls1 and pathological changes secondary to disease of the vessels4 ,the ,anmia of ,lead ,poisoning and ,saturnine ,anmia4--,from the early days of medicine it has been known that lead produces poverty of the blood1 and the white or yellowish-white appearance of persons who have been subjected to long-continued inhalation of lead dust or fumes constitutes striking evidence of blood-alteration4 ,at the same time it is a common fact that the facial pallor does not always go hand in hand with diminution in the hmoglobin4 ,the conjunctiva may be observed as a test for colour1 and here may be seen the curious vaso-motor disturbances which are partially responsible for the facial pallor4 ,facial pallor in some forms of lead cachexia owes its origin to interference with the nerve-supply to the vessel walls1 and it is a noticeable fact that a lead-worker whose face shows unmistakable signs of pallor rapidly flushes when spoken to suddenly or if mentally disturbed4 ,the anmia of lead poisoning is1 however1 a very definite fact4 ,all observers are agreed that a marked diminution in the hmoglobin of the blood takes place1 to as low1 often1 as #ce per cent41 without necessitating abstention from work1 and without any serious interference with respiration1 even when performing heavy manual labour4 ,in persons in whom the hmoglobin is diminished there is frequently a yellowish or icterous hue of the skin1 particularly the conjunctiva1 due to staining of the tissues with altered blood-pigment4 ,the hmoglobin derivative--hmatoporphyrin--can also be found in the urine of persons suffering from a marked degree of reduction in the blood-pigment1 and may be taken as confirmatory evidence of destructive or hmolytic anmia4 ,the symptom is1 however1 a later one than is frequently stated by the ,french observers1 and can only be regarded as a later and confirmatory symptom1 and not as an early one of diagnostic importance4 ,as would be expected from the destruction of blood-pigment1 the morbid process leaves its imprint upon the individual red cells1 and basophile staining of a number of the red corpuscles is to be found in a very large proportion of persons poisoned by lead4 ,moritz#f first pointed out that these alterations in the red cells were present in lead poisoning4 ,the basophile granules are by no means confined to lead anmia1 but are to be found in any severe secondary anmia where hmolysis has taken place1 as in nitrobenzene and aniline poisoning1 carbon bisulphide1 etc4 ,in addition to the basophile-staining granules in the blood-cells1 the whole corpuscle may take on a bluish-grey tint when stained4 ,the best stain to demonstrate these bodies is ,leishman's modification of ,romanowski's1 and there is no occasion to stain the blood in the fresh condition1 as the presence of the granules may be demonstrated easily1 even after two or three months4 ,schmidt#g thinks that if the basophile corpuscles reach #ajj per million red cells the cause is undoubtedly lead poisoning4 ,alterations are also to be observed in the structure of the red blood-cells in addition to the basophile staining4 ,distinct vacuoles appear1 but as a general observation--first noted by ,glibert#h--the blood appears to be more resistant to damage when making the films1 and the red corpuscles themselves seem to be more elastic than normal 7increased viscosity74 ,alteration in the shapes of the corpuscles also takes place1 and not only small varieties--microcytes--but also the large macrocytes are to be found4 ,nucleated red cells are rare4 ,the diminution in the number of the red cells is not so pronounced as would be supposed from the diminution in the quantity of hmoglobin2 but in the later stages1 as in other secondary anmias of toxic origin1 the total quantity of red cells sinks to a count of a million or less per cubic millimetre4 ,according to ,garrod1 etc41 the alkalinity of the blood is decreased in lead absorption4 ,the white blood-corpuscles do not show any change in their structure by the ordinary methods of staining1 but they apparently show1 as do the red cells1 more resistance to injury in spreading blood-films--that is to say1 the viscosity of the blood1 which is apparently increased in lead poisoning1 is also exhibited by the white cells4 ,in the early stages of lead poisoning1 more especially in acute lead poisoning1 distinct leucocytosis may be observed1 such a leucocytosis showing itself rather in relation to the lymphocytes than to the polymorphonuclear cells4 ,in addition1 the large mononuclear cells are also greatly increased1 and a differential blood-count from a case of lead poisoning which also shows the presence of basophile granules in the cells invariably brings to light a definite increase in the percentage number of lymphocytes1 and a decrease in the number of polymorphonuclears1 and this even when the total leucocyte count is not outside the ordinary limit of normal variation4 ,on the whole1 the number of leucocytes present in the blood of persons suffering from lead absorption will always be found to tend rather towards the higher than the lower limit of normal variation4 ,at times a considerable increase in the number of eosinophile cells is found in films made from persons suffering from lead poisoning1 particularly when there has been prolonged obstinate constipation4 ,the count is never high1 and is rarely more than #e or #f per cent4 ,it is not usual to find any of the other forms of white cells in the blood1 and in this way the anmia of lead poisoning may be easily differentiated from the other forms1 such as pernicious anmia1 lymphatic leucmia1 spleno-medullary lymphocythmia4 ,by examining a number of blood-films derived from persons subjected to lead absorption1 and shuffled with a number of films from normal persons1 one of us 7,k4 ,w4 ,g47 has been able to separate out1 by the above method1 the blood-films taken from the suspected persons4 ,the criteria in the determination were-- #a4 ,the presence of basophile granules4 #b4 ,total basophile staining and size of corpuscles--poikilocytosis4 #c4 ,differential count1 showing increase in a number of lymphocytes and large mononuclear cells4 ,determination of the presence of lead poisoning from the examination of the blood1 therefore1 receives considerable support2 but at the same time it is open to some objection from the fact that it is not in lead poisoning alone that basophile granules make their appearance in the blood4 ,any cause producing destruction of the red blood-cells1 and even their depletion by prolonged hmorrhage1 is followed by an increase in the output of the red cells from the bone-marrow#i4 ,during this output of extra blood-cells from the bone-marrow1 numerous cells gain entrance to the blood1 in which the nuclei are not entirely degenerated2 and it is these particular cells which give the phenomena of basophile staining1 and their presence is rather indicative of the increased blood-formation that is progressing1 following blood-destruction1 rather than direct evidence of blood-destruction itself4 ,in a number of forms of anmia--in fact1 in almost all forms of severe secondary anmia1 and certainly all forms of anmia associated with hmolysis--the presence of basophile granules may be demonstrated4 ,they are commonly found in pernicious anmia1 secondary septic anmia1 and the anmia of malaria4 ,practically1 the use of basophile granules in the presence of the blood of lead-workers is being utilized in ,leipzig for the early detection of lead poisoning4 ,by means of the ,zeiss eyepiece enumeration disc the relative number of basophile granule cells to normal red cells is determined2 and when the number of red cells containing basophile granules exceeds #ajj per million red cells1 the individual from whom the blood is derived is regarded as in a presaturnine condition1 and given proper treatment4 ,by this means it has been found possible to diminish the number of persons actually suffering from lead poisoning4 ,the adoption of such a method has some drawbacks1 especially in view of the fact that substances other than lead may cause the basophilia4 ,at the same time there is no doubt that1 if all persons employed in lead trades who showed basophilia were suspended from their employment at the present time1 a very large number of persons would be dealt with4 ,yet the practical application of this method is by no means impossible under industrial conditions1 and would at any rate give a definite test upon which diagnosis could be made1 though it would be quite impossible to expect the general practitioner or the certifying surgeon to estimate the basophilic content4 ,all such estimations would necessarily have to be performed at some properly equipped pathological laboratory1 such as at the present time many municipal authorities possess4 ,these facts are of importance1 as a differential count of the white cells1 together with a careful inspection of a blood-film for basophile staining and alteration in the red cells1 as well as other phenomena noted1 together with an estimation of the hmoglobin contained in the blood1 are to our mind of considerably more value in the diagnosis of lead poisoning than is the quantitative estimation of the red or white cells4 ,the following tables give a certain number of enumerations1 etc41 made from the blood of lead-poisoned persons3 ,,blood-,,examination ,,of ,,lead ,,an,,mia--,,differential ,,count ,,per ,,cent4 ---------------------------------------- ----------- ,no4 ,hb4 ,r4,b4,c4 ,w4,b4,c4,index4,a4,b4,c4,d4,e4,f4,g4,h4 ,i4,j4,k4 ---------------------------------------- ----------- ,per ,cent4 #a #fj #c1dfj1jjj #g1jjj #jg #fcbj #f #c #h #j - - #b #de #a1gjg1jjj #i1jjj #ad #dfch #h #a #g #j #c #ee #b1fbj1jjjbj1jjj #aj #ehcb #d #b #d #j - - #d #fj #a1ccd1jjjaj1jjj #cj #eece #h #j #e #j - #e #ed #c1baj1jjj #h1jjj #ji #ebda #d #b #a #j - #f #fj #a1cdg1jjjaj1jjj #cj #eicb #c #b #c #a #g #fe #c1gfj1jjj #i1jjj #ji #h #fe #b1bjj1jjjaj1jjj #jg #i #ej #c1hfj1jjj #h1jjj #jf - #aj #fj #c1dbj1jjj #i1jjj #aj #gfafac #c #j #j ---------------------------------------- ----------- ---------------------------------------- ---------------------- ,no4 ,work4 ,notes4 ---------------------------------------- ---------------------- #a,paint mill #e years4 #b,paint mill #aj years4 #c,paint mill #g years4 #d,packer white lead #e years4 #e;,grinder #f years4 #f,white lead #h years4 #g,press and stoves #h years4 #h,zinc distillation still#bj years2 double wrist-drop #b years4 #i,white lead beds #aj years4 #aj,packer ---------------------------------------- ---------------------- ,a ,polymorphonuclears4 ,b ,lymphocytes4 ,c ,large hyaline4 ,d ,eosinophile4 ,e ,transitional4 ,f ,basophile4 ,g ,microcytes4 ,h ,megalocytes4 ,i ,poikilocytes4 ,j ,nucleated red4 ,k ,plehn's bodies4 ,corpuscles1 ,thoma-,zeiss4 ,hmaglobin1 ,haldane's instrument4 ,films1 stained ,leishman4 ,the form of lead inhaled is immaterial1 and definite poisoning with alteration in the blood may be occasioned1 not only with white lead and lead fume1 but also even with lead sulphate and lead silicate4 ,the following table gives the result of blood-counts performed upon the blood of persons employed in the manufacture of a paint erroneously supposed to be innocuous1 as the base consisted of lead sulphate and oxysulphate3 ,,differential ,,counts ,,per ,,cent4 ,,of ,,blood-,,films ,,from ,,lead ,,sulphate ,,workers4 ---------------------------- ,no4,a4,a,b4,c4,d4,e4,f4,g4,h4,i4,j4,k4 ---------------------------- #a #ee #af #e #a #j - #c #eg #afbf #a #j - - - #f #fg #bc #i #a #j #g #gb #ah #e #e #j - - - #h #fe #bf #g #b #j - - ---------------------------- ,a ,a ,polymorphonuclears4 ,b ,lymphocytes4 ,c ,mononuclears4 ,d ,eosinophiles4 ,e ,myelocytes4 ,f ,basophiles4 ,g ,microcytes4 ,h ,megalocytes4 ,i ,poikilocytes4 ,j ,vacuolated red cells4 ,k ,normoblasts4 ,sand-papering surfaces of painted objects1 walls1 coaches1 etc41 also throws a definite amount of lead dust into the air whenever the sand-papered paint contains lead4 ,the following table gives the differential counts of the blood of persons employed in the furniture-painting trades3 ,,differential ,,counts ,,per ,,cent4 ,,of ,,blood-,,films ,,from ,,furniture-,,makers 7,,sand-,,paperers74 ---------------------------- ,no4,a4,a,b4,c4,d4,e4,f4,g4,h4,i4,j4,k4 ---------------------------- #aj #dh #ciaa #a #a #ac #ed #ce #i #b #j - #ae #ec #cbac #a #a - - - - - #af #eh #cj #i #c #j - - - - #ai #ef #caab #j #a - - - ---------------------------- ,a ,a ,polymorphonuclears4 ,b ,lymphocytes4 ,c ,mononuclears4 ,d ,eosinophiles4 ,e ,myelocytes4 ,f ,basophiles4 ,g ,microcytes4 ,h ,megalocytes4 ,i ,poikilocytes4 ,j ,vacuolated red cells4 ,k ,normoblasts4 ,circulatory ,system4--,a very large number of the symptoms referable to chronic and well-defined lead poisoning are referable to circulatory lesions1 and1 as has been elsewhere pointed out1 the ultimate nerve degeneration occurring in various parts of the body is probably but a final symptom of the earlier hmorrhage which has taken place4 ,certain symptoms are1 however1 more closely related to the circulation than others1 and may therefore be more conveniently grouped together under the present heading4 ,the smaller changes1 many of them connected with special organs 7such1 for instance1 as the eye7 or particular regions 7as the mesenteric vessels71 have been already referred to in dealing with colic and eye changes4 ,vaso-motor changes precede the actual change in the vessel walls themselves4 ,on the other hand1 the alterations in the structure of the liver1 lung1 spleen1 and more especially the kidney1 are secondary to change in the structure of the walls of the vessels themselves4 ,vaso-motor disturbances may or may not be of nervous origin1 although the former view is probably correct1 and it is also equally possible that the direct affection of the vessels is associated with the nerve irritation4 ,on the other hand1 direct inflammation of the vessel walls1 resulting in obliterative arteritis1 in arterio-sclerosis1 and degeneration and exudation in the kidney1 lung1 and liver1 are practically due to degenerative changes either in the intima or the middle coats of the finer vessels4 ,the common symptoms of arterio-sclerosis1 vertigo1 headache1 and pulsation in the vessels1 and of the persistent headache already referred to1 all suggest changes taking place in the vessels complicated by dema4 ,in the early stages of kidney degeneration1 however1 it is common to find an interstitial nephritis due apparently to exudation from the vessel walls4 ,such an hypothesis is to some extent supported by the somewhat allied condition of engorgement and fibroid change in the liver and lung1 and to a lesser extent in the spleen4 ,in the lung1 even in persons not exposed to inhalation of lead1 and in animals1 as pointed out by ,glibert1 secondary changes in the lung follow lead intoxication1 such changes taking the form of emphysema and generalized fibrosis2 whilst the liver is engorged with blood1 and later undergoes similar degenerative changes4 ,the bloodvessels in these organs are found to have lost a considerable amount of their elasticity1 to have yielded here and there1 and in other places to be completely closed by obliterative arteritis4 ,microscopical hmorrhages are to be found mainly in the veins leading from the capillaries4 ,in the kidney such vessel changes as are outlined are the precursors of disease1 and albumin is found in the urine1 but the quantity is rarely very large4 ,casts are not common1 and the amount of lead present in the urine may be exceedingly small1 difficult to trace1 and in many cases entirely absent4 ,in the later stages of chronic saturnism the heart may show degenerative changes4 ,microscopical examination of the heart muscle shows that alteration of the fibres of the muscles takes place in a manner similar to that of the voluntary muscles4 ,disease of the heart valves is uncommon2 alterations in the heart sounds are infrequent2 the clinical picture of the cardiac condition is that of a 8flabby0 heart4 ,,references4 #a ,,meill,,re1 ,g43 ,le ,saturnisme4 ,paris1 #aijc4 #b ,,blyth1 ,,wynter3 ,proc4 ,chem4 ,soc1 #ahhg-hh4 #c ,,peyrusson ,,and ,,pillault3 ,meillre's ,le ,saturnisme1 chap4 iv4 #d ,,newton ,,pitt3 ,trans4 ,path4 ,soc1 ,no4 #db1 #ahia4 #e ,,glibert3 ,le ,saturnisme ,exprimental3 ,extrait des ,rapports ,ann4 de l',inspect4 du ,travail1 ,brussels1 #aijf4 #f ,,moritz3 ,mediz4 ,woch41 ,st4 ,petersburg1 #aija4 #g ,,schmidt3 ,arch4 fr ,hygiene1 vol4 lxiii41 p4 #a1 #aijg4 #h ,,glibert3 ,ibid4 #i ,,boycott3 ,journal of ,hygiene1 #aiaj4 ,,chapter ,,ix ,,the ,,nervous ,,system ,symptomatology and ,diagnosis 7,continued7--,the ,nervous ,system4--,the most definite objective symptoms of chronic poisoning by means of lead are those of the nervous system4 ,from the time of ,tanquerel#a affections of the hands and fingers and the muscles of the back have all been well known4 ,associated with the paralysis are local vaso-motor effects1 such as cyanosed condition of the skin over the paralyzed muscles1 cold hands1 etc42 whilst later1 if the paralysis be severe and persists1 atrophic changes take place in the skin1 muscles1 bone1 whilst definite contracture occurs from unopposed contraction of the unaffected muscles4 ,paralysis will therefore be associated with two of the great systems into which the body is divided for the purposes of medical and physiological description--namely1 the muscular and the nervous--and1 on account of the similarity of the clinical symptoms of lead paralysis1 attention has been drawn rather to the nerve changes preceding muscular paralysis and degeneration than to other influences affecting the nerve inflammation4 ,lancereaux#b considered that lead poisoning resulting in paralysis takes the form of a gradual impregnation of the nervous tissue with lead salts1 until such a time as degenerative effects are set up1 and with it muscular paralysis4 ,meillre#c1 who has given much attention to the tiology of lead poisoning1 as well as to the clinical study of the disease1 considers that plumbism may be divided into three periods3 7a7 ,impregnation of the tissues of the body1 the nervous tissue being the chief one affected by lead salts4 7b7 ,retardation of the general oxidation changes of the body1 resulting in malnutrition and general loss of tone4 7c7 ,establishment of intoxication1 with the generalized affections1 paresis1 etc4 ,if three such periods can be recognized1 as no doubt they can1 as divisions of the time during which lead gradually affects the tissues1 the symptoms in the more severe cases would be expected to be those associated with the more prolonged exposure4 ,this1 no doubt1 is true to a limited extent1 more particularly in industrial poisoning1 depending for its development on a long-continued dosage of lead in minute quantities1 and for the most part of metallic lead4 ,on the other hand1 with some of the salts of lead1 notably the hydrated carbonate1 acute disease may take place during the first stage--namely1 impregnation of lead--the determining factor then being either the retardation of the elimination of lead1 or a suddenly increased quantity in lead dosage1 or some intercurrent disease1 or even alcoholic excess1 whereby a sudden large excess of the poison is thrown into the general circulation4 ,the commonest type of paralysis occurring is the one affecting the muscles of the hands1 which may for a considerable time show some diminution in their extensor power before the actual onset of the disease takes place4 ,the onset of paralysis is practically always unaccompanied by pyrexia2 the only occasions in which pyrexia may be associated with the onset of the attack are those cases in which some secondary cause determines the paralysis1 and the pyrexia in these instances is due to the intercurrent disease1 and not to the lead infection4 ,although weakness of the extensor muscles of the hands may be present in persons subjected to lead absorption for a considerable time1 the actual onset of the disease itself is frequently sudden2 but in the majority of cases it is distinctly chronic1 and is rarely1 in the case of paresis1 associated with any definite prodromal symptoms4 ,prodromal symptoms have been noted1 such1 for instance1 as lassitude1 general debility1 and more especially loss of weight4 ,cramps of the muscles the nerve-supply of which is becoming affected1 alteration of the skin over areas corresponding to definite cutaneous nerves1 hypersthesia1 ansthesia1 or analgesia1 may occasionally be present4 ,neuralgic pains have also been described1 but these are inconstant1 and generally of the arthralgic type related to the periarticular tissues of joints rather than to pain in the course of the nerves4 ,the pain is rather of the visceral referred type than a definite neuralgia4 ,tremor is1 however1 frequently associated with the preliminary condition of paresis1 and in several cases variations in the amount of weakness of the extensor muscles of the wrist have been noticed1 as far as can be estimated clinically without the use of a dynamometer4 ,associated with this weakness is tremor of a fine type1 often increased by movement 7intention tremor71 and in every case more marked during the periods of increased weakness4 ,instances have occurred where definite wrist-drop followed after a prolonged period of weakness2 in others the weakness has temporarily cleared up for six months1 and no difference could be determined in the extensor power of the two wrists2 while in others1 again1 the weakness is progressive1 but slight1 and insufficient to warrant the removal of the workman from his occupation4 ,again1 progressive weakness may remain a symptom of the wrists of workmen for years4 ,the ,forms of ,lead ,paresis4--,the paralysis may be partial or generalized1 but the chief muscles affected are the extensors of the wrists and the forearm1 and the interossei of the hand4 ,as a rule1 the first muscles to be affected are the extensor communis digitorum and the extensor indicis4 ,the muscles of the shoulder--mainly the deltoid--come next in order1 followed by the muscles of the leg1 particularly the peroneus longus and brevis1 with occasionally the interossei of the foot2 the muscles of the back1 neck1 and abdominal walls1 are occasionally affected1 as are those of the larynx and diaphragm1 and it is of interest to note that ,trousseau pointed out that among horses employed in lead works paralysis of the superior laryngeal nerve often occurred4 ,considerable difficulty is experienced in estimating the reason of the predilection of lead for the musculo-spiral nerve1 this being the nerve mainly affected in wrist-drop4 ,owing to the fact that the supinator longus receives an additional nerve-supply to the musculo-spiral1 this muscle frequently escapes paralysis when the whole of the other extensors of the hand are involved4 ,moreover1 the predilection for given nerves differs in different animals1 and one of us 7,k4 ,w4 ,g47 has found experimentally that in cats the first nerve to be affected is the anterior crural supplying the quadriceps extensor1 whilst the second group of muscles affected are the spinal muscles1 particularly in the lumbar region4 ,among the speculations which have been made with regard to this predilection for definite groups of muscles supplied by one nerve1 ,teleky#d examined forty cases of paralysis with special reference to ,edinger's theory--namely1 that the function of muscles 7and of other organs7 breaks down under certain circumstances before the strain set upon them4 ,in this way ,edinger explains paralysis following lead poisoning as being due to excessive strain on the particular group of muscles affected1 based on a consideration of the relative volumes and weights of the muscles of the hand and forearm1 and the demands made on the several groups1 flexors1 extensors1 supinators1 etc41 by the coarse or fine work respectively demanded of them in industrial employment4 ,he concludes that-- #a4 ,of the forearm1 the flexors 7triceps1 anconeus1 extensors1 biceps1 brachialis anticus1 and supinator longus7 possess a high degree of capacity for work1 but are not called into play mainly in the execution of fine work2 while the supinators are characterized by great mass1 and are brought into play mainly in work of coarse and heavy nature1 and not during fine manipulations4 #b4 ,the muscles concerned in pronation are of small capacity for work1 and are not called on for sustained work4 ,as for the muscles acting on the wrist and hand1 he concludes that the extensors 7carpi radialis longior and brevior1 carpi ulnaris1 and the extensors of the fingers7 are powerful1 and much exceed in capacity for work the flexors 7flexor carpi radialis1 flexor carpi ulnaris1 the flexors of the fingers1 etc471 but in all fine manual work1 and specially where close grasping movements enter into association with the flexors1 external strain is put upon them1 whilst the flexors merely support their action4 ,the extensor communis digitorum is the weakest of all the long finger muscles2 its volume is hardly one-fourth that of the corresponding flexors1 and while it acts only on the first of the phalanges1 the flexors act on all three4 ,in all fine work they are called on for heavy strain1 especially the interossei and the lumbricals1 but in harmony with the long flexors when grasping movements are performed4 ,the small muscles of the fingers have nearly the same mass as the extensor communis1 and in all fine movements the grasping efforts are taxed severely2 but their play is under considerably more favourable physical relations than that of the extensors1 whilst in addition they are aided in their work at times by the long flexors4 ,the chief adductor muscle of the thumb 7extensor metacarpi pollicis7 is particularly powerful2 the other extensors of the thumb are very weak1 and work under unfavourable physical conditions1 but are supported in their action by the strong abductor muscle4 ,the muscles of the abductor1 opponens and flexor brevis1 in the complicated work thrown on the thumb in manipulation1 are much exerted1 so that the effects of overexertion show themselves first in this region4 ,thus1 ,edinger maintains that the muscle-supply of the arm is designed for coarse heavy work1 the muscles of the fingers and the hand having to carry out more work than can be expected of them from a consideration of their volume and their physical action4 ,the commonest form of lead palsy1 the antibrachial type of ,djerine-,klumpke#e1 is explicable from consideration of overexertion of the particular group of muscles named4 ,the supinator muscle1 supplied also by the musculo-spiral nerve which serves the paralyzed muscles1 escapes because of its size1 and the fact that functionally it belongs to the flexor group1 and the first-named reason also1 explain the frequent escape of the long abductor of the thumb4 ,teleky#f investigated thirteen slight cases of the antibrachial type4 ,in one both hands were affected1 in one the left only1 and in all the others the right only--facts which he thinks bring out the rule of causation by employment4 ,of fourteen painters1 three had the right forearm affected only1 the other eleven both right and left1 but always more marked in the right4 ,amongst them he cites cases where the shoulder muscles were paralyzed1 which he considered was due to the extra strain of unusual employment1 involving a raising of the arms above the head1 or lying on the back painting the under parts of carriages4 ,in several of the painters the index-finger was the least affected1 by reason of the less exertion thrown on it by the position assumed in holding the brush between the second and third fingers4 ,the long abductor1 probably because of its size and power1 is in no case completely paralyzed4 ,in file-cutters he insists that the predominant share1 falling on a single or on several small muscles of the hands1 makes the early appearance of paralysis of the small muscles the characteristic sign4 ,in this connection we have frequently observed decrease in the size of the thenar and hypothenar eminences amongst lead rollers2 in fact1 in the majority of lead rollers who have followed their occupation for a large number of years the flattening of both thenar and hypothenar eminences is well marked1 but it is only fair to point out that in these cases very considerable stress is thrown on the muscle of this part of the hand by the pressure of the lead plate in pushing it inwards into the roller and grasping it on its appearance back again through the roller1 and that1 further1 the use of large and clumsy gloves with all the fingers inserted into one part1 and the thumb only into the other1 tends to produce inaction of portions of the lumbricals and of the opponens pollicis1 and may1 therefore1 from purely mechanical reasons cause damage to this part of the hand4 ,teleky#g cites cases of right-sided paralysis of the adductor brevis pollicis supplied by the median nerve1 and partial paralysis of the long extensors and of the extensor ossis metacarpi pollicis supplied by the radial nerve1 and in one or two cases complete paralysis of the thenar muscles and adductor1 whilst the extensors of the fingers and wrists were only partially paralyzed4 ,the cases all occurred in lead capsule polishers4 ,this particular selection of muscles is clearly the result of the peculiar movement necessary in polishing the capsules of bottles on a revolving spindle1 involving specially the use of the opponens muscle4 ,this observation of ,teleky's is in direct accord with the observation quoted above of the hands of persons engaged in lead rolling4 ,in the lower extremity1 paralysis of the muscles associated also with paralysis of the adductor and extensors of the thumb was found by ,teleky in a shoemaker who had contracted plumbism by the use of white lead4 ,he explains this lower extremity paralysis by the exertion thrown on the adductor muscles of the thigh whilst holding the shoes4 ,in children affected with lead palsy the lower extremities are more frequently paralyzed than the upper1 due to the relatively greater strain in childhood on the legs than on the arms4 ,edinger's theory1 supported as it is undoubtedly by ,teleky's observations1 is a matter of the greatest importance in the production of paralysis2 for if we accept the view that lead is a poison that has a selective power on certain nerves1 we have still to consider which is the greatest force1 the selection of certain groups of muscles or the effect of functional action4 ,the theory of muscular overexertion certainly falls in with the type of paralysis1 and ,teleky has undoubtedly shown that under certain circumstances1 by special exertion of other muscle groups not usually affected1 these muscles alone1 or to a greater extent than those usually affected1 are involved in the paresis4 ,if1 therefore1 lead has a selective action1 which is exceedingly doubtful1 it must be very slight4 ,such selective action is1 of course1 exceeded by a functional activity which brings about the affection of those nerves which supply the muscles most used4 ,if1 therefore1 we judge of paralysis as being due to the selective action of lead on certain nerves1 we are met at once with the objection that the muscles affected do not always correspond to such a nerve distribution1 and that muscles supplied by other than the musculo-spiral nerve are affected by paralysis4 ,careful consideration of the chapter on ,pathology1 and more particularly of the histological findings described1 in which the preliminary action of lead is found to be typically and invariably on the blood1 setting up degenerative changes microscopical in size and limited in area1 affecting the vessel walls and producing a yielding of the vessel1 determining minute microscopical hmorrhages distributed1 not necessarily in one position of the body1 but all over the body1 and peculiarly in the case of the cat affecting those muscles called upon to perform sudden and violent movement--namely1 jumping--enables us to regard such microscopical hmorrhages as an adequate explanation of the association of paralysis in muscle groups1 functionally related to various trades and industrial processes4 ,it may be argued1 and we think with considerable reason1 both from pathological and clinical findings1 that1 as muscular exertion is apparently associated with the onset of paralysis1 particularly in those muscles which may be regarded as physically somewhat inadequate to the work they have to perform1 and that1 as the paralysis is associated with definite functional groups of muscles1 and to a curious extent varies according to the trade in which the sufferer is engaged1 therefore greater stress thrown upon the muscular tissue at some period or another during occupation determines the microscopical hmorrhage in the nerve supplying the muscles1 or in the muscle itself1 so that the paralysis affects just such muscles as have an increased strain thrown upon them4 ,it does not necessarily follow that the preliminary initial hmorrhage occurring should be a large one--in fact1 from the whole of the histological history1 hmorrhages are exceedingly minute2 neither does it follow that it is essential for such hmorrhages to take place in the whole length of the nerve itself2 but it is only necessary that the finer branches of the nerve should have their venioles or arterioles affected1 and it is of course in the finer branches particularly1 as has been pointed out in relation to the venioles1 that degeneration of the intima of the vessels takes place4 ,finally1 the effect of early treatment on lead palsy tends to bear out this theory4 ,if a case of lead palsy be treated in the early stages1 the clinical course of the case is good2 increased paralysis generally takes place in the first week1 and1 where1 perhaps1 only two or three fingers are involved when the case is first seen1 spreads generally to other regions within a week1 and the whole hand is affected2 but from this moment onwards improvement takes place on the application of suitable treatment1 and1 if continued1 almost invariably results in the entire recovery from the paresis4 ,there is little doubt that this is the true explanation of the ordinary paresis of lead poisoning1 and a very great deal more evidence is required to combat it and to prove the selective action of lead upon individual nerves1 since the theory of hmorrhage does not owe its origin to conjecture1 but is based on clinical and histological examination of early cases of poisoning4 ,in attempting to find a cause for the paralysis of the hands so commonly present in painters1 it has been suggested that lead is absorbed through the skin1 and affects the nerves at their junction with the muscles1 setting up a peripheral neuritis ,gombault#h4 ,the theory breaks down at once when such commonly-occurring affections as paralysis of the ocular muscles1 paralysis of the peroneal type1 paralysis of the muscles of the shoulder1 etc41 are considered4 ,for the convenience of description lead paralyses are generally divided into a series of groups1 the grouping varying according to the function of the various muscles rather than to their anatomical grouping4 ,the various types of paralysis have to be considered in detail3 #a4 ,antibrachial ,type 7,djerine-,klumpke--,remak74--,the first muscle affected is the extensor communis digitorum1 with dropping of middle and ring fingers1 while extension of the first and fourth is possible because of their separate muscles of extension 7extensor minimi digiti and extensor indicis74 ,paralysis may be limited to these1 and not advance farther1 but it is common to see these two muscles primarily affected1 and for other muscles to become involved after the patient is put on treatment1 although exposure to lead has ceased4 ,usually1 however1 the paralysis advances1 involving the extensors of the index and little fingers1 so that the basal phalanges of the four fingers cannot be extended4 ,the long extensor of the thumb is next involved1 but this may be delayed4 ,the two terminal phalanges are still able to be extended by the interossei 7as shown by ,duchenne7 when the basal phalanx is passively extended on the metacarpal4 ,abduction and adduction of the fingers also remain unaffected4 ,the wrist muscles are affected next4 ,the hand remains in semi-pronation1 and when hanging down forms a right angle with the forearm1 the fingers slightly flexed with the thumb towards the palm1 and the hand deflected to the ulnar side4 ,in grasping an object the flexors remain unaffected1 the wrist is much flexed owing to the shortening of the flexors in consequence of the extensor paralysis4 ,the hand cannot pass the median line4 ,the long abductor of the thumb--that is1 the extensor ossis metacarpi pollicis1 also known as the 8extensor primi internodii pollicis0--is only very rarely involved1 but has been described as being the muscle alone involved in the paralysis affecting persons engaged in polishing lead capsules4 #b4 ,the ,superior or ,brachial ,type 7,remak74--,the muscles affected are those of the ,duchenne-,erb group--namely1 the deltoid1 biceps1 brachialis anticus1 and supinator longus4 ,the supra- and infrascapular muscles are also as a rule involved1 but the pectoralis major rarely4 ,this type of paralysis is usually found in old cases associated with other forms of paralysis1 but may be found as a primary affection 7as already noted amongst painters72 sometimes the deltoid is the only muscle affected1 with diminution in electrical contractility of the other muscles of the group4 ,the arm hangs loosely by the trunk1 with the forearm semi-pronated4 ,the arm cannot be raised1 nor can the forearm be bent on the upper arm4 ,extension is unaffected1 as the triceps is never involved4 ,supination is impossible because of paralysis of the supinator brevis4 ,movement effecting rotation of the shoulders is involved1 due to the paralysis of the supra- and infra-spinatus4 ,electrical reactions are said to be less marked in the brachial than the antibrachial type1 and complete loss of faradic contractility is rare2 but in one of the three cases described below1 in which electrical reactions were carefully tested1 the right deltoid showed entire loss of contractility to faradism4 #c4 ,aran-,duchenne ,type4--,the muscles of the thenar and hypothenar eminences and interossei are affected4 ,this type of lead paralysis may be distinguished from progressive muscular atrophy by the electrical reactions1 and the fact that the atrophy is accompanied by more or less pronounced muscular paralysis4 ,the atrophy is almost always most marked1 and advances pari passu with the paralysis4 ,this form may occur alone1 or be complicated with the antibrachial type1 which is the most common4 ,it is seen in file-cutters as the result of overstrain of the muscles in question4 ,moebius#i1 in his observations on file-cutters1 noted in one case paralysis of the left thumb1 with integrity of the other muscles of the left upper extremity4 ,opposition of the thumb was very defective2 there was paralysis of the short flexor and of the adductor and atrophy of the internal half of the hypothenar eminence4 ,reaction of degeneration was noted in the muscles named1 but not in the extensors of the fingers and wrist4 ,in another case1 in addition to feebleness of the deltoid1 flexors of forearm on the upper arm1 and small muscles of hand1 there was paralysis and atrophy of the adductor of the thumb and first interosseous and paralysis of the opponens4 #d4 ,peroneal ,type4--,this is a rare type1 and nearly always associated with the antibrachial or with generalized paralysis4 ,in the former the paralysis is slight1 especially when it affects the psoas2 but there is predilection for certain groups of muscles1 especially the peroneal and extensor of the toes1 while the tibialis anticus escapes4 ,hypersthesia1 or more rarely ansthesia1 precedes the onset4 ,the patient walks on the outside of the feet1 has difficulty in climbing stairs1 and cannot stand on the toes4 ,the toes drag on the ground in walking1 so that the foot has to be swung round at each step1 and the inner side is lifted in excess by the action of the tibialis anticus1 with uncertainty in gait4 ,if walking is continued1 the toes drag more1 and 8stepping0 gait is assumed by bringing into action the muscles of the thigh4 ,the foot cannot be flexed on the leg2 abduction of the foot and extension of the basal phalanx of the toes is impossible4 ,later the peroneal muscles1 extensor communis of toes1 and extensor of great toe1 are paralyzed1 from which fact arises the difficulty of walking and of descending stairs1 as the whole weight of the body is supported then by the tibialis anticus4 ,this type corresponds with the antibrachial type of the upper extremity4 ,if the tibialis anticus is paralyzed1 it is in association with the gastrocnemius4 #e4 ,paralysis of ,special ,sense ,organs4--,tanquerel#aj called attention to the aphonia of horses in lead works1 necessitating tracheotomy1 and ,sajous#aa described adductor paralysis of the glottis in a house-painter4 ,morell ,mackenzie#ab also described unilateral paralysis of the adductors in persons suffering from lead poisoning1 whilst ,seifert#ac particularly describes a curious case in which paralysis of the transverse and oblique arytenoid muscles prevented contraction of the cord in its posterior quarter1 and in a second case of paralysis1 affecting the posterior crico-arytenoid muscles on both sides1 the adductors remained unaffected4 ,what is still more interesting in ,seifert's case is the fact that at the post-mortem old hmorrhages were found in the mucosa of the arytenoids and aryepiglottidean folds4 ,occasionally sensory paralysis may be found in the special sense organs--such1 for instance1 as loss of taste1 loss of smell1 and1 in addition1 diminished power of hearing--but these defects rarely if ever occur unless accompanied by distinct mental changes and generalized paralysis4 #f4 ,eye4--,poisoning affects the eye in two ways3 7a7 ,defects of the visual mechanism4 7b7 ,defects of the muscular mechanism of the eye4 ,lockhart ,gibson#ad describes a large number of cases of paralysis of the muscles of the eye met with amongst children in ,queensland4 ,the cause was traced to the painted railings near which the children had been playing4 ,the white lead paint had somewhat disintegrated under the action of the sun's rays1 forming an efflorescence2 the children admitted to have rubbed the paint and then sucked their fingers4 ,between ,july1 #aije1 and #aijh1 sixty-two cases of plumbism in children were admitted to the children's hospital1 and of these sixty-two cases thirteen had well-marked ocular symptoms4 ,the paralysis of the muscles of the eye was almost invariably one of the external rectus1 but other muscles were at the same time affected2 occasionally paralysis of the whole of the oculo-motor muscles was seen with the exception of the superior oblique4 ,it is worthy of note that amongst these children a very large number suffered1 in addition to their eye paralysis1 with foot-drop and wrist-drop1 and1 on the whole1 suffered from foot-drop to a much larger extent than from paralysis of the hands4 ,galezowski#ae describes paralysis of accommodation of the eye1 and in cases described by ,folker#af some amount of orbital paralysis was also present4 #g4 ,generalized ,paralysis4--,these types do not differ in form from the previously described types1 except1 perhaps1 as regards their rapidity of onset4 ,where the onset is slow 7chronic7 the subject is usually one who has been previously affected with paralysis of the extensors of the hand1 followed by development of the paralysis in the shoulders1 hand1 leg1 thorax4 ,in the acute form1 paralysis may affect all the muscles in a given limb or group1 and reduce them in a few days to a complete condition of paralysis4 ,in extreme cases the patient lies on the back and is incapable of rising1 and sometimes even unable to eat4 ,the intercostals1 diaphragm1 and larynx1 are also affected1 while there is generally dyspna and aphonia4 ,the muscles of the head and neck appear to escape4 ,in these acute cases1 pyrexia may be a common symptom4 ,electrical ,reactions4--,the diagnosis of the affected muscle is greatly assisted by careful examination of all the muscles in the affected physiological group by means of the galvanic and faradic currents4 ,the battery for the purpose of testing the electrical reactions must have an available electromotive force of over #dj volts4 ,a battery of thirty-two ,leclanch dry cells is ample4 ,for the faradic current1 a small induction coil operated by two ,leclanch cells is sufficient4 ,one large1 flat electrode should be used1 and several smaller ones4 ,the faradic current should be used first1 as it stimulates the nerves directly1 and the muscles only indirectly1 through their nerve-supply4 ,each nerve trunk should be examined systematically4 ,the motor points correspond for the most part with the points of entry of the motor nerves into the muscles which they supply4 ,a small electrode1 either a button or a small disc about the size of a sixpence1 should be used for the examining electrode1 while the larger electrode should be placed either on the abdomen or between the shoulders4 ,the electrodes should be well soaked in normal saline4 ,the intensity of the minimum current required to produce a contraction for each point should be noted1 and compared with the effect of a similar current on the opposite side of the body4 ,the reaction of degeneration of the faradic current consists in no contraction at all being elicited1 even when a very strong current is employed4 ,if there be unilateral wrist-drop in the left hand1 consisting of loss of power of the extensor communis digitorum on that side1 no movement of the muscle is produced at all when the electrode is placed across the motor points of the muscle4 ,these are situated to the outer side of the arm when the dorsum of the hand is uppermost1 about #a to #b inches below the olecranon4 ,the same quantity of current1 when applied to the unaffected muscle on the opposite side1 produces a brisk reaction4 ,having observed the effect with the faradic current1 and the results having been recorded1 the continuous current is used1 and the electrodes made use of in an exactly similar fashion4 ,when a small electrode is used1 the superficial nerves and muscles are more stimulated than those lying deeply4 ,it is necessary1 therefore1 to begin with a small current and gradually increase it until the individual muscle responds4 ,the strength of the current employed is registered by means of a milliampremeter4 ,with the continuous current quantitative as well as qualitative alterations may be determined1 and with the quantitative change of the galvanic current the muscular excitability is increased1 contraction following the application of a weaker current than is necessary to produce it in health or in the sound muscle on the other side of the body4 ,with the qualitative change1 the contraction is no longer sharp1 but sluggish4 ,the anodal closing contraction is elicited with a weaker current than kathodal closing contraction1 so that ,,acc,,kcc4 ,the quantitative change depends partly on the nutrition of the muscle2 the qualitative change depends on the fact that the nerve no longer regulates the character of the contraction1 and also to a small extent is the result of changes in the muscle itself4 ,in a complete reaction of degeneration in an affected muscle1 reaction to the faradic current is absent1 contraction to the galvanic current is sluggish1 and is produced with a smaller current in the anode than the kathode4,a ,a ,the kathode1 or negative electrode1 is attached to the zinc rod2 the anode1 or positive electrode1 to the copper or carbon4 ,as the nerve lesion passes away1 the voluntary contraction generally begins to return before the nerves show any reaction to electrical stimulus4 ,the following three cases in which the electrical reactions of the muscles were determined1 give examples of typical cases of lead paresis4 ,in ,no4 #c1 owing to the fact that the case was treated immediately the paralysis occurred1 complete recovery had taken place1 and1 as will be seen1 the electrical reactions have again become normal4 ,,case #a4--,litharge and blast-furnace worker4 ,employed in lead works1 where a large number of different metallurgical processes associated with the recovery of lead from the ore were carried on4 ,double wrist-drop1 existing for eight years1 untreated until some four years after paralysis took place1 when slight improvement occurred4 ,the electrical reactions show that the extensor communis digitorum on the right side is completely degenerated1 whilst the first interosseous of the right side show reactions of degeneration4 ,on the left side the extensor communis digitorum showed normal but very feeble reaction4 ,this latter point is one of considerable importance if early hmorrhage accounts for lead paralysis1 for if the nerve itself was completely destroyed1 or if1 as was the case1 the muscle appeared completely paralyzed on inspection1 obviously the nerve-supply must be completely cut off if the lesion was due to destruction of the nerve of the spinal cord or to the destruction of the lower motor neuron4 ,on the other hand1 the presence of small localized fibrillar contraction1 found by the galvanic current1 together with the presence of a slight reaction to faradism1 suggests that some small portion of the nerve has remained unaffected1 and that for this reason certain portions of the muscle have not undergone degeneration--a circumstance which can hardly be expected if the cause of the paralysis is in the destruction of the whole of the nerve-supply4 ,,electrical ,,reactions ,,in ,,lead ,,paralysis4 7,,case #a47 ---------------------------------------- ------------------------ ,muscle4 ,galvanism4 ---------------------------------------- -------------------- ,m4,a4 ,m4,a4 ,r4 ,deltoid 7anterior ,k4,c4,c4 #h ,a4,c4,c4 #h portion7 ,l4 ,deltoid 7anterior ,k4,c4,c4 #f ,a4,c4,c4 #i portion7 ,r4 ,deltoid 7posterior ,k4,c4,c4 #f ,a4,c4,c4 #i portion7 ,l4 ,deltoid 7posterior portion7 ,r4 ,supinator longus ,k4,c4,c4 #f ,a4,c4,c4 #aj ,reaction brisk ,l4 ,supinator longus ,k4,c4,c4 #e ,a4,c4,c4 #f ,reaction brisk ,r4 ,extensor communis ,no reactions either ,a4,c4,c4 or ,k4,c4,c4#ae digitorum ,l4 ,extensor communis ,k4,c4,c4 #h ,a4,c4,c4 #ab ,brisk1 but feeble digitorum ,r4 ,extensor primi ,k4,c4,c4 none,a4,c4,c4 #ac ,brisk internodii pollicis at #ac ,l4 ,extensor primi ,k4,c4,c4 #f ,a4,c4,c4 #ab ,reaction brisk internodii pollicis ,r4 ,extensor carpi ,k4,c4,c4 #h ,a4,c4,c4 #h ,brisk ,contraction ulnaris ,l4 ,extensor carpi ,k4,c4,c4 #h ,a4,c4,c4 #ab ,brisk ,contraction ulnaris ,r4 ,first interosseous ,k4,c4,c4 #h ,a4,c4,c4 #f ,contraction slow ,l4 ,first interosseous ,k4,c4,c4 #f ,a4,c4,c4 #f ,brisk contraction ,r4 ,second interosseous,k4,c4,c4 #h ,a4,c4,c4 #aj ,brisk contraction ,l4 ,second interosseous,k4,c4,c4 #f ,a4,c4,c4 #h ,brisk contraction ,r4 ,third interosseous ,k4,c4,c4 #i ,a4,c4,c4 #f ,brisk contraction ,l4 ,third interosseous ,k4,c4,c4 #f ,a4,c4,c4 #h ,brisk contraction ,r4 ,fourth interosseous,k4,c4,c4 #h ,a4,c4,c4 #f ,brisk contraction ,l4 ,fourth interosseous,k4,c4,c4 #aj ,a4,c4,c4 #i ,brisk contraction ---------------------------------------- -------------------- ---------------------------------------- -------------------------- ,muscle4 ,faradism4 ,remarks4 ---------------------------------------- -------------------------- ,r4 ,deltoid 7anterior ,good ,evidently extensor communis portion7 digitorum on right side is ,l4 ,deltoid 7anterior ,good completely degenerated4 ,first portion7 interosseous on right side ,r4 ,deltoid 7posterior ,good show reactions of degenera- portion7 tion4 ,on left side extensor ,l4 ,deltoid 7posterior ,good communis digitorum shows portion7 normal but feeble contrac- ,r4 ,supinator longus ,good tions ,l4 ,supinator longus ,good ,r4 ,extensor communis ,no reaction digitorum ,l4 ,extensor communis ,feeble reaction digitorum ,r4 ,extensor primi ,good internodii pollicis ,l4 ,extensor primi ,good 7but less internodii pollicisthan right7 ,r4 ,extensor carpi ,good ulnaris ,l4 ,extensor carpi ,good ulnaris ,r4 ,first interosseous ,no reaction ,l4 ,first interosseous ,good ,r4 ,second interosseous,slight reaction ,l4 ,second interosseous,good ,r4 ,third interosseous ,slight reaction ,l4 ,third interosseous ,slight reaction ,r4 ,fourth interosseous,slight reaction ,l4 ,fourth interosseous,good ---------------------------------------- -------------------------- ,,electrical ,,reactions ,,in ,,lead ,,paralysis4 7,,case #b47 ---------------------------------------- ----------------------- ,muscle4 ,m4,a4 ,galvanism4 ,faradism4 ,remarks4 ---------------------------------------- ----------------------- ,r4 ,deltoid #i ,slow reaction ,no ,reaction of ,a4,c4,c4 ,k4,c4,c4reaction degeneration ,l4 ,deltoid #i ,slow reaction ,slow ,a4,c4,c4 ,k4,c4,c4reaction ,r4 ,extensor communis #i ,slow reaction ,no digitorum ,a4,c4,c4 ,k4,c4,c4reaction ,l4 ,extensor communis #i ,slow reaction ,no digitorum ,a4,c4,c4 ,k4,c4,c4reaction ,ante brachial and brachial groups give normal reaction ---------------------------------------- ----------------------- ,,electrical ,,reactions ,,in ,,case ,,of ,,recovered ,,wrist-,,drop4 7,,case #c47 ---------------------------------------- ----------------------- ,muscle4 ,m4,a4 ,galvanism4 ,faradism4 ,remarks4 ---------------------------------------- ----------------------- ,r4 ,extensor communis #i ,good reaction ,good ,all muscles digitorum ,k4,c4,c4 ,a4,c4,c4reaction react well to ,l4 ,extensor communis #i ,good reaction ,good both currents2 digitorum ,k4,c4,c4 ,a4,c4,c4reaction no sign of any ,r4 ,extensor ossis #i ,good reaction ,good reaction of metacarpi pollicis ,k4,c4,c4 ,a4,c4,c4reaction degeneration ,l4 ,extensor ossis ,good reaction ,good metacarpi pollicis ,k4,c4,c4 ,a4,c4,c4reaction ,r4 ,deltoid ,good reaction ,good ,k4,c4,c4 ,a4,c4,c4reaction ,l4 ,deltoid ,good reaction ,good ,k4,c4,c4 ,a4,c4,c4reaction ,r4 ,extensor carpi ,good reaction ,good ulnaris ,k4,c4,c4 ,a4,c4,c4reaction ,l4 ,extensor carpi ,good reaction ,good ulnaris ,k4,c4,c4 ,a4,c4,c4reaction ,r4 ,interossei ,good reaction ,good ,k4,c4,c4 ,a4,c4,c4reaction ,l4 ,interossei ,good reaction ,good ,k4,c4,c4 ,a4,c4,c4reaction ---------------------------------------- ----------------------- ,this case is a typical one of the anterior brachial type1 showing partial recovery of function4 ,the man is able to grasp1 although the wrist becomes strongly flexed in so doing4 ,,case #b4--,we are indebted to ,dr4 ,gossage for this case1 which was presented at the ,out-patients of the ,westminster ,hospital2 and to ,dr4 ,worrell1 who made the electrical investigations4 ,we are further indebted to ,dr4 ,worrell for the reports which are given in tabular form of the electrical reactions of these three cases4 ,this is a case of brachial type1 with weakness of both deltoids1 and the patient was unable to raise his right arm at the shoulder4 ,it will be seen that there is here also evidence that the electrical contractility diminishes before the entire loss4 ,it will be also noticed that the supinators are unaffected4 ,,case #c4--,these are the electrical reactions of a case which had recovered4 ,this man showed the ordinary anterior brachial type1 which came on suddenly1 although he had shown distinct weakness of wrists when forcible flexion was performed for nine months previously1 but there had been no obvious increase in the weakness4 ,he was immediately removed from his work1 and within seven days paralysis1 which at first only affected the extensor communis digitorum1 had spread to the minimi digiti and the extensor indicis1 the opponens pollicis being also involved on the right side4 ,he was treated from the start with faradic current1 and was instructed to use the battery himself1 which he did twice a day for a year4 ,at the end of two months he was sufficiently recovered to be given light work1 and at the time of taking the reactions his wrists have so far recovered their power that we were unable to flex them forcibly4 ,the progressive weakness noted in the three cases has already been referred to1 and may be a prodrome of paralysis1 but there may be recovery without paralysis supervening4 ,tremor4--,tremor may be observed in a large number of cases of lead poisoning1 and is invariably associated with paralysis1 although the symptom of tremor by no means always progresses to definite palsy4 ,two types of tremor are described--fine and coarse--and ,gbler further describes a type of tremor which is both rhythmic and intermittent4 ,the tremor is usually distinctly increased on attempting to grasp or point the hand 7intention tremor71 but it is difficult to separate tremor from alcoholic tremor1 and1 further1 it must not be forgotten that persons engaged in arduous work may show a certain amount of tremor due to muscular fatigue4 ,persistent tremor1 however1 is a symptom that is always to be noted and carefully watched4 ,of the types of paralysis1 the antibrachial is the most common1 and1 secondly1 probably the brachial4 ,the least common is the peroneal4 ,the table on p4 #ed shows the distribution of cases of paralysis1 so far as they can be made out from reports received since #aijd4 ,closely associated with paralysis are affections involving the brain4 ,tanquerel1 in his classical description of affections of the brain associated with lead poisoning1 gives the following classification3 #a4 ,delirium4 #b4 ,lead mania4 #c4 ,psychic depression4 #d4 ,coma4 #e4 ,convulsions1 saturnine eclampsia1 or epilepsy4 ,there is probably a very considerable relationship between insanity and lead poisoning1 as pointed out by ,robert ,jones#ag1 the resident physician and ,superintendent of ,claybury ,asylum4 ,rayner#ah remarked that the compulsorily careful habits of life of painters and lead-workers ought to protect them against vicious habits1 and should protect them against a too free indulgence in the use of alcohol6 ,our own experience is that paralysis1 and particularly affections of the brain1 occur in the majority of cases in persons who are addicted to alcohol1 and the experiments quoted in the chapter on ,pathology on the influence of alcohol in the production of encephalitis in animals is strong presumptive evidence that alcohol is one of the chief predisposing causes in the determination of saturnine encephalopathy4 ,encephalitis is given as a cause of death in the report already referred to in #adc per cent4 of #bfd fatal cases4 ,amongst this number encephalopathy accounted for #adc per cent41 cerebral hmorrhage #ih per cent41 and paralysis #ib per cent4 ,now1 all these are cases in which cerebral lesions may be confidently stated to have existed1 which brings the total to #cdd per cent4 of deaths at least due to brain involvement4 ,we have already referred to the high incidence of paralysis amongst file-cutters--#dj per cent4 as against #baa per cent4 for all industrial forms of poisoning4 ,when encephalitis occurs1 it is usually an acute symptom1 and often develops before paralysis is set up1 but as a rule is preceded by a period of persistent headache1 such headache being invariably temporal or occipital4 ,robert ,jones1 in his paper1 states that of the #acc cases who1 from the nature of their work 7painters1 plumbers1 etc471 were liable to lead impregnation1 #ai had signs of poisoning upon admission1 whilst #bb had a distinct history of lead poisoning at some time or other4 ,he gives the following analysis of the mental condition3 ,mania #cg ,melancholia #cc ,dementia #ai ,dementia with epilepsy #aj ,dementia with general paralysis #bd 8 ,general paralysis #g ,alcoholic mania #c --- #acc ,savage#ai is of opinion that lead will produce any of the symptoms of general paralysis of the insane1 and may even be a contributory cause of the disease1 but no statistics are available of the ,wassermann reaction in these cases4 ,goodall#bj refers to the fact that nerve poisons1 such as syphilis1 alcohol1 and fevers1 injury or sunstroke1 which are intermediate in fixity between alcohol and lead1 seem to have an intermediate influence in the production of general paralysis4 ,jones states that the mental symptoms found in the cases are to be grouped amongst one or other of the following varieties3 #a4 ,of a toxmic nature1 with sensory disturbances1 which tend to get well rapidly4 #b4 ,hallucinations of sight and hearing1 more chronic in nature1 which may be permanent4 ,the delusions in this class are almost invariably those of being poisoned or followed about1 and are in the main persecutory4 #c4 ,those resembling general paralysis with tremors1 increased knee-jerk1 inco-ordination1 accompanied with listlessness amounting to profound dementia1 but which tend to get well4 ,eye ,changes4--,two main forms of eye change are to be found amongst lead-workers4 ,in the first place1 temporary and sudden amaurosis makes its appearance1 due no doubt to vascular change1 either vaso-motor or hmorrhagic4 ,the trouble may occur in one or both eyes1 may come on gradually1 the patient merely being unable to distinguish letters or faces at a distance1 or he may become suddenly totally blind4 ,in the majority of cases the affection disappears under treatment1 but in a small number of cases total blindness persists4 ,occasionally nystagmus may be seen1 but is not a common symptom2 but dilatation of the pupils1 quite apart from retinal changes1 is not unusual4 ,inequality of the pupils may be observed1 but partial dilatation of both pupils is more common1 and is often associated with early anmia4 ,conjunctival hmorrhages are to be noted from time to time1 without obvious cause1 such as injury1 etc41 but in the majority of cases these have been associated with other symptoms4 ,the first feature noticed in the eye is loss of brightness1 and a curious lack-lustre of the eyes of persons intoxicated by lead is one of the general features making up the saturnine cachexia4 ,loss of brightness of the eye is associated in many other diseases with anmia1 but is particularly prominent in lead poisoning1 much more so than is to be accounted for alone by the degree of blood-destruction1 and is a point of which the examining surgeon should always take notice4 ,one other form of eye change requires attention--namely1 retinal changes due to circulatory disturbances4 ,in an advanced case the whole picture is one of severe albuminuric retinitis1 but in the earlier stages some engorgement of the vessels without alteration of the surrounding tissue is seen4 ,elschnig#ba associated this alteration in the vessels of the eye with vaso-motor changes caused by direct action of the poison1 producing a vascular constriction or dilatation1 and is inclined to regard the kidney disease frequently associated with this condition of the eye as something quite apart4 ,he would regard the two affections as independent1 and merely correlated through their common origin--lead intoxication4 ,it has even been suggested by some observers that the change in the eye is secondary to cerebral dema4 ,thus ,mannaberg#bb regards the encephalitis of saturnine origin as associated with chronic dema of the brain and spinal cord1 which thus produces reflex irritation of the nervous system of the eye4 ,bikler#bc and ,weber#bd consider the symptoms as circulatory4 ,from whatever cause the disease is set up1 sooner or later changes in the form of obliterative arteritis take place1 with gradual but ultimately complete loss of vision4 ,there are said to be no characteristic eye symptoms in acute cases of lead poisoning1 whereas with chronic lead poisoning in many cases there is central and peripheral affection4 ,the affections may be further divided into subjective and objective4 ,many of the subjective symptoms1 such as loss of sight and blindness1 are associated with definite eye lesions1 which may be seen with the ophthalmoscope1 but other definitely objective lesions may be present without any influence on sight to commence with4 ,folker#be describes five cases of lead amblyopia in lead-workers from a pottery district1 in all of which there was a peculiar symptom--the gradual failing of sight associated with colour flashes4 ,when examined1 the discs were described as white1 and the vessels small4 ,lockhart ,gibson#bf1 in describing the cases of eye disease amongst the children in ,queensland1 found one symptom apparently in all the eyes examined--namely1 great swelling of the discs4 ,this swelling of the discs might be accompanied with no loss of sight whatever1 and at other times had been accompanied with defective sight for many months previously4 ,some of the discs were excessively swollen4 ,there were also to be seen patches of pigment and irregular swelling of the vessels1 but no definite hmorrhages4 ,in the more acute cases1 and particularly those associated with complete paralysis of the ocular muscles1 total blindness usually followed4 ,as a rule1 when complete amaurosis occurs in lead poisoning1 blindness follows through double optic neuritis or neuro-retinitis1 but amblyopia may be present without fundus changes4 ,occasionally the loss of sight may be regarded as of central origin4 ,the renal disease so often associated with lead poisoning may cause the retinal changes accompanying it4 ,an albuminuric neuro-retinitis may occur without albumin in the urine4 ,as a rule1 the eye of a lead-worker reacts to light and accommodation4 ,ophthalmoscopic examination may show very pink discs1 patches of pigment scattered about irregularly outside the discs1 with occasional definite hmorrhage4 ,the edge of the discs may show blurring1 with further sclerosis and peri-arteritis of the vessels1 a white sheath around the arteries being often visible4 ,the neuritis on one or both sides may be associated with disturbances of sight1 and diffusely red and cloudy papilla1 with swelling or hmorrhages4 ,in choroidal atrophy pigmentation may also be seen4 ,muscular ,system4--,one further point may be referred to in relation to the muscular system--namely1 the occurrence of pain of a rheumatic type4 ,quite a number of cases of mild degrees of lead poisoning complain of arthralgic symptoms--that is to say1 8rheumatism40 ,careful examination of such cases shows no evidence that the pain is a true arthralgia1 neither does it seem to have a true relation to gout4 ,the pain as a rule is referable to the muscles themselves1 and in such instances digital examination of the muscle in the region of the pain generally exhibits deep-seated tenderness4 ,there does not appear to be any special marked tenderness along the trunks of the nerves supplying the muscle1 nor is there evidence of hypersthesia of the skin4 ,such hypersthesia does occur in lead poisoning1 but is generally associated with cerebral lesions4 ,the pain1 therefore1 must be regarded rather as myalgic1 and intercostal distribution of the pain is not infrequent2 but although the symptom is one that is often complained of1 it is an exceedingly difficult one to differentiate from other myalgias as a definite symptom of lead poisoning4 ,the chief point in favour of the inclusion of this so-called lead rheumatism as a symptom of lead poisoning is the frequency with which it is noted in the reports by certifying surgeons4 ,while1 therefore1 having no evidence to regard it as necessarily a definite symptom of poisoning1 it is one which has been recorded in a considerable number of cases4 ,as has been already suggested1 there is some reason to think these myalgic pains may be due to minute hmorrhages taking place in the muscles1 thereby producing localized irritation to some extent comparable with the 8bends0 of divers4 ,post-,mortem ,signs of ,plumbism4--,very real difficulty exists in determining from naked-eye appearances at a post-mortem examination whether the cause of death be due to chronic plumbism or not4 ,the changes produced by several other forms of intoxication1 notably chronic alcoholism1 produce many of the same changes in the tissues as lead4 ,inspection of the organs in the case of plumbism can only give rise to a surmise that the cause of death is due to lead poisoning4 ,there are1 however1 certain macroscopical appearances at an autopsy in the case of saturnism which should be carefully noted1 and although alone they do not constitute sufficient evidence upon which to pass a definite opinion1 they are still important as diagnostic signs in the light of histological and chemical examination4 ,particular note should be paid at an autopsy of a case of suspected lead poisoning to the following points3 #a4 ,mouth1 for the presence or absence of blue line1 which1 if present1 must be examined with a lens4 #b4 ,general condition of the abdominal viscera1 and particularly of the mesenteric and perinephritic fat4 ,in plumbism this is invariably reduced in quantity4 #c4 ,the condition of the mesenteric vessels1 as to whether or not they are engorged with blood1 or whether or not leakage appears to have taken place4 #d4 ,general condition of the arteries1 for the presence of atheroma1 etc4 #e4 ,the heart muscle1 which in plumbism is generally pale1 flabby1 and with a tendency to general dilatation of the cavities4 #f4 ,intestines4 7a7 ,the presence of injection of the muscular coat1 particularly the lower portion of the intestine1 and about the ileo-ccal valve4 7b7 ,the presence or absence of minute ulcerations1 or even hmorrhages along the intestine1 even in the mucosa of the stomach4 7c7 ,the presence of dark staining in the coats of the lower intestine1 not altogether disappearing when washed under a gentle stream of water4 ,should there be any evidence of this staining1 it is highly important to remove some of the fces1 as well as a portion of the intestine1 for chemical examination4 #g4 ,the condition of the liver1 which in poisoning by lead1 as by alcohol1 frequently shows a considerable amount of enlargement1 and may even show patches of perihepatitis due to secondary causes4 ,but the cirrhosis occurring in lead poisoning is not so great as in alcohol4 ,in lead poisoning the liver as a rule is large and soft1 and engorged with blood4 #h4 ,the kidney1 for signs of interstitial rather than tubular nephritis1 adherent capsule1 and blood-stained exudate4 #i4 ,if paresis of any sort has been present during the illness1 examination of the cord and brain should be made with especial care1 and in addition the nerves on the affected side supplying the affected muscles should also be examined4 ,in the brain definite small but coarse hmorrhages may be occasionally observed1 but as a rule the only signs to be found are injection of the cortical vessels1 frequently over certain definite areas1 and not involving the whole of the vascular system of the brain4 ,minute hmorrhages may be also found in the spinal cord4 ,for the purposes of histological examination1 a portion of the following organs should be removed and placed in a #e per cent4 formalin solution at once3 ,liver1 spleen1 kidney1 intestine1 the last-named specimen being selected from any area which shows injection1 or ulceration1 or dark staining4 ,smears may also be made from the bone-marrow1 as in prolonged anmia of saturnine origin definite changes may at times be found in the bone-marrow cells4 ,where paresis has existed1 a portion of the particular nerve supplying the muscles should be obtained1 and histological examination made1 as well as a portion of the cord above the lesion1 and where cerebral symptoms have been present1 a portion of the brain1 the portions taken being part of that showing engorgement of the vessels4 ,for the nervous tissue generally1 it is better to place some of the specimens in ,mller's solution1 and others in spirit4 ,equal parts of ,mller's solution and formalin may be used if desired4 ,material for ,chemical ,examination4--,for the purposes of chemical examination1 any of the organs which appear to be mainly affected by chronic inflammation may serve1 but it is usually important to examine the brain1 kidney1 and liver4 ,if any dark staining exist in the intestine1 a portion of this1 together with the contained fces1 should be removed4 ,it is better to tie ligatures round the intestine1 and divide the coat between the ligatures1 and place the whole of the specimen in dilute formalin4 ,specimens thus obtained should be sent off for examination at once4 ,the whole of the organ need not necessarily be despatched for examination in every case1 but if only a portion is sent1 it is essential that the weight of the whole organ be accurately taken before any portion is removed1 and the total weight noted with the specimen when sent4 ,,references4 #a ,,tanquerel3 ,trait des ,maladies de ,plomb ou ,saturnines4 ,paris1 #ahci4 #b ,,lancereaux3 ,gaz4 ,md41 #ahfb2 ,tribune ,md41 #ahif4 #c ,,meill,,re1 ,g43 ,le ,saturnisme1 chap4 iv4 #d ,,teleky3 ,deutsch ,zeitschrift fr ,nerven ,heilk41 vol4 xxxvii41 #aiji4 #e ,d,,jerine-,,klumpke3 ,thesis on ,des ,polynephrites en ,gnral et des ,paralysies et ,atrophiques ,saturnines en ,particulier4 ,paris1 #ahhi4 #f ,,teleky3 ,ibid4 #g ,,teleky3 ,ibid4 #h ,,gombault3 ,arch4 ,phys41 #ahgc4 #i ,,moebius3 ,ueber einige ,ungewhnliche ,flle von ,bleilhmung4 ,cent4 fr ,nervenheilk4 #ahhf4 #aj ,,tanquerel3 ,ibid4 #aa ,,sajous3 ,archiv fr ,laryng41 iii41 #ahhb4 #ab ,,morell ,,mackenzie3 ,brit4 ,med4 ,journ41 epitome1 p4 #abjb1 #ahic4 #ac ,,seifert3 ,berl4 ,klin4 ,woch41 #ahhd4 #ad ,,lockhart ,,gibson3 ,brit4 ,med4 ,journ41 vol4 ii41 p4 #adhh1 #aijh4 #ae ,,galezowski3 ,jahr4 f4 ,aug41 p4 #chb1 #ahgg4 #af ,,folker3 ,brit4 ,med4 ,journ41 ii41 p4 #aeef1 #ahih4 #ag ,,robert ,,jones3 ,brit4 ,med4 ,journ41 ,september #bb1 #aijj4 #ah ,,rayner3 ,journ4 of ,mental ,science1 #ahhj4 #ai ,,savage3 ,clifford ,allbutt's ,medicine1 vol4 vii41 p4 #feg4 #bj ,,goodall3 ,ibid41 p4 #fic4 #ba ,,elschnig3 ,wien4 ,med4 ,woch41 ,nos4 xxvii1 xxix41 #ahih4 #bb ,,mannaberg3 ,ber4 ,klin4 ,woch41 #ahif4 #bc ,,bikler3 ,arch4 fr ,augenheilk41 b4 xl41 #aijj4 #bd ,,weber3 ,thse de ,paris1 #ahhd4 #be ,,folker3 ,ibid4 #bf ,,lockhart ,,gibson3 ,ibid4 ,,chapter ,x ,,chemical ,,investigations ,very great assistance is afforded by chemical and histological diagnosis in the determination of cases of lead poisoning1 especially when the case is likely to involve proceedings under the ,workmen's ,compensation ,act4 ,in addition1 a large amount of information is afforded to the certifying or appointed surgeon and the medical practitioner by adoption of certain easily carried out methods of diagnosis4 ,it will be our purpose in the present chapter to describe as far as possible methods by which chemical or other investigation of a case of lead poisoning can be pursued1 and the clinical methods of diagnosis which are applied in ordinary routine4 ,the majority of the methods described1 especially the chemical investigation of material obtained from alleged fatal lead poisoning for the purpose of determining the presence or absence of lead1 the histological examination of such tissues1 and the examination quantitatively of excretions for lead1 are processes which can only be carried out in a fully equipped laboratory1 and certainly do not belong to the ordinary routine of medical work4 ,the medical practitioner cannot be expected in the ordinary course of his routine work to examine blood-films for basophile staining or to make differential blood-counts4 ,especially is this the case in the routine examination of large numbers of factory hands4 ,further1 many of the processes involved in either the chemical or histological examination of the tissues require so much special apparatus1 without which such work cannot be undertaken1 that the mere cost of the necessary instruments precludes the investigation being carried on except in special laboratories4 ,at the same time1 our purpose is to point out how additional methods of research may be made use of in obscure cases1 and how recourse should be had to a well-equipped laboratory in doubtful cases4 ,further1 the coroner1 when ordering a post-mortem examination1 may ask for a histological and chemical examination4 ,methods of ,chemical ,diagnosis4--,the presence of lead may require to be determined qualitatively and quantitatively1 and the procedure may differ slightly as to which process it is necessary to adopt4 ,the quantitative determination of the amount of lead present in organs or excretions of the body is of far more importance than the estimation or determination of the fact of its presence4 ,we have already referred to the work of ,gautier#a1 who has found lead present in the tissue of normal persons with such constancy that ,french observers1 at any rate1 now speak of 8normal lead10 to distinguish it from lead which may be found in pathological conditions4 ,there is1 however1 little doubt that the quantity of lead existing in the human body is exceedingly small4 ,it is possible1 with certain refined methods of chemical examination1 that qualitative traces of this substance might be found4 ,on the other hand1 the methods of determination of lead are some of the most difficult in toxicological analyses1 on account of the presence of other metals1 particularly iron1 which are exceedingly difficult to get rid of1 and may easily lead to errors4 #a4 ,qualitative ,tests4--,the group reagent for lead is sulphuretted hydrogen in acid or alkaline solution4 ,lead is precipitated by this reagent as a black precipitate4 ,where no other metals are present1 and where no organic matter is present at the same time1 there is very little difficulty1 and the usual method of the determination of lead in water by means of sulphuretted hydrogen is exceedingly easy4 ,potassium iodide gives a yellow precipitate soluble on warming1 and forms large crystals on the tube4 ,hydrochloric acid and chlorides give needle-shaped crystals1 soluble in heat1 and crystallizing out when cold4 ,but the double chloride of potassium and lead is more soluble in heat1 and still more soluble in cold1 than is the pure chloride4 ,this fact is made use of in the process to be described presently in separating lead from organic mixtures4 ,the direct examination is rarely possible or satisfactory1 but the potassium cupric acetate method is one that may be applied to the qualitative estimation of lead in the tissues4 ,method for detecting ,small ,quantities of ,lead qualitatively4--,dry and incinerate the material to be tested4 ,extract with hot dilute nitric acid1 after repeated incinerations1 finally extracting with ammonium acetate4 ,filter1 incinerate1 and take up the residue in dilute nitric acid4 ,evaporate to dryness and add a few drops of dilute acetic acid1 and transfer drop to microscope slide4 ,to the drop on the microscope slide add one drop of dilute copper acetate solution1 and two to three drops of saturated solution of potassium nitrate4 ,stir up the drops and well mix with a platinum wire1 allow to stand for a few minutes1 and then examine with a two-thirds objective4 ,if lead is present1 violet-black cubes of potassium copper lead nitrate appear 7,k,cu,pb,,no74 ,this test is said to give a reaction in the presence of #jjjjjc gramme4 ,determination of ,lead in the ,urine4--,the quantity of lead passed by the kidneys into the urine is always small1 even in acute lead poisoning4 ,further1 the lead is excreted in organic combination1 and is therefore difficult to detect4 ,for absolute quantitative examination it is essential to evaporate the whole bulk1 using at least gallon of the fluid1 and proceeding with the concentrate in the manner indicated in the estimation of lead4 ,for the qualitative examination many methods have been suggested1 but all of them are more or less fallacious4 ,in certain instances in acute lead poisoning1 or where a relatively large quantity of lead is excreted by the kidney1 acidulation of the fluid with strong sulphuric acid direct will at times produce a precipitate of lead sulphate1 which may be filtered off and the filtrate examined by the usual tests--namely3 ,a white precipitate with dilute sulphuric acid4 ,a yellow precipitate with potassium chromate1 hardly soluble in nitric acid1 but soluble in alkalies4 ,a blue flame on heating on a platinum wire1 and finally1 if sufficient substance is present1 the reduction to metallic form with the blowpipe flame4 ,a method has been recommended of suspending a small bag of calcium sulphide in the sample to be examined1 the supposition being that1 if the calcium sulphide in the bag showed blackening1 it would be due necessarily to lead4 ,this is highly questionable1 and in the hands of one of us 7,k4 ,w4 ,g47 has not given satisfactory results4 ,a further method1 which is quite simple in application1 and occasionally gives confirmatory results1 may be applied in the following manner3 ,the urine to be examined is inoculated with the ,bacillus coli communis4 ,for this purpose a small quantity of fces may be used4 ,the ,b4 coli in its growth makes use of the organic substances in the urine1 and at the same time sets free sulphuretted hydrogen4 ,the urine left is filtered1 the filtrate dissolved in #aj per cent4 nitric acid 7minimal quantity71 and the filtrate examined by the usual tests4 ,this method has occasionally given quite good results in the hands of one of us 7,k4 ,w4 ,g471 and is1 moreover1 an exceedingly easy one to carry out4 ,passing sulphuretted hydrogen direct through the fluid is of no value1 as it is necessary first of all to split up the organic compound before it will react to sulphuretted hydrogen4 ,electro-,chemical ,methods4--,of all the methods at present in use for the estimation of the presence of lead in the urine1 the electro-chemical gives by far the most satisfactory results4 ,several methods are described3 ,the first method consists in using magnesium1 which is left for some hours in the urine1 which has been previously strongly acidulated4 ,in this manner ,marsden and ,abram#b say that they have been able to detect #a part in #ej1jjj in the urine without difficulty4 ,the method adopted is as follows3 8,a strip of pure magnesium is placed in the fluid to be examined4 ,ammonium oxalate in the proportion of about #a gramme to #aej c4c4 is added4 ,if lead is present1 it is deposited on the magnesium4 ,a deposit is seen within half an hour1 but we have usually left it twenty-four hours4 ,the slip is then washed with distilled water and dried4 ,confirmatory tests3 7#a7 ,warm the slip with a crystal of iodine 7yellow iodide proves lead1 cadmium may be ignored72 7#b7 dissolve deposit in ,,hno1 and apply usual tests4 ,the magnesium can be used again after careful washing with acid and distilled water4 ,the surface of the magnesium1 when used1 must be bright and free from oxide4 ,the delicacy of the method has been tested with aqueous solutions containing known quantities of lead1 also with normal urine to which known quantities of lead have been added4 ,in all cases a control experiment was performed to insure the freedom of the materials from lead4 ,lead has been detected when present in the proportion of #a part to #ej1jjj1 whether in simple aqueous solution or in urine40 ,shufflebotham and ,mellor#c describe the following method as one by which lead may be detected in organic tissue1 and in each case this necessitated a large amount of evaporation4 ,the method has value1 but the difficulty of dealing with large quantities of fuming nitric acid1 and the addition of this acid from time to time during the operations1 render it difficult unless a good fume chamber is at hand4 ,shufflebotham and ,mellor state that they obtained no reaction with the potassium chloride-hydrochloric acid method suggested by ,dixon ,mann4 8,on the ,detection of ,lead in ,urine and ,post-,mortem ,specimens4--,a piece of kidney of #bj c4c4 capacity was cut up into about a dozen pieces4 ,these were placed in an evaporating basin1 and about #ej c4c4 of fuming nitric acid were poured into the dish4 ,dense brown fumes of nitrogen oxides were evolved4 ,when the action had subsided 7in from two to three minutes71 the dish was placed upon a sheet of asbestos1 and allowed to simmer over the ,bunsen flame for about an hour4 ,if the frothing appears in danger of running over the sides of the dish1 stirring with a glass rod or removal of the flame for a short time may be necessary4 ,twenty-five c4c4 of the fuming acid were added at intervals of a quarter of an hour1 and this process was repeated three times4 ,the destruction of the organic matter was so complete that the whole of the piece of kidney passed into complete solution4 ,the solution was then evaporated down to a few c4c41 neutralized with caustic soda1 filtered1 and treated with hydrogen sulphide4 ,a dark-brown precipitate of lead sulphide was obtained4 ,with potassium chromate a yellow precipitate of lead chromate was obtained with the same specimen of kidney which gave a negative result with the ,k,cl,o-,h,cl method of destroying the organic matter4 ,our reagents1 dishes1 etc41 were then examined with a blank test1 but we found no lead4 8,urine4--,we then sought the presence of lead in the urine of ,cases #b1 #c1 and #d4 ,half a gallon of urine was evaporated down to dryness in each of two basins4 ,in one basin the residue was heated until it was charred4 ,both residues were then treated separately with fuming nitric acid1 as just described4 ,the uncharred residue passed into solution1 and on cooling deposited a white sediment4 ,the mother-liquor was neutralized and tested in the usual way4 ,a brown precipitate of lead sulphide was obtained in ,case #b1 while in ,case #c a well-marked black precipitate was obtained4 ,the urine of ,case #d gave a negative result4 ,the charred residue did not pass completely into solution1 and the tests for lead were not so well defined as when the residue was uncharred4 ,this shows that care must be taken to prevent charring of the residue during evaporation40 ,a method has recently been described by ,hebert#d--;a modification of ,trillet's4 ,this method is based upon the fact that peroxide of lead1 when mixed with tetramethyl of diphenyl-methylen1 gives in acetic acid solution a fine blue coloration4 ,unfortunately1 a number of other peroxides give the same blue coloration1 amongst them manganese1 potash1 copper1 magnesium4 ,in addition1 the sodium peroxide used to convert the lead present into the peroxide also gives a bright blue coloration with the reagent1 even if present in minute quantities4 ,the test is made in the following manner3 ,the substance is incinerated1 sulphuric acid added in the usual way1 and the substance evaporated to dryness4 ,it is treated with a cold solution of sodium hypochlorite4 ,the hypochlorite is then removed partly by washing and partly by heating1 and the reagent is then added directly to the substance in the capsule1 and if a peroxide is present the blue colour results4 ,unfortunately1 this dissociation-point of the hypochlorite and the temperature at which peroxide of lead is changed back again to the oxide are very close together1 being only about #be ,c4 ,in addition1 it is very difficult to remove the last traces of the substances which give a blue coloration in addition to lead4 ,one of us 7,k4 ,w4 ,g47 has made extensive trials with this method1 as1 if it had been a reliable process1 it would have been one which would have considerably facilitated the estimation of lead in small quantities4 ,the method has been adopted by certain ,french observers1 who by drawing #b c4c4 of blood from the median basilic vein1 and estimating the lead present in this small amount by means of the blue coloration1 have sought to show that at least #be milligrammes of lead were circulating in the blood of the body4 ,in addition to other grave considerations1 the fact that the reagent itself is colourable by certain other peroxides which exist in the blood-ash renders these figures entirely untrustworthy4 #b4 ,quantitative ,methods of ,estimation4--,two methods may be used in the detection of lead in organic substances1 either in organic fluids or in solids1 and are generally termed the 8wet0 and 8dry0 methods1 from the original treatment of the substance4 ,in the dry method the substance is incinerated with or without the addition of sulphuric and nitric acid2 in the wet the material is treated with hydrochloric acid and potassium chlorate4 ,subsequent treatment in both cases is on the same lines4 ,method of ,fresenius and ,von ,babo#e--,moist ,method4--,the substance which is suspected to contain the poison1 if solid1 is reduced to a pulp1 and is mixed with sufficient water until of the consistency of thin gruel4 ,the urine should be evaporated to one-fourth or one-sixth of its volume4 ,fces should be well stirred up with distilled water4 ,the substance is then placed in a large flask together with crystals of potassium chlorate2 each #ajj grammes of the substance require #c to #d grammes of potassium chlorate4 ,pure ,h,cl of the same weight as the original substance is then added1 the flask is placed on a water-bath and gently heated4 ,care must be taken that the heating is not too brisk1 as otherwise the evolution of the chlorine peroxide takes place too rapidly4 ,if necessary1 additional crystals of potassium chlorate are added from time to time until the fluid becomes limpid and of a slight yellow colour1 or1 if there is much organic matter1 until it assumes the appearance and colour of thin oatmeal gruel4 ,on account of more gradual evolution of chlorine1 the chlorate that is present before the flask is heated acts much more energetically1 weight for weight1 than fragments added after the liquid is heated1 as a great deal of the gas then escapes without rendering any service4 ,if the substance contains sugar1 starch1 or alcohol1 extra care must be taken to avoid frothing over4 ,when the fluid contents are clear or reduced to a thin consistency1 the liquid is transferred to an evaporating basin1 and allowed to remain on a water-bath until the smell of chlorine has disappeared2 it is then filtered while hot4 ,the whole of the organic matter is not destroyed by this process1 fatty substances especially being resistant2 but if the organic matter is reduced to small fragments1 any mineral poison present will be liberated4 ,the objections raised against this process are that some important poisons--such1 for instance1 as arsenic and antimony1 specially the former--are liable to escape partially in the form of vapour1 and that others1 such as lead and silver1 may remain as insoluble precipitates on the filter4 ,as regards the first objection1 it is to be observed that1 when the hydrochloric acid is diluted with water 7as in a moist method of destroying organic matter71 any arsenic which may be present in the hot solution is not given off with its acid aqueous vapour1 arsenious chloride dissolved in hydrochloric acid being volatile only when the solvent is concentrated4 ,any possibility of loss may be avoided1 however1 by furnishing the flask1 in which the organic matter is being destroyed1 with a condenser and receiver4 ,the second objection1 as far as lead is concerned1 is met by taking care to filter the solution whilst hot2 if only a limited amount of lead is present1 it then remains in solution as chloride so long as the liquid is hot1 and will consequently pass through the filter4 ,a considerable quantity is kept in solution in the cold1 as it forms a combination with potassium chloride1 which is more soluble than lead chloride alone4 ,if a large amount is present1 it will not all be found in the filtrate2 the substance left on the filter1 therefore1 must always be tested for lead4 ,in toxicological work1 however1 the amount of lead present is not as a rule more than will remain dissolved in the cold4 ,silver chloride1 being insoluble either in hot or cold water1 will not pass through the filter2 consequently the salts of silver require dealing with in a special manner4 ,dry ,method4--,this is effected by heating the finely divided substance to redness1 so that it is either carbonized or completely incinerated4 ,when cold1 the residue is drenched with nitric acid1 and sufficient heat is afterwards applied to drive off the free acid4 ,the nitrate of the metal is then dissolved in water1 filtered1 and dealt with according to the kind of metal present4 ,the dry method is unsuitable in the case of the more volatile metals1 as arsenic1 antimony1 and1 in a lesser degree1 lead1 tin1 and zinc4 ,further1 it is extremely difficult and troublesome to carry out with large masses of organic matter4 ,it is convenient with small amounts1 and in the absence of the more volatile metals yields good results4 ,the following two methods are given by ,glaister#f on the one hand1 and ,dixon ,mann#g on the other4 ,both methods are good4 ,it will be seen that ,glaister recommends the estimation of the lead as sulphide4 ,when minute quantities of lead are present in combination with large amounts of organic matter1 the dry process is tedious1 difficult to carry out1 and uncertain in its results4 ,the plan adopted in the elimination of lead by ,dixon ,mann is as follows3 ,the urine is evaporated down to the consistency of gruel1 and the fces mixed in distilled water to a like consistency4 ,they are then treated by the wet method1 as given above4 ,the filtrate after cooling is placed in a glass cell1 the bottom of which consists of a sheet of vegetable parchment2 the cell is immersed to such a depth in a deeper cell1 containing distilled water acidulated with a few drops of sulphuric acid1 that the liquids in the inner and outer cells stand at the same level4 ,a piece of platinum-foil enclosing a surface of about #ej square centimetres1 constituting the kathode1 was submerged in the liquid contained in the inner cell1 a similar piece of platinum-foil1 constituting the anode1 being immersed in the outer cell4 ,the pieces of foil are so placed as to be opposite each other1 separated by the parchment diaphragm4 ,a current1 #c or #d volts1 is then passed through for from six to eight hours1 after which the foil is removed from the inner cell and gently washed and dried4 ,the metallic lead is dissolved off the foil with dilute nitric acid aided by heat1 and after driving off most of the free acid the solution is decomposed with dilute sulphuric acid with an equal volume of alcohol added4 ,it is then set aside for twenty-four hours4 ,the precipitate of lead sulphate is washed with water containing #ab per cent4 of alcohol1 until all the free acid is removed2 it is then separated by decantation1 ignited1 and weighed4 ,the amount of lead is calculated from the weight of the sulphate2 #ajj parts of sulphate are equal to #fhcai parts of metallic lead4 ,whether the moist or the dry process is used1 the residue after the primary filtration should be tested for lead1 which may be present as sulphate and remain undissolved4 ,if the original substance contains lead as sulphate1 the salt should be dissolved with heat in an aqueous solution of ammonium tartrate to which a little free ammonia has been added1 then precipitated with sulphuretted hydrogen 7#ajj parts of lead sulphide equal #hffa parts of metallic lead74 ,it is better1 however1 to convert the sulphide into sulphate by treating it with nitric and subsequently sulphuric acid1 after which it is ignited1 weighed1 and the amount of the metal calculated by the lead sulphate factor4 ,having obtained the substance by decomposing the organic matter1 two methods of estimation may be made use of3 7#a7 ,colorimetric2 7#b7 gravimetric4 ,where the estimation is to be made gravimetrically1 the substance is always obtained as a sulphate1 and the lead estimated by weighing as a sulphate4 ,this process is an exceedingly tedious one when a large number of small samples have to be estimated1 as in the determination of the amount of lead dust present in the air4 ,on the other hand1 it is probable that the use of the balance in the estimation of lead as sulphate is more accurate where larger quantities up to #aj milligrammes are present2 but where only #b or #c milligrammes are present in the amount of substance examined1 the experimental error in washing is too large to warrant the expenditure of time required in this form of estimation1 and the colorimetric method is used4 ,detection of ,lead in ,organic ,mixtures4--,acidulate the organic substances1 reduced to fine proportions1 with nitric acid1 heat for some time1 then permit to cool2 filter1 wash residue1 and mix washings with filtrate2 concentrate filtrate2 pass ,h,s2 place mixture in warm place to allow precipitate to settle2 after which decant supernatant fluid1 collect precipitate on tared filter1 thoroughly wash1 dry on water-bath1 and weigh4 ,one part of sulphide is equivalent to #jicca part of lead oxide and #aehcg parts of acetate of lead4 ,the electrolytic method is better adapted for the detection of minute quantities of lead1 as1 for example1 in the urine or fces or in vomited matter4 ,the urine may be evaporated to a viscous state2 the others1 finely broken up1 are treated in the same way1 after ,h,cl is added1 as recommended above1 the mixture heated1 and pinches of powdered chlorate of potash added1 as necessary1 to break down organic matter4 ,the heating is continued until the odour of chlorine disappears1 after which it is filtered and the filtrate allowed to cool4 ,the filtrate is then placed in the outer cell of a two-celled arrangement1 not unlike a dialyser1 the bottom of which is formed of vegetable parchment1 the outer cell containing distilled water acidulated with ,h,,so4 ,into the inner cell is placed a piece of platinum-foil measuring about #ej square centimetres of exposed surface1 which is connected with the kathode or negative pole of four ,grove cells1 and into the outer cell is placed a like-sized piece of platinum-foil connected with the anode or positive pole4 ,these pieces of foil are so placed in relation to one another that they are only separated by the parchment4 ,the galvanic circuit being now closed for some hours1 any lead in the filtrate will be deposited on the platinum-foil connected with the kathode in the inner cell4 ,the foil is then removed1 carefully washed1 and the metallic lead dissolved by dilute nitric acid aided by heat1 after which the solution is concentrated until most of the free acid is driven off2 dilute sulphuric acid is added to throw down the sulphate1 alcohol being also added to expedite precipitation4 ,the precipitate is allowed to settle for twenty-four to thirty-six hours1 filtered on a tared filter1 washed with water containing #ab per cent4 of alcohol1 dried1 ignited1 and weighed4 ,one part of sulphate is equivalent to #jfhcai part of metallic lead and to #abe parts of acetate of lead4 ,the estimation of the lead1 especially if the amount be small1 may be more accurately made by the volumetric colorimetric method4 ,the metallic lead deposited on the platinum-foil is dissolved in nitric acid1 and distilled water added1 and an aliquot portion placed in a ,nessler glass4 ,a few drops of freshly-prepared ,h,s water1 or ,h,s gas itself1 may be added to or bubbled through the contents of the glass so as to form lead sulphide4 ,the colour formed is now matched in a similar glass1 using a standard solution of lead nitrate1 and forming the lead sulphide as before4 ,some have advocated the magnesium wire deposition test1 originally devised by von ,jaksch1 and modified by ,hill ,abram1 for the detection of lead in the urine of persons who are suspected to be suffering from chronic lead poisoning 7see ante74 ,the colorimetric method of estimating lead has been made use of with very great success by ,duckering in the estimation of lead in the air of potteries4 ,the method is that devised by ,mr4 ,vernon ,harcourt#h1 with a few modifications4 ,the whole of the method is given1 as observation on the quantity of lead present in the air of lead factories helps greatly in suggesting rational methods of precaution4 8,after drying and weighing the filters1 the following is the method4 ,solutions required3 8,nitric ,acid4--,one part of pure concentrated nitric acid to three parts of water4 8,caustic ,soda4--,one hundred grammes of pure caustic soda dissolved in #bej c4c4 of water4 8,sugar4--,a saturated solution of sugar in water4 8,sulphuretted ,hydrogen4--,a saturated solution of sulphuretted hydrogen in water4 8,coloured ,solution4--,cotton-wool dissolved in concentrated nitric acid and evaporated to dryness1 and the residue dissolved in a little water and filtered2 the solution is deep yellow in colour4 8,standard ,lead4--,a solution of lead acetate or lead nitrate made up to contain exactly #jjjja gramme of lead per c4c4 of solution4 8,the bulk of the dust in the filter was removed to a beaker 7,no4 #a71 by gently tapping the inverted funnel4 ,the cotton-wool was then removed from the funnel1 and the upper one-third1 containing the remainder of the dust1 was cut off and added to the dust in beaker ,no4 #a4 ,the remainder of the cotton-wool was placed in a second beaker 7,no4 #b72 #b c4c4 of hot nitric acid was dropped on the dust in beaker ,no4 #a from a pipette1 a little water added1 and the whole heated4 ,the solution was filtered into a #ej c4c4 ,nessler glass1 and the liquid remaining in the cotton-wool also removed by squeezing the wool with a glass rod against the side of the beaker4 ,the cotton-wool in beaker ,no4 #b was similarly extracted with #b c4c4 of nitric acid1 and the solution added to that remaining in beaker ,no4 #a4 ,the liquid was heated1 the cotton-wool macerated in it and filtered as before4 ,the wool was then washed with hot water about three or four times1 and the liquid filtered into the ,nessler glass4 ,a number of standards were then made up by running into ,nessler glasses1 from a burette1 varying amounts of standard lead solution covering a fair range4 ,usually five standards were made up1 containing #je1 #jh1 #aj1 #ab1 and #ad c4c4 lead solution1 depending on the volume of the air aspirated and the quantity of lead expected in the known weight of dust found4 ,to each standard #d c4c4 nitric acid was added1 and #e c4c4 of the caustic soda solution and #d c4c4 of the sugar solution were run into all the six solutions--i4e41 one test and five standards--from pipettes4 ,it was invariably found that the test was coloured faintly yellow1 and if this is not allowed for in the standards high results are obtained4 ,hence a drop or two of the coloured solution 7see solutions required7 was added to the standards placed on white paper till they matched the test4 ,lastly1 to the contents of each of the six glasses was added #d c4c4 of sulphuretted hydrogen solution1 and the liquid in each made up to the #ej c4c4 mark1 and the whole well stirred4 ,usually it was found that the colour of the test came somewhat deeper than that of one standard1 and a drop or two of lead solution was added to the standard till its colour matched that of the test4 ,the elaborate method of making up a number of standards was adopted because it was found that any other way gave high results4 ,in the way described many trial experiments were made1 and they were invariably correct within half a drop of the standard solution40 ,the estimation of the quantity of lead present in organic fluids1 with the disturbing influence of the presence of other metals1 is a factor which always complicates the use of the sulphuretted hydrogen colorimetric estimation4 ,it is almost impossible1 when dealing with fces1 with blood1 or1 on the other hand1 with artificial digests containing bread and milk1 to eliminate the disturbing influence of iron4 ,further1 if steps are taken to remove the iron and other metals1 so much loss takes place in the manipulations necessary that the results arrived at are not satisfactory4 ,whenever dealing with organic matter1 such as urine and fces1 it is best to make a blank test with a similar quantity of the substance under examination obtained from other sources1 and to subtract the error found due to iron1 when a rather closer approximation may be arrived at4 ,so far as can be estimated1 the minimal quantity of lead required to produce poisoning is #jjje gramme per kilogramme of body weight2 but1 on the other hand1 persons who have swallowed much larger doses than this have exhibited no symptoms of poisoning4 ,there is every reason to suppose that lead absorbed through the lung produces a maximum toxic effect1 and1 from the estimation of the quantity of lead found in the body after death1 it is highly probable that exceedingly minute quantities of lead have1 when absorbed over long periods1 produced changes not only by their actual presence in the tissues1 but also have set up degenerative changes which progress even after the elimination of the metal from its local position4 ,histological ,examination4--,in addition to the chemical examination of tissues from a person who has died of suspected lead poisoning1 it is of the highest importance to make histological examinations1 as the naked-eye appearance of post-mortem examination is frequently insufficient to give any clue to the cause of the poisoning4 ,moreover1 in a large number of instances the necropsy may exhibit a number of signs of disease1 such1 for instance1 as granular kidney1 cirrhosis of the liver1 and so forth1 which are associated with diseases other than lead poisoning1 and1 in the absence of any present or past evidence of definite hmorrhages found associated with the other lesions already mentioned1 an ordinary autopsy must be inconclusive4 ,it is true that such pathological conditions are consistent with poisoning by lead2 and if the individual has been a lead-worker1 it is easy1 but frequently erroneous1 to conclude that the symptoms owe their origin to the worker's occupation4 ,we are entirely in sympathy with the remarks of ,king ,alcock#i1 who says3 8,i plead none the less for an impartial investigation of the symptoms presented by a lead-worker1 before assigning full or even partial responsibility of the disease to the occupation4 ,if any and every departure from the normal in a lead-worker is at once assigned--the occupation being known--to plumbism1 early diagnosis naturally presents very few difficulties to the exponents of such methods4 ,and however severely we may condemn in the abstract such a careless1 unscientific attitude1 the tendency has1 in practice1 to be reckoned with and combated4 ,the balance of probabilities would possibly suggest that the occupation is1 after all1 responsible1 in one sense or another1 for the more usual illnesses classically associated with the poison2 nevertheless1 the attending practitioner is in duty bound to take into consideration1 and to estimate the relation of1 all the concurrent causes of such symptoms40 ,on the extremely unsatisfactory position the certifying surgeon may find himself in at a coroner's inquest ,king ,alcock says3 8,the problem1 from a strictly scientific point of view1 is complicated--one might almost say that the truth is stifled--by the fact that the tiological relations of the symptoms of any suspended worker are swamped by the insistent legal relations under which he claims and receives compensation4 8,when once a formal certificate of suspension has been issued1 which has embodied a recognition of lead as a cause of certain existing symptoms1 then it becomes almost hopeless ever to reopen the question of causation of these or other supervening troubles1 be their origin independent of lead or not4 ,the doctor1 in a legal cross-examination1 is1 in scientific honesty1 bound to admit at last the bare possibility of any fantastic chain of remote sequel2 and his protests against the probabilities of such sequel are of no avail1 as opposed to his own admission4 ,the post1 ergo propter1 appeal carries the day easily40 ,for the purpose of histological examination it is essential that portions of the brain1 spinal cord1 liver1 kidney1 and intestine1 should be examined microscopically4 ,the nervous tissue should be placed in formalin and ,mller's fluid1 and a portion in alcohol for the examination of the fibres4 ,the liver1 kidney1 etc41 should be placed in #e per cent4 formaldehyde4 ,the tissues are then treated by the ordinary histological methods1 and sections prepared4 ,with nervous tissue it is essential that those prepared for the examination of the cells should be made by the celloidin method2 the others may be treated by imbedding in paraffin4 ,the points to be sought for in the tissues are sufficiently indicated in the chapter on ,pathology and ,symptomatology1 but may be briefly recapitulated3 ,in the brain1 as well as in all the tissues1 careful search should be made for minute microscopical hmorrhages1 and for evidences of old hmorrhages in the form of small masses of fibrous tissue1 etc4 ,parenchymatous degeneration1 chromatolysis of nuclei1 etc41 nerve degeneration4 ,the arteries and veins should also receive close scrutiny1 as the presence or absence of arteritis should be noted4 ,in the kidney particularly1 search should be made for both interstitial and parenchymatous nephritis4 ,the liver frequently shows signs of microscopic hmorrhage1 and it is as well1 in taking a portion of tissue for examination1 to choose those portions which appear to be specially congested4 ,in the brain and spinal cord and nervous tissue1 search is to be made for the same hmorrhages as already noted4 ,in addition1 the condition of the nerve fibres should be noted1 the presence or absence of periaxial neuritis1 as well as degeneration of the axis cells1 and the various ganglion cells both in the brain and spinal cord should be closely examined for chromatolysis and nuclear atrophy4 ,no evidence is afforded by micro-chemical tests of any of the sections thus obtained1 except those of the lung4 ,it may be possible in the case of the lung to determine the presence of lead granules in the alveolar cells1 and attention should be paid to this4 ,it is possible also that some evidence may be afforded by examination microscopically of the red bone-marrow4 ,the intestinal walls should be examined for evidence of lead particles4 ,if any dark staining1 deep or superficial1 be found in the intestine1 it should be removed for chemical analysis4 ,necrotic areas of the intestinal wall should be sought for4 ,hmatology4--,for all practical purposes1 the best stain for detection of basophile granules in the erythrocytes is ,wright's modification of ,romanowski's stain4 ,this stain may be obtained in appropriate tablets1 and may be prepared immediately before use1 although a stain which has been standing for ten days or a fortnight gives much better results than a quite new stain4 ,the stain consists of a solution of polychrome methylene blue1 together with eosin in methyl alcohol1 and the method of procedure is as follows3 ,blood is obtained by a small puncture1 and slides smeared and allowed to dry4 ,immediately on drying the slip is flooded with the stain1 and allowed to remain for two minutes4 ,this causes fixation4 ,at the end of the two minutes the stain is diluted with an equal volume of distilled water1 and allowed to remain on for a further three minutes4 ,at the end of this time the stain is poured off1 and the slip washed in distilled water for another three minutes1 or until the characteristic purple-violet appearance is produced4 ,it is better to examine such films with an oil-immersion lens1 the oil being placed directly upon the films1 and not covered with a cover-slip1 as the action of ,canada balsam tends to decolorize the blue4 ,if such specimens are required to be kept1 the oil may be washed off with xylol4 ,it is possible to observe basophile staining with a good sixth1 but an oil-immersion lens gives much the best result4 ,the typical staining produced by this means gives darkish bodies scattered about the red corpuscles1 staining sometimes deeply as the nuclei of the white corpuscles4 ,in other cases the appearance is like that of fine dust scattered throughout the cell4 ,in addition to these two forms1 the whole red cell may take on a slight generalized lilac tint1 the normal cells remaining free from granules1 and stained red by the eosin4 ,search of #ajj fields of the microscope should be made1 and if no basophile granules are found in such fields it is unlikely that they will be found4 ,basophile staining is not more pathognomonic of lead poisoning than of any other form of anmia1 but may be regarded as a highly important confirmatory diagnostic sign4 ,a differential count of the leucocytes present may be also made on the same film in which basophile staining is observed2 #cjj should be counted at least4 ,in a typical case of lead poisoning it is found that diminution in the polymorphonuclear leucocytes has taken place with a corresponding increase of the lymphocytes1 and possibly also the large mononuclears1 and probably a slight increase in the number of eosinophiles4 ,this hmatological method of diagnosis is of the utmost importance in lead poisoning4 ,a differential count such as is given on p4 #acg1 showing a large diminution in the polymorphonuclears1 an increase in the lymphocytes1 evidence of changes in the red cells1 consisting of basophile staining1 alteration in the shape of individual cells1 poikilocytosis1 with vacuolation1 is strong presumptive evidence of lead absorption4 ,to complete the hmatological examination1 the hmoglobin should be estimated4 ,this is best performed with ,haldane's instrument--an exceedingly simple one to use4 ,the estimation of the number of red cells and white cells present is useful1 but does not by any means give such valuable information as does the differential count and search for basophile granules4 ,blood-,pressure4--,several methods are available for the estimation of the blood-pressure4 ,the pressure may be roughly estimated as too high or too low by means of the finger4 ,the presence of thickening of the arteries may be also estimated in this way1 but for determining the absolute blood-pressure it is necessary to use one or other of the instruments on the market4 ,the estimation of blood-pressure is an important point in relation to the suspected presence of arterio-sclerosis1 and should be performed wherever possible4 ,sphygmographic tracings may also be taken4 ,such a tracing in a case of typical poisoning gives a peculiar form of curve1 which1 however1 may be present in alcoholism and heavy work1 and arterio-sclerosis of many types4 ,urine ,examination4--,in suspected cases of lead poisoning the examination of the urine may reveal the presence of lead4 ,in addition1 albumin is frequently present1 especially in the early stages of kidney inflammation4 ,the ordinary tests for albumin should be carried out1 and it is also advisable to examine the urine spectroscopically1 as at times hmoglobin1 methmoglobin1 hmatoporphyrin1 may be present in small quantities1 each of which can be detected by means of spectroscopic examination4 ,blood is not common in the urine of lead-poisoned persons1 although microscopically hmorrhages undoubtedly take place in the kidney4 ,these hmorrhages are interstitial1 and as a rule do not cause any blood-pigment to be passed in a quantity that can be determined4 ,it is as well1 however1 to centrifugalize the urine1 and examine the deposit for red blood-cells4 ,the presence of hmatoporphyrin1 as suggested by ,steinberg#aj1 is probably due to hmorrhages in the intestine1 and its presence in the urine should be regarded with suspicion in a lead-worker4 ,where a lead-worker is suffering from continued absorption of lead1 even without the manifestation of other symptoms1 a change has been noted in the acidity of the blood--namely1 a loss of normal alkalinity4 ,the estimation of the alkalinity or acidity of the blood direct is an exceedingly difficult process1 but much information may be obtained by careful estimation of the acidity of the urine1 and of the acidity of the urine in relation particularly to the phosphates4 ,joulie#aa has pointed out the extreme value which may be obtained from a knowledge of the urinary constituents by the means of estimation of the acidity with suchrate of chalk4 ,the reagent is made by slaking lime in such a way that the resulting compound is practically dry4 ,a quantity of this--about #be grammes--is then thoroughly shaken up with #aj per cent4 solution of cane-sugar1 allowed to stand1 and the solution titrated against decinormal acid until it is of one-twentieth normal4 ,the urine is then estimated directly1 the suchrate is run into the #be c4c4 of urine until a faint white flocculent precipitate appears4 ,the number of c4c4 of the solution of suchrate is then noted1 and multiplied by the factor of the solution4 ,this gives the acidity related to the phosphate and other organic acid contents1 and is similar to the method used to determine the acidity of wines4 ,the second estimation consists of estimating the phosphates present by means of a standard solution of uranium nitrate1 using either potassium ferrocyanide or cochineal as an indicator4 ,the specific gravity of the urine is also determined4 ,the result is then expressed in terms of this specific gravity1 or1 rather1 in the terms of the density of the urine in relation to distilled water1 and the whole answer returned per litre4 ,by this method it is not necessary to obtain a twenty-four hours sample of the urine1 the urine passed first thing in the morning being taken for examination4 ,by using this density figure the quantity of acid and phosphate is expressed in relation to the density1 the equation being-- ,the observed acidity --------------------- ,acidity per litre4 ,the density per litre ,the phosphate content is expressed in the same manner1 while the ratio of phosphate to acidity gives the ratio of excretion of phosphate to acidity4 ,there is in lead-workers a considerable diminution in the amount of phosphate excreted1 and1 as has been pointed out by ,garrod and others1 lead apparently produces alteration in the solubility of the uric acid content of the blood1 and may therefore allow of its decomposition4 ,probably lead as a urate is stored up in the tissues4 ,for further particulars of this method of the estimation of the urine1 the reader is referred to 8,urologie ,pratique et ,thrapeutique ,nouvelle10 by ,h4 ,joulie4 ,an examination of the fces of persons suspected of lead poisoning may often give definite results both of the presence of lead and hmatoporphyrin4 ,if small hmorrhages have occurred high up in the intestine1 the presence of hmatoporphyrin in the fces may result4 ,the substance may be easily determined by means of the characteristic absorption bands4 ,a quantity of fces is taken and extracted with acid alcohol1 and the filtrate examined spectroscopically4 ,urobilin bands are commonly present1 and1 particularly1 where much constipation exists these bands are very well marked4 ,there is no difficulty whatever1 however1 in distinguishing them from the characteristic bands of acid hmatoporphyrin4 ,examination of the ,fces for ,lead4--,the moist method or chemical examination given above is the best one to apply for the determination of lead in the fces4 ,as has already been pointed out1 lead is commonly excreted in the fces1 and1 if only about #b milligrammes per diem are being excreted by the fces in a lead-worker1 the quantity cannot be regarded as indicative of poisoning4 ,one of us 7,k4 ,w4 ,g47 has at times found as much as #h to #aj milligrammes of lead excreted in the fces of persons engaged in a lead factory1 and exhibiting no signs or symptoms whatever of lead poisoning4 ,if1 however1 the quantity of lead in the fces rises to anything above #f milligrammes per diem1 there is definite evidence of an increased absorption of lead1 and if at the same time clinical symptoms be present1 suggesting lead poisoning1 such a chemical determination is of the first importance4 ,in estimating the presence of lead in fces1 it may be necessary to deal with the separation of iron1 which may be precipitated as phosphate and filtered off1 the quantitative estimation being proceeded with in the filtrate4 ,lead is much more commonly present in the fces of lead-workers than in the urine1 and it is better to examine the fces rather than the urine in suspected cases4 ,,references4 #a ,,gautier3 ,meillre's ,le ,saturnisme1 p4 #gd4 #b ,,marsden ,,and ,,abram3 ,the ,lancet1 vol4 i41 p4 #afd1 #ahig4 #c ,,shufflebotham ,,and ,,mellor3 ,ibid41 vol4 ii41 p4 #gdf1 #aijc4 #d ,,hebert3 ,comptes ,rendus1 tome cxxxvi41 p4 #abje1 #aijc4 #e ,,fresenius ,,and ,,von ,,babo3 ,liebig's ,annalen1 vol4 xlix41 p4 #bhg1 #ahhd4 #f ,,glaister3 ,medical ,jurisprudence and ,toxicology4 #aiaj4 #g ,,dixon ,,mann3 ,forensic ,medicine and ,toxicology1 p4 #dif4 #h ,,vernon ,,harcourt1 ,a43 ,a ,method for the ,approximate ,estimation of ,small ,quantities of ,lead--,transactions of the ,chemical ,society1 vol4 cxvii41 #aiaj4 #i ,,king ,,alcock1 ,s43 ,brit4 ,med4 ,journ41 vol4 i41 p4 #acga1 ,june #bd1 #aije4 #aj ,,steinberg3 ,international ,congress ,industrial ,hygiene4 ,brussels1 #aiaj4 #aa ,,joulie1 ,h43 ,urologie ,pratique et ,thrapeutique ,nouvelle4 ,,chapter ,,xi ,,treatment ,in laying down the general lines of treatment for both lead poisoning and lead absorption1 it is essential in the first place to distinguish carefully between the two states2 for although lead absorption may gradually drift into definite lead intoxication and lead poisoning1 with all the classical symptoms associated with the saturnine cachexia1 a large number of cases1 particularly those in industrial processes1 do not and should not progress beyond the early symptoms of lead absorption4 ,the treatment1 therefore1 will depend in the first place on whether the case be one so constantly met with in industrial processes1 where generalized symptoms of lead absorption are manifest without any definite and disabling symptoms traceable and sufficiently pronounced to enable a diagnosis of lead poisoning to be made4 ,the facts given in the chapter on ,pathology1 on the methods of entrance of lead1 on the toxic manifestations1 and the blood-changes1 and1 above all1 the facts relating to microscopical hmorrhages and other profound changes in the bloodvessels1 point clearly to the lines along which the general treatment for amelioration1 prevention1 or cure of poisoning should be undertaken4 ,the treatment of the so-called 8presaturnine state10 or what is preferably termed the 8state of lead absorption10 is one that the appointed surgeon or certifying surgeon in lead factories or other processes in which lead is manufactured or used1 is constantly called upon to treat4 ,lead poisoning is a definite entity as a disabling disease1 whereas lead absorption1 although the prodromal stage of such disease1 cannot be defined as actual lead poisoning1 as in many instances persons may show signs of continued lead absorption1 but their powers of elimination can be maintained at such a level that the ratio of absorption to elimination remains in equilibrium4 ,with the preventive treatment of lead poisoning we have dealt in another place 7see p4 #aii74 ,what is particularly required here is the medicinal treatment1 which may be helpful in preventing lead absorption passing on to definite lead poisoning4 ,for many years it has been customary in the treatment of men employed in lead works to give occasional purgatives1 and it is1 moreover1 a common and proper precaution to keep a stock of some simple aperient medicine1 preferably saline composed of sodium sulphate and magnesium sulphate1 at the works in charge of the foreman1 so that any man who so desires may obtain a dose of an ordinary aperient mixture4 ,we have seen from the pathological evidence that the largest proportion of lead is excreted by the bowel1 and that1 therefore1 the sweeping away of the bowel contents--particularly where constipation is set up--will naturally tend to remove from the body a good deal of the lead which has been already excreted into the intestine and which may presumably become reabsorbed unless it be swept away4 ,in a large electric accumulator factory ,epsom salts in the form of the granular effervescing preparation is much appreciated4 ,in winter #ej per cent41 and in summer #ij per cent4 of the men are said to take a daily dose4 ,in an important white-lead works chocolate tablets containing hypo-7thio-7sulphite of sodium are supplied to the workers4 ,another medicine made use of in lead works is the sulphuric acid lemonade1 this being acidulated with sulphuric acid and flavoured with lemon4 ,it is very questionable whether this substance has any definite effect in the special direction in which it is supposed to work--namely1 that of forming an insoluble sulphate of lead in the stomach and so preventing its absorption4 ,the use of this drug was suggested on the presumption that lead poisoning as a rule took its origin from the dust swallowed and converted into a soluble form in the stomach4 ,as we have seen1 there is very little evidence that this entrance of lead is of much importance1 although it does occasionally take place4 ,furthermore1 from the experiments of one of us ,k4 ,w4 ,g4#a1 it has been found that the sulphate of lead is at any rate as soluble as other lead salts1 such as white lead or litharge1 when acted upon by normal gastric juice4 ,with regard to the drinks supplied to workers in lead factories1 it is highly important that some form of fluid should be supplied which the men may drink without harm1 particularly in the more laborious forms of employment1 and1 above all1 in the factories where smelting1 desilverizing1 etc41 of lead is carried on4 ,in these factories the use of some type of lemonade containing sodium citrate is to be recommended1 as it has been shown that one of the pathological effects of lead absorption is to produce an increased viscosity of the blood1 and the use of such drugs tends to some extent to diminish this4 ,a drink containing a few grains of sodium citrate to the ounce and flavoured with lemon is freely drunk by workmen engaged in the laborious processes4 ,finally1 as a general routine treatment1 it is advisable to keep at the factory some form of mixture containing iron1 which may be given to those persons who are showing signs of slight anmia1 generally associated with some degree of constipation1 and it is therefore better to use a form of iron cathartic4 ,this medicine should also be kept in the care of the foreman1 who will see that it is administered to the men properly4 ,in this way any persons who at the weekly examination exhibit signs of anmia may be promptly treated1 and what is more1 the surgeon is assured that the workmen in question actually obtain the medicine prescribed regularly4 ,during the routine weekly or monthly examination1 or at whatever intervals the medical examination takes place1 particular attention should be paid to the records kept of the state of health of the various persons1 and whenever possible alteration of employment should always be enjoined when early signs of anmia make their appearance4 ,the surgeon should spare no pains to determine if any of the workmen are confirmed alcoholics1 and such persons should be removed from work in dangerous processes1 while at the same time care should also be taken to eliminate any persons suffering from those diseases which are known to be predisposing causes of lead poisoning4 ,the card system of registration of any symptoms noted or treatment given facilitates supervision of the health of the men4 ,in times of stress where some particularly dangerous process is in operation1 as1 for instance1 where portions of a building which has become thoroughly impregnated with lead dust is being pulled down1 or where machines are being altered1 removed1 or rebuilt1 especial care should be exercised with the workmen so employed1 and it is advisable in such cases to adopt preventive measures on the supposition--generally correct--that such persons are absorbing a larger quantity of lead owing to their peculiarly dusty employment than they were under normal circumstances4 ,at such times1 also1 it may be advisable to administer some form of mild iron cathartic to all persons employed in the factory for1 say1 a week at a time4 ,it must not be supposed1 however1 that these methods of treatment in any way supersede the precautions for the prevention of lead poisoning by mechanical and hygienic means2 they are merely additional precautions which may be put in force under special circumstances4 ,the ,treatment of ,lead ,poisoning4--,the treatment of definite lead poisoning1 as the treatment of lead absorption1 is directed towards the elimination of the poison1 the promotion of repair to the damaged tissues1 and special treatment directed towards those special organs which suffer mostly in lead poisoning4 ,at the same time1 special treatment of urgent symptoms may be called for2 but in the treatment of the urgent symptoms the fact of the general elimination of the poison must not be lost sight of4 ,we have already seen that the channel through which the poison leaves the body is mainly the fces4 ,treatment must therefore be directed1 as in the former instance 7lead absorption71 towards eliminating the poison by this means as much as possible1 both by the use of enemata1 and later the use of sulphate of magnesia1 which may be added to the ordinary fluid enema2 and it is far better in obstinate cases of constipation and colic to give enemata than to continue with the huge doses of salines or other aperients1 such as croton-oil1 elaterinum1 or castor-oil4 ,colic4--,lead colic may be simple1 acute1 recurrent1 or chronic and continued4 ,in whatever form colic appears pain is invariably referred to the lower part of the abdomen1 frequently into the groins1 and occasionally to the umbilicus4 ,the pain has to be distinguished particularly from acute gastritis1 and occasionally from appendicitis1 and sometimes from that of typhoid fever4 ,acute colitis--not common in this country--and dysentery1 may1 to some extent1 simulate the pain of lead colic1 but ,john ,hunter's#b original definition of 8dry bellyache0 conveys very vividly the type of pain4 ,occasionally diarrha may be met with1 but as a rule obstinate constipation is present4 ,in continued colic1 or chronic colic1 sometimes lasting for several months1 obstinate constipation is the rule4 ,in the simple acute colic the pain passes off in the course of five or six days1 generally disappearing about four days after the lower intestine has been thoroughly cleared4 ,the pain of lead colic is relieved by pressure upon the abdomen1 whereas that of gastritis and most other forms of abdominal pain may be generally elicited along the descending colon and splenic flexure2 mucus is commonly found in the stools1 especially the first evacuation1 after obstinate constipation occasionally of several days' duration associated with an ordinary attack of lead colic4 ,blood may be passed1 but this symptom is not common4 ,the pain in the acute form is paroxysmal2 it is rarely persistent1 being typically intermittent4 ,during the paroxysm distinct slowing of the pulse-rate with an increased blood-pressure takes place1 and the administration of vaso-dilators--such1 for instance1 as amyl nitrite--during a paroxysm rapidly relieves the pain and lowers the blood-pressure1 and in this way distinguishes acute colic of lead poisoning from1 say1 subacute appendicitis4 ,vomiting may or may not be present1 though the patient usually complains of feeling sick1 but there may be at times vomiting of a frothy mucus4 ,it is unusual for a patient to die from acute colic1 but acute paroxysms have been recorded in which yielding of the blood-vessels of the brain has occurred4 ,recurrent colic is as a rule less severe than the simple acute form1 but may last for several weeks1 clearing up for three or four days at a time and then recurring with little diminution in violence from the first attack4 ,such cases are probably due to the gradual excretion of lead by the intestine1 and should be treated on this supposition4 ,in the continued or chronic colic the pain may persist for as long as two months1 during the whole of which time the patient complains of uneasiness and even constant pain in the lower part of the abdomen1 which becomes considerably worse after each evacuation1 and almost invariably is associated with exceedingly obstinate constipation4 ,it is this type of case that olive-oil or liquid paraffin relieves1 while in the acuter forms drastic purgatives such as castor-oil1 croton-oil1 or pulv4 jalap comp4 may be administered4 ,for the treatment of pain in colic one of the various vaso-dilators should be used1 as1 in addition to the spasm of the intestine1 a very considerable vaso-constriction of the whole of the vessels in the mesenteric area occurs4 ,amyl nitrite gives immediate relief1 but the effect passes off somewhat rapidly1 whilst scopolamine1 although taking somewhat longer to act1 is better for continuous use1 as its action is longer maintained4 ,sodium nitrite1 liquor trinitrini1 and antipyrin are also of use4 ,atropin may be used1 but it is perhaps better given in conjunction with magnesium sulphate4 ,whatever form of purgative is given1 some form of anodyne should be combined4 ,drissole and ,tanquerel#c are said to have obtained excellent results with croton-oil2 one drop is given1 followed seven or eight hours later by another1 and then by an enema of #b pints of normal saline4 ,after two or three days the croton-oil may be again given1 one drop at a time each day4 ,in addition1 ,tanquerel made use of belladonna and opium together1 finding that their combined action was better than that of opium alone1 as the physiological effect of belladonna probably assists in preventing the intestinal cramp4 ,hoffmann#d recommends the use of olive-oil and opium1 giving #c to #d ounces of olive-oil4 ,he says that this relieves the spasm of the pylorus1 and is of particular use where severe vomiting is associated with the colic4 ,this use of olive-oil1 first suggested by ,hoffmann in #agfj1 and revived by ,weill and ,duplant#e in #aijb1 is somewhat interesting1 in view of the modern tendency to administer paraffinum liquidum in the treatment of chronic constipation4 ,briquet#f recommends #d grammes of alum and #d grammes of dilute sulphuric acid three times daily1 with the addition of #jje gramme of pulv4 opii at night4 ,briquet says that although the purgative method rapidly diminishes the colic1 the elimination of the poison does not take place as rapidly as by means of the treatment he recommends1 though it is open to doubt whether the use of either of these two drugs is likely to produce any further neutralization or excretion of absorbed lead than sulphate of magnesia4 ,it is quite certain that the magnesium sulphate does not act as a neutralizer of the poison1 as in a factory where sulphate of lead is manufactured some cases of definite lead poisoning occurred1 in which at least half must have been due to the inhalation of lead sulphate dust4 ,under these circumstances it seems hardly worth while to attempt to form a sulphate of lead in the body4 ,the action of magnesium sulphate and other salines1 however1 in promoting the flow of fluid towards the intestines1 and rapidly diluting and washing out the contents1 tend to eliminate such lead as has already been excreted into the bowel4 ,a number of other drugs have been given from time to time for the purpose of forming an insoluble compound with the metal in the intestine1 such1 for instance1 as sulphur in many forms1 which is still much used in ,french hospitals4 ,peyrow#g advises sulphide of soda1 whilst ,meillre prefers potassium sulphide as being less irritating4 ,he considers sulphuretted hydrogen a proper prophylactic against reabsorption4 ,both experimental work and clinical observation show that a change to sulphide does take place in the lower bowel1 and that staining of this part of the intestine is due to lead sulphide2 but as the figure on ,plate ,,ii4 shows1 the lead may exist in the form of granules of a dark nature1 deeply embedded in the intestinal wall1 besides being situated in the exterior4 ,stevens#h suggests the use of -grain doses of calcium permanganate thrice daily to relieve pain4 ,a certain number of other drugs may be also made use of from the point of view of diminishing the pain1 and one ,french observer advocates the hypodermic injection of cocaine1 but it is doubtful whether any good would follow from such a procedure4 ,hypodermic injections of morphia should be given whenever the pain is great1 and diaphoretics as well as diuretics should also be given1 such1 for instance1 as ammonium acetate1 citrate of potash1 or soda4 ,chloroform water and chloral and bromine water may be also used1 and when no other drug is at hand1 the inhalation of chloroform will rapidly relieve the acute vaso-motor spasms associated with colic4 ,during the attack of colic1 and for at least a day subsequent to its disappearance1 the patient should be kept on a fluid diet2 milk is best1 and #aj grains of sodium citrate should be added to each glass of milk4 ,after the colic has subsided1 a light farinaceous diet should be given1 and it is better not to give meat until at least a week has elapsed4 ,alcohol is to be avoided4 ,the ,anmia of ,lead ,poisoning4--,as has been pointed out in ,chapter ,,viii 7p4 #ace71 the anmia of lead poisoning is one due to the destruction of the red blood-cells4 ,this is evidenced not only by the curious sallow complexion1 by the occasional presence of hmatoporphyrin in the fces and urine1 and often by the curious yellow of the sclerotics1 but also by an increase in the viscosity of the blood itself4 ,moreover1 the urine of persons suffering from lead poisoning is invariably highly coloured1 and may even show the presence of methmoglobin4 ,as the anmia is generally a symptom of continued lead absorption for a long period1 and does not necessarily occur with every case of colic--in fact1 acute colic may often supervene without any symptoms of continued anmia--the persons suffering from lead anmia should be removed from their direct contact with the dangerous processes1 and should be given1 if possible1 work in the open air4 ,iron and arsenic may be used1 preferably in combination1 whilst the iodide of iron often gives good results4 ,whatever preparation of iron is given1 care should always be exercised in avoiding any constipating effect1 and the free action of the bowel should be maintained1 together with a liberal supply of milk4 ,potassium iodide may be also given4 ,with regard to the action of potassium iodide1 there is division of opinion amongst various physicians as to the efficacy of the drug in the elimination of lead from the body4 ,at the same time a very large number of persons hold that the administration of fairly large doses of potassium iodide in the case of a person suffering from chronic lead absorption may at times be associated with sudden exacerbation of the disease1 and that the drug apparently may determine the production of acute symptoms1 such as encephalopathy or paralysis1 when these have not been previous features of the case4 ,our experience supports this statement1 and on more than one occasion one of us 7,k4 ,w4 ,g47 has seen a distinct increase of symptoms follow the administration of large doses of potassium iodide4 ,from a comparison with other cases it seems that these symptoms would have been unlikely to make their appearance without some secondary cause4 ,against this point of view must be quoted further experiments already referred to by ,zinn#i1 who found that when lead iodide was administered to experimental animals iodine alone was found in the urine2 but it must be pointed out that no estimations were made of the fces1 and it is possible that a certain amount of lead was eliminated in this way4 ,what exactly is the action of iodide on the solubility of lead in the body it is difficult to say2 yet the use of iodine compounds has been followed with considerable success in a number of chronic inflammatory diseases1 and it is possible that it may have the action of splitting off the particular lead compound from its organic association with the tissues1 especially as it is well known that iodine plays a very important rle in the process of cell metabolism4 ,another point which tends to support the use of iodine is the fact that the other two halogens1 bromide and chloride1 both of which enter largely into cell metabolism1 also have a slightly beneficial effect on the excretion of lead4 ,the dose of the iodine given should not be large to commence with1 #c grains three times a day is sufficient1 the dose being run up to some #cj or #dj grains per diem1 the symptoms meanwhile being carefully watched4 ,other symptoms often associated with the anmia of lead poisoning are-- ,rheumatic ,pains4--,these pains are suggestive of muscular affection1 and are possibly due to minute hmorrhages occurring in the muscle tissue1 which have been discovered in the muscles of experimentally poisoned animals4 ,for the rheumatic pains diaphoretics and citrates of soda and potassium may be given4 ,lumbago4--,the lumbago constantly complained of in chronic lead poisoning and even in the early stage of lead absorption1 is very generally related to chronic constipation rather than to a definite affection of the lumbo-sacral joints4 ,nephritis4--,affections of the kidney associated with lead poisoning are almost entirely confined to sclerosis4 ,the presence of albumin in the urine is not a very common symptom4 ,as has been pointed out already1 the presence of lead in the urine is by no means a regular feature of lead poisoning1 though it may at times be present1 and the urine should always be examined for changes in the kidneys2 but as a number of cases of chronic lead poisoning are associated with alcohol poisoning1 the changes in the kidney cell are almost certain to be present4 ,on p4 #ie the illustration showing the disease in the kidney produced by experimental dosage with lead1 and the kidney of a fatal case of lead poisoning in a man who at the same time had a strong alcoholic history1 shows fairly definitely the difference between these two points4 ,acute nephritis occurs so rarely in the course of industrial lead poisoning that it cannot be considered to be a disease due to lead4 ,in chronic nephritis treatment should be along the ordinary lines and the same remark applies to enlargement of the liver4 ,heart4--,symptoms due directly to disease of the heart are rarely caused by lead alone4 ,the heart muscle may suffer in the same way as the other muscles of the body1 and in lead poisoning in animals distinct hmorrhages are found between the muscular fibres in the heart muscle1 and it is therefore probable that a form of myocarditis may exist in lead poisoning4 ,this1 together with the increased arterial tension1 may cause dilatation1 but the symptoms are those related more to the general condition of arterio-sclerosis than to any direct heart lesion1 and as a rule these symptoms do not call for any special treatment4 ,treatment of ,nervous ,manifestations in ,lead ,poisoning4--,with one or two exceptions1 the diseases of the nervous system associated with lead intoxication only appear when actual lead poisoning is established4 ,certain evidences of affection of the nervous system are occasionally seen in the prodromal stage1 or stage of lead absorption4 ,these may be merely temporary and disappear often under treatment1 by change of employment and reduction in the quantity of lead absorbed4 ,thus1 dilatation of the pupils--the reaction to light being extremely sluggish or absent--is often a feature of the later stages of the condition of lead absorption4 ,tremor may also be a symptom1 the outstretched hands exhibiting a fine undulatory movement1 often increased on attempting to perform some act such as touching the nose1 or touching the two fingers together1 and when these symptoms occur they must always be regarded as of somewhat grave import4 ,but it must be remembered that tremor may occur as a common complication of alcoholic cases1 and further1 follows excessively hard manual work1 though there is usually little difficulty in distinguishing between the various forms4 ,the symptomology of nervous diseases associated with lead poisoning has already been carefully set out in ,chapter ,,ix41 and the pathological changes underlying these symptoms in ,chapter ,v4 ,of the general treatment1 little needs to be added to what has already been stated for the treatment of lead anmia and general lead intoxication4 ,iron and arsenic 7not strychnine1 especially in presence of colic71 and other similar drugs1 should be employed together with iodides either as potassium iodide or as an injection in the form of an organic compound1 of which there are several varieties on the market4 ,the injection of normal serum has been advised1 as well as saline injections1 and in some instances venesection has been practised1 but it is doubtful whether anything is to be gained by this form of treatment4 ,further1 it has been stated that some lead is excreted through the skin1 and for this reason sulphur baths1 bathing in sulphuretted hydrogen water1 etc41 have been recommended to neutralize any lead that has gained access to the skin4 ,serafini#aj has claimed that by means of electrolytic baths a certain amount of lead can be found present in the water after continuous passing of a current1 and it has been supposed by these observers that the lead has been actually driven out of the body under the action of the electric current4 ,it is1 of course1 possible that such lead as is discoverable in the water was merely that which had already become incorporated with the patient's skin through mechanical contact4 ,whatever form of treatment be adopted of a general type1 the patient must certainly be removed from the chance of any further lead absorption2 a person who is suffering from wrist-drop or other form of paresis should not be employed in any portion of a lead works where he may come into contact with any form of lead or its compounds for at least a year after the paresis has disappeared1 and even then it is inadvisable for such a person to return to any form of dangerous lead work4 ,the electrical treatment of the injured nerves and muscles should be undertaken energetically2 both the galvanic or faradic currents may be used4 ,probably the best form is the galvanic4 ,a small medicinal battery may be utilized1 the method of application being as follows3 ,one pole of the battery should be placed over the affected muscle1 and the other pole placed in a basin of water into which the patient's hand is dipped4 ,the current should then be passed4 ,it is better not to use a current of too great intensity1 particularly at the start1 although it is found in practice that a much greater current can be borne in the early stages of the treatment than when the muscles and nerves commence to recover4 ,as a rule the patient experiences no inconvenience whatever from a considerable current during the first week of his affection1 but at the end of a fortnight or three weeks less than one-third of the initial current can be borne4 ,the current should not be passed continuously1 but should be used for a short time and then shut off1 being again switched on for five or six minutes1 and then again shut off4 ,the applications may also be modified by placing one hand in the vessel of water and stroking the affected muscle and nerve with the free electrode4 ,the application of the current should be for not more than half an hour at a time1 and may be applied twice in the twenty-four hours4 ,it is quite easy to instruct the patient to perform the electrical treatment for himself in this manner when the paresis is affecting either the upper or lower extremity4 ,with the faradic current the circuit should be closed while the current is at a minimum1 and then the quantity of current raised to some #ae to #bj milliampres4 ,for affections of the lower extremity the application may be made by means of one of the usual baths in which the foot is immersed1 the other electrode being placed on the back or other suitable position4 ,if both the lower extremities are involved1 then both feet should be placed in a bath into each of which the source of electricity is connected4 ,ionization by means of the faradic current may also be made use of4 ,for this purpose one of the halogens1 preferably iodine or chlorine1 should be used1 it being remembered that chlorine and iodine ions enter from the negative pole1 so that in such a case the bath in which the affected limb is placed must be connected with the negative pole of the battery4 ,subsequently1 with either form of electrical treatment1 the part should be well rubbed1 and passive movements as well as massage are an advantage in promoting the return of normal function4 ,as the muscles gradually return towards their normal state1 graduated muscular exercises should be used4 ,when treated in the first week or two of the onset1 lead paresis frequently recovers1 and in a person suffering from lead palsy for the first time1 confined only to the hands or to a group of muscles in the shoulder1 prognosis is good4 ,the prognosis of palsy of the lower limbs is not so good4 ,paralysis of the facial nerve is occasionally seen in lead poisoning1 and where this occurs it should be treated as previously recommended1 by means of iodides in association with localized electrical treatment4 ,one pole of the battery should be placed below the external auditory meatus1 and the other one passed over the face on the affected side4 ,in long-standing cases where no attempt has been made at treatment in the early stages of the disease1 and where considerable muscle degeneration has already taken place1 the prognosis as a rule is very bad4 ,efforts should always be made in an early case by passive movements and massage of the affected muscles to improve their nutrition as far as possible4 ,the diet should be light1 and alcohol should not be given at any time4 ,affections of the ,central ,nervous ,system4--,the typical form of affection of the central cerebral nervous system caused by lead1 is lead encephalopathy4 ,the disease may be insidious in its onset1 and may be preceded by a long stage of chronic headache with slight or total remissions4 ,headaches may last for several months before the actual acute stage of the disease is reached4 ,in the examination of several brains of persons who have died from lead encephalitis1 microscopic sections of the brain have shown signs of hmorrhages which must have taken place some considerable time prior to death1 and were no doubt associated with the headache that had been complained of for some time previously1 before the onset of the fatal illness4 7,see ,plate ,,iii47 ,persistent headache occurring in a lead-worker should always be regarded with grave suspicion1 and such a case should be treated on the assumption that it is an early case of lead encephalitis4 ,bromides and iodides should be given1 and the patient placed in quiet surroundings1 and fed on light1 nutritious diet1 and every attempt made to produce elimination of the poison4 ,in the acute attacks vaso-motor spasm is no doubt partially accountable for the symptoms1 and various dilators1 previously noted in discussing colic1 may be made use of1 such1 for instance1 as amyl nitrite1 scopolamine1 etc41 whilst pyramidon1 antipyrin1 phenacetin1 and other similar drugs may be given between the attacks4 ,under no circumstances should any person who has suffered from encephalitis or other cerebral symptom of lead poisoning be allowed to resume work in a lead industry4 ,the treatment of eye affections in lead poisoning requires little comment1 as the essential treatment must be the same as in other cases1 mainly devoted towards the elimination of the poison4 ,attempts may be made to treat paresis of the ocular muscles by means of mild electric currents1 but of this we have had no experience4 ,about #ej per cent4 of cases of lead amaurosis and amblyopia recover1 but a number progress to total and permanent blindness1 and prognosis in such cases must always be guarded4 ,prognosis4--,the prognosis of the first attacks of lead poisoning of simple colic or even slight unilateral paresis is good2 practically all cases recover under proper treatment4 ,it is unusual for a person to succumb to a first attack of simple colic1 or paresis4 ,in most cases the serious forms of poisoning only make their appearance after three or four previous attacks of colic1 but a single attack of paresis is much more frequently followed by a severe form of poisoning1 such as encephalitis4 ,a limited number of persons are highly susceptible to lead poisoning1 and these persons rapidly show their susceptibility when working in a dangerous lead process4 ,lead poisoning occurring in an alcoholic subject is more likely to result in paretic and mental symptoms than in a person who is not addicted to alcohol1 and the prognosis of lead poisoning in an alcoholic is much less favourable than in the case of a normal person4 ,mental symptoms very rarely follow from a single attack of lead colic1 and as a rule do not become established under three or four attacks at least4 ,a small number of persons exposed to excessive doses of lead absorption through the lungs develop mental symptoms1 such as acute encephalitis1 without any prodromal stage4 ,the prognosis in such cases is always exceedingly grave4 ,sudden generalized forms of paralysis are not common in the early stages1 but are invariably of grave import4 ,a few cases of paresis1 particularly those of the peroneal type1 and affecting the lower limbs1 become progressive1 and eventually develop into a condition resembling progressive muscular atrophy with spinal cord degeneration4 ,the prognosis of simple colic in women is about as good as for males1 but if an attack of abortion is associated with lead poisoning1 eclampsia often supervenes and permanent mental derangement may follow4 ,in the dementia associated with lead poisoning the prognosis is not so grave as in other forms of dementia1 especially alcoholic1 but depression is an unfavourable symptom4 ,the mania of lead poisoning is not so noisy as that of alcoholic mania1 but where there is suspicion of alcoholic as well as lead poisoning the prognosis is exceedingly grave4 ,as a rule the prognosis of cases of lead poisoning occurring in industrial conditions is more favourable when colic is a marked feature than when it is absent1 and there is no doubt that the prognosis in cases of industrial lead poisoning at the present time is more favourable than it was before the introduction of exhaust ventilation and general medical supervision--a fact no doubt to be explained by the relative decrease in the amount of lead absorbed4 ,,references4 #a ,,goadby1 ,k4 ,w43 ,journ4 of ,hygiene1 vol4 ix41 #aiji4 #b ,,hunter1 ,,john3 ,observations of ,diseases of the ,army in ,jamaica4 ,london1 #aghh4 #c ,,drissole ,,and ,,tanquerel3 ,meillre's ,le ,saturnisme1 p4 #afd4 #d ,,hoffmann3 ,journ4 de ,md41 ,october1 #agej4 #e ,,weill ,,and ,,duplant3 ,gazette des ,hpitaux1 lxxix41 #gif1 #aijb4 #f ,,briquet3 ,bull4 ,thrap41 ,aot1 #aheg4 #g ,,peyrow3 ,thse de ,paris1 #ahia4 #h ,,stevens3 ,bulletin of ,bureau of ,labour1 ,u4,s4,a41 ,no4 #ie1 p4 #ach1 #aiaa4 #i ,,zinn3 ,berl4 ,klin4 ,woch41 ,nr4 #ej1 #ahii4 #aj ,,serafini3 ,le ,morgagni1 ,no4 #aa1 #ahhd4 ,,chapter ,,xii ,,preventive ,,measures ,,against ,,lead ,,poisoning ,amount of ,lead ,fume and ,dust in the ,atmosphere ,breathed4--,lead fuses at #cbe ,c4 and boils at between #adej and #a1fjj ,c4 ,it is volatile when heated to a cherry-red colour--about #eej ,c4 ,experiments,a carried out in the laboratory of a lead smelting works in ,london to determine the temperature at which leady fumes rise from the surface of open baths of molten lead1 showed that unless pure lead is heated to about #ejj ,c41 and at the same time stirred1 no appreciable fume comes off1 and that from lead1 at the same temperature1 under ordinary working conditions1 little or no lead in the form of oxide passes into the air4 ,from lead that has been unrefined or which contains zinc--that is1 lead in the earlier stages of its manufacture 7in the reverberatory furnace7--leady fume was not given off at temperatures less than #gfj ,c4 even when stirred1 because at a temperature of #fjj ,c4 the surface of the molten metal became covered with fluid slag1 which will not allow any oxide to be given off4 ,impurities such as tin or antimony prevent the oxidation of molten lead at lower temperatures1 and give it a bright1 shiny colour4 ,when heated to about #fjj ,c41 these impurities form a slag on the surface of the lead containing antimoniates and stannates of lead1 which do not evolve lead fumes unless heated to temperatures never likely to be reached in open lead pots4 ,the reason why molten refined lead can give off lead fume more readily than those named is because the oxide formed on the surface is a dry powder and not in the form of slag4 ,hence1 when the bath is stirred1 some of the dry oxide is broken up and may rise into the air4 ,when a bath of molten lead is not stirred at all1 it can be heated to over #gdj ,c4 without finding oxide in the air aspirated--a temperature not obtained under ordinary working conditions4 ,a ,in these experiments air was aspirated through an iron funnel having an area of #aac square inches 7#ab inches diameter71 placed at a height of #a inches above the molten metal1 and connected to an iron tube #c feet in length and inch in diameter4 ,inside the iron tube was a glass tube1 one end reaching own to the top of the funnel and the other connected with a tube containing pure loose asbestos wool1 and continued down to a tightly stoppered bottle holding dilute sulphuric acid4 ,another glass tube connected this bottle with an aspirator4 ,the asbestos tube was weighed before and after each test1 and the asbestos then treated with nitric acid1 and the lead determined volumetrically4 ,in none of the tests made was lead found in the bottle containing sulphuric acid4 ,were there nothing else to consider but escape of lead fume from a pot or bath of molten metal1 obviously hooding over of the bath and removal of the fume from the atmosphere of the workroom would be unnecessary until this temperature was reached4 ,usually1 however1 the bath is kept standing exposed to the air1 and the oxide which forms on the surface has to be skimmed off periodically1 and whenever the ladle is emptied a small cloud of dust arises4 ,or at times1 in certain processes1 chemical interaction takes place in the bath1 as in the dipping of hollow-ware articles previously cleaned in hydrochloric acid1 with evolution of fume of volatile chloride of lead4 ,any vessel1 therefore1 of molten metallic lead in which skimming is necessary1 or in which chemical action gives rise to fume1 requires a hood and exhaust shaft1 even although the temperature is little1 if at all1 above the melting-point--unless1 indeed1 a separate exhaust can be arranged for the removal of the dust immediately above the point where the skimmings are deposited4 ,of many samples of dust collected in workrooms where there are baths of molten lead1 it is impossible to say definitely how much of the lead present is due to fume1 and how much to dust4 ,thus1 a person tempering the tangs of files was attacked by plumbism1 and a sample of dust collected from an electric pendent directly over the pot1 at a height of #d feet from the ground1 was found to contain #aef per cent4 of metallic lead4 ,similarly1 a sample taken above a bath for tempering railway springs contained #dha per cent4 metallic lead#a4 ,and1 again1 a sample collected from the top of the magazine of a linotype machine contained #hah per cent4 ,such analyses point to the necessity of enclosing1 as far as possible1 the sources of danger--either the fume or the dust1 or both4 ,determination of the melting-point of the molten mass will often help in deciding whether there is risk of fume from the pot1 and1 if there is not 7as in the sample of dust from the linotype machine referred to71 will direct attention to the sources of dust in the room4 ,proceeding on these lines1 ,s4 ,r4 ,bennett#b1 using a thermo-electric pyrometer which had been previously standardized and its rate of error ascertained1 and checking the results in some cases by a mercury-in-glass thermometer 7the bulb of which was protected by metal tubing71 determined the temperature of the various pots and baths of molten lead used in the ,sheffield district4 ,as was anticipated1 temporary cessation of work1 stirring up of metal1 recoking of furnaces1 and other causes1 produced fluctuations of temperatures from minute to minute in the same pot1 and in its different parts4 ,the compensated pyrometer used gave for file-hardening pots a maximum of #hej ,c41 and a minimum of #gfj ,c41 the average mean working temperature being about #hjj ,c4 ,the variations of temperature of lead used for tempering tangs of files and rasps was found to be high1 and largely unrestricted from a practical standpoint4 ,the maximum was #gce ,c41 and the minimum #ebj ,c41 the average mean working temperature being #fej to #gjj ,c41 varying more than this within a few hours in the same pot4 ,spring tempering is carried out at some comparatively constant temperature between a maximum of nearly #fjj ,c4 and a minimum of #daj ,c41 depending on the kind of steel and the purpose for which the steel is to be employed4 ,generally1 the temperature required rises as the percentage of carbon in the steel is diminished4 ,as these baths are larger than file-hardening pots1 the temperature range is higher at the bottom than at the top unless well stirred up4 ,some lead pots are set in one side of a flue1 and the temperature in the mass is then greater on the furnace side4 ,from further observation of these pots during experiments1 he was inclined to believe that the lead did not volatilize directly into the atmosphere1 as heated water does1 but that the particles of coke1 fused oil1 etc41 which rise from the surface1 act as carriers of the rapidly oxidized lead particles which cling to them4 ,similar experiments were carried out in letterpress printing works4 ,the average temperature was #cgj ,c4 in the stereo pots1 and in the linotype pots at work #cjc ,c4 ,scrap lead melting-pots when hottest registered #dbd ,c41 but registered as low as #caj ,c41 according to the amount of scrap added1 the state of the fire underneath1 etc4 ,the best practical working temperature depends largely on the composition of the metal used4 ,that at some factories is the same for stereo drums as for lino pots--viz41 #haf per cent4 lead1 #afc per cent4 antimony1 and #bj per cent4 tin1 added to harden the lead4 ,on the other hand1 some printers use a higher percentage of antimony in the lino than in the stereo metal4 ,lead melts at #cbe ,c41 and antimony at #fcj ,c41 but by adding antimony to lead up to #ad per cent4 the melting-point is reduced at an almost uniform rate to #bdg ,c41 after which further addition of antimony raises the melting-point4 ,this explains why temperatures as low as #bij ,c4 are practicable for linotype pots4 ,the molten eutectic has a specific gravity of about #aje1 whereas the cubic crystals average #fe only2 therefore in these pots the latter float on the top1 and excess of antimony is to be expected in the skimmings or on the surface4 ,administration of certain sections of the ,factory and ,workshop ,act1 #aija1 would be simplified were there a ready means available for determining the extent of contamination of the air--especially of ,section #a1 requiring the factory to be ventilated so as to render harmless1 as far as practicable1 all gases1 vapours1 dust1 or other impurities1 generated in the course of the manufacturing process1 that may be injurious to health2 of ,section #gd1 empowering an inspector to require a fan or other means if this will minimize inhalation of injurious fumes or dust2 of many regulations having as their principal object removal of dust and fumes2 and of ,section #ge1 prohibiting meals in rooms where lead or other poisonous substance is used1 so as to give rise to dust or fumes4 ,unfortunately1 owing to the difficulty hitherto of accurate collection1 only a very few determinations of the actual amount of lead dust and fume present in the atmosphere breathed have been made4 ,this lends peculiar value to a series of investigations by ,g4 ,elmhirst ,duckering1 which have thrown much light on the amount of lead fume present in the air of a tinning workshop1 and the amount of lead dust in the air during certain pottery processes1 and the process of sand-papering after painting4 ,incidentally1 also1 they help to determine the minimal daily dose of lead which will set up chronic lead poisoning#c4 ,aspirating the air at about the level of the worker's mouth for varying periods of time1 he determined the amount of lead in the fume1 or in the dust1 per #aj cubic metres of air1 and from knowledge of the time during which inhalation took place he calculated the approximate quantity inhaled per worker daily4 ,we have summarized some of his conclusions in the table on pp4 #bjd1 #bje3 ,duckering's experiments as to the presence of fumes containing compounds of lead in the atmosphere breathed were carried out in a workshop for the tinning of iron hollow-ware with a mixture consisting of half lead and half tin4 ,the process of manufacture and the main sources of lead contamination in the air 7knowledge arrived at from these experiments7 are explained on p4 #ei4 ,as the result of laboratory experiments designed to show the effect of the violent escape of vapour produced below the surface of molten metal in causing contamination of the air1 and the nature of the contaminating substances1 he was able to conclude that the chemical action of the materials 7acid and flux7 used1 and subsequent vaporization of the products of this action1 was a much more important factor than the mechanical action of escaping vapour4 ,subsequently1 experiments carried out on factory premises gave the results which are expressed in the table as to the relative danger1 from lead1 to 7a7 a tinner using an open bath2 7b7 a tinner working at a bath provided with a hood and exhaust by means of a furnace flue2 and 7c7 the nature and extent of air contamination caused by the operation of wiping excess of metal 7while still in a molten state7 from the tinned article4 ,in all three experiments aspiration of air was made slowly3 it was maintained at the rate of #c to #d cubic feet an hour in the first experiment for between seven and eight hours2 in the second for twenty-eight to twenty-nine hours2 and in the third for twenty-four to twenty-five hours4 ,the person engaged in tinning at the open bath was shown to be exposed to much more danger than one working at a hooded bath1 while the wiper was exposed to even more danger than the tinner using an open bath1 since not only was he inhaling fume from the hot article1 but also fibre to which considerable quantities of metallic lead and tin adhered4 ,analysis of samples of dust collected in different parts of the workroom bore out the conclusions derived from analysis of the fumes4 ,thus1 samples collected from ledges at varying heights above the tinning bath containing the mixture of tin and lead contained percentages of soluble lead 7lead chloride7 in striking amount as compared with samples collected at points in the same room remote from any source of lead fume1 while the insoluble lead present1 as was to be expected from the fact that it consisted of lead attached to particles of tow floating in the air1 was less variable4 ,,table ,,xii41 ,,showing ,,quantities ,,of ,,lead 7,,pb7 ,,in ,,the ,,atmosphere ,,at ,,breathing ,,level4 7,g4 ,e4 ,,duckering',s ,,experiments47 ---------------------------------------- ------------------------- ,esti- mated ,present ,time 7in ,approximate in #aj ,cubic ,hours7 ,quantities ,metres of during of ,lead 7,pb7 ,air 7,milli- which expressed in grammes74 ,in- ,milligrammes ------------halation inhaled ,total ,lead took by ,worker ,occupation4 ,dust4 7,pb74 place4 per ,day4 ---------------------------------------- ------------------------- 7#a7 7#b7 7#c7 7#d7 7#e7 ,tinner using open bath -- #cggi #e #ajgj ,tinner using bath covered by -- #fcf #e #ahj hood1 and having fumes exhausted by draught of furnace ,wiping off 7tinning7 -- #abdca #e #cebj furnace furnace furnace furnace ,earthenware dipping 7pottery7 #ch #ahj #g #jfi 7average of #d expts47 ,earthenware dipping 7pottery7 #hd #fbg #g #bdj 7single furnace expt47 furnace ,china dipping 7pottery7 #cf #bab #g #jhc 7average of #d expts47 ,rockingham ware dipping #dd #bbf #g #jhf 7single 7pottery7 expt47 ,earthenware cleaning 7pottery7 #dg #bbi #g #jhh 7average of #g expts47 ,china ware cleaning 7pottery7 #abc #accd #f #djh 7single expt47 ,earthenware drying 7pottery7 #be #bai #h #jib 7average of #c expts47 ,earthenware glost placing #cd #bjh #h #jic 7average 7pottery7 of #c expts47 ,china glost placing 7pottery7 #cj #ajh #i #jej 7single expt47 ,china glost placing 7pottery7 #ba #jcb #i #jaf 7single expt47 ,majolica-painting of tiles #fa #iaa #g #cdh 7single 7pottery7 expt47 #bjf #ecgj -- -- ,sand-papering and dusting railway coaches #bda #aafaj -- -- #dec #hcaj -- -- ,sand-papering coach wheels #acdc #ajbefj -- -- ,sand-papering motor-car body #fjj #bghcj -- -- #hh #chgj -- -- ,sand-papering motor-car wheels #ce #dgj -- -- ,sand-papering van wheel #did #adchj -- -- ,burning off old paint #eb #cdj -- -- ---------------------------------------- ------------------------- ---------------------------------------- -------------------------- ,per- cent- age of ,lead in ,occupation4 ,dust4 ,remarks4 ---------------------------------------- -------------------------- 7#a7 7#f7 7#g7 ,tinner using open bath -- ,the whole inhaled in the form of vapour of lead or similar compound4 ,tinner using bath covered by -- ,the whole inhaled in the form of hood1 and having fumes vapour of lead or similar exhausted by draught of compound4 furnace ,wiping off 7tinning7 -- #ada milligrammes of metallic furnace lead inhaled as lead chloride1 furnace and #baa milligrammes as furnace metallic lead adhering to furnace floating fibres of tow4 ,earthenware dipping 7pottery7 #hcj;,dipping boards not used4 ,earthenware dipping 7pottery7 #gdb,very dirty dipping boards used4 furnace ,work very rapid1 and much furnace shaking of ware after dipping4 ,china dipping 7pottery7 #edc;,china glaze usually contains about two-thirds as much lead as that of earthenware4 ,rockingham ware dipping #dcg;,dirty dipping boards in use4 7pottery7 ,glaze contains three times as much lead as ordinary earthen- ware glaze1 but the ware is not shaken after dipping4 ,earthenware cleaning #eij;,cleaning done in or at front of 7pottery7 exhaust hood4 ,china ware cleaning 7pottery7#ajhe,very defective exhaust2 hood so arranged that cleaning had to be done outside4 ,glaze contains about two-thirds as much lead as that for earthenware4 ,earthenware drying 7pottery7 #heh;,filter placed at breathing level in centre of drying stillage4 ,earthenware glost placing #feh 7pottery7 ,china glost placing 7pottery7 #cfd;,boards used were fairly dirty4 ,china glost placing 7pottery7 #aej,one man only working4 ,majolica-painting of tiles #aejj,tiles cleaned1 while still damp1 7pottery7 with knife4 ,much dry waste glaze on wooden floor1 and much traffic4 ,several cases of lead poisoning in this room4 #bfaj,passenger fish truck after one ,sand-papering and dusting coat of lead colour4 railway coaches #dhaj,railway coach after one coat of lead colour on filled and faced surface4 #ahcj;,after two coats of quick-drying ,sand-papering white lead paint4 coach wheels #gfdj,old cream-painted wheel before repainting4 ,sand-papering motor-car body #dfdj;,door of motor body after one coat of lead colour and quick- drying sand-paper stopping4 ,urgent work4 #ddjj,wooden motor wheels after two coats of lead colour and sand- ,sand-papering papering between4 ,exhaust not motor-car wheels running4 #accj,same point1 but with exhaust running4 ,sand-papering van wheel #biaj;,after one coat of quick-drying permanent red on two coats of flesh colour 7sand-papering after each coat74 ,burning off old paint #fej,white paint of ,london and ,north- ,western coach4 ,gas-burner used4 ---------------------------------------- -------------------------- ,dust4--,reference to the table shows that the conditions in the pottery workrooms1 as stated in ,column #g1 are reflected in ,columns #c and #e4 ,further details from his experiments may be useful4 ,thus1 in a dipping room where low-solubility glaze was in use1 the amount of lead in the dust collected per #aj cubic metres of air was #jgj milligramme4 ,the average of four experiments where there were no dipping boards was #ahj milligrammes1 and where dipping boards were used1 #cge2 i4e41 #aie milligrammes of lead in the dust per #aj cubic metres of air is added by the use of dirty dipping boards4 ,as the result of his experiments1 ,duckering believes that approximately #aie milligrammes of lead per #aj cubic metres of air was due to the fine spray given off in the shaking of the ware4 ,in bright sunlight1 he says1 the spray can be seen dancing high above the dipping tub4 ,in a dipping house where work was done slowly by two occupants only1 the proportion of lead in the measured quantity of air was also low--#jeh milligramme per #aj cubic metres4 ,where1 in the absence of special provision made for admission of fresh air to a fan1 the air was drawn from a neighbouring room in which lead processes were carried on1 the amount of lead rose to #egf milligrammes at the level breathed by the gatherer at a mangle4 ,in ware-cleaning the average of all his observations where lead was used 7eleven7 was #cdd milligrammes2 and he concluded that 8wet cleaning of ware causes less direct contamination of the atmosphere1 even where no local exhaust is applied4 ,a still more important result of wet cleaning1 however1 is that the overalls keep much freer of dust40 ,the highest results were obtained when the process of ware-cleaning was done outside the influence of the exhaust draught4 ,in one instance1 where the ware was cleaned at a distance of #f feet from the exhaust opening1 #accd milligrammes per #aj cubic metres of air were found4 ,subsequently at the same point1 after the exhaust system of ventilation had been remodelled1 #jie milligramme only was present4 ,even in a stillage room in which no work was done other than the placing on and removal of the boards from the racks1 the lead content per #aj cubic metres of the air was #ajh milligrammes4 ,in glost-placing1 the average of four experiments was #ahc milligrammes--no doubt the result of glaze on the boards4 ,as much as #iaa milligrammes of lead was found per #aj cubic metres of air in the centre of a large majolica-painting room1 with wooden floors and much traffic in it4 ,wooden floors generally appeared to influence the results1 as determinations of the lead present were higher in rooms with them than with tiled floors4 ,in coach-painting the proportion of lead found by ,duckering in the air breathed during the actual time of sand-papering explains the severe incidence of poisoning in this class of work4 ,the table shows the amount of lead in the air to be enormous1 and in many cases much in excess of the amount found in the air when wiping off in the tinning of hollow-ware4 ,the work of sand-papering is1 however1 very rarely continuous1 the time occupied in it being1 for the painter1 about one to two hours daily2 for the brush hand1 two to three and a half hours2 and for the painter's labourer1 four to five hours4 ,knowing intimately the processes at which the estimations recorded in the table were made1 the relative frequency of cases of plumbism reported among those employed at them1 and the duration of employment prior to attack1 we believe that1 if the amount of lead present in the air breathed contains less than #e milligrammes per #aj cubic metres of air1 cases of encephalopathy and paralysis would never1 and cases of colic very rarely1 occur4 ,and this figure is a quite practical one in any process amenable to locally-applied exhaust ventilation4 ,somewhere about #b milligrammes1 or #jjjb gramme1 of lead we regard as the lowest daily dose which1 inhaled as fume or dust in the air1 may1 in the course of years1 set up chronic plumbism4 ,local ,exhaust ,ventilation4--,in considering preventive measures against lead poisoning1 precedence must be given to removal of fumes and dust by locally-applied exhaust ventilation1 as1 unfortunately1 the wearing of a respirator is neither in itself a sufficient protection1 nor1 if it were1 could the constant wearing of one be enforced4 ,a respirator is of no use against lead fume4 ,in the case of dust1 the conditions which it must fulfil to be effective are1 first1 that the air breathed is freed from dust1 and1 secondly1 that it should not incommode the wearer4 ,further1 it should be simple in construction1 easily applied1 and allow of frequent renewal of the filtering medium4 ,no existing respirator of moderate price conforms quite satisfactorily with these requirements4 ,the more closely to the face it is made to fit1 and the more effectually the air is filtered1 the greater is the inconvenience experienced when it is worn4 ,this inconvenience is due to the exertion 7showing itself in increase of the respiratory movements and pulse-rate7 caused in aspirating the air through the filtering medium1 and rebreathing some portion of the expired breath1 containing a much greater proportion of carbonic acid gas and of moisture at a higher temperature than are present in fresh air4 ,respirators1 therefore1 except for work lasting a short time--half an hour to an hour--cannot be considered an effective or sufficient means of protecting the worker against dust4 ,if a respirator must be worn1 the simplest form is a pad of ordinary non-absorbent cotton-wool 7absorbent wool quickly becomes sodden and impervious71 about #c inches by #d inches1 placed over the mouth and nostrils1 and kept in position by elastic bands passed round the ears4 ,the pad should be burnt after use4 ,with a smooth1 impervious floor1 however1 and ventilation designed to remove the fumes and dust at1 or as near as possible to1 the point of origin1 lead poisoning would become very rare in most of the industries to be described4 ,the essential points of such a system are--7#a7 ,the draught or current of air set in motion either by heat or by a fan2 7#b7 the ducts along which the current travels2 7#c7 the hoods or air-guides designed to intercept and catch the fumes and dust at the point of generation2 7#d7 inlets from the outside air into the room to replace continuously the air extracted1 and1 in many cases1 7#e7 a suitable dust filter or collector4 ,exhaust by ,heat4--,processes giving rise to fumes or to dust liberated on stirring or skimming1 which can be dealt with by the draught created in the furnace flue or over a bath of molten metal provided with adequate hood and duct up which the heated air travels1 are--,smelting1 refining1 spelter manufacture1 and the numerous operations necessitating the melting of lead1 such as tinning with a mixture of tin and lead1 sheet lead and lead piping1 stereo pots in letterpress printing1 pattern-making1 tempering springs1 file-hardening1 etc4 ,the dusting of red-hot metallic surfaces1 as in vitreous enamelling1 might possibly also be dealt with in the same way4 ,the disadvantage of the exhaust by heat is the uncertainty and inequality of the draught1 and the size of the duct necessary to cope with the volume of rarefied air from above the molten vessel4 ,the closer the hood is brought down over the point where the fumes escape1 the less risk is there of cross-currents deflecting them into the workroom4 ,hence all baths of molten metal should have the sides and back closed in1 leaving as small a space open in front as is practicable in view of necessary skimming or other operations4 ,in the case of tinning baths1 ,duckering#d describes completely successful results when from the top of the hood a shaft at least #bd inches in diameter was carried vertically upwards into the open air to a height of #ah feet1 and the top of the shaft fitted with a wind screen in the form of a very large cone1 having its lower edge below the upper edge of the shaft1 and its nearest point at least #h inches from the top of the shaft4 ,smoke produced in large quantity at any point #f inches outside the front of the hood was entirely drawn into it4 ,as1 however1 the inrush of air caused an eddy of the fumes at the upper edge of the opening1 the edges of the hood were turned inwards1 so that the operation of wiping was done in a sort of short tunnel4 ,in general1 it may be said that the diameter of pipes leading from hoods to the outer air 7on the efficacy of the draught in which success depends7 is much too small4 ,frequently mere increase in size will convert an indifferent draught into a good one4 ,the height of the hood also--i4e41 the distance between its lower border and the point where it joints the duct--is of importance4 ,the shorter this distance is1 the less serviceable does it become for the removal of fume4 ,indeed1 it may even retain the fume which1 were the hood not present1 would rise to the roof4 ,sometimes safety is increased by making the hood double1 leaving a space between the two sheets1 and so concentrating the draught at the centre and at the margin4 ,with a fan1 ducts of less diameter can be used than when dependence is placed on heat alone4 ,a duct carried into a chimney-stack has the advantage of dispersing the fume at a safe distance from the workroom4 ,the variableness of the draught produced by heat makes it unsuitable for removal of dust1 except such as arises from skimming4 ,the receptacle for the skimmings should always be kept inside the canopy of the hood4 ,we have1 however1 seen the dust given off in the heading of yarn dyed with chromate of lead successfully carried away under hoods connected up by branch ducts with the main chimney-stack4 ,illustration3 ,,fig4 #a4--;,,davidson',s ,,sirocco ,,propeller ,,fan4 ,exhaust by ,fans4--,the draught for removal of dust1 and frequently also of fumes1 is produced by a fan1 of which there are two types3 7#a7 low-pressure volume fans and 7#b7 high-pressure centrifugal fans4 ,in the first the draught is created by the rotation of a wheel with inclined vanes1 causing the air to be driven transversely through the wheel parallel to the axis of rotation 7,fig4 #a74 ,during a revolution a portion of the air is cut off from one side of the wheel1 and transferred through the wheel to the other4 ,such fans are light1 run easily1 and are cheap4 ,they are of many forms1 both with regard to the number of blades--from two to eight--and general manner in which they are arranged4 ,some closely resemble the screw-propeller of a ship1 while others have blades turned over and fastened on an outer rim4 ,their main defect is inability to overcome any but slight resistance in the course of suction behind1 as from constriction in1 or friction along the sides of1 the ducts and right-angled bends1 or of outflow in front1 as from wind-pressure4 ,under favourable conditions1 however1 and when carefully fitted1 a volume fan will exhaust dust and fumes through a system of ducts several feet in length1 as1 for example1 from mono and linotype machines and electro melting-pots in letterpress printing works4 ,but1 in order to avoid resistance from friction1 the ducts have to be somewhat larger in diameter than when a centrifugal fan is used4 ,with nine,a linotype machines connected up to a #ad-;inch propeller fan1 the branch ducts should be about #d inches in diameter1 and the main duct #ab inches1 increasing from #ab to #ae inches within #b feet of the fan-box4 ,the shorter and straighter the course of the duct to the propeller fan1 the more efficiently it works4 ,wind-guards are necessary to overcome resistance from this source in front1 but their position requires to be carefully considered1 so as to prevent the screen itself crippling the outflow4 ,a ,if gratings are also inserted in the same duct for general ventilation the number of machines must be decreased pro rat4 ,all fans require frequent cleaning1 and in this respect propeller fans have the advantage over centrifugal1 in that they are usually more accessible4 ,illustration3 ,,fig4 #b4--;,,davidson',s ,,dust ,,centrifugal ,,fan4 ,centrifugal ,fans4--,generally1 in the removal of dust1 a strong suction has to be set up in a system of narrow ducts by means of a centrifugal fan--i4e41 a fan-wheel formed by a number of vanes attached to an axle mounted in a spiral-shaped casing--so that when the wheel rotates air is carried along by the vanes1 and flies off tangentially into the space between the blades and the casing1 and thence to the outlet 7,fig4 #b74 ,the air inlet or junction of the fan with the exhaust duct is at the centre of the fan1 an arrangement by which the kinetic energy created by the rapid motion of the air leads to increase of draught instead of being wasted in production of eddies in the surrounding spaces4 ,they are made in many different patterns1 according to the nature of the work to be done4 ,their advantage over the propeller type in the removal of dust lies in the fact that they overcome greater internal resistance1 and a uniform high velocity in a complicated system of pipes can thus more easily be maintained4 ,illustration3 ,,fig4 #c shows adjustable hoods and ducts fitting closely over rollers for mixing coloured inks1 and serving not only to prevent inhalation of lead dust by the workers1 but also the colour from one machine affecting that on another4 ,in the particular room where the installation is fitted there are thirteen separate sets of rollers2 the diameter of the branch duct of each machine is about #e inches1 and that of the main duct close to the fan about #bj inches4 ,the special points we have considered as to entrance of all branch ducts into the main duct tangentially1 gradual tapering of the main trunk1 and collection of the dust in filter-bags1 are noticeable4 ,further1 when one set of rollers is not in use the raising of the hood automatically cuts off the draught through it4 7,drawing supplied by the ,sturtevant ,engineering ,company1 ,limited1 ,london47 ,ducts4--,the main duct should be of metal 7steel1 sheet-iron1 or zinc72 it should be circular in shape1 have as straight and short a course as possible1 and be tapered in such manner that the area of cross-section at any point shall equal the combined areas of all the branch pipes which have entered it at that point 7,fig4 #c74 ,proper dimensions must be studied in relation to the size of the fan and the work to be done4 ,wooden ducts1 unless chosen for specific reasons1 such as the presence of acid in the fumes to be removed1 are very unsatisfactory1 as it is difficult to maintain them in an air-tight condition or to make branch pipes enter with rounded junctions4 ,where several branch ducts enter a main duct1 situation of the fan midway between them has advantage1 not only in saving metal in piping1 but also in causing the distance of the fan from the farthest branch duct to be only half what it would be were the fan placed at the end of the system 7see ,fig4 #g1 p4 #bag74 ,further1 the sectional area of the two collecting ducts will be less than that of one main duct1 and greater uniformity of flow thereby secured4 ,where the two ducts join up into the single duct of the fan1 the bends must be easy2 otherwise the draughts would collide and neutralize one another4 ,branch ducts1 if they cannot be made tangential to a rounded curve1 should enter the main duct at an angle of #cj degrees1 as by so doing equalization of the draught at different openings is made fairly uniform4 ,the very common defect of a right-angle joint diminishes the draught by nearly one-half4 ,branch ducts should never be made to enter a main duct on the outer side of a bend1 because at this point the pressure of the current of air inside the duct is increased4 ,they should join up on the inside of a bend1 where the pressure is reduced4 ,hoods and ,air-,guides4--,as the object of hoods is to concentrate the draught on the fumes or dust to be removed from the worker1 position in regard to origin of the fumes or dust requires first consideration4 ,the more restricted the opening consistent with unimpeded work1 the more effective is the draught1 and the less disturbed will it be by cross-currents in the workroom4 ,pendock lays it down as a useful principle that the area of the front opening into the hood should not be more than four times that of the exhaust throat--i4e41 the point of junction of the hood and duct 7,fig4 #d74 ,not less important is it that the draught should operate below the breathing level4 ,preference as to the direction to be given to the exhaust current should be in the order named3 7#a7 ,downwards2 7#b7 downwards and backwards combined2 7#c7 backwards and upwards combined2 and 7#d7 upwards only4 ,use should be made1 for the removal of the fumes or dust1 of any initial current of hot air set up from a bath of molten metal or from a heated metallic surface1 as in vitreous enamelling4 ,hence under such circumstances only 7#c7 and 7#d7 need be considered4 ,generally hoods applied err in having too wide an opening1 or they are placed too far away from the source of danger4 ,they require sometimes to be adjustable to suit different-sized articles4 ,care is necessary to see that1 when a hood has been adjusted for large articles1 it is readjusted for smaller-sized articles4 ,the principle of ventilation downwards and backwards is recognized as right for grinding and polishing on a wheel1 since the tangential current set up by the wheel in its rotation is utilized4 ,pug-mills in paint-works are perhaps best ventilated by applying the exhaust to a dome-shaped hood covering the posterior half of the mill4 ,edge-runners must be encased1 with an exhaust pipe attached to the casing and sliding doors or shutters for introduction or removal of material 7,fig4 #e74 ,a small negative pressure inside the casing is all that is necessary1 so as to insure passage of air inwards and not outwards4 ,branch ducts must protect the casks out of which material is scooped1 and the receptacle into which it is discharged4 ,in scooping out dry colour from a barrel1 it is unwise to attempt to remove the dust created at every displacement of air on removal of a scoopful by means of a hood suspended over the barrel4 ,instead1 the last joint of the duct should be a telescopic one1 so that it can be lowered into the barrel1 and be kept at a distance of about #f inches above the material4 ,the air is thus drawn downwards into the barrel 7,fig4 #f74 ,illustration3 ,,fig4 #d shows a well-designed arrangement of hoods1 duct1 and fan1 in the packing of white lead1 and the filter-bags for collecting the dust so removed4 ,an additional safeguard is introduced1 as the casks stand upon grids through which a down-draught is maintained by connecting the space underneath with the exhaust system4 7,drawing supplied by the ,sturtevant ,engineering ,company1 ,limited1 ,london47 ,processes such as colour-dusting1 aerographing1 ware-cleaning1 enamel-brushing1 and the like1 are best carried out at benches under hoods with glass tops4 ,air will enter from in front1 and carry the dust or spray away into the exhaust duct placed at the back of the bench4 ,illustration3 ,,fig4 #e shows a pan mill with edge runners fitted with casing 7partially open74 ,the casing is connected to a powerful fan1 and branch ducts with telescopic terminal sections control the dust in scooping out from the barrel1 in feeding into the mill1 and at the point where the ground material is discharged4 ,collection of ,dust4--,frequently no heed is paid to the collection of the dust4 ,sometimes a dust chamber is arranged to intercept it on the far side of the fan1 or attempt is made to blow the dust into a tank of water4 ,the fine dust of which we are speaking cannot be satisfactorily collected by either of these methods1 nor even by a cyclone separator1 so useful for the collection of many kinds of dust4 ,in lead works generally1 the dust removed by the fan is best collected in filter-bags made of some porous fabric4 ,various efficient filters constructed on these lines by ,messrs4 ,henry ,simon1 ,ltd42 ,messrs4 ,beth and ,co41 ,ltd42 and the ,sturtevant ,engineering ,company1 ,ltd41 are on the market4 ,illustration3 ,,fig4 #f shows an arrangement of piping with balanced telescopic joints fitted to a ,sirocco dust fan for removal of dust1 in an electric accumulator works1 when scooping out litharge from a cask into the receptacle prior to emptying the weighed quantity into the mixing machine1 also under a hood connected with the exhaust system4 7,illustration supplied by ,davidson and ,company1 ,limited1 ,belfast47 ,in collecting the dust1 care must be taken to provide an adequate outlet for the spent air1 so as to prevent creation of a source of friction in front which might destroy the effectiveness of the installation4 ,illustration3 ,,fig4 #g4--;,,exhaust ,,ventilation ,,on ,,the ,,patent 8,,pentarcomb0 ,,principle ,,applied ,,to ,,linotype ,,and ,,monotype ,,machines ,,in ,,printing ,,works1 ,,as ,,installed ,,by ,,the ,,zephyr ,,ventilating ,,company1 ,,bristol4 ,p1 ,patent 8pentarcomb0 for equalizing exhaust2 ,v1 patent 8pentarcomb0 for general ventilation2 ,d1 main and branch ducts2 ,f1 fan2 ,u1 upcast from fan2 ,m1 hoods over metal-pots of monotype machines1 constructed to raise and lower1 and swing out and in with metal-pot2 ,l1 hoods over metal-pots of linotype machines1 constructed to raise and lower4 ,in the illustration 8pentarcomb0 grids connect the branch ducts over the metal-pots of mono and linotype machines with the main duct4 ,the 8pentarcomb0 grids are arranged also elsewhere in the main duct itself to assist in the general ventilation of the workroom4 ,the hoods over the metal-pots are constructed to be raised and lowered1 and to swing out and in radially with the melting-pot arm4 7,drawings supplied by the ,zephyr ,ventilating ,company1 ,bristol47 ,in order to secure equality of flow from a number of branched ducts1 the ,zephyr ,ventilating ,company apply a special grating of curved and slanting inlets--the 8pentarcomb0--to each branch duct4 ,the air passing through the comb is split up into numerous small columns1 and the inclination of the curve which each is made to take is such as to reduce friction to a minimum4 ,by means of this device we have found1 in a trunk with twenty branches1 the draught at the one farthest from the fan as serviceable as that next to it4 ,the method is illustrated applied locally to remove the fumes from linotype machines1 and generally in the main duct for removal of foul air near the ceiling4 ,where electricity is available as a motive power for driving the fan1 some modification in the views expressed as to the curvature of the pipes and system of installation can be allowed4 ,in a red lead plant1 for instance1 it may be desirable to have the pipes leading to the sifter or packing machine with sharp angles1 so as to prevent tendency of such heavy dust to collect in them4 ,the electric current allows a fan to be installed at any point desired2 and if applied with knowledge that the increased friction due to an acute angle has to be overcome1 the result may be quite satisfactory4 ,the various forms of vacuum cleaning apparatus with mouthpieces designed to aspirate the dust from different surfaces are sure to be increasingly used4 ,in our opinion1 wherever electric power is available1 they will obviate barbarous methods involving use of hand-brushes to collect dust from machines1 such as those for litho-dusting or for sweeping lead dust from benches and floors1 or use of bellows to blow out the dust from compositors' cases4 ,finally1 the carrying out of lead processes by automatic methods and with the interior of the casing under a negative pressure1 so that the material is transported from one process to another by means of worms or conveyors1 is everywhere to be aimed at4 ,or1 again1 it has been found possible on a commercial scale1 by means of compressed air in a closed system of receivers and pipes1 to force material in very fine state of division from one place to another1 as1 for instance1 of litharge from the cask into the mixing machine for preparation of the paste for manufacture of accumulator plates1 without risk of contact4 ,indication of the efficiency of the draught may be gained by holding smoke-paper at the orifice of the hood4 ,the definition of efficient exhaust in some regulations for the removal of fumes1 as in the ,tinning ,regulations1 is that it shall not be deemed to be efficient unless it removes smoke generated at the point where the fume originates4 ,accurate gauging1 however1 of the draught can only be done with an anemometer1 so as to determine the number of linear and cubic feet passing through the throat per minute4 ,only rarely does one find an occupier alive to the value of the use of such an instrument4 ,the importance of this point has been recognized in the ,regulations for ,heading of ,yarn1 by the requirement that the speed of each exhaust opening shall be determined once in every three months at least1 and recorded in the general register4 ,we prefer to use ,davis's,a self-timing anemometer1 which gives readings in feet per second without the need of a watch4 ,other useful anemometers--,casella's or ,negretti and ,zambra's--require to be timed4 ,a ,it is not available for velocities exceeding #a1bjj linear feet per minute4 ,the details of all routine observations on localized exhaust ventilation might well be entered on a card hung up in the workroom4 ,such a card drawn up by our colleagues1 ,miss ,lovibond and ,mr4 ,c4 ,r4 ,pendock1 has the following headings3 ,,firm4444444444444444444444444444444 ,,process444444444444444444444444444 ,,fans3 ,no44444 ,kind4444444444444444 ,size4444444 ,maker44444444444444444 ,motive power44444444 ,h4,p44444444 ,method of driving44444 ,other load4444444444 ,condition of driving44 ,screen44444444444444 ,dust col- ,direction44444444444 lection4444 ,periodic cleaning444 ,,hoods3 ,no44444 ,kind4444444444444444 ,size4444444 ,structure44444444444 ,distance between each44 ,,ducts3 ,no44444 ,kind4444444444444444 ,size4444444444444444 ,length44444 ,section444444444444444 ,structure44444444444 ,periodic cleaning444 ,,fresh-,,air ,,inlets3 ,no4444 ,kind4444444444444444 ,position444444444444 ,size4444444444444444 ,fixed or temporary44 ---------------------------------------- ----------------------- ,hood3 ,position,date4444444444444444,date44444 44444444444 ,refer- of ence ,anemo- ,external ,external ,number4 meter4 ,conditions4444444444,conditions44444444 44,remarks4 ---------------------------------------- -------------------- ,speed,volume ,speed,volume ,area of ,f4 ,c4,f4 ,area of ,f4 ,c4,f4 ,throat4 p4m4 p4m4 ,throat4 p4m4 p4m4 ---------------------------------------- -------------------- ---------------------------------------- -------------------- ,frequent cleaning and inspection of exhaust installations are very important1 as accumulation of dust greatly impedes the flow of air at all points of the system4 ,the person employed in cleaning the fan should wear a respirator4 ,hoods and ducts should always be cleaned with the exhaust in full action4 ,,references4 #a ,annual ,report of the ,chief ,inspector of ,factories for #aiaj1 p4 #agb4 #b ,ibid41 pp4 #agb1 #agc4 #c ,g4 ,,elmhirst ,,duckering3 ,a ,report on an ,experimental ,investigation into the ,conditions of ,work in ,tinning ,workshops1 and ,appendices4 ,included in ,special ,report on ,dangerous or ,injurious ,processes in the ,coating of ,metal with ,lead or a ,mixture of ,lead and ,tin4 ,cd4 #cgic4 ,wyman and ,sons1 ,ltd4 ,price #as4 ,g4 ,,elmhirst ,,duckering3 ,the ,cause of ,lead ,poisoning in the ,tinning of ,metals4 ,journal of ,hygiene1 vol4 viii41 pp4 #dgd-ejc1 #aijh4 ,g4 ,,elmhirst ,,duckering3 ,report on an ,investigation of the ,air of ,workplaces in ,potteries4 ,included as ,appendix ,,xlix4 in ,report of the ,departmental ,committee appointed to inquire into the ,dangers attendant on the ,use of ,lead1 and the ,danger or ,injury to ,health arising from ,dust and ,other ,causes in the ,manufacture of ,earthenware and ,china1 vol4 ii41 pp4 #ic-aac1 #aiaj4 ,cd4 #ebgh4 ,price #as4 #i;d4 #d ,g4 ,,elmhirst ,,duckering3 ,annual ,report of the ,chief ,inspector of ,factories for #aiaj1 p4 #dg4 #e ,c4 ,r4 ,,pendock 7one of ,h4,m4 ,inspectors of ,factories73 ,report on ,systems of ,ventilation in ,use in ,potteries4 ,included as ,appendix ,,xlviii4 in vol4 ii4 of ,potteries ,committee's ,report referred to under#c4 ,c4 ,r4 ,,pendock3 ,second ,report of the ,departmental ,committee appointed to inquire into the ,ventilation of ,factories and ,workshops1 part i41 and especially part ii41 #aijg4 ,cd4 #ceeb and #ceec4 ,price together1 #ds4 #h;d4 ,other works referred to include--,construction des ,usines au ,point de ,vue de l',hygine1 by ,ingnieur-,architecte ,maniguet4 ,ch4 ,branger1 ,paris1 #aijf2 ,hygine ,industrielle1 by ,,mm4 ,leclerc de ,pulligny1 ,boulin1 and others4 ,j4 ,b4 ,baillire et ,fils1 ,paris1 #aijh2 and many excellently illustrated trade catalogues issued by ventilating engineering firms1 such as the ,sturtevant ,engineering ,company1 ,ltd41 ,london2 ,henry ,simon1 ,ltd41 ,manchester2 ,davidson and ,company1 ,ltd41 ,belfast2 ,john ,gibbs and ,son1 ,liverpool4 ,,chapter ,,xiii ,,preventive ,,measures ,,against ,,lead ,,poisoning--,continued ,periodical ,examination4--,in various codes of regulations a surgeon is required to make periodical medical examination of the workers4 ,the term 8surgeon0 is defined as the 8,certifying ,factory ,surgeon of the district1 or a duly qualified medical practitioner1 appointed by written certificate of the ,chief ,inspector of ,factories1 which appointment shall be subject to such conditions as may be specified in that certificate40 ,the wording of the regulation varies somewhat in different codes1 but the intention in all is the same1 and the following example from the ,tinning ,regulations will indicate the purpose and scope3 8,every person employed in tinning shall be examined by the surgeon once in every three months 7or at such shorter or longer intervals as may be prescribed in writing by the ,chief ,inspector of ,factories71 on a day of which due notice shall be given to all concerned4 ,the surgeon shall have the power of suspension as regards all persons employed in tinning1 and no such person after suspension shall be employed in tinning without written sanction from the surgeon entered in the health register4 8,every person employed in tinning shall present himself at the appointed time for examination by the surgeon4 ,no person employed in tinning shall1 after suspension1 work at tinning without written sanction from the surgeon entered in the health register40 ,under the ,special ,rules for white-lead works1 examination is required at weekly intervals2 under the ,special ,rules for ,earthenware and ,china1 ,manufacture of ,litho-,transfers and ,red ,lead1 and under the ,regulations for ,electric ,accumulators1 and ,paints and ,colours1 monthly2 under the ,regulations for ,tinning1 ,yarn dyed with ,chromate of ,lead1 and ,enamelling1 at quarterly intervals1 subject to the limitation or extension specified in the regulation quoted4 ,the limitation as to quarterly examination is useful to meet conditions1 on the one hand1 where special incidence calls for increased safeguards2 and1 on the other1 relaxation1 by reason of adoption of special processes or measures lessening risk4 ,thus1 in a yarn-dyeing factory1 in consequence of occurrence of six cases within five months1 a weekly instead of a quarterly examination was prescribed4 ,after eight months1 as no further cases were reported1 a monthly examination was substituted for the weekly1 and eventually1 with continued absence of illness1 the normal quarterly examination was resumed4 ,an appointed time for the surgeon's attendance at the factory has been found necessary1 because1 in conformity with the literal wording of the regulation1 the occupier should not continue to employ a worker who1 for one reason or another1 has not been examined by the surgeon during the prescribed interval4 ,with knowledge of the date and hour posted in a conspicuous place in the factory1 excuse for absence becomes difficult4 ,alteration by the surgeon of his appointed time should1 whenever possible1 be given beforehand4 ,surgeons in the past frequently made examination of the persons employed with the view of taking them unawares1 and so of precluding special preparation beforehand--a practice which had its advantages2 but they are outweighed by the hardship inflicted on workers who were unavoidably absent1 as1 for example1 night-workers4 ,a health register is supplied to all occupiers where periodical medical examination is enjoined1 the headings of which and manner of entry are indicated later on in this chapter4 ,the objects which the surgeon should have in mind in making his examination are3 #a4 ,to prevent lead poisoning and minimize lead absorption4 #b4 ,to obtain information for the occupier and ,inspector of ,factories of the relative danger of one process and another with a view to adoption of remedial measures4 ,in safeguarding the health of the workers1 he should make effort to gain their confidence1 in order to be able to attach proper value to statement as to subjective symptoms4 ,suspicion in their minds that the examination is made solely in the interests of the employer militates against success1 and increases inclination to conceal symptoms and to give untruthful answers as to the state of health since the last examination4 ,in our opinion1 the surgeon will best carry out the first object by attention to the second4 ,the study of thousands of reports on cases of lead poisoning convinces us that #ij per cent4 at least are due to inhalation of dust and fumes4 ,the surgeon1 therefore1 should utilize the earliest sign of lead absorption to warn the occupier and inspector of conditions favourable to the development of plumbism1 and due probably either to some unguarded spot in the manufacturing process whereby dust or fumes are not being removed completely1 or to ignorance or carelessness 7often excusable in the absence of proper instruction7 on the part of the worker4 ,he should direct1 therefore1 especial attention to new workers1 not only because of their need for guidance as to precautions to be observed and greater liability to attack during the first year of employment1 but also because development of signs in them constitutes the surest guide to defects in the process of manufacture4 ,occasionally symptoms in a worker may be so menacing as to demand immediate suspension1 but generally before the power is exercised attempt to rectify the condition which gives rise to them should be made4 ,the surgeon can do much by influencing the foremen and forewomen1 who will necessarily come before him for examination1 in insisting on the supervision by them of care and cleanliness by the workpeople under their charge4 ,should suspension1 despite attention in the manner suggested1 be necessary1 he will recognize that transference to a non-lead process1 if feasible1 is preferable to entire cessation from work in very many cases4 ,the surgeon1 therefore1 should know what departments are possible alternatives to lead work4 ,the fact that an examination is made on factory premises1 is directed to detection and prevention1 treatment taking a subordinate place1 and is often made on persons who1 unlike hospital patients1 seek to conceal their symptoms1 causes it to be an examination sui generis4 ,hence the surgeon must trust his sight more than his hearing4 ,a surgeon with experience of such work has said3 8,the worker in lead must be surveyed as an individual1 and idiosyncrasies must be carefully studied and allowed for2 the #8personal equation' is of vital importance0#a4 ,for the examination a well-lighted room affording privacy is essential4 ,while it is desirable for the surgeon periodically to see the processes and conditions under which work is carried on1 systematic examinations of workers should not be made elsewhere than in a private room4 ,the custom of marshalling workers in a queue1 although perhaps unavoidable in many cases1 is liable to detract from the seriousness of the proceedings1 a sense of which it should be one of the aims of the examination to arouse4 ,in discussing the method of interrogation and usual examination1 ,dr4 ,king ,alcock#b1 ,certifying ,factory ,surgeon of ,burslem1 says3 8,note the general manner assumed in answering questions and any indications of carelessness in dress and toilet4 ,inquire into the state of digestion1 existence of colicky pains1 regularity of bowels1 menses1 history of pregnancies and miscarriages1 whether before1 in the intervals of1 or during lead employment2 existence of headache1 diplopia1 or amaurosis4 ,note the type1 facies1 state of teeth and nails1 complexion1 speech1 tongue1 strength of grasp 7if possible1 with dynamometer71 any tremor in outstretched hand1 resistance to forcible flexion of wrist4444 ,if strabismus is present1 note whether of old standing or recent2 and if ocular troubles seem imminent1 examine for optic neuritis1 either at once or at home 7this is very important1 as cases of acute and serious optic neuritis still baffle examination by their intermensual development740 ,he recommends the surgeon1 apart from entry in the health register1 which must necessarily be very brief1 to keep a private notebook1 and to enter in it as a matter of routine such details as name1 process1 age1 duration of employment1 condition 7married or single71 pregnancies1 state of bowels and menses1 dental toilet1 and any special point worthy of note in individual workers4 ,a card index1 if in use1 might conveniently serve for such entries4 ,in the actual routine examination it may be useful to describe the procedure where a large number of workers pass before the surgeon in a white-lead works every week4 ,the points noted are3 #a4 ,the general appearance of the man as he walks forward1 especially the face with regard to anmia1 which in the majority of cases of early lead absorption is not a true anmia1 but is due to vaso-motor spasm of the arterioles of the face and eyes4 ,frequently1 on speaking to a lead-worker1 the face1 apparently anmic1 flushes directly4 #b4 ,the brightness of the eyes1 state of the pupils1 and condition of the conjunctiva and of the ocular muscles4 #c4 ,the mouth should next be examined1 and search made for any evidence of blue line around the gum4 #d4 ,the gait should be watched both on advancing to1 and retiring from1 the surgeon4 ,if necessary1 the man should be made to walk a few steps4 ,although the peroneal type of palsy is extremely rare1 the possibility of its occurrence should never be absent from the mind of the surgeon4 #e4 ,the man should then be directed to stretch his hands out in front of him1 with wrists extended and fingers widely spread4 ,presence or absence of tremor should be looked for1 and the condition of the finger-nails1 as to the practice of biting1 etc4 ,the extensor power should then be tested1 firstly of the fingers4 ,while the hands of the workman remain outstretched1 the surgeon places the forefinger of his hand in the outstretched palm of the workman1 and the ball of the thumb upon the extreme tip of each finger1 and by gently pulling it down1 noting the spring present in the muscles4 ,this test is probably the most delicate there is for detection of early extensor paralysis4 ,the condition of the lumbricals and interossei are noted on movement of the fingers4 ,the extensors of the wrist are then further examined1 the workman being directed to flex his arm at the elbow and strongly pronate the wrist1 so that the palm of the hand is directed forwards4 ,he is then told to close the fist when the surgeon endeavours to flex the wrist1 the workman at the same time resisting by forcible extension of his wrist4 ,ordinarily the extensor communis digitorum and minimi digiti are sufficiently powerful to resist a very powerful pull upon the wrist2 and if the wrist is found to yield1 it is a sign that the muscles are affected4 ,sometimes the strength of the wrists and fingers is judged by the surgeon placing his palms on the dorsum of the patient's outstretched hands1 and seeing whether the patient can be prevented from lifting them without flexing the wrists or finger-joints4 ,the test detects 7#a7 paralysis which has been recovered from to a large extent2 7#b7 commencing partial paralysis2 and 7#c7 weakness of muscular power1 especially in those who have worked in lead for a number of years4 ,this weakness appears to be an effect of lead upon the muscular tissue or dependent on debility1 the result of lead absorption1 and independent of nerve implication4 ,we have known the condition to remain unaltered for years1 and also to undergo alteration1 being at times absent for months together4 ,occasionally reports of definite paralysis refer to pre-existing weakness4 #f4 ,the pulse is next noted4 ,the pulse-rate need not ordinarily be counted1 but if it is either very slow or fast careful examination at the conclusion of the general inspection should be made4 ,it is well to make all these points before asking any questions4 ,after they are completed inquiry as to regularity of the bowels1 existence of pain or discomfort1 would follow4 ,the speech should be noted1 as slurring or hesitating speech is occasionally associated with early lead poisoning4 ,all these points can be gone through quite rapidly1 and at the conclusion of the general examination1 if judgment is in suspension1 careful examination in the routine medical manner should be made4 ,in some factories all new workers are examined by the surgeon before they commence work in dangerous processes4 ,at any rate1 a list of such persons should be given to the surgeon at his visit1 as naturally the question of personal fitness for employment should be decided at his first examination4 ,conditions which should lead to rejection are tubercular disease of every kind1 idiopathic epilepsy1 all forms of mental disease or weakness 7hysteria1 feeble-mindedness1 and neurasthenia71 obvious alcoholism1 women who are pregnant or who give a history of repeated miscarriages prior to work in lead1 persons with marked errors of refraction unless corrected by glasses1 kidney disease of all kinds1 evidence of previous chronic saturnism1 and bad oral sepsis4 ,special attention will have to be paid to casual labourers1 and it should be the aim of the surgeon to discourage this class of labour in lead industries4 ,work under special rules or regulations requires to be carried out under strict discipline1 and this it is extremely difficult to maintain on other than regular workers1 who recognize the need for cleanliness and observance of regulations4 ,other aids to diagnosis cannot be carried out as a matter of routine1 but will necessarily be used in particular cases1 such as ophthalmoscopic examination of the fundus1 electrical reactions of muscles1 analysis of the urine1 and examination of the blood-pressure4 ,a few words may be added on the significance of the two commonest signs--the blue line and anmia4 ,it cannot be too strongly insisted on that presence of the ,burtonian line on the gums is1 as a rule1 indicative of lead absorption1 and not of lead poisoning4 ,as a danger signal its value is immense1 and hardly less so its value in clinching diagnosis in doubtful cases4 ,whenever the line is seen risk is imminent1 and poisoning 7not necessarily of the individual in whom it is pronounced7 among the workers is inevitable in the absence of adoption of precautions4 ,unfortunately1 careful dental toilet1 which the surgeon will necessarily lay stress on1 may prevent development1 or the practice1 when adopted1 cause disappearance of the line after the lapse of a few months4 ,under these circumstances1 the merest trace will have all the significance of the fully-developed line in a worker neglectful of care of the teeth4 ,among new workers a commencing blue line should be strong evidence of the need for dust removal at some point in the process of manufacture4 ,the line1 in our experience1 is dense in occupations giving rise to fumes or to dust of compounds of lead1 but comparatively rare in those handling metallic lead or its alloys1 as compositors1 tea-lead rollers1 solderers1 and the like4 ,some degree of pallor is so commonly met with in adolescence that it is the progressive development of the anmia which the surgeon must especially watch for4 ,as a danger signal1 therefore1 it has the same significance nearly as the blue line2 but when lead absorption has affected the elements in the blood1 progressive anmia in new workers1 attributable to the employment1 and showing no tendency to improve after watching for a few months1 is an indication for suspension or transference to other work4 ,in older workers1 with a duration of employment of five years or more1 there may be a quasi-pathognomonic pallor which does not vary from year to year4 ,in them it must be supposed that an equilibrium has been established1 and development of other symptoms1 such as tremor1 wrist weakness1 or albuminuria1 becomes significant4 ,attention has already been directed to the distinct saturnine facies associated with anmia1 and characterized by loss of fat1 particularly noticeable in the orbit and buccinator region of the face4 8,so far as the question of any worker's suspension is concerned10 says ,dr4 ,king ,alcock1 8,i prefer to make my instinctive prim facie distrust of a saturnine pallor the basis for action4 ,the pallor of plumbism cannot be summed up in hmoglobin and corpuscular content2 it is the expression of a complex toxmia resulting from defective assimilation and excretion0#c4 ,the knowledge the surgeon should gain of the idiosyncrasies of the workers by his periodical examination will enable him to appraise at their proper value the nature and degree of the symptoms in notified cases4 ,sometimes a rule is made that no lead-worker who has suffered from an attack of plumbism should be allowed to resume work4 ,this we consider too harsh a measure4 ,it may be true for painters1 but when remedial measures1 such as locally applied exhaust ventilation1 can be applied1 with consequent removal of the danger in the process at which the poisoning has arisen1 prohibition of employment seems an unnecessarily drastic measure4 ,the health register in general use where periodic medical examination is required in pursuance of special rules and regulations is divided into two parts1 in each of which entries by the surgeon are required at each visit4 ,,part ,i4 ---------------------------------------- ----------------------- ,list of ,persons ,employed in ,particulars of ,examination4 ,processes4 ---------------------------------------- ----------------- ,first ,employed in such ,worker's ,process4 ,date ,date ,date ,date ,name1 ------------------------------------- ,no4in full4,process4,age4,date4,result4,result 4,result4,result4 ---------------------------------------- ---------------- 7#a7 7#b7 7#c7 7#d7 7#e7 7#f7 7#g7 7#h7 7#i7 ---------------------------------------- ---------------- ,,part ,,ii4 ---------------------------------------- --------------------- ,particulars of any ,directions given by the ,surgeon4 ,any ,cer- tificate of ,suspen- ,reference sion or ,certificate to ,part #a4 ,number ofpermitting ,resumption,signature --------- ,date of ,persons of ,work must be of ,page4,col4,examination4,examined4entere d here in full4 ,surgeon4 ---------------------------------------- -------------------- 7#a7 7#b7 7#c7 7#d7 7#e7 7#f7 ---------------------------------------- -------------------- ,in ,part ,i4 of the register the surgeon should1 at the times of examination1 enter the date at the head of one of the columns numbered #f to #i2 and in the space below1 opposite the name of each person examined on that date1 a brief note 7see next page7 of the condition found4 ,in ,part ,,ii4 he should again enter1 in ,column #c1 the date of examination1 with a statement of the total numbers examined on that occasion 7,column #d72 and in ,column #e any certificate of suspension from work1 or certificate permitting resumption of work1 and particulars of any other direction given by him1 appending his signature in ,column #f4 ,it is the duty of the occupier to enter in ,part ,i4 the following particulars with regard to each person examined3 7#a7 ,name in full 7,column #b72 7#b7 the process in which he or she is employed 7,column #c72 7#c7 age when first employed 7,column #d72 and 7#d7 date of first employment in that process 7,column #e72 and these particulars1 in respect of each person so employed1 must be entered immediately on commencement of work in the process named4 ,various methods of noting the state of health of the workers have been adopted4 ,use of the words 8,good10 8,very fair10 and 8,fair10 is common as indicating the state of general health1 with special note in addition1 often in the form of a symbol1 of the presence and character of definite ill-effects4 ,the object of the register1 however1 is to keep a record intelligible not only to the ,certifying ,surgeon1 ,factory ,inspector1 and occupier1 but also to the workers4 ,entries1 therefore1 on a uniform system are desirable1 taking account of the two aspects of the health of every lead-worker1 which must be considered 7a7 that indicative of specific effects from the occupation1 and 7b7 that of general health uninfluenced by the employment4 ,with this in mind1 the following system of entry in the health register has been adopted3 ,the entries should be made upon a uniform system1 as below1 indicating degrees of deviation from normal health1 and distinguishing 7by use of numerals7 those attributable 7or possibly attributable1 in whole or part7 to work in lead1 from those not so attributable1 for which latter letters should be used4 ,the conclusion is perhaps best expressed as a fraction #a #b ---1 ---1 ,a ,c and so on4 ,the numerals should be taken to mean3 #a4 ,passed without comment 7no observed effect of lead74 #b4 ,blue line 7or indication thereof74 #c4 ,marked 7quasi-pathognomonic7 anmia1 or other signs of impairment of health4 7,albuminuria1 or slight deficiency in tone of the extensor muscles of the forearm1 would1 and miscarriage1 or other suspicious history of illness between examinations1 might1 come under this head47 #d4 ,suspension or transfer1 by reason of impairment of health from effects of work in lead4 7,in such cases the surgeon would be prepared to entertain an application for a certificate under the ,workmen's ,compensation ,act47 ,except in the case of a worker whose exposure to lead is only recent1 renal disease should always be indicated by a numeral4 ,letters should bear the following meaning3 ,a4 ,no comment 7i4e41 fair general health74 ,b41 ,c4 ,increasing degrees of impairment of general health4 7,pregnancy1 if without suspension1 should be entered as ,c47 ,d4 ,suspension or transfer1 for reasons other than impairment of health from effects of work in lead4 ,x4 ,carelessness1 or neglect of precautions1 or unsuitability for work in lead4 7,suspensions for such reasons should be marked ,,dx47 ,such entries of numerals and letters will in general suffice for the intended purpose2 but the surgeon may1 of course1 find it desirable to make other notes for his own information1 and it is within his discretion to supply further details to occupiers or workers concerned4 ,,references4 #a1 #b ,s4 ,,king ,,alcock1 ,b4 ,m4 ,,bond1 ,a4 ,,scott and others1 in discussion on the ,value of ,systematic ,examination of ,workers in ,dangerous ,trades4 ,brit4 ,med4 ,journ41 vol4 ii41 pp4 #gda-gdi1 #aijb4 #c ,,king ,,alcock3 ,the ,early ,diagnosis of ,industrial ,lead ,poisoning4 ,paper contributed to the ,second ,international ,congress for the ,study of ,industrial ,diseases held at ,brussels1 #aiaj4 ,,chapter ,,xiv ,,preventive ,,measures ,,against ,,lead ,,poisoning--,continued ,overalls and ,head ,coverings4--,stress has been laid on the wearing of overalls and head coverings in processes giving rise to dust or to splashes of glaze or paint in special rules and regulations in the past4 ,with the improvement that has taken place in exhaust ventilation1 they have become less important4 ,indeed1 the aim of all manufacturers and ventilating engineers should be to render processes so free of dust as to make them altogether unnecessary4 ,increasing knowledge of the insidious manner in which lead dust can arise has shown that from this point of view overalls of the cotton or linen material ordinarily worn constitute a real source of danger4 ,splashes of glaze dry on them1 and at every movement involving rubbing of the surface dust is generated4 ,some operations almost oblige the worker to press the article worked upon against the chest1 so that chance of inhalation of dust from this source alone is considerable4 ,taking them off creates dust1 and after this is done a reprehensible practice exists of either shaking or beating them against a post4 ,in large factories they are usually washed on the premises1 and the water in which this is done will become a solution containing some lead in suspension4 ,hence1 even when washed and dried ready for wear1 overalls may not be quite free of lead4 ,apart from the general obligation recognized that an employer should provide and maintain everything necessary to guard against danger contracted in his factory1 we think that the risk run by a worker in taking the overall home and washing it there is negligible1 and offers advantages in the ultimate cleanliness of the overall over washing on factory premises4 ,laundresses shaking overalls prior to washing them have been known to contract plumbism4 ,where work with the arms is incessant1 as in the heading of yarn1 overalls are burdensome1 and for this reason and the fact that with efficient exhaust ventilation there should be practically no dangerous dust1 the regulations for the heading of yarn enjoin provision of them only on written certificate of the ,chief ,inspector of ,factories4 ,protection for the clothing1 however1 where splashing is incidental to the operations1 cannot be dispensed with4 ,hence either the overalls themselves or the front of them should be made of some light ventilated waterproof material1 or a waterproof apron worn over overalls of the kind at present in use4 ,daily sponging would then take the place of washing4 ,if lead dust be visible on the hair of workers1 there must be a defect in the conditions of work to be rectified by other means than cumbering the head4 ,in our opinion1 head coverings ought never to be necessary4 ,we cannot think that an attack of plumbism can ever be precipitated by the amount of lead dust inhaled on brushing the hair4 ,a common provision in regulations for overalls is3 8,overalls shall be provided for all persons employed in lead processes1 and shall be washed or renewed every week4 8,the occupier shall provide and maintain for the use of all persons employed in lead processes--7a7 ,a cloakroom or other suitable place in which such persons can deposit clothing put off during working hours1 and separate and suitable arrangements for the storage of overalls required by regulation2 7b7 a dining-room1 unless all workers leave the factory during meal-hours4 8,all persons employed in lead processes shall wear the overalls provided 444 and shall deposit such overalls and any clothing put off during working hours in the places provided under the regulations4 ,the overalls shall not be removed by persons employed from the factory or workshop40 ,general sense of propriety--and it is on this ground1 and not from danger attaching to non-observance1 that we press it--suggests that overalls should be kept apart from working clothes1 and preferably outside any room in which a lead process is carried on4 ,so long as actual contact between the two sets of garments is prohibited1 we do not see objection to the same cloakroom sufficing for both4 ,the best arrangement that we have seen is a room in which each worker has two lockers--one for the storage of overalls1 and the other for clothing put off during working hours4 ,this presupposes supervision and effective discipline4 ,we think that all reasonable need in the provision to be made is met by numbered pegs on one side of the room or wide passage for clothing1 and on the other pegs correspondingly numbered for the overalls4 ,means for heating and drying the clothes should not be overlooked 7see ,fig4 #h74 ,illustration3 ,,fig4 #h shows a good arrangement in a white-lead factory1 by which1 as is best1 cloakroom1 meal-room1 and washing and bath accommodation1 are all under one roof4 ,the men on entering hang up their clothes in the private clothes lobby1 and pass through the swinging doors to the lobby where the overalls are hung4 ,on leaving the factory and at midday they enter by the door leading into the lobby for storing overalls1 and from that pass to the lavatory and bathroom4 ,having washed and put on their ordinary clothes1 they enter the meal-room4 ,the building throughout is lined with white glazed bricks4 ,illustration3 ,,fig4 #h;,a4--,,well ,,lighted ,,mess-,,room ,,in ,a ,,smelting ,,works4 ,meal-,room ,accommodation4--,wherever lead processes are carried on the provision of a mess-room is called for in a part of the factory remote from possible contamination from lead dust4 ,this we hold on general grounds of cleanliness and self-respect1 and not because we think the eating of meals in rooms where lead is used would noticeably increase the number of cases4 ,the more conveniently situated in relation to the workrooms the mess-room is1 the more will it be used4 ,set out briefly1 the requirements of a mess-room are that it should be-- #a4 ,well ventilated1 warmed1 and lighted4 #b4 ,not less than #aj feet high1 and with floor-space ample for each person likely to occupy it at any one time4 #c4 ,have walls the surface of which is smooth and impervious to a height of at least #d feet from the ground4 #d4 ,have pigeon-holes or other arrangement in which each person can deposit his food separate from that of others4 #e4 ,have means of warming and cooking food4 #f4 ,be kept properly clean and dry4 ,no part of a factory becomes so unsightly in the absence of daily cleaning as a mess-room1 especially where provision has only to be made for five or six workers4 ,reid#a has suggested the following scale of floor-space per person in mess-rooms3 #f persons and under #aj square feet per person4 ,over #f and up to #ab #g #ab #bj #f #bj #bh #e #bh and any number #e ,in a factory well known to us for manufacture of white lead there is a restaurant originally started in connection with the sick club of the factory4 ,for fivepence the workman obtains a hot meal of meat1 bread1 and vegetables4 ,any profits go to the sick fund4 ,since this has been started improvement in the physical condition of the men has been marked2 several cases of anmia and malnutrition have entirely cleared up4 ,no workman1 as has already been emphasized1 should commence work in a lead factory unless he has had a good meal--that is1 unless there is some food at least in the stomach--particularly albuminous food1 such as milk1 cocoa made with milk1 or caf au lait4 ,the most suitable foods generally for lead-workers are those containing proteids--meat1 eggs1 milk1 cheese1 and fatty foods4 ,acids--vinegar1 pickles1 and the like--are especially to be avoided4 ,section #ge 7#b7 of the ,factory and ,workshop ,act1 #aija1 requires that1 where lead or other poisonous substance is used so as to give rise to dust or fumes1 meal-room accommodation shall be provided4 ,the question1 as a rule1 is easily decided1 but there are border-line cases where doubt may arise1 as1 for example1 in letterpress printing factories in regard to dust1 and in soldering operations in regard to fume4 ,operations in the composing-room undoubtedly give rise to dust1 and in stereotyping and casting the dbris trodden underfoot causes dust to rise4 ,in linotype rooms1 however1 in the present state of knowledge1 a difficult burden of proof would rest on the person who sought to show that dust or fumes were present to such an extent as to justify action under the section4 ,and the same view holds1 in our opinion1 in regard to soldering4 ,lavatories4--,the usual requirement for this in nearly all regulations is3 ,the occupier should provide and maintain in good repair for all persons employed in lead processes-- 7#a7 ,suitable lavatory accommodation1 including at least one lavatory basin for every five such persons1 fitted with a waste pipe1 or placed in a trough having a waste pipe1 and having a constant supply of hot and cold water laid on2 or alternatively troughs of enamel or similar smooth impervious material1 fitted with waste pipes without plugs1 and having a constant supply of warm water laid on1 and affording a length of at least two feet of trough for every five such persons4 7#b7 ,soap1 nail-brushes1 and a sufficient supply of clean towels1 renewed daily4 ,discipline1 and responsibility placed on some one person to see to the cleanliness of the lavatory appliances and adequate supply of the necessary means for washing1 can alone insure proper use of them by the persons employed4 ,the workman has so narrow a margin of time in which to get his breakfast and dinner that he cannot be expected to wash if facilities for doing so fail4 ,the alternative of an enamelled iron trough with jets of warmed water is in our experience much the most satisfactory installation where the number employed is more than five or six4 ,provision of soft soap or of soap in the form of powder1 and nail-brushes nailed to the table1 hinder peculation4 ,wooden stands for holding wash-basins present almost invariably a most uninviting appearance unless covered with sheet lead4 ,well-equipped wash-hand basins with hot and cold water laid on close to the work-place are sometimes provided in addition to the lavatory proper4 ,if looked after they are valued and used1 but if not they become converted into receptacles for oddments4 ,illustration3 ,,fig4 #i4--;,,good ,,washing ,,and ,,bath ,,accommodation ,,in ,a ,,lead ,,smelting ,,works4 ,illustration3 ,,fig4 #aj4--,,washing ,,trough1 ,,douche ,,baths1 ,,and ,,clothes ,,cupboards4 ,type common on the ,continent4 ,roller towels should be at least #ae square feet in area for every three persons employed1 and renewed daily4 ,the merits of soluble sulphides in 8akremnin0 soap have been advanced on the ground that the lead is converted into the insoluble black sulphide1 which is thereby made visible to the eye1 and the sight of which will1 it is hoped1 still further stimulate the desire to wash4 ,probably such lead as remains on the hands after well washing with soap is so closely adherent to the skin as to render risk of contamination of the food in this way negligible4 ,dr4 ,robertson1 ,chemist of the ,royal ,gunpowder ,factory at ,waltham ,abbey1 has found that results as good as those to be obtained from use of akremnin soap 7and without any discoloration of the skin7 are obtained from use of a solution made up as follows3 ,sal ammoniac added to saturation to a solution containing #he c4c4 of commercial hydrochloric acid 7specific gravity1 #aae7 per #ajj c4c4 of water4 ,the procedure adopted at ,waltham ,abbey is--7#a7 ,usual washing with soap1 water1 and a nail-brush2 7#b7 scrubbing with the special solution by means of a nail-brush dipped in it2 7#c7 rinsing in water2 and 7#d7 washing with soap and water4 ,sommerfeld#b1 from his wide experience1 considers that pumice-soap1 with the addition of turpentine1 is the best cleansing material lead-workers can use4 ,baths4--,provision of bath accommodation is required under the special rules for white-lead factories and the regulations for electric accumulators4 ,in several factories1 however1 baths are provided for the use of the workers4 ,they naturally make for improvement in general health1 but we cannot regard provision of them1 any more than cloakrooms and mess-rooms1 as likely to influence materially incidence of lead poisoning in a factory4 ,the three requisites of 7#a7 convenience and quickness1 7#b7 comfort1 and 7#c7 regular use1 can best be secured by the use of shower baths in place of slipper baths4 ,the advantage they have are--7#a7 ,initial cost of installation is less2 7#b7 economy in space2 7#c7 economy in water2 7#d7 economy in time required for bathing2 7#e7 no worker comes into contact with water used by another2 7#f7 cleansing must be from the head downwards4 ,danger of scalding can be absolutely excluded by use of valve levers1 so placed in relation to one another that steam cannot be turned on until the cold-water valve has been opened1 and the heater can be so arranged that the water is not raised above a definite temperature4 ,separation of ,processes4--,lead processes should1 as far as possible1 be carried on in such a way that there is aerial disconnection of one process from another4 ,separate workrooms1 although desirable unless very small1 may not always be possible1 but by exhaust ventilation processes may be arranged so that dust is not a source of danger to persons working elsewhere4 ,instances could be given where1 in paint and colour works1 persons employed in the grinding of earth colours1 in which no lead entered1 succumbed to attacks of plumbism from contiguity of the plant with that for grinding lead colours4 ,threading up of castor runners on a wire previous to dipping used to be done1 prior to #aija1 in the dipping-house itself1 with the result that some severe cases of poisoning occurred4 ,by the rules of #aija the process was required to be done in a place separate from any place where dipping 7or other scheduled process7 was carried on1 and very few cases have occurred since4 ,and if exhaust ventilation is relied on1 ,duckering's experiments 7p4 #bjf7 show the attention to detail necessary to prevent air charged with lead dust being drawn to the spot by the fan4 ,the need for separation of processes becomes less in proportion as the cubic space of the room increases1 and dust and fumes are locally removed4 ,age of ,employment4--,the same considerations as have been stated above govern this point also4 ,wherever lead dust or fumes arise1 whether exhaust ventilation is applied or not1 persons of either sex under eighteen years of age are probably rather more susceptible to attack by reason of natural failure to appreciate the risk run4 ,when periodical medical examination in addition to exhaust ventilation has been adopted1 the age limit can safely be reduced to sixteen4 ,where handling only of metallic lead and ordinary soldering with an iron are done1 risk of contracting plumbism is so remote that an age limit may be unnecessary4 ,wall ,surface4--,wherever walls are likely to be splashed1 as in dipping rooms and enamelling workshops1 the inner surface of the walls should be of glazed bricks or tiles or enamelled plates1 any of which help also in increasing the light necessary in such rooms4 ,if1 on account of the cost1 such perfectly smooth material is impracticable1 the walls should be painted with oil colour1 which will enable them periodically to be wet-cleansed4 ,dusting the walls is to be deprecated4 ,hence accumulations of dust and dbris on ledges1 rafters1 beams1 roofs1 etc41 should1 in our opinion1 only very occasionally be cleaned down4 ,we consider that the risk from one big cleaning down is less than that from repeated small ones4 7,see p4 #bah74 ,floors4--,these should be smooth and impervious4 ,wood flooring can hardly be regarded as coming within this category2 it is unsuitable where lead processes are carried on4 ,preference must be given to floors of concrete and the like material1 which can be washed down easily rather than swept4 ,frequently the dust raised in sweeping the floor has determined an attack of lead poisoning4 ,no objection can be raised to wooden grids and iron roll matting placed on the concrete floor for the workers to stand on4 ,cold feet and transference of lead dust by the boots are lessened by their use4 ,where traffic is heavy1 as is often the case in lead works1 vibration is set up with wooden floors1 and dust disseminated4 ,in smelting works cast-iron plates are serviceable as flooring4 ,instruction of the ,worker4--,too much stress cannot be laid on this point4 ,to insist upon it1 however1 is useless unless the occupier has installed the necessary exhaust ventilation1 and equipped his factory with the other essentials for enabling the workman to guard against dust and free his hands of adhering lead1 in whatever form4 ,when this has been done1 then the worker himself can do something4 ,often he creates dust unnecessarily4 ,in shovelling out of a cask with spade or trowel1 in order to get out the last trace of the material to be transferred1 he generally gives it a knock1 which causes dust to fly so sharply as to escape the exhaust2 or he removes the implement quickly from the exhaust1 before it has been completely emptied and while dust is still being given off4 ,he will use a brush to clean his bench in preference to cleaning it by a wet method4 ,the printer may hold type between his teeth4 ,many workers bite their nails4 ,moustache and beard may be fingered1 and because of this workers may even be advised to be clean-shaven4 ,they may chew or smoke constantly while at work1 and will frequently eat with unwashed hands4 ,notices enjoining care and cleanliness may be1 and often are1 hung up in the workrooms1 or a leaflet1 such as the one here printed1 is handed to the worker on his first examination by the surgeon4 ,nothing1 however1 can take the place of actual verbal instruction from occupier1 foreman1 and fellow-worker impressed with the importance of the matter4 ,,lead ,,poisoning3 ,,how ,,caused ,,and ,,how ,,best ,,prevented4 ,unless great care is taken1 work in lead and lead compounds is injurious to health1 because the lead enters the system and causes lead poisoning4 ,danger is greatest from breathing leady dust or fume1 but eating with unwashed hands1 and biting nails or putting such things as sweets or pipes into the mouth while the fingers are soiled with lead1 all help to cause poisoning4 ,many workers in lead have a blue line round the edge of the gums1 but the first actual symptoms of the injurious action of lead on the system are costiveness1 colicky pains in the stomach1 headache1 and marked paleness4 ,occasionally headache is associated with epileptic fits1 a very serious condition1 which may be followed by loss of sight4 8,wrist-drop10 loss of power in the muscles moving the fingers and wrist1 results sometimes from lead poisoning1 and may cause permanent disablement from work4 ,it does not usually come on until after a person has worked in lead for some years4 ,lead1 even if absorbed in small quantities1 has a tendency to remain in the system1 and if care be not taken it will go on accumulating1 so that in time the health may become permanently damaged1 even without any definite attack recognized as lead poisoning4 ,girls and boys1 because they are not so likely to observe the necessary precautions as grown-up people1 should be closely watched4 ,women should be especially careful1 as the injurious effect of lead in them may seriously interfere with the healthiness of their children4 ,as lead does not enter the system through the pores of the skin1 it can in great measure be avoided by-- #a4 ,taking special care to avoid raising dust4 ,it is to the interest of everyone to see that ventilating arrangements are in order for carrying dust away at the point where it is produced4 ,any little cloud constantly made at work is sure1 if breathed1 to set up lead poisoning4 ,where lead colours are used wet1 danger arises from the splashing of the material and its subsequent drying into dust4 #b4 ,paying scrupulous attention to cleanliness of the hands1 face1 teeth1 and clothing4 ,the hands and nails should always be cleaned with soap and nail-brush before food is eaten1 and it is a wise practice also to wash out the mouth4 ,the teeth should be brushed at least once a day1 preferably before the evening meal4 #c4 ,never commencing work on an empty stomach4 ,food containing fat1 such as bacon and milk1 is suitable4 ,overall suits1 if worn1 should never be shaken to rid them of dust4 ,they require washing at least once a week4 ,aperient medicine1 such as ,epsom salts 7one or two teaspoonfuls in water71 can be taken once or twice a week with advantage by lead-workers4 ,experience shows that the habits and home life of the workers influence their liability to lead poisoning4 ,intemperate persons are the first to fall victims4 ,those who begin work on an empty stomach incur additional risk by so doing4 ,carefulness while at work1 and cleanliness1 offer the best means of escaping attacks of lead poisoning4 ,those who work in lead should keep in mind every hour of every working day the importance of not breathing lead dust and not carrying lead to the mouth in any way4 ,medical advice should at once be obtained if signs of lead poisoning present themselves4 ,,references4 #a ,,george ,,reid3 ,memorandum on ,mess-room ,accommodation3 ,appendix ,,xxv4 of the ,potteries ,committee's ,report1 vol4 ii41 #aiaj4 ,cd4 #ebgh4 #b ,,th4 ,,sommerfeld3 ,die ,bekmpfung der ,bleigefahr1 edited by ,leymann1 p4 #gf4 ,,chapter ,,xv ,,description ,,of ,,processes ,lead smelting--,red and orange lead and litharge--,letterpress printing--,file-cutting--,file-hardening --,tinning of metals--,plumbing and soldering--,brass4 ,lead ,smelting and ,silver ,refining4--,lead poisoning very rarely occurs in lead mining in ,europe1 as galena 7sulphide of lead71 the principal ore in which the metal is found1 is insoluble4 ,galena always1 and other lead ores very often1 contain a small proportion of silver1 ranging from #jjja to #a per cent41 and at times traces of gold4 ,owing to the great affinity of lead for silver1 lead smelting is necessarily a process preliminary to the extraction of silver and gold from it#a4 ,lead ores1 drosses1 etc41 on arrival at the factory1 are1 after sampling1 deposited in bins or heaps 7often in the open air71 and watered to prevent dust4 ,all ores may1 and refractory ores 7containing over #d per cent4 silica7 and dross must1 be smelted in a blast furnace by aid of coke4 ,the bulk of the charge in a blast furnace may consist of more or less complex ores of the precious metals1 especially silver4 ,when galena is treated in a blast furnace1 preliminary roasting is indispensable1 and in many smelting works its treatment takes place in a reverberatory or open-hearth furnace1 and not in a blast furnace4 ,the three principal methods applicable to extraction of lead from ores are--7#a7 ,the roast and reaction method2 7#b7 the roast and reduction method2 and 7#c7 the precipitation process4 ,by the roast and reaction method a part of the galena is first converted into oxide and sulphate of lead with access of air4 ,subsequently1 on shutting off the air-supply and increasing the temperature1 a reaction takes place4 ,the sulphur in the unchanged sulphide combines with the oxygen of the oxide and sulphate to form sulphur dioxide1 which is carried away by the draught into the bricked flue1 leaving metallic lead behind4 ,the process is carried on in a reverberatory or open-hearth furnace4 ,in the roast and reduction method the first portion of the process is carried out in a reverberatory furnace1 the galena being roasted pretty completely to lead oxide and sulphate1 which are then--usually in a blast furnace--reduced to the metallic state with coke and other reducing agents1 such as iron4 ,by the precipitation process galena was decomposed at a high temperature by means of metallic iron1 forming a mixture of iron and lead sulphide4 ,this method was only applicable to rich lead ores1 and is now given up4 ,the three methods are hardly ever independent of one another1 as the rich slag or residues1 for instance1 which are obtained by the first method are retreated by the second1 and the second is1 as has been stated1 almost always combined with the first4 ,on tapping the blast or reverberatory furnace1 the lead is drawn off into a lead well or sump1 from which1 when cool1 it is ladled into moulds1 while the slag is run into movable metal pots or along specially-prepared channels4 ,the slag run off from the reverberatory furnace contains much lead locked up as silicate1 which requires to be retreated1 usually in the blast furnace4 ,during the roasting process much raking of the material is necessary4 ,the slag from the blast furnace should contain less than #a per cent4 of lead4 ,on the ,continent and in ,america1 the ,huntingdon-,heberlein process has been extensively adopted1 with lessened incidence of poisoning1 the result of mechanical methods of working1 obviating hand labour1 and the low temperature 7diminishing risk from lead fume7 at which the roasting is carried on4 ,in this process the crushed ore is desulphurized by first mixing with lime and heating in presence of air in a revolving furnace1 provided with automatic rabble1 at moderate temperature 7about #gjj ,c474 ,subsequently the roasted material is conveyed from closed bins1 into which it falls automatically1 by dust-proof elevators to a converter1 in which atmospheric air at slight pressure is forced through it4 ,the agglomerated mass so formed1 when tipped out of the converter 7in doing which there is risk from dust71 is well damped1 broken by hand1 and charged with coke in the usual way into the blast furnace4 ,in some lead-smelting works the material arrives on the premises in the form of ingots of base bullion--i4e41 impure lead rich in silver--the product of previous smelting of the ore where it is mined in ,australia or ,spain4 ,and one of the main objects of the blast-furnace smelting of galena in the factory is to produce a base bullion rich in precious metals4 ,the lead so obtained requires further softening or refining to get rid of copper1 antimony1 arsenic1 and tin4 ,this is effected in a reverberatory furnace1 first at a low temperature to allow of formation of furnace dross1 which is removed through the working doors1 and secondly with increase of heat and access of air to oxidize1 in the order named1 the tin1 arsenic1 and antimony4 ,finally the lead is tapped into kettles or pots4 ,if free from silver1 such lead1 when poured into moulds1 is ready for the market2 but if rich in silver1 it is treated for the recovery of that metal either by 7a7 ,pattinson's process1 depending on the higher temperature of crystallization of lead than of an alloy of lead and silver1 which enables a separation of one from the other to be made by a process of ladling the crystalline from the liquid portion2 or1 much more commonly1 by 7b7 ,parkes's process1 depending on the formation1 on addition of zinc to a pot of molten lead1 of crusts consisting of an alloy of silver1 lead1 and zinc4 ,the crusts obtained in the latter process1 after cooling1 are broken up1 placed in a crucible1 and the zinc driven off at a temperature of #a1jjj ,c4 in a dezincing ,faber du ,faur retort4 ,the rich bullion1 retained either in the last kettle by the ,pattinson process1 or remaining in the crucible after dezincing1 next undergoes cupellation--i4e41 exposure to a blast of air in a furnace4 ,the lead is oxidized into litharge1 which drops into a receptacle below the furnace1 leaving the silver behind4 ,in all lead-smelting works the draught from the furnace carries much dust of ore and fuel1 and fume1 consisting of sulphide1 sulphate1 and oxides of lead1 into the flues4 ,the dust is easily collected in dust chambers1 but the fume requires ducts of great length--sometimes a mile or more--in which to deposit4 ,dangers and ,prevention4--,the risk from dust in general labouring work1 in depositing the ores in bins1 in removing them to1 and charging them into1 the furnace1 can only be controlled by watering1 preferably by a spray4 ,from the blast furnace lead fume and carbon monoxide may escape at the point where charging is done1 if there is back pressure from blockage in the flues1 or if the furnace blast is not working perfectly4 ,in tapping the lead and in manipulations such as charging1 drossing1 and skimming1 conducted through the doors of furnaces of all descriptions1 hoods1 extending at the sides down to the floor level1 require to be arranged over the working doors1 and connected either with ducts passing vertically through the roof or directly with the exhaust created in the furnace or flue itself4 ,dross and skimmings removed through the working doors should be received into iron trolleys capable of being covered1 and not be allowed to fall on to the floors1 to be shovelled up later on to barrows4 ,before such dross or slag from reverberatory furnaces is broken up for further treatment it should be well watered4 ,lead absorption among the men actually employed in the ,pattinson and ,parkes's processes is comparatively rare1 as the temperature of the molten metal does not exceed #dej to #ejj ,c4 ,when1 however1 the zinc-silver-lead and gold alloy is removed for treatment in special furnaces for distillation off of the zinc1 prior to cupellation1 the lead from the ,parkes's pot1 now free from silver1 but containing traces of zinc1 antimony1 and other impurities1 is run in some works into what are termed 8market pots0 for a final refining4 ,air and steam are blown through to oxidize the impurities4 ,the pot is skimmed twice1 the first dross containing antimony1 etc41 and the second a fine dust consisting of lead 7#fj per cent47 and zinc4 ,the risk of poisoning at this point is considerable1 although an exhaust fan connects up the cover of the pot with a cyclone separator1 to carry away the fume when the steam is blown through4 ,in other works this dezincing is done in a refining furnace1 the material being then in a slaggy state1 thus hindering development of fumes4 ,after the condensation of the zinc in the distillation of the silver-lead and zinc crust the cover of the pot is raised1 and the remaining metal1 containing #hj per cent4 of lead at a temperature of about #b1jjj ,f41 is ladled out into moulds for treatment in the cupelling furnace4 ,the temperature at which this ladling operation has to be done makes the work impossible for those unaccustomed to it4 ,exhaust ventilation in the operation of emptying the pot1 and cutting off the heat by a water-cooled jacket1 suggest themselves as means to combat the undoubted risk4 ,in cupellation the temperature is high 7about #b1jjj ,c471 and fume will escape from the working door and from the opening where the rich lead is fed into the furnace4 ,the danger here is sufficiently recognized by hoods and ducts placed in front of the furnace1 but the draught1 unless the ducts are connected up with a high-pressure fan1 may prove inadequate to carry away all the fume4 ,flue-cleaning1 carried out usually at quarterly or half-yearly periods1 is dusty work1 as much of the dust is in so fine a state of division as to repel contact with water4 ,smelting of other metals when the ores contain appreciable amounts of lead is equally productive of plumbism4 ,thus1 in the year #aija fourteen cases were reported from an iron works for the manufacture of spiegeleisen1 the ore 7now no longer used7 coming from ,greece#b4 ,in previous years it would appear to have been even greater4 ,a remarkable feature of all the reported cases from this factory was that the form assumed was colic1 and never paralysis4 ,the poisoning was due to vaporization of the molten lead by the very high temperature to which it was raised as the molten iron flowed out of the furnace on tapping4 ,the danger from fume was limited to the first few feet of the channel1 as the heavier molten lead gravitated down between loose brickwork into a pit4 ,dust collected above the point where the furnace was tapped contained #cigg per cent4 of lead monoxide1 and the flue dust #dbb per cent4#c4 ,a flannel respirator worn once only by one of the furnace men contained lead equal to #af milligrammes of lead monoxide4 ,in #aijf three cases were reported in the extraction of copper4 ,the persons affected were employed in charging ore into the cupola#d4 ,heavy incidence of poisoning 7twelve cases in two months7 in a smelting works 7now closed7 led to examination of sixteen men4 ,the gums of only one man were free of a blue line--in most it was particularly dense--eight were anmic1 one had paralysis of the wrists1 and five others weakness4 ,analysis of the air was made at different points in the factory by the chemist of the works1 ,g4 ,d4 ,cowan1 with the following results3 ,the samples from the cupola were taken from inside the hood 7about #e feet above the men's heads74 ,the gas was filtered through cotton-wool1 so that all solid particles were retained1 and the remaining gas was treated separately4 ,the solid particles will be called 8dust10 and the gas1 after filtration1 8fume40 ,the cupola samples on being examined gave-- ,dust1 first sample #jjhaeb grain of lead per cubic foot4 second sample #jjgbig ,fume1 first sample #jjjebf second ,the samples from the lead well were taken #ab inches above the molten metal at the end of the lead siphon1 and gave the following results3 ,dust #jjefec grain per cubic foot4 ,fume ,nil4 ,the briquetting machine samples were taken from the platform where all the ore and fluxes are mixed before briquetting4 ,the results obtained here were as follows3 ,dust #jiegae grain of lead per cubic foot4 ,fume1 or fine dust that passed through filter #jjacad ,the reason for these high results was owing to dust raised when waggons of ore were tipped prior to mixing4 ,assuming that #bj cubic inches of air pass in and out of the lungs at each respiration1 a man in eight hours would inhale and exhale #idd cubic feet4 ,this amount of air1 inhaled at the position in the cupola where the sample was taken1 would contain #gchah grains of lead2 at the lead well1 #ecjfd grains2 and at the briquetting machines1 #iaeiec grains4 ,although the condition of the air where the men actually worked must have contained much less than these amounts1 the analyses quite serve to explain the heavy incidence4 ,collis#e quotes the following analysis of dust and fumes from ,hofman's 8,metallurgy of ,lead40 ,,lead ,,smelting3 ,,analyses ,,of ,,dust ,,and ,,fumes 7,,from ,,hofman',s 8,,metallurgy ,,of ,,lead074 ---------------------------------------- ------------------------- ,percentage of-- ----------------------------- ,arse- ,lead ,lead ,ar- nious ,monox- ,sul- ,material ,analysed4 senic4,oxide4,lead4 ide4 phate4 ---------------------------------------- --------------------- 7#a7 7#b7 7#c7 7#d7 7#e7 7#f7 ,all dust collected in ten years1 -- -- #bef -- -- average ,dust from-- ,downcomers of eleven blast -- -- #dge -- -- furnaces ,roof of blast-furnace building -- -- #bga -- -- ,fumes from-- ,slag pot while boiling -- #dh -- #daj #bfb ,reverberatory settling furnace #bc -- -- #caj -- ,flue dust-- ,friedrichshtte1 ,silesia -- -- -- #fbh -- ,a #ge -- #bfb -- -- ,freiberg1 ,saxony ,b #cge -- #bac -- -- ,c #dfd -- #afb -- -- ,pribram1 ,bohemia -- #aj -- #dee -- ---------------------------------------- --------------------- ,collis#f estimated the attack rate in lead-smelting works at #cj1 and in spelter works at #aj1 per #a1jjj per annum4 ,in one factory he found it #hj per #a1jjj1 and in a spelter works five cases occurred in a few months among seven workers4 ,the distribution of the reported cases from year to year was as follows3 ---------------------------------------- --------- ,process4 #aijj4aija4aijb4aijc4aijd4aije4aijf4 ---------------------------------------- --------- ,lead smelting #ba #bf #ac #ac #g #aj #af ,desilverizing #a #c #i #aj #af #f #i ,spelter #e #aa #c #d #d #e #i ,other 7copper1 #g #ad #c #aj #f #c #d iron1 etc47 ----------------------------------- #cd #ed #bh #cg #cc #bd #ch ---------------------------------------- --------- ---------------------------------------- ----- ,process4 #aijg4aijh4aiji4aiaj4aiaa4,total4 ---------------------------------------- ----- ,lead smelting #ba #ca #bh #ba #cc #bdj ,desilverizing #d #c #f -- #c #gj ,spelter #b #ca #be #ab #aa #abb ,other 7copper1 #a #e #g #a #a #fb iron1 etc47 ------------------------------- #bh #gj #ff #cd #dh #did ---------------------------------------- ----- ,spelter 7,zinc7 ,manufacture4--,lead is present in zinc ores in a proportion of from #a to #aj per cent4 7usually #c per cent474 ,despite this small proportion1 incidence of chronic plumbism among those engaged in the manufacture is high1 as in the present state of knowledge the lead fume given off in distillation of the zinc cannot be efficiently removed4 ,blende 7zinc sulphide7 is first calcined1 and the residue1 after mixture with calamine 7zinc ashes7 and anthracite1 forms the charge for the furnace4 ,the retorts are arranged in long rows one above the other1 and frequently back to back in the furnace1 so that there may be #bej or more to each furnace1 and of the furnaces there may be several in a shed4 ,attached to the retort is a fireclay receptacle 7condenser7 into which the zinc distils1 and an iron nozzle 7prolong7 to prevent oxidation in the condenser4 ,while distillation goes on the carbonic oxide gas evolved burns brightly1 tinged with the greenish-white colour imparted by the zinc4 ,the products of combustion1 with traces of lead fume from the hundreds of prolongs1 are discharged into the atmosphere of the sheds1 where temperature is high4 ,the latest design of prolongs1 however1 has an exit at which the products of combustion escape near the furnace1 so that the greater portion pass up into the ventilating hoods4 ,periodically--three times to each charge--the workman removes the prolong1 ladles out such zinc as has condensed1 and pours it into moulds4 ,finally1 when distillation is completed1 the contents of the retorts are raked out1 and it is in the fuming hot residues so deposited on the floors that much of the danger arises4 ,in distilling furnaces of modern design the hot residues fall through openings in the window of the furnaces into 8pockets10 in which they cool off considerably before they are drawn out into iron skips4 ,in another form of furnace used in the manufacture of spelter 7,silesian71 the workman after charging can leave the furnace until the time for tapping arrives4 ,the two operations involve work for six hours a day only4 ,dangers and ,prevention4--,during distillation the detrimental effect of a current of air 7formation of zinc oxide7 on the zinc is an obstacle to the removal of the fume by exhaust ventilation locally applied over the prolongs of the condensers4 ,exhaust ventilation of a kind can1 however1 be arranged1 except under unfavourable weather conditions1 by erecting hoods of material such as galvanized iron right across the roof of the shed over1 and parallel with1 the furnaces1 up which the heated current of air from the furnaces travels4 ,lofty1 roomy sheds assist materially in the escape of the fumes4 ,various forms of modification in the condensers1 designed to lessen escape of fume1 and so recover more zinc1 are being tried4 ,samples of fume condensed as a grey powder1 and collected by ,collis from different kinds of prolongs1 showed #ac to #bg per cent4#g of metallic lead respectively1 and a sample of dust deposited from material containing #aj per cent4 of lead1 #cbe per cent4#h4 ,manufacture of ,red and ,orange ,lead and ,litharge4--,these processes are frequently carried on as part of lead-smelting works4 ,red lead is produced by oxidation1 first1 of metallic pig-lead1 in a reverberatory furnace at dull red heat1 into massicot 7yellow monoxide74 ,during the process the material is constantly raked4 ,the massicot is withdrawn from the furnace1 and subsequently1 after drying and sieving1 is again subjected to similar treatment at slightly lower temperature4 ,orange lead is made by treating white lead in the manner described4 ,during the ten years #aijj-aiji the number of reported cases from the manufacture of red lead was #ajh1 of which #dg were attributed to work at the furnaces1 #dc to packing and sieving1 and #af occurred among general labourers1 part of whose duty it was to sweep up the floors4 ,collis estimates the attack rate in the five years #aije-aiji1 in a certain number of factories employing #aga persons1 at #ej per #a1jjj4 ,reference to the table on p4 #dh shows that the proportion of those suffering from encephalopathy is higher than in any other industry--an observation previously noted by ,layet#i4 ,dangers and ,prevention4--,danger is practically limited to escape of dust in 7#a7 raking the charge out from the hearth on to iron trolleys1 7#b7 sieving1 and 7#c7 packing4 ,in all these operations exhaust ventilation is essential1 and for sieving and packing the installation requires to be designed with especial care1 so as to be able to keep within the sphere of the exhaust the spading and shovelling of the material1 in very fine state of division1 into the cask4 ,sometimes the material is elevated from pits1 and eventually packed by mechanical means into barrels resting on a jolter4 ,unless the elevators are quite dust-proof1 and the collar hermetically seals the connection of the shoot with the barrel1 the vibration of the heavy machinery and pressure of air inside the casing will cause dust to escape4 ,red lead can be1 and is1 now made on an extensive scale in such a way that all operations1 from commencement with pig-lead to the final packing1 are carried out by mechanical means so entirely closed in that the worker does not come into contact with the material4 ,the person who then may be affected is the fitter attending to repairs of the machinery4 ,the pig-lead is melted1 stirred1 and mixed in a covered-in melting-pot4 ,the massicot which is formed is drawn off by an exhaust into a hopper1 from the bottom of which it is fed mechanically on to the floor of the furnace4 ,mechanical rabbles stir it from the centre to the outside of the furnace floor1 from where it is conveyed1 under negative pressure1 to the hopper of a grinding mill4 ,from here it is again similarly fed into another furnace4 ,the exhaust pipe from this furnace collects the finished product1 carrying it mechanically to a hopper which automatically feeds the red lead into casks4 ,negative pressure throughout prevents escape of dust4 ,manufacture of ,litharge4--,pig-lead is placed in a cupellation furnace1 and constantly stirred and raked over to cause entire oxidation1 and then is either raked out or run out from the furnace hearth into moulds1 and allowed to cool in the form of large balls4 ,these balls1 of a roughly crystalline nature1 are deposited on the floor1 where they are exposed to the air4 ,disintegration is accelerated by breaking up the large fragments by hand4 ,subsequently the material is placed in a disintegrator for fine division and packed4 ,dangers and ,prevention4--,manufacture of litharge may cause a greater amount of dust than any other process with which we are familiar4 ,the nature of the operations is such that it is impossible at all stages to control this dust4 ,danger is greatest in the early operations of shovelling up the disintegrated powdery material from the floors into receptacles1 and in discharging the contents into the disintegrating machine4 ,the work is heavy1 and a respirator is with difficulty worn4 ,a movable hood attached to a flexible duct in connection with an exhaust which could be moved from place to place on the floor suggests itself1 but when tried it has not effectively controlled the dust1 owing to both the trouble involved and the difficulty of bringing the exhaust near enough to the work4 ,when once the material reaches the disintegrator1 exhaust over the hopper1 and in connection with the enclosed sifter and grinder and packing machine1 can readily be secured4 ,bins should be provided for the litharge lumps1 so as to avoid trampling the powder underfoot1 and covered barrows for removing the semi-powdered material4 ,alternation of employment lessens risk1 and should be always arranged4 ,in any new plant the possibility of automatic methods of carrying out the process as far as possible should be considered4 ,sheet ,lead and ,lead ,piping4--,this industry also is not infrequently carried out on smelting premises4 ,to make lead piping1 molten refined lead is run into a cylinder containing an adjustable mandrel in its centre4 ,the cylinder is forced by hydraulic pressure against a hollow ram having an adjustable orifice to form the desired thickness of pipe4 ,in the case of sheet lead the thick plates are gradually reduced to the desired thickness by pressure of heavy steel rollers4 ,dangers and ,prevention4--,little risk attaches to handling the clean sheet lead or drawn lead4 ,danger is in the early stages4 ,old oxidized lead piping1 lead cisterns1 tea lead1 old accumulator plates1 etc41 lie in heaps on the premises4 ,these cannot be handled without generation of dust4 ,when melted and stirred1 copious fumes arise1 carrying up dust1 from which1 and from that raised in drossing the surface of the metal1 absorption of lead is inevitable unless the melting-pot is fully protected from side-draughts and provided with a hood and duct leading into the main chimney-stack4 ,doors in front of the hood serve still further to confine the fumes4 ,the skimmings from the pot require to be placed in a receptacle under the hood4 ,of #aji cases reported in the ten years #aijj-aiji1 operations at the melting-pot accounted for at least #dg4 ,we are in agreement with ,dixon ,mann1 who remarks3 8,workers in metallic lead do not suffer unless they are frequently in the presence of large quantities of the molten metal1 or inhale fine particles of solid lead or its oxide whilst manipulating old metal4 ,lead1 though not usually classed amongst the volatile metals1 is capable of volatilization at a high temperature1 and in the form of vapour may be taken into the system through the respiratory tract1 and also into the stomach4 ,one of the worst cases of chronic lead poisoning ,i ever saw was that of a man who bought the sheets of lead linings of old tea-chests1 and melted them down into pig-lead4 ,he did the work in a small room1 without any contrivance for ventilation1 and attended to the whole process himself0#aj4 ,letterpress ,printing4--,in this industry account has to be taken of contact with-- #a4 ,molten lead in 7a7 casting the type in different kinds of machines1 including the monotype and linotype2 7b7 in stereotyping2 and 7c7 in recasting into moulds the line or single type after it has been once used1 together with dbris from the stereo machine and sweepings from the floor4 #b4 ,metallic lead in handling and dressing the type1 and subsequent use of it by the compositor4 ,the type metal itself usually consists of--,lead1 #ge per cent42 antimony1 #bc per cent42 and tin1 #b per cent4 ,during the ten years #aijj-aiji1 #bjj cases were reported--#ib compositors1 #ga stereotype and linotype operators1 and #cg in subsidiary processes1 mainly in the casting-room4 ,thus1 apparently1 operations involving contact with molten metal are more likely to cause lead poisoning than actual handling4 ,type-,casting4--,in letter founding and in the monotype letter-casting machine the molten metal1 heated by a coal fire in the former and ,bunsen burner in the latter1 at regular intervals fills the matrices at a point where it is cooled by a jet of compressed air1 and the formed letter is then mechanically ejected into a receptacle4 ,the temperature of the molten metal has to be carefully regulated1 and does not usually rise above #djj to #dej ,c4--a temperature at which it is extremely doubtful if lead fume can be produced4 ,sommerfeld#aa states that in #fj cubic metres of air aspirated close to a type-casting machine no trace of lead was found1 because vaporization does not take place below #eej ,c4 ,such skimming as must occasionally be made of the small surface of molten metal is in a slaggy state1 and does not appear to contain much oxide4 ,this is deposited usually in a small box and removed to be remelted once a day4 ,what fume1 often of unpleasant odour1 is noted is probably due to acroleic acid vapour from the grease and dirt4 ,the letters having been cast1 the type may be rubbed on sandstone or on a file1 by which small quantities of metallic dust are given off2 set up on setting-boards so that all letters face the same way 7work on which female young persons are usually engaged72 certain portions of letters undercut so as to make them lie perfectly parallel2 dressed1 planed1 and examined1 so as to be of precisely the same height2 and finally assorted into founts and packed in the warehouse4 ,in all these operations the fingers necessarily get blackened by contact1 and there must be slight dislodgment of metal particles to account for the cases reported4 ,in the linotype machine1 matrices are brought down from the magazine by touching the corresponding letters on the type indicator until they are arranged so as to form the line2 a lever then carries them sideways into position1 so as to allow the molten metal to flow into the mould and cast the line4 ,another lever then raises the matrices1 which are carried into the magazine again1 the slab of metal with the cast line upon it falling into a receptacle4 ,here1 again1 danger of lead fume is hardly in question4 ,as the matrices drop down from the magazine1 particles of lead which they have gathered when in contact with the metal are detached1 and are visible on every linotype machine at this point4 ,the brass cover of the magazine1 if not frequently cleaned1 soon becomes coated with fine dust4 ,although lead fume may not be given off1 it is none the less necessary to remove the products of combustion from the heating apparatus1 in order to prevent constant vitiation of air and to reduce the temperature in the neighbourhood of the machines4 ,monotype machines give off much heat4 ,exhaust ventilation by hoods reaching well over the pots1 and branch ducts entering the main duct in connection with a fan tangentially1 can alone accomplish this satisfactorily4 ,hoods and ducts leading merely into a shaft running up the side of the building fail to prevent condensation of the water vapour1 which in consequence trickles back4 ,wherever a well-thought-out system of exhaust ventilation has been installed1 reduction in temperature and comfort to the operatives has been secured4 ,temperatures above #fe ,f4 must incommode a linotype operator4 ,illustration3 ,,fig4 #aa4--;,,exhaust ,,ventilation ,,on ,,the ,,patent 8,,pentarcomb0 ,,principle ,,applied ,,to ,,metal ,,melting-,,pots1 ,,etc41 ,,in ,,printing ,,foundry1 ,,as ,,installed ,,by ,,the ,,zephyr ,,ventilating ,,company1 ,,bristol4 ,p1 ,patent 8pentarcomb0 for equalizing exhaust2 ,d1 main and branch ducts2 ,u1 upcast from fan2 ,f1 fan2 ,h1 hoods over melting-pots and dross drums2 ,s1 stereo metal melting-pots2 ,b1 boxes or drums for dross4 ,the illustration shows exhaust ventilation applied to the melting and stereo pots and dross drums in a letterpress printing foundry4 ,the draught over each pot is equalized at the point where the branch ducts join the main duct by insertion of a patent 8pentarcomb0 grid1 which breaks up the columns of air into numerous smaller channels by specially curved metal plates so as to minimize friction4 ,the ducts are graduated1 and the exhaust is provided by a volume fan4 ,in the foundry the recasting of old used type1 etc41 is effected1 and periodically scraps and sweepings are melted down4 ,these melting-pots should have telescopic hoods so balanced that they can readily be lowered1 so as to enclose the bath of molten metal and allow the fume to be drawn by the fan into a duct of such width as to offer no obstacle to escape4 ,a duct too narrow to deal with the great expansion the heated air undergoes is a defect very frequently found4 ,a principal source of danger is the skimming of the melting-pot for sweepings1 etc41 and deposit of the large amount of dross by the side of the pot4 ,receptacles for the dross in connection with the exhaust system are imperatively needed4 ,exhaust1 where practicable1 over the often large melting-pot for stereotype casting is desirable1 in order to secure a reasonable temperature4 ,here there is the danger of splashing of molten metal1 which is subsequently trodden underfoot4 ,compositors' ,work4--,the letters are distributed in the small compartments of the type cases4 ,from attrition dust may lie thick in the compartments1 and when at work there is always tendency for small quantities of this dust to be dispersed4 ,while this is the principal source of poisoning1 inasmuch as dust containing lead must adhere to the fingers1 lead may thus enter the system with food or when smoking4 ,it is quite as easy1 also1 to believe that lead poisoning may result from solvent action of the blood and tissue fluids on small spicules of lead type which penetrate the skin as to credit the well-substantiated cases of plumbism ensuing on retention of bullets or shot in the body4 ,compositors sometimes contract the habit of holding type between their teeth4 ,the old dangerous method of blowing out the dust on the staircase by means of a bellows should before long be entirely supplanted by use of suction bellows or use of printers' case dust-extractors4 ,in the ,clements apparatus the cases are placed on a shelf1 which is made to oscillate2 air is forced into the compartments from numerous jets1 so as to raise the dust1 which is removed by suction and collected4 ,the cases are thus cleaned with great saving of time in the composing-room itself1 and without contamination of the general atmosphere by dust4 ,the dust removed from a composing box by a vacuum cleaner was found in the ,government laboratory to contain #ih per cent4 of metallic lead1 and that collected from the top of the magazine of a linotype machine #hah per cent4 ,regulations issued in #aiaa in ,austria require1 among other things--7#a7 ,melting-pots1 and1 so far as is practicable1 linotype pots also1 to be provided with hoods and ducts to carry the fumes to the outside air or into a chimney2 7#b7 the type cases to fit either close on to the floor or with a sufficient space below the lowest drawer to enable the floor underneath to be easily cleaned2 7#c7 the interior of all compositors' boxes to be cleaned at least once every three months--if possible1 by means of a vacuum suction apparatus2 and 7#d7 quarterly periodical medical examination to be made of persons employed in casting1 stereotyping1 linotyping1 assorting type1 and composing4 ,sommerfeld#ab believes that in ,berlin #ajg per cent4 of the compositors suffer from lead poisoning every year1 and that #be per cent4 of all the diseases they suffer from are due to lead4 ,among #c1fda printers applying for sick relief1 ,silberstein#ac found #fe suffering from lead poisoning 7#ag per cent474 ,where1 however1 diagnosis of lead poisoning is based upon examination of the blood1 as in ,leipzig1 the amount of compensation paid by the ,sickness ,insurance ,society has diminished considerably4 ,thus1 of #bjg compositors who were either sent by medical men as cases of1 or went themselves suspecting that they were suffering from1 lead poisoning1 only #ag 7#hb per cent47 showed basophilia to such degree as to warrant the diagnosis4 ,the proportion1 on the other hand1 among letter founders and electrotypers was #bhf per cent4 ,printers suffer extensively from phthisis1 their comparative mortality from this cause as compared with the figure for all occupied males being #bij 3 #agead4 ,this high mortality is probably due mainly to the vitiation of the atmosphere1 and reluctance1 on account of extreme sensitiveness to draughts1 to admit fresh air4 ,this closing of windows by persons employed should be an additional reason for checking the vitiation from ,bunsen burners in connection with linotype and monotype machines by the only practicable means of preventing perceptible draught--namely1 exhaust ventilation4 ,file-,cutting#ae4--,the steel file to be cut is placed on a stone block in the centre of which is inserted a smaller steel block1 called a 8stiddy40 ,the worker holds in his right hand a hammer1 weighing sometimes #g or #h pounds1 and in his left1 closely gripped1 a chisel4 ,each tooth in the file--and there may be as many as #c1hjj teeth to be cut--is the result of a blow on the chisel1 and we have counted as many as #abj blows with a #g-pound and #bjj with a #d-pound hammer per minute4 ,to offer resistance to the blow and yet prevent a recoil1 the file 7in the case of the finer kinds7 is placed on a lead bed--that is1 a thin strip of metallic lead4 ,with attrition from repeated impact the lead bed becomes worn away in the course of a few days1 and part of what is so worn away necessarily takes the form of lead in fine particulate state4 ,dangers4--,absorption of lead follows from the dust generated by each blow1 from brushing the dust off the cut file1 and from licking the finger and thumb holding the chisel4 ,other conditions predisposing to plumbism before the present regulations came into force1 and not altogether without effect still1 were--too close proximity of one stock to another1 defective ventilation of the 7frequently7 small shed in which the work was done1 overcrowding1 accumulation of dust on the benches1 uneven floors1 inadequate washing facilities1 and1 apparently1 lack of appreciation of the danger4 ,the remarkable feature of plumbism in this industry is the long duration of employment before pronounced symptoms manifest themselves 7see p4 #ea74 ,the insidious onset is1 however1 accompanied by an undermining of the constitution1 showing itself eventually in atrophy of the muscles1 especially of the thenar and hypothenar eminences of the hand1 and of the lumbricals and interosseous muscles of the fingers1 the result of continual gripping of the hammer and chisel1 chronic interstitial nephritis1 with its associated arterio-sclerotic changes1 and heavy incidence of phthisis4 ,provision of locally applied exhaust ventilation has never been suggested for this industry1 owing to absence of power to drive a fan in the small workshops1 and because no lead dust is seen to be given off4 ,diminution in the number of cases is due to the fact that machine file-cutting 7with zinc as the bed7 has been substituted for hand file-cutting for coarse files4 ,in hand cutting1 in some instances1 beds of pewter1 or of alloys with comparatively small proportion of lead1 have replaced the use of lead beds4 ,the remedial measures prescribed in the regulations have also played a part4 ,at the time the regulations came into force1 in #aijc1 there were about #gjh file-cutting shops in the ,united ,kingdom1 of which #eag were in ,sheffield4 ,immediately after they came into force #abf certificates of exemption were granted for use of beds containing less than #e per cent4 of lead1 and every year fresh applications are received#af4 ,there does appear1 however1 to be difficulty in securing beds which conform to the standards laid down4 ,thus1 in the four years #aijg-aiaj1 of #bc samples submitted as containing less than #e per cent41 #af were in excess4 ,the number of reported cases of poisoning in the five years #aijj-aijd was #aea1 and #ea in the five later years #aije-aiji4 ,the attack rate is about #aj per #a1jjj1 but1 although this may be low compared with other trades1 the much greater severity of the attacks has to be borne in mind4 ,file-,hardening4--,the process consists in keeping the files in a bath of molten lead at high temperature1 covered with charcoal4 ,the file is removed when red-hot1 straightened if necessary1 and plunged into a solution of brine4 ,dangers and ,prevention4--,poisoning is attributable to fume given off by the molten lead 7a temperature of #hej ,c4 was recorded by ,s4 ,r4 ,bennett--see p4 #bja71 risk of which can only be met by efficient hooding and exhaust unless an alternative method of hardening is adopted1 dispensing with the lead bath--e4g41 by exposure to heat on a hearth1 in a gas furnace1 or by other means4 ,in this small industry in and around ,sheffield three cases were reported within a year1 each involving partial or complete paralysis of the extensors of the forearm4 ,of ten men employed at the work1 three showed presence of a blue line1 three were cachectic1 and one had weakness of the arms and wrists4 ,in two of the three factories attempts had been made unsuccessfully to carry the fumes away by a hood and duct#ag4 ,hardening of forks and similar articles in the same manner has also given rise to poisoning4 ,we are informed that methods of hardening and tempering drills1 tools1 etc41 by the use of fused metallic salts1 are being adopted in some works4 ,by mixing together two or more salts in definite proportions1 suitable fusing-points can in all cases be produced4 ,these baths can be raised to any desired melting-point to suit the requirement of different steels4 ,for example1 sodium nitrate and potassium nitrate in certain proportions give melting-points from #bbj to #cdj ,c41 and can be used for tempering baths up to #fjj ,c4 ,for tempering above #fjj ,c4 mixtures of sodium chloride and potassium chloride can be used1 whilst for hardening1 sodium chloride or barium chloride give adequate ranges of temperature4 ,similarly1 mixtures of sodium sulphate 7melting-point1 #hij ,c47 and lithium sulphate 7#hfj ,c47 can be made to give any melting-point from #fje to #hfj ,c4 ,tinning of ,metals#ah4--;,cheap hollow-ware vessels such as kettles and frying-pans are often coated with a mixture of 7usually7 half lead and half tin by dipping them into a bath of the molten metal1 after cleaning in hydrochloric acid4 ,danger and ,prevention4--,duckering has shown 7see p4 #bjc7 that fumes of chloride of lead are given off which are especially noticeable when the dipped article is removed to a stand to have the superfluous metal wiped from it with tow while still in a molten state4 ,detailed reference is made on p4 #bjd to the nature of the fume given off and the amount of lead present in the atmosphere breathed and inhaled daily by the worker4 ,the danger from fumes can be in great measure removed1 both from the bath and from the wiping stand1 by locally applied exhaust ventilation1 which may be secured by utilization of the draught from the fire under each melting-pot1 or by a hood and duct carried vertically through the roof if arranged as described on p4 #bji4 ,danger from dust arises also from the skimmings1 if not deposited in a receptacle within the hood1 from dust and dbris on the floor1 and possibly from traces of metallic lead and lead chloride attached to particles of tow floating in the air4 ,risk of lead absorption is less in later processes1 such as affixing the spout and handle 7mounting71 and hammering or denting4 ,occasionally roughnesses are removed by rubbing the coating with emery paper4 ,harness ,furniture4--,hames1 buckles1 bits1 etc41 are usually coated with nickel or copper1 more rarely with silver4 ,the process is in the nature of soldering1 and the steel1 prepared in the same way as has been described for hollow-ware1 has a mixture of two parts tin and one part lead poured over it on a hearth4 ,the strip of thin nickel sheeting is passed through a similar mixture1 and is wiped with tow--the operation to which such poisoning as occurs in this industry is mainly due1 in consequence of the difficulty of efficiently removing the vapour of lead chloride from the molten metal upon the long strip of nickel4 ,subsequently the prepared steel article and the strip of nickel or copper are made to unite under pressure of a soldering-iron4 ,in silver plating danger from fume is slightly less1 as the steel portion 7for example1 the hame7 only is tinned4 ,in the final operation of polishing on a mop danger arises from dust1 unless locally applied exhaust is provided4 ,iron ,drums and ,kegs4--,use of a tinning mixture of lead and tin in this industry is obviously in the nature of soldering4 ,the body of the drum is made either of black sheet-iron or of terne 7lead-coated7 sheet4 ,in order to unite the seam and to fix the bottom sheet1 the drum is made to stand in a shallow bath and laid on its side4 ,the danger from lead chloride vapour is considerable1 and the method of prevention is precisely of the kind described above4 ,similar coating of articles first cleaned in hydrochloric acid is met with1 as1 for example1 of the component parts of radiators of motor-cars1 of steel bars1 and of wire4 ,incidence of poisoning has not occurred to an extent to make necessary more than the application of locally-applied exhaust to remove the fumes4 ,manufacture of ,terne ,plates4--,the manufacture of lead-coated sheets for roofing purposes is carried on in a few works in ,south ,wales along with the manufacture of tin plates4 ,lead poisoning in the industry is practically unknown4 ,we can only recollect occurrence of one case1 despite the fact that the mixture contains from #fe to #ie per cent4 of lead4 ,for cleaning the plates prior to passing them through the concentrated zinc chloride flux into the molten mixture1 dilute sulphuric acid is used1 and not hydrochloric acid4 ,as to the remarkably different results on health of the two processes1 ,duckering concludes3 8,the absence of lead poisoning among terne-plate workers and tinners would appear to be explained by--7#a7 ,the use of cleaning agents and a flux of such a nature1 and in such a way1 as to involve a minimum contact with the tinning metals1 and under such conditions as to inhibit extensive interaction between them1 and also under such conditions as to inhibit production of fume or vapours1 even if any interaction occurs2 7#b7 use of a scientifically prepared flux containing no uncombined acid or excess of water in such a way as to prevent introduction of these substances1 or of ferrous compounds coming into intimate contact with the tinning metal2 7#c7 so conducting the operation of tinning that any chlorides possibly adhering to the plates are removed before the plate reappears in the open air1 under conditions preventing them from appearing in the air as vapour1 but it is very doubtful whether any chlorides could adhere to the plates2 and 7#d7 absence of any manual work on the plates before the metallic coating is set and hard4 ,on the other hand1 the existence of widespread lead poisoning in tinning of hollow-ware is explained by--7#a7 ,use of cleaning agents and flux in such a way as to bring these materials into intimate contact with the tinning metals under conditions eminently favourable to chemical interaction and vaporization of resultant compounds2 7#b7 use of an unscientifically prepared flux containing a large excess of water and much free acid2 7#c7 so conducting the operations as to favour the escape into the atmosphere of vapours of soluble lead compounds1 such as lead chloride1 and of metallic lead and soluble lead compounds1 carried mechanically by fibres of tow during processes subsequent to tinning1 as in wiping2 and 7#d7--;a minor point not to be lost sight of--possibility of contamination of the hands by soluble lead compounds1 due to manipulating the material with which the articles are wiped4 8,it should be added that while use of a scientifically prepared flux 7#b7 above in hollow-ware tinning would no doubt lessen the possibility of the production of fumes1 it is not to be anticipated 7unless a flux containing no chlorides were used7 that this would do away with lead poisoning4 ,in other words1 the method of use is1 as indicated above1 a far more important factor40 ,in the ten years #aijj-aiji the number of reported cases in tinning hollow-ware was #ic among about #bjj persons employed1 in harness furniture #bc among about #aej persons employed1 and in iron drums and kegs #dg among about #bej persons employed4 ,plumbing and ,soldering4--,the figures included in the table on p4 #dg have reference only to these processes as carried on in factory premises4 ,house plumbers1 when reported1 are included with house painters4 ,the figures are made up of two classes--7#a7 ,those handling white and red lead paste1 and 7#b7 those engaged in soldering and lead burning4 ,the number of cases reported in the ten years #aijj-aiji was1 in the first class #abb1 and in the second #ie4 ,any worker using red lead as a jointing paste who is not a house plumber or a coach or ship builder is included under the first heading1 as1 for example1 electricians1 persons engaged in mechanics' workshops1 lead-light making where red lead cement is brushed between the lead lines and the glass to render them water-tight1 and such occupations as placing strips of canvas coated with red lead between sheets of iron work before riveting1 so as to afford protection against rust4 ,in several reports there is reference to the dust created in the breaking up of old joints with aid of hammer and chisel before proceeding to recaulk them4 ,dust in making up the paste is the principal source of danger4 ,this is crudely done1 and unless large quantities of paste are made exhaust ventilation is never provided1 in view of the intermittency of the work4 ,the wearing of a respirator should be possible1 but it would be unsafe to recommend that as a sufficient means of prevention4 ,installation1 whenever possible1 of localized exhaust ventilation at the mixing bench is most desirable4 ,personal cleanliness is important1 as the hands become ingrained with the paste4 ,the heading 8,soldering0 includes in the main 7a7 the soldering of tins of all descriptions1 bicycle lamps1 etc41 with a stick of solder1 either held in the hand or lying on the bench1 which is touched by the hot soldering-iron1 the surface to be soldered having previously been cleaned with 8killed spirit0--i4e41 zinc chloride flux2 and 7b7 lead burning1 by means of a hydrogen or oxy-hydrogen blowpipe flame1 of lead-lined boxes1 vats in sulphuric acid and other chemical works4 ,some cases are included which occurred in the manufacture of solder itself4 ,green wood is held at the bottom of the pot of molten metal1 and the gases distilled from the wood pass upwards through the metal and escape at the surface1 carrying small quantities of lead into the atmosphere of the workroom4 ,dangers and ,prevention4--,it can be confidently said of soldering that1 bearing in mind the very large number of persons employed1 the number of cases reported is remarkably small1 and it is difficult to assert generally1 as can easily be asserted of tinning1 that inhalation of soldering fumes must necessarily set up lead poisoning4 ,moreover1 examination of persons employed in soldering for signs of lead absorption is almost always negative1 a blue line on the gums even being rarely visible4 ,on the other hand1 the process of soldering is so analogous to that of tinning that such poisoning as occurs is probably due to inhalation by susceptible persons of lead chloride fumes4 ,and this is borne out by the results of analysis in the ,government laboratory of a sample of deposit collected from a duct where exhaust ventilation had been applied to take away the fumes4 ,the material was a black mass1 obviously containing a large proportion of carbon4 ,on completely extracting with water1 the solution was found to show an acidity equal to #jbj per cent4 of hydrochloric acid calculated on the original sample1 and in this solution the following metallic substances were present--viz43 ,percentage on ,original ,substance4 ,zinc1 calculated as zinc chloride #aiec ,copper1 calculated as copper chloride #agg ,lead1 calculated as lead chloride #jai ,tin and arsenic were both absent1 and the chlorine present closely corresponded with the proportion of chloride shown above4 ,the portion of the substance which was insoluble in water was found to contain the following metallic substances3 ,percentage on ,original ,substance4 ,tin1 calculated as tin oxide #fji ,lead1 calculated as lead oxide #acc ,copper1 calculated as copper oxide #jeg ,zinc1 calculated as zinc oxide #jbj ,this portion of the sample was also free from arsenic4 ,we believe that where soldering is done by several persons in a workroom1 inhalation of the fumes is prejudicial to health1 and that the usual methods of localized ventilation are desirable4 ,where this has been done the result has been in every way satisfactory4 ,in lead burning the heat from the blowpipe flame is sufficient1 if kept long enough in contact with the lead sheet1 to cause volatilization of the metal1 and1 as the worker's face must necessarily be close to the flame1 inhalation of fume is inevitable4 ,such work1 however1 has often1 unfortunately1 to be carried on in confined spaces where exhaust ventilation cannot be applied4 ,brass#ai4--,the malady the brass caster has suffered from in the past is par excellence brassfounders' ague4 ,lead1 however1 is introduced 7rarely exceeding #aj per cent47 for the purpose of softening the alloy of copper and zinc4 ,of #gg cases of lead poisoning in the ten years #aijj-aiji included under the heading 8,brass10 #ch were polishers1 #bh casters and others1 and #aa chandelier fitters4 ,cases occur among the casters probably from inhalation of the fumes in pouring1 and among the polishers from inhalation of the small proportion of lead in the dust given off in the absence of adequate exhaust4 ,in a factory where there were two emery wheels1 one with a hood and fan to carry the dust away1 while the other remained unprotected1 the worker at the unguarded wheel suffered from lead poisoning4 ,in filing and dressing the article is held in a clamp with leaden claws1 which gradually become worn away1 just as does the lead bed used by the file-cutter4 ,this may account for the poisoning reported among filers and dressers4 ,a sample of dust taken from under a calico mop for brass polishing was found in the ,government laboratory to contain #ba per cent4 of lead4 ,the joints of chandelier fittings are sealed with a white lead paste4 ,instead of always testing the completeness of the seal by means of an air pump and pressure gauge1 the fitter frequently tests it by applying his lips to the unsealed end and blowing through the pipe4 ,all the cases among chandelier fitters are caused in this way--perhaps the clearest instance of poisoning by absorption through the alimentary canal1 as distinguished from absorption through the lungs1 that can be cited4 ,while use of an air pump and immersion of the joint in water or pressure gauge only is an entire protection1 and should be provided wherever this work is done1 constant supervision as to its use is called for4 ,the sealing of the joint can be done with a material known as 8caulkite10 containing neither white nor red lead4 ,for references1 see end of ,chapter ,,xvii4 ,,chapter ,,xvi ,,description ,,of ,,processes--,continued ,manufacture of ,white ,lead#bj4--,the usual method in this country is that known as the 8,dutch process10 although the ,german chamber process1 precipitation processes1 and others1 are all practised4 ,dutch ,process4--,a layer of spent tan is placed on the floor of the stack 7a chamber with walls of brick some #be feet high1 and a vertical opening from top to base through which the men enter71 upon which are arranged earthenware pots partially filled with dilute acetic acid4 ,strips of lead are then placed on small square 8cockney0 pots1 or more rarely in the form of folded grids1 inside deep1 long 8castle0 pots1 and the whole covered with boards1 resting on special 8bearer pots0 containing dilute acetic acid4 ,ten to fifteen of such layers 7blue beds7 one on the top of the other are built into the stacks to a height of some #bj feet4 ,when completed1 the stacks remain for #hj to #ajj days before being emptied4 ,during this period the temperature rises to #ge to #hj ,c41 considerable evolution of carbonic acid gas takes place1 and the lead is converted first into acetate and subsequently the white basic carbonate4 ,the layers 7white beds7 are uncovered and the corroded strips 7corrosions7 collected by hand4 ,they are placed in trays and carried to heavy steel rollers by means of which and subsequent raking in wash becks the carbonate is detached from the uncorroded central core of blue lead4 ,in many factories corrosions are now conveyed from the stacks to the wash becks or rollers by travelling cranes4 ,the recovered blue lead is removed in a wet state to be remelted and recast4 ,the corrosions1 after passing through the rollers and wash becks1 are shovelled on to a picking-board and transferred gradually to the grindstones4 ,from the stones the ground pulp passes to the settling becks through several gratings of fine copper mesh4 ,in the form of pulp the material is ladled by hand into bowls for conveyance to the drying stoves4 ,when dry1 the contents of the bowl are emptied into barrels and headed1 or into hoppers1 from whence the material is conveyed to be packed either by hand or automatically by mechanical packers1 or to be converted into paint4 ,dangers and ,prevention4--,in casting the strips1 risk does not arise from lead fume1 as the temperature at which this is effected 7#cej ,c47 is too low for appreciable fume to be given off4 ,danger here is from skimmings and deposit of them on the floor or into a receptacle unprovided with exhaust draught4 ,pots in which remelting of the uncorroded cores 7returns7 is done should be provided with hoods and exhaust1 because of the dust given off in stirring and skimming and the spurting which occurs as they are thrown in wet4 ,in making the blue beds1 dust arises from particles of white lead adhering to the pots and in the tan bark4 ,pots1 on removal from the white beds1 should have all white lead inside them removed by washing in a tank4 ,screening of the bark should be dispensed with4 ,emptying the white beds accounts1 perhaps1 for the largest number of cases1 owing to the impossibility1 in the present state of knowledge1 of dealing with the dust by means of exhaust ventilation1 or quite adequately by watering or wearing of respirators4 ,watering by means of a hosepipe with rose attached is1 however1 the main safeguard4 ,substitution of the square cockney pots for the long castle pot is also of moment1 as the flat plates of lead form a denser and more porcellanous corrosion than that of the grids in the castle pots4 ,moreover1 in stripping the beds the flat corrosions can be lifted into trays without creating dust1 whereas to dislodge the contents of the castle pots may require a sharp tap1 and the unglazed portion of the interior surface of the latter retains some carbonate when moistened4 ,watering requires to be thorough and done with care1 or else the softer material of the corrosion may be washed into the tan4 ,no less important is it to water the layers of tan1 and at a time while they are yet warm and slightly damp1 otherwise the tan becomes so dry that the water runs through1 and does not adequately prevent dust formation on its removal4 ,a requirement of the special rules is that the trays for collecting the corrosions shall not stand directly upon the beds4 ,when corrosions contain an undue proportion of lead acetate1 they are termed technically 8floury10 and much dust may arise from them on watering unless this be done with a very fine rose4 ,dust at the rollers and wash becks is usually checked by preliminary immersion of the tray of corrosions in a trough of water1 but the extra weight of the water causes this sometimes1 in the absence of mechanical arrangements for immersion1 to be done perfunctorily4 ,where there are rollers1 the tray is inserted in a small opening above them1 the contents saturated by a spray1 and then tipped over4 ,this method also may fail to control the dust1 as1 unless the men engaged in washing the corrosions in the wash beck keep the mass tipped in from piling up in a heap1 the contents of the trays are discharged on to the heap1 and not into water4 ,in some factories exhaust ventilation at the rollers or wash becks has been necessary4 ,during subsequent wet processes of grinding danger is mainly from splashing4 ,from the settling tanks the white lead is pumped into filter presses1 and the resulting cake is dried4 ,here the considerable risk from splashing is again almost unavoidable4 ,concrete floors are necessary4 ,emptying the stoves involves much handling1 with inevitable creation of dust1 especially when the bowls are withdrawn from the racks4 ,risk has been greatly lessened by reducing the height of the shelves to #aj feet and prohibiting the piling of one bowl upon another4 ,mechanical drying stoves into which men need not enter either for filling or drawing are now commonly met with4 ,of these there are various types--7#a7 ,horses similar to those common in laundries1 which can be withdrawn on rails2 7#b7 small chambers built up one upon another somewhat in the form of gas retorts in a gasworks1 heated by steam jackets and coils1 each chamber containing only two or three cakes of white lead pulp1 the cakes themselves being removed by a mechanical process from the press into the drying chambers2 7#c7 bogies carrying the white lead in bowls on racks made to pass through the tunnel-like stove2 7#d7 drying machines--i4e41 closed cylinders fitted with a series of platforms so arranged that they may be charged with white lead on one side1 and so fixed as to be turned round by means of mechanical appliances4 ,when dry1 the material is discharged into a chute by a series of scrapers into a small enclosed compartment1 holding the barrel to be filled4 ,with the drying machine1 however1 there is considerable risk of dust leakage1 especially when the doors are opened4 ,in packing by hand1 safety depends on efficient exhaust ventilation when the contents are tipped into the barrel1 but a danger constantly present is that1 to get through the work quickly1 the bowls may be withdrawn from the influence of the exhaust before the last traces of dust have been removed from the bowl4 ,mechanical packing1 by means of a large bladed screw forcing the white lead into the barrel1 which as it becomes filled is lowered automatically1 is everywhere desirable4 ,an essential condition of this method is that a dust-proof collar should connect the automatic packer with the barrel4 ,some dust almost inevitably escapes1 and a hood and exhaust should be provided1 however perfectly the machine is said to act4 ,much of the white lead is converted into paint on the premises1 being ground in oil either in pug mills1 ,torrance mills1 or under edge-runners4 ,a negative pressure must be maintained inside the casing1 which must enclose the stones4 ,here the conditions are precisely those described under the manufacture of paints and colours4 ,in some white lead works conversion into paint is done without the dangerous process of stove drying1 either by drying under a vacuum or by mixing the white lead directly with oil4 ,in the process of grinding the oil incorporates itself with the white lead1 and the water is forced out1 running away in a clear stream4 ,chamber ,process4--,in this method1 almost universally used in ,germany1 and adopted in at least one large white lead works in this country1 a chamber arranged with numerous sets of parallel bars on which the thin strips of lead are set saddle-wise takes the place of the stack in the ,dutch process4 ,carbonic acid gas and acetic acid vapour act on and corrode the strips4 ,in a period of from eight to ten weeks the corrosions mostly fall to the ground4 ,such of the strips as do not fall have to be lifted off the bars1 having been previously well saturated with water from a hosepipe1 and are dropped on to the floor of the chamber4 ,we are not satisfied that working in the dark1 confined chamber by artificial light is less dangerous than working on the stacks4 ,chamber-made lead undergoes practically the same subsequent processes as have been described4 ,precipitation ,processes4--,these also dispense with stacks and the consequent risks attending work on the blue and white beds1 but they substitute another--namely1 use of oxide of lead 7litharge or the suboxide7 as the initial product to be carbonated1 with the inevitable danger1 in the absence of mechanical contrivances entirely closed in1 of shovelling dusty material4 ,in many of these methods1 however1 mechanical arrangements obviate hand labour or contact with dust in all but the first process4 ,the ,brimsdown process#ba1 for instance1 is automatic and free from dust1 except in the initial stage of preparation of litharge in cupellation furnaces4 ,the great risk from the disintegration of this material 7see p4 #bej7 by turning it out on the floors is obviated by allowing disintegration to take place in the pots 7which must not1 therefore1 be completely filled71 and tipping these when cooled directly into a breaker under powerful exhaust draught4 ,from the bin into which it falls the material is conveyed by dust-proof elevators to 7a7 screens and packing arrangements when the object is flaked litharge1 or 7b71 in the case of the bulk of the material for manufacture of white lead1 by enclosed conveyors to reducers and mixing mills1 where reduction and hydration take place4 ,it is then charged automatically into weak solution of acetic acid1 and by agitation with carbonic acid gas converted into basic carbonate of lead4 ,from the carbonators pumps force it into filter presses1 where the acetate is drained off and washed out by pure water4 ,the cakes of white lead are fed into mixing machines and pugged with linseed-oil until the water has been entirely removed1 and finally passed through the roller mills to be packed in casks4 ,dry white lead is made by feeding a metal travelling lattice with pulp white lead inside a drying chamber entirely closed in4 ,when dry1 the white lead is automatically brushed off1 elevated1 and automatically packed in a chamber under efficient exhaust draught4 ,in this part of the process1 therefore1 risk to the workers is very small4 ,the stringent ,special ,rules for the ,white ,lead ,industry show what other precautions1 in addition to exhaust ventilation1 are necessary--especially personal cleanliness4 ,the effect of one other factor--casual labour--however1 must be referred to4 ,the condition at the present time is very different from that which existed twelve years ago4 ,from one factory in #ahii1 depending much on casual labour1 #aaa cases were reported1 and from another #gb4 ,in an inquiry made by one of us in #ahih1 information was obtained of the actual number employed on any one date1 and of the total number passing through the factories in a year4 ,among the firms with regular employment at that time1 the incidence of lead poisoning was #fj per #a1jjj on the average number employed1 and in those with casual employment #cij per #a1jjj4 ,work in lead had secured a bad name1 and no one who could get employment elsewhere would take to it4 ,consequently1 the class of men applying for work was a low one--men discharged from other employment and those unfitted for skilled labour4 ,not a few were addicted to alcohol4 ,the work was unskilled1 and had the additional advantage to men of that class that much of it was piece work1 paid at a good rate1 which could be finished as a rule by three o'clock in the afternoon4 ,diminution in the number of cases from #cii in #ahii to #cd in #aiaj has been brought about mainly by--7#a7 ,improved structural conditions2 7#b7 adoption of mechanical means 7cranes1 rails1 hoists1 etc47 for conveyance of material in substitution for hand carrying2 7#c7 exhaust ventilation1 where dust arises as in packing and paint-mixing2 7#d7 periodical medical examination2 7#e7 diminution in height of the stoves or adoption of mechanical drying stoves2 7#f7 conversion of white lead into paint by means of direct mixture with oil while in the pulp stage2 and 7#g7 substitution of small1 square1 glazed pots--cockney pots--requiring the lead strips to be placed on them1 for the deep castle pots into which the lead grids are folded in the white beds4 ,prohibition of female employment in the dangerous processes was made prior to the ,special ,rules of #ahii4 ,their greater susceptibility as compared with men1 the special effect of lead on the uterine functions1 and the unsuitability of much of the work for women1 fully justified the step recommended by the ,white ,lead ,committee in #ahih4 ,earthenware and ,china#bb4--,the industry includes the manufacture of earthenware1 china1 tiles1 majolica ware1 ,rockingham ware 7teapots71 sanitary ware1 china furniture1 and electrical fittings1 and any other articles made from clay2 but of the total #f1hfe persons employed in lead processes in the whole of the ,united ,kingdom in #aijg1 #e1hcd are included in the manufacture of the first three4 ,and even in the manufacture of earthenware1 china1 and tiles1 the poisoning which occurs is not distributed evenly over the whole of the factories4 ,these number #eej1 and1 taking the period #aijd-aijh1 #e potteries were responsible for #ge cases1 #ag for #aai1 and #aea for #cbc1 leaving #cgg factories out of the #eej from which no case was reported4 ,incidence seems to depend more on the scale and rapidity of the output of cups1 saucers1 plates1 and tiles1 in everyday use1 than on anything else4 ,the number of reported cases year by year from #aijj to #aiji has been as follows3 ,,all ,,lead-,,workers ,,in ,,places ,,under ,,earthenware ,,and ,,china ,,special ,,rules4 ,,whole ,,of ,,united ,,kingdom 7,,including ,,north ,,stafford74 ,,number ,,of ,,persons ,,employed4 ---------------------------------------- ------------------ ,china1 ,furni- ture ,jet and and ,elec- ,earth- ,ma- ,rock-trical ,totals1 ,chi- en- joli- ing- ,fit- ,sani- ,m4 and na4ware4 ,tiles4 ca4 ham4tings4tary4,totals4 ,f4 ---------------------------------------- ------------------ #aijd ,m4 #ecf #b1gea #eeg #ajj #baf #dd #aij #d1cid #f1fid ,f4 #bch #a1abb #efb #aaj #ga #aeh #ci #b1cjj #aijg ,m4 #fbe #b1hce #dgd #if #aga #ff #bcg #d1ejd #f1hfe ,f4 #cjb #a1aaa #dhg #agj #gj #agi #db #b1cfa ---------------------------------------- ------------------ ,,number ,,of ,,cases ,,of ,,lead ,,poisoning4 ---------------------------------------- ------------------ ,attack ,attack ,attack ,attack ,rate ,rate ,rate ,rate per per per per ,cases4#a1jjj4;,cases4#a1jjj4;,cases4#a1 jjj4;,cases4#a1jjj4 ---------------------------------------- ------------------ #ahii ,m4 #ac #bd #ajf #ci #g #ac #b #bj ,f4 #h #cd #hc #gd #ba #cg #d #cf #aijj ,m4 #aa #ba #fb #bc #ab #bb #c #cj ,f4 #aj #db #fg #fj #ae #bg #b #ah #aija ,m4 #g #ac #cg #ac #i #af -- -- ,f4 #b #h #bh #be #g #ab #b #ah #aijb;,a ,m4 #c #f #cj #aa #f #aa -- -- ,f4 #b #h #cc #bi #e #i #b #ah #aijc ,m4 #a #b #bi #aa #h #ad #a #aj ,f4 #f #be #cb #bi #i #af #f #ee #aijd;,b ,m4 #b #d #ca #aa #f #aa -- -- ,f4 #a #d #da #cg #ai #cd #a #i #aije ,m4 #d #h #be #i #d #g -- -- ,f4 #c #ac #bc #bj #ad #be #d #cf #aijf ,m4 #e #h #cd #ab #g #ae -- -- ,f4 #b #g #da #cg #aj #ba #c #ah #aijg ,m4 #f #aj #ch #ac #d #h -- -- ,f4 #g #bc #cc #cj #f #ab #a #f #aijh ,m4 #d #f #de #af #c #f -- -- ,f4 #a #c #db #ch #h #af #a #f #aiji ,m4 #b #c #bb #h #d #h -- -- ,f4 #a #c #ag #ae #g #ad -- -- ---------------------------------------- ------------------ ---------------------------------------- ------ ,attack ,attack ,attack ,rate ,rate ,rate per per per ,cases4#a1jjj4;,cases4#a1jjj4;,cases4#a1 jjj4 ---------------------------------------- ------ #ahii ,m4 -- -- -- -- -- -- ,f4 -- -- #e #cb -- -- #aijj ,m4 #e #bc #a #bc #a #e ,f4 -- -- #aa #gj -- -- #aija ,m4 #c #ad #a #bc -- -- ,f4 #a #ad #i #eg -- -- #aijb;,a ,m4 -- -- -- -- #a #e ,f4 #a #ad #d #be -- -- #aijc ,m4 #c #ad -- -- #a #e ,f4 -- -- #a #f -- -- #aijd;,b ,m4 -- -- -- -- -- -- ,f4 #a #ad #d #be -- -- #aije ,m4 -- -- #b #de #a #e ,f4 #b #bh #b #ac -- -- #aijf ,m4 -- -- -- -- #a #d ,f4 -- -- #c #ag #a #bd #aijg ,m4 #a #f -- -- #c #ac ,f4 -- -- #c #ag #a #bd #aijh ,m4 #a #f #a #ae #b #h ,f4 -- -- #h #de #a #bd #aiji ,m4 -- -- -- -- -- -- ,f4 #b #bi #b #aa #a #bd ---------------------------------------- ------ ---------------------------------- ,attack ,total,attack ,rate ,cases1 ,rate ,total per ,m4 per ,cases4#a1jjj4 ,f4 #a1jjj4 ---------------------------------- #ahii ,m4 #abh #bi #bdi #cg ,f4 #aba #ec #aijj ,m4 #ie #bb #bjj #cj ,f4 #aje #df #aija ,m4 #eg #ac #ajf #af ,f4 #di #ba #aijb;,a ,m4 #dj #i #hg #ac ,f4 #dg #bj #aijc ,m4 #dc #aj #ig #ad ,f4 #ed #bc #aijd;,b ,m4 #ci #i #ajf #af ,f4 #fg #bi #aije ,m4 #cf #h #hd #ac ,f4 #dh #ba #aijf ,m4 #dg #aj #ajg #af ,f4 #fj #be #aijg ,m4 #eb #ab #ajc #ae ,f4 #ea #bb #aijh ,m4 #ef #ab #aag #ag ,f4 #fa #bf #aiji ,m4 #bh #f #eh #h ,f4 #cj #ac ---------------------------------- ,a ,lord ,james's ,code--,rule #c onwards--came into force4 ,b ,medical examination of men began4 ,the processes in so far as lead enters can best be divided into--7#a7 ,glaze2 7#b7 decorative4 #a4 ,glaze ,processes4--,the charge of glaze is made by weighing out and mixing carbonate of lead with the necessary silicates and silico-borates in the lead house or mixing-room1 where wet grinding prepares the mixture for the dipping-tub4 8,putters-up0 hand the ware to the dipper1 from whom 8takers-off0 place it on boards for removal to the drying still1 or place it 7in large works7 directly on to the shelf of an appliance known as a 8mangle10 in which an endless chain carries the ware through a heated chamber4 ,subsequently superfluous glaze has to be removed from the base1 rims1 and not infrequently also other parts of the articles4 ,this ware cleaning is performed with a wet sponge or flannel1 either while the ware is still moist or by scraping1 the particles removed dropping into a vessel of water2 or1 if the glaze is dry1 over a grating provided with exhaust draught4 ,the ware is next removed by the glost-placer on boards1 and each piece is separately placed by him in the sagger 7fireclay receptacle7 and carried into an oven to be fired4 #b4 ,decorative ,processes4--,majolica painting is the application of a coloured glaze rich in lead by means of a brush4 ,ground-laying consists in dusting powdered enamel colour on to a pattern first printed on glazed ware with an oily medium4 ,colour dusting differs from the same only in detail4 ,aerographing 7colour blowing7 is the blowing on to the ware1 by means of a jet of compressed air1 coloured glaze1 or enamel colour held in suspension in oil or other liquid in a glaze kettle or aerograph instrument4 ,dangers4--,apart from risk inseparable from1 and increased by1 defective lighting1 uneven floors of wood or brick1 collection of dust on benches and floors1 and the risk entailed in the sweeping of these even when watering is practised1 and lack of care and attention to detail on the part of the worker1 the following special dangers are incidental to the various processes3 ,in dipping the glaze 7except in tiles1 where the surface only is allowed to touch the liquid71 splashes on to the face and overalls of the dipper1 8hander-up10 and 8taker-off0 7dipper's assistants71 and 8threader-up0 7in the case of china furniture71 especially when1 as with plates1 there is much shaking of the ware4 ,these splashes dry1 and the overalls may become so coated with glaze that every movement1 such as carrying boards or leaning against the mangle1 crumbles it off as dust into the air4 ,as the dipper shakes the ware1 some of the drops are disseminated into the atmosphere as a fine spray4 ,in ware cleaning the work may have to be done so rapidly that it is difficult always to observe proper care1 and the worker is tempted to withdraw the article from the range of the exhaust4 ,sometimes a ware cleaner is seen blowing away with her mouth dust lying on the ware4 ,dipping-boards1 unless freed from adherent glaze by washing after use1 create dust whenever ware is placed on1 or removed from1 them1 when they are handled and placed on or taken off the stillage bars1 and when they are stacked4 ,persons gathering at the mangle are exposed to dust if there is any outward current of air from it4 ,the glost-placer raises a slight amount of dust as he takes the ware from the board and places it in the sagger4 ,the dangerous practice formerly almost universal of rubbing the bottoms and rims of cups1 etc41 either together 7without use of an exhaust7 or rubbing them on a piece of leather fixed round the chest1 is generally replaced by removal of the glaze on a moist piece of flannel1 but it is still possible to find men doing it in outlying potteries4 ,in majolica dipping and painting 7apart from the obvious risk of splashing and contamination of the hands71 danger arises mostly from scraping the edges and under surfaces of the tiles on to which glaze1 when applying the background1 has overflowed4 ,the amount of glaze so removed is considerable1 and if it is not all caught in the trough of water1 the floor becomes an added source of danger4 ,in all the decorative processes--ground-laying1 aerographing1 colour-dusting1 and grinding of colours for aerographing1 etc41 the danger is one solely arising from dust4 ,prevention4--,meticulous attention to detail1 not only in the provision1 but also in the maintenance1 of the locally-applied exhaust ventilation1 alone can allay the danger in the processes to which dust is incidental1 such as ware cleaning1 gathering at the mangle1 glost-placing1 and the decorative processes4 ,the ,lead ,committee considered that1 as there was no rapid method of testing the actual degree of moisture1 exhaust ventilation might be required in the case of ware that was not cleaned within fifteen minutes of the application of the glaze4 ,such a requirement would prevent the practice now prevalent of painting as many as three dozen tiles1 piling them one on top of another1 and then proceeding to the operation of scraping4 ,no danger attaches to removal of glaze with a damp sponge or flannel1 but means must always be at hand for washing and damping them4 ,in the dipping-house1 7a7 impervious floors should be provided1 which could be washed down so as to prevent the risks from sweeping1 and from glaze drying1 and being raised as dust2 7b7 partial covering of the dipping-tub to prevent splashing and spray2 and 7c7 substitution for the overalls at present worn by persons in the dipping-house1 glost-placers1 millers and mixers of glaze1 majolica paintresses1 and others1 of overalls of some light waterproof material which could be sponged1 or of aprons of waterproof material worn in front of the overalls4 ,dipping-tubs and walls and floors in close proximity to them can with advantage be painted red4 ,dipping-boards should be washed with clean water after every time of use4 ,automatic machines for washing and scrubbing boards are in use in some factories4 ,to reduce risk or remove the danger of lead poisoning in this industry1 use of low solubility glazes or of leadless glazes are advocated4 ,on this point the ,lead ,committee say3 8,the effect of melting the lead with silicious matter amounts to imprisoning it in such a manner as to render it less liable to the action of the acids which it meets in passing through the human body1 and in consequence largely reduces the likelihood of its absorption into the blood4 ,if the frit is properly compounded1 all but a small fraction of the lead is rendered insoluble1 and glazes so made are spoken of as #8low solubility glazes4' ,the finished glaze generally contains from #ab to #bb per cent41 or more1 of lead oxide1 but after the process of fritting with sufficient silicious material only from #b to #e per cent4 remains soluble40,a ,a ,raw lead comprises red lead1 white lead1 and litharge4 ,if introduced in this form as a constituent of glaze it is soluble in dilute acids4 ,if1 however1 the raw lead is fluxed by heating with a part or the whole of the silica1 it is converted into 8fritted lead40 ,the solubility of the frit depends upon the relative proportions of material taken4 ,thorpe#bc1 as a result of numerous analyses of lead silicates 7after determining their solubility as regards lead71 both simple and complex1 in use in the potteries and on the ,continent1 found that the quantity of lead dissolved had no necessary relation to the quantity of lead in the silicate4 8,primarily and in the main the insolubility of the lead depends not upon any one oxide or group of oxides1 but upon the maintenance of a certain proportion between the whole of the basic oxides on the one hand and the whole of the acidic oxides on the other4 ,if the value of ratio bases_/acids is higher than1 or approximately equal to1 two1 the amount of the lead extracted is small1 but if it fall much below two1 the quantity of lead dissolved begins rapidly to increase40 ,on the subject of the use of leadless glazes1 the ,committee conclude that in all classes of pottery ware a great many articles can be manufactured in a very high state of perfection1 with reduction in the cost of production of certain classes of common ware1 such as jampots and ,persian painted ware2 but that in certain other classes1 owing to the excessive number of 8seconds10 their use would entail increased cost or sacrifice of quality1 so much so as to involve loss of important markets2 and1 finally1 that certain kinds of ware1 in consequence of difficulties relative to accuracy in reproducing old patterns1 colours1 or methods of decoration1 cannot at present be made at all without use of lead4 ,in the case of manufacturers who are able to conform to the ,thorpe test of low solubility--i4e41 glaze which yields to a dilute solution of hydrochloric acid not more than #e per cent4 of its dry weight of a soluble lead compound1 calculated as lead monoxide 7,pb,o7--important relaxation of certain special rules are allowed1 such as limitation placed on the employment of females and young persons1 and periodical medical examination of the workers4 ,h4 ,r4 ,rogers#bd1 one of ,h4,m4 ,inspectors of ,factories1 ,stoke-on-,trent1 has worked out a simple test to show approximately how much lead has been used in the glaze of a piece of pottery4 ,thus1 by treating glazes with hydrofluoric acid for forty seconds1 absorbing the liquid with filter paper1 precipitating the lead on the paper as the sulphate1 dissolving out the sulphate soluble in water1 and then precipitating the lead on the paper as sulphide1 stains are produced varying1 in depth of colour1 according to the proportion of lead in the glazes concerned 7see ,plate ,,iv474 ,briefly summarized1 the recommendations of the ,potteries ,committee in regard to the processes are-- ,manufacture of ,glazes4--,no handling of white or red lead without at least #e per cent4 of added moisture1 and no weighing out1 etc41 nor employment in the room1 to be allowed within thirty minutes of such weighing out1 etc41 without the wearing of a respirator4 ,lawning--i4e41 straining glaze so as to remove insufficiently ground material through a fine lawn sieve--to be done by an adult male only1 except where less than a quart of glaze is lawned4 ,dipping4--,impervious floors sloped towards a drain to be cleaned by an adult male1 after work has ceased1 with a jet of water and a mop4 ,walls adjacent to dipping-tubs to be tiled or painted with washable paint1 and cleaned daily4 ,dipping not to be done where artificial light is necessary during hours of daylight4 ,threading-up and ,thimble-picking to be done in a room sufficiently separated from any place where scheduled processes are carried on4 ,drying ,ware after ,dipping4--,the same requirement as to floors as in dipping-house4 ,boards4--,to be cleaned with clean water by an adult male after each time that dipped ware has been placed on them and before subsequent use4 ,boards for use in lead processes to be painted red at the ends4 ,mangles4--,ventilation to be so arranged as to maintain a flow of air into the hot chamber from the workroom4 ,mangle shelves to be thoroughly wet cleansed once a week4 ,ware ,cleaning4--,local exhaust ventilation to be applied except when the process is carried on entirely with use of wet materials 7damp sponges1 etc471 or when done within fifteen minutes of application of glaze4 ,troughs to be provided to collect glaze1 and to be cleaned out and supplied with fresh water at least once a week4 ,the floors and standard of lighting to be the same as for the dipping-house4 ,glost-placing4--,boards to be treated as already described4 ,floors to be impervious4 ,women1 young persons1 and children to be excluded1 except that women to be allowed to place china furniture and electrical fittings4 ,majolica ,painting and ,mottling4--,a sponge and clean water to be placed beside each paintress2 special washing accommodation in the painting-room or adjoining it2 splashes to be removed immediately by wet sponging4 ,work-benches and floors to be subject to the same conditions as potters' shops4 ,flow ,material--i4e41 the substance usually containing much lead in the form of powder and placed in the sagger to cause certain colours applied to biscuit ware to run slightly--to be weighed out in front of an exhaust draught and delivered to the glost-placer by an adult male4 ,,plate ,,iv ,illustration3 ,,fig4 #a4--,,no ,,lead ,,used4 ,illustration3 ,,fig4 #b4--;,,fritted ,,lead ,,used4 #ji per cent4 solubility4 ,illustration3 ,,fig4 #c4--;,,fritted ,,lead ,,used4 #ae per cent4 solubility4 #aci per cent4 total lead4 ,illustration3 ,,fig4 #d4--;,,fritted ,,lead ,,used4 #ej per cent4 solubility4 #ej per cent4 total lead4 ,illustration3 ,,fig4 #e4--,,raw ,,lead ,,used4 #aid per cent4 solubility4 #aid per cent4 total lead4 ,illustration3 ,,fig4 #f4--,,raw ,,lead ,,used4 #dda per cent4 solubility4 #deb per cent4 total lead4 ,illustration3 ,,fig4 #g4--,,rockingham 7,,raw ,,lead7 ,,used4 #eji per cent4 solubility4 #eji per cent4 total lead4 ,ground-laying1 colour-dusting1 and aerographing to be done under locally applied exhaust ventilation4 ,proper receptacles to be provided for cotton-wool used and waste cotton-wool to be burnt4 ,no short-sighted person to be employed to do either glaze or colour blowing1 unless wearing suitable glasses1 and certificate to this effect to be entered in the ,health ,register4 ,litho-,transfer ,making#be4--,transfers for the decoration of earthenware and china are made in special factories1 of which there are seven1 employing #beg persons4 ,the patterns are impressed in the ordinary chromo-lithographic fashion1 but as the enamel colours1 containing high percentages of lead1 are dusted either mechanically in the machine1 or by hand by means of a pad of cotton-wool1 danger from dust is great in the absence of maintenance of a negative pressure inside the dusting machine and an efficient exhaust draught behind the bench where the final dusting with flour1 to remove the superfluous colour1 is done4 ,in one factory1 before a fresh colour was applied to the adhesive pattern on the sheets1 the machines had to be cleaned as far as possible of the previous colour used4 ,to do this it was necessary for the attendant to enter a closed chamber at the back of each machine1 so as to supply the powder to the hoppers which feed the rollers1 or to clean them by means of a brush1 sometimes as often as every half-hour4 ,the upward exhaust ventilation applied to the interior of the machine tended to draw the dust created in brushing past the worker's face1 and led to severe incidence of poisoning4 ,the remedy suggested by ,pendock#bf was to dispense altogether with the need for entering the chamber1 to maintain a slight negative pressure inside the machine by downward exhaust1 and to remove the dust by means of a small vacuum cleaning plant4 ,at the same factory the flouring bench was in the same room as the machines1 and the locally applied exhaust drew its air-supply from the general atmosphere of the room4 ,apart from faulty arrangement of the exhaust ducts leading to effects of too local a character1 dust was drawn from other parts of the room1 including the machines1 so much so as to necessitate frequent cleaning of the glass hoods4 ,poisoning among those employed in flouring occurred4 ,to remedy this1 an air-grid with curved inlets at intervals of #b inches apart1 leading into a trunk in connection with a fan1 was placed along the back of the bench and under the top of the glass hood4 ,in order1 however1 that its action should not interfere unduly with the general ventilation of the room1 but be1 in large measure1 independent of this1 a somewhat similar grid1 introducing air from the street outside1 was fitted along the front of the bench4 ,the whole arrangement was operated by one suction fan4 ,ten cases occurred in this factory in the year before this arrangement was carried out4 ,in the three years since1 three cases only have been reported4 ,in the ten years #aijj-aiji1 #dh cases were reported among #beg persons employed4 ,vitreous ,enamelling#bg4--,surfaces1 such as sheet iron for advertisement signs1 cast iron for baths and gas stoves1 copper for copper letters and tablets1 brass for jewellery1 and glass for lettering and decoration1 are treated with glaze or enamel colours1 which1 either in the mode of application or subsequent treatment before final vitrefaction1 give rise to dust4 ,in the manufacture of advertisement signs1 glaze is swilled on to the sheet of iron4 ,after drying1 it is fired or vitrified1 and upon this surface as many other coats of glaze are applied as may be wanted4 ,as soon as the colour is dry1 lettering is effected by brushing away the dried 7but not fired7 glaze exposed through stencils4 ,dangers and ,prevention4--,exhaust ventilation for the removal of the dust is essential1 but it is1 unfortunately1 unable to draw the dust away when brushing is done at a distance of more than about #ah inches from the exhaust opening4 ,and some of the plates required are very large4 ,no exhaust-pipe has yet been invented which will follow the hand of the worker without impeding movement4 ,in consequence of severe incidence of poisoning1 mainly on young women who do the work of brushing1 when the process was first introduced with enamel glazes containing from #ae to #ge per cent4 of lead1 manufacturers quickly turned their attention to use of enamels free from lead4 ,for this class of work they appear to have been entirely successful1 and now lead poisoning is almost a thing of the past4 ,thus1 of #abb samples examined in #aiaj from factories claiming exemption from the regulations by reason of the use of enamels containing less than #a per cent4 of lead1 excess was found in three only#bh4 ,porcelain ,enamelling4--,the cast-iron bath or stove is heated to redness in a muffle furnace4 ,on withdrawal from the furnace it is placed by the helpers on a table capable of being turned in every direction4 ,enamel powder is then dusted on to the heated metallic surface through a sieve attached to a long wooden handle1 held by the duster1 who protects himself from the intense heat by a mask and an asbestos cloth covering4 ,illustration3 ,,fig4 #ab4--,the first glaze is sprayed on with an aerograph4 ,the portion of the stove to be glazed is shown on supports on the sliding table1 which is half out of the cabinet4 ,when the casting is fully in the cabinet1 the end piece and the centre piece close the cabinet sides1 and1 fitting on a felt beading1 make an air-tight joint4 ,the spray1 shown in front of the cabinet1 is worked through the holes in the glass front4 ,exhaust is provided at the top4 ,dangers and ,prevention4--,the heated column of air carries up much of the powdered glaze as it is unevenly distributed by jolting the handle of the receptacle1 and in the absence of very efficient exhaust ventilation this dust will1 as the current of air strikes the roof and cools1 fall down again4 ,the hood placed over the bath must have steep sides and be brought down as low as is possible without interfering with work1 and the duct leading to the fan must be unusually wide1 so as to be able to cope with the up-rush of heated air4 ,if the sides of the hood be shallow1 not only will the dust fail to be removed1 but the hood itself may become so hot as noticeably to increase the discomfort from heat to which the men are exposed during the three or four minutes1 five or six times an hour1 that the dusting operation lasts4 ,a method has been patented by ,m4 ,dormoy of ,sougland#bi1 ,aisne1 ,france1 for carrying out automatically in a closed chamber the process of dusting on to small red-hot castings1 such as are required in the manufacture of stoves4 ,it is not applicable for baths4 ,occasionally1 in the case of small castings1 again1 the enamel is sprayed on by means of an aerograph4 ,for this excessively dangerous process we have seen simple and ingenious devices for carrying it on quite safely in a space under negative pressure1 and covered in except for the necessary openings through which to work the spray 7see ,figs4 #ab1 #ac1 #ad74;,a ,a ,the cabinets have been patented by ,messrs4 ,wilsons and ,mathiesons1 ,ltd41 ,leeds1 by whom they are made and supplied4 ,since using them there has been no trace of illness among the persons employed4 ,illustration3 ,,fig4 #ac4--;,after firing the casting is lifted out for treatment with dry glaze1 which is sprinkled on with a sifter shown on the table4 ,the turntable enables the operator to manipulate the red-hot casting more easily4 ,white enamel powders free from lead are used entirely by some firms1 but the black and coloured enamels on stove grates contain lead4 ,a frit analyzed in the ,government ,laboratory was found to contain #bfff per cent4 of lead oxide4 ,the fact that all the lead used is in the form of a silicate1 even although the silicate is readily soluble in dilute acid1 tends1 we believe1 to cause incidence of poisoning to be less than might have been expected from the amount of dust often present in the air1 and attacks1 when they occur1 to be less severe1 as a rule1 than they would be were raw carbonate of lead alone used4 ,for the arduous work entailed the men are specially selected4 ,despite their exposure to lead dust1 the majority continue to work for many years without marked signs of lead absorption4 ,the management should provide a suitable room for the men to cool themselves in the intervals of dusting4 ,illustration3 ,,fig4 #ad4--,the cabinet is shown when dry dusting is being done4 ,the casting is worked by tongs through a slot in the side of the cabinet 7not seen71 while the worker dusts the casting with his arms through the two front holes4 ,he can see his work through the square pane of glass4 7,photographs kindly made by ,mr4 ,f4 ,w4 ,hunt1 ,leeds47 ,manufacture of ,electric ,accumulators#cj4--;,electric accumulators are secondary batteries which serve for the storage of electricity1 in order to allow of a current when desired4 ,a primary battery is one in which the materials become exhausted by chemical action1 and1 unless a portion or the whole of the materials is renewed1 fails to supply electricity4 ,the secondary battery becomes exhausted in the same way1 but the chemical contents are of such a nature that it is merely necessary to pass a current of electricity through the battery 7charging7 in order to recharge them4 ,in the accumulator battery the positive element is peroxide of lead1 and the negative element spongy lead4 ,the elements--several positive connected together and several negative--are placed in dilute sulphuric acid contained in vessels of glass4 ,the form of accumulator in almost universal use now is the pasted plate1 but it varies greatly in size1 according to the use for which it is required4 ,it may be either large1 to act as an equalizer or reservoir of current in electric-lighting installations1 or quite small for ignition purposes in motor-cars4 ,the litharge smeared on to one plate becomes converted into the positive element1 peroxide of lead1 during what is called the 8forming process0 7passage of the electric current through the dilute sulphuric acid solution in which it is placed71 and red lead smeared on to the other becomes spongy lead to form the negative4 ,the industry gives employment to about #a1bjj persons4 ,plates are first cast in moulds from a bath containing molten lead or of lead with admixture of antimony4 ,irregularities in the plates so cast are removed by a saw or knife 7trimming71 and sometimes filed or brushed with a wire brush4 ,the interstices in the plates are next filled in by means of a spatula with paste of litharge or red lead1 as the case may be1 which has been previously mixed either by hand at the bench or in a special mechanical mixing machine4 ,after drying1 the plates are removed to the formation room to be charged4 ,to allow of the passage of the current1 positive elements are connected together1 and negative also1 by means of a soldering iron or1 more frequently1 of an oxy-hydrogen blowpipe flame4 ,after formation is complete the plates have to be built into batteries1 or 8assembled40 ,tailpieces1 technically known as 8lugs10 have to be connected with each plate1 effected usually by the oxy-hydrogen blowpipe flame4 ,finally1 a connecting bar of lead is cast on or burnt on to the lugs4 ,dangers and ,prevention4--,in casting1 danger is mainly from dust in depositing the skimmings1 and from fume also when old accumulator plates are melted down4 ,for these reasons exhaust ventilation over the melting pots should be provided1 embracing also 7by branch ducts if necessary7 the receptacles into which the lead ashes are thrown4 ,in mixing and pasting1 the danger is from dust of oxides of lead to be controlled 7see ,fig4 #f7 by--7#a7 ,exhaust ventilation by branch ducts protecting 7a7 the barrel from which the material is scooped1 7b7 the mechanical mixer into which the weighed quantity of oxide is discharged1 7c7 the bench at which the mixing by hand is done2 7#b7 dampness of benches and floor to prevent raising of dust either by manipulation of the 7often7 heavy plates or trampling into powder the paste which may fall on the ground4 ,in assembling or putting together of the formed plates1 and in earlier stages of the manufacture also1 filing or use of a wire brush causes production of metallic lead dust and of the oxides when the brush touches them--a danger only to be met by exhaust ventilation4 ,how far the poisoning to which the lead burners engaged in assembling plates is attributable to lead fume1 produced by the high temperature of the blowpipe flame1 and how far to handling 7with inevitable dislodgment of dust7 has not been satisfactorily settled4 ,incidence of poisoning on this class of worker in the past has been marked4 ,generally there is need for impervious floors1 solidly built1 so as to prevent vibration and the raising of dust from passage of trolleys conveying the heavy plates4 ,gloves are frequently provided1 more to protect the hands from contact with the sulphuric acid used in making the paste and jagged edges of the plates than as a preventive of lead absorption4 ,in the #aj years #aijj-aiji incidence1 according to precise occupation1 has been--,casting1 #cc2 pasting1 #aad2 lead burning1 #fi2 and assembling the plates1 etc41 #fi4 ,glass-,cutting#ca4--,red lead enters largely into the mixture of raw materials for the manufacture of glass4 ,flint glass1 for instance1 contains #dc per cent4 of lead4 ,the raw materials 7white sand1 red lead1 and generally saltpetre7 require to be very carefully mixed1 and a few cases of poisoning have been reported from the dust raised in sieving4 ,one man works the sieve1 resting on two runners across the bin1 while another shovels the mixture into the sieve4 ,the operation is not a continuous one1 and respirators have principally been relied on to protect the workers4 ,it should be possible to carry out the mixing operations in a dust-tight closed apparatus4 ,poisoning from lead fumes generated in a glass furnace is unknown4 ,lead poisoning used to be common in the process of polishing cut glass on a brush by means of 8putty powder0 7oxide of tin1 #bi per cent42 and oxide of lead1 #ga per cent471 mixed with water to the consistency of a paste4 ,the brush was made to revolve at high speed1 with dissemination of the putty powder as a fine spray into the atmosphere of the workroom4 ,although rouge and oxide of iron have replaced putty powder to some extent--especially for the polishing of the bevelled edges of plate glass--no substitute can at present be found to give the final lustre and brilliancy required in the case of cut glass and in certain kinds of high-class work1 such as polishing lenses4 ,locally applied exhaust ventilation has robbed the process of its dangers4 ,pyramidal-shaped hoods enclose the spindle and putty box and brush before which the workman sits4 ,the draught of the fan prevents escape of spray4 ,the lad who feeds the brush with putty powder stands at the side1 and in our experience his cap and clothes are now free from signs of splashing4 ,formerly the polishing was done by each man at his own berth1 thus endangering the health of all working in the vicinity1 as the custom of the trade is that the same man carries through the work both of cutting and polishing4 ,polishing occupies only about a fifth of a man's time1 and it has now1 owing to the position of the fan1 to be carried out in one particular part of the room4 ,dr4 ,d',arcy ,ellis#cb1 ,certifying ,surgeon for the ,stourbridge district1 has described the processes as formerly carried out3 8,the mixture of lead and tin is heated over a bright fire in a shallow iron pan4 ,as it melts1 the top scum which forms is skimmed off1 dried1 pounded to a powder in an iron mortar1 and afterwards sieved4 ,the person who does this work always suffers more or less4 ,he usually protects himself by wearing a respirator--there is a good draught at the flue1 and the sieve is enclosed in a box--but there is always a certain amount of dust4 ,this putty-powder is used on the wooden wheel1 and is dabbed on the wheel as it revolves4 ,all good bold work can be polished in this way1 and there is not much risk to the workman1 as the speed at which the wheel revolves causes the mixture to cling and not fly about4 ,this process does not answer for any fine work1 so it is contended2 and to enable this kind of work to be properly polished brushes made of bristles are used4 ,they are mounted on an iron spindle1 and are usually about #f inches to #g inches in diameter1 with a face of #a inch to #a inches broad4 ,they are driven at a speed of about #b1jjj revolutions a minute4 ,the putty powder is applied to these brushes 7which are of various sizes7 in the same way as to the wooden wheel--that is1 by dabbing it on4 ,for smaller work1 such as tumblers and wine-glasses1 the workman applies the putty mixture himself1 holding the glass against the brush with his right hand1 and using his left underneath to apply the mixture4 ,where1 however1 larger work has to be done in which the workman cannot manage with one hand1 the service of a boy is called in1 who does what is called the #8feeding up4' ,this boy stands partly in front and partly at the side of the brush1 and applies the mixture with one hand with the wisp of straw4 ,in this position the boy gets splashed with the putty mixture which flies off the brush1 and it is generally believed by the workmen to be the most dangerous occupation4 ,at one time--not very long ago--all the various processes of the work were done indiscriminately in the workshop1 and consequently the men were frequently found working in a perfect haze of fine dust1 which had been thrown off from the brushes4 ,there was no attempt made to separate and detach the less injurious part of the work1 such as the roughing and cutting1 from the general workshop1 the lead polishing only occupying about one-fifth of the workmen's time4 ,after the glass has been polished by the putty it is taken away to another department1 where girls are employed as #8wipers out4' ,they take the glass with the dried putty upon it1 dip it into a basin of water1 and then wipe it dry4 ,some of these girls have been known to suffer from lead poisoning4444 ,drop-wrist was frequently to be seen--in fact1 there was hardly a workshop in the district in which cases of wrist-drop could not be found4 ,they were all anmic1 and the albuminuric and prematurely aged were frequently met with40 ,in this small industry in the past the poisoning must have been considerable4 ,in #ahih nineteen cases were reported4 ,reference to the table on p4 #dg shows that the number now is greatly reduced4 ,those reported are generally cases which have ended fatally from the sequel of lead poisoning contracted many years previously4 ,stained-glass painting--a form of vitreous enamelling--very rarely gives rise to poisoning1 as no dust is generated 7see vitreous enamelling for use of aerograph in glass-painting74 ,paints and ,colours#cc4--,most of the cases have occurred in the manufacture of white-lead paint1 although manufacture of chromate of lead and of ,brunswick greens 7barytes with which ,prussian blue and chrome yellows are mixed7 account for several4 ,the following table shows the precise occupation of persons affected1 the number of cases distributed according to precise occupation1 and the proportion of these to the total in #bbe cases which were closely examined3 ---------------------------------------- ---------------------- ,number of ,cases ,proportion of ,precise ,occupation in each ,cases to ,total of ,person affected4 ,subdivision4 7per ,cent474 ---------------------------------------- ---------------------- ,mixing and grinding 7mainly of white #add #fdj lead7 ,packing 7mainly of red lead7 #ai #hd ,sieving #b #ji ,manufacture of chrome yellow #bb #ih ,colour house and filters #af #gb ,painting and stencilling #f #bg ,other processes #af #gj ---------------------------------------- ---------------------- ,knowing the conditions of work1 we can confidently assert that the poison must have entered the system in the form of dust in at least #ijj per cent4 of the cases1 and in the remainder the possibility of dust having been the cause is not excluded4 ,in a small factory the cask of white lead is broken and the material scooped out into a pail4 ,scales are at hand1 and when the amount of lead removed weighs half a hundredweight the contents of the pail are discharged either into a cylindrical pug-mill or into the pan of an edge-runner to be mixed with oil4 ,in large factories the dry white lead is generally shovelled directly from the cask down openings or shoots in the floor to the grinding mills below4 ,dangers and ,prevention4--,dust arises in unheading the casks from the displacement of air following the scooping or shovelling out of the lead1 in filling the pails1 and in discharging the lead into the mill4 ,all points should1 and can1 be adequately protected by locally applied exhaust ventilation at each one of the points enumerated4 ,a telescopic arrangement of the branch duct in connection with the barrel enables dust generated in scooping out to be removed as the contents of the barrel get lower and lower 7see ,fig4 #ae74 ,illustration3 ,,fig4 #ae4;,a ,a ,,fig4 #ae shows the arrangement for preventing dust at every point where it is produced in a factory where dry colours are ground1 sifted1 and packed on a large scale4 ,on the upper floor1 the chamber is shown in which the contents of a cask are tipped down a shoot leading in the one case to the burr stone mill on the left1 and in the other into the ,blackstone sifters4 ,exhaust is arranged at two levels to catch the dust arising from the displacement of air4 ,after grinding in the closed-in burr stone mill1 a hood and duct is arranged over the point where the material is discharged into the barrel4 ,similarly1 the casing of the two ,blackstone sifters is connected with the exhaust fan1 and also the cover of the barrel into which the ground material falls4 ,inside the edge-runner 7the door of which is shown open7 a negative pressure is maintained1 and one branch duct controls the dust in the scooping out of the material from the barrel1 while another is connected to the cover of the receptacle into which the ground material is discharged4 ,tapering of the ducts1 tangential entry of branches1 fan-box1 and collecting filters1 are all shown4 ,in the factory in question there are four edge-runners1 three burr stone mills1 and two ,blackstone sifters4 ,altogether exhaust ventilation is applied at twenty-five points4 7,drawing kindly supplied by the ,sturtevant ,engineering ,company1 ,limited1 ,london47 ,the lighter shades of yellow chrome are made by a cold precipitation process1 or 7as is usual for the deeper shades of chrome1 orange1 and red7 by boiling the ingredients--lead acetate1 pulp white lead1 bichromate of potash and soda1 and sulphate of soda--while barytes is added as the colour is being made4 ,danger in the first method does not arise 7or only in minor degree when steam is injected to bring about more speedy solution7 until drying and grinding 7in edge-runners71 sieving1 and packing1 are effected4 ,the dust1 when inhaled1 is quickly absorbed1 and in all these dry processes danger1 in the absence of very carefully thought out exhaust ventilation1 is great4 ,in processes involving ebullition1 danger is present in the steam which carries up with it chromate of lead in fine particulate state4 ,vats and vessels1 therefore1 in which the boiling is effected require partial hooding over and connection of the hood with an efficient exhaust4 ,in subsequent wet processes of pressing the cakes of chromate of lead1 the hands1 arms1 and overalls become thickly coated with pigment4 ,danger from chrome greens is practically limited to the dust created in dry grinding1 usually effected in large edge-runners4 ,for references1 see end of ,chapter ,,xvii4 ,,chapter ,,xvii ,,description ,,of ,,processes--,continued ,coach-,painting#cd4--,lead poisoning is peculiarly prevalent in this industry1 and no corresponding reduction in the number reported can be observed from year to year 7see the table on p4 #dg71 or in the many industries grouped under the heading1 8,paint used in ,other ,industries10 such as is noted for lead industries taken as a whole4 ,of the #fig cases included in returns during the ten years #aijj-aiji1 #ceb were reported from railway carriage and waggon works1 #bii from ordinary carriage works and wheelwrights' shops1 and #df 7separate tabulation was only commenced in #aije7 in motor-car works4 ,in the year #aijc inquiry was made in #fjc factories and workshops1 including all classes of coach and carriage building1 railway carriage and engine works1 and agricultural implement works4 ,information was asked 7among other things7 as to--7#a7 ,the number of persons employed in painting with lead paints2 7#b7 description of the method adopted for smoothing the coats of paint2 and 7#c7 the substitutes tried for white-lead paint4 ,persons employed numbered #i1fjh4 ,in #eb factories and workshops smoothing of the coats of paint was not practised1 while in the remaining #eea it was affirmed that a wet method alone 7pumicestone and water7 was used in #agh1 a dry method alone 7sandpaper7 in #ci1 and both wet and dry methods at some stage or other of the work in #ccd4 ,substitutes were mentioned as having been tried in #id instances1 but this was almost exclusively for filling and jointing1 and not for the first or priming coat4 ,the figure #agh 7wet method alone7 is probably much too high1 because1 while it is true that pumicestone and water alone are used for the flat surfaces of the body--the bulk of the work--dry sandpapering of the first two priming coats and of the final finishing coats 7when of white1 cream1 or yellow colour71 of the under parts of carriages1 iron chassis of motor-cars1 and of curved surfaces1 such as the spokes of wheels1 is almost universal4 ,the reason for thus treating the priming coat dry is that a wet process would raise the grain of the wood4 ,the #eb factories in which it was stated that no smoothing was done were nearly all premises for the repair or manufacture of railway trucks1 requiring no special finish1 and the #ci factories in which only sandpaper was said to be used in smoothing were premises in which rough1 cheap1 or common vehicles1 such as carts1 were made4 ,use of sandpaper is quicker and less expensive than use of pumicestone1 and water and wet methods cannot be used very well on iron surfaces4 ,in ordinary coach and carriage painting1 after the sandpapering of the first two priming coats1 six or seven coats of 8filling0 7usually ground slate mixed with gold size and turpentine7 are applied1 and each coat is rubbed down wet4 ,joints and interstices of woodwork and irregularities in iron surfaces are generally filled in with a stopping or paste of white lead1 in the smoothing of which sandpaper is used4 ,in the manufacture of motor-cars1 the terne 7lead7 coated sheets which form the body1 after preliminary preparation1 receive two coats of a lead paint4 ,these are either lightly sandpapered or 8flatted0 with pumice and water4 ,three coats of non-poisonous filling follow1 and are flatted with pumice or ,german brick and water4 ,the body then passes to a skilled workman1 who applies the final coats of colour4 ,for facing mouldings and for corners throughout all stages of the processes1 dry sandpaper takes the place of pumice and water4 ,all stopping on the chassis1 the first lead coat on the bonnet1 and all coats of paint on the wheels1 are sandpapered dry4 ,sometimes a third of a man's time may be taken up in sandpapering alone4 ,dangers and ,prevention4--,grave risk of inhaling lead dust is present 7see the table on p4 #dg7 when sandpaper is used1 often at a point just above the mouth and nostrils4 ,rubbing down the wheels is perhaps the most dangerous work1 and for this exhaust ventilation can be applied locally4 ,inventive genius has yet to be directed to some modification of the vacuum-cleaning apparatus1 so that an exhaust can be attached to the back of the worker's hand or in connection with a frame in which the sandpaper is held4 ,in the process of wet rubbing1 the abraded coats drip on to the floor1 and when dry may rise as dust into the atmosphere4 ,precisely similar operations1 or only modified in detail1 have accounted for heavy incidence of lead poisoning in the painting of perambulators1 of safes1 of bicycles1 of bedsteads1 of gas-meters1 the 8metallic0 enamelling of baths 7in which also chipping off of the old paint not infrequently occasions an attack71 in engineering and machine-making works1 in cabinet and furniture making1 in ,french polishing1 in the making of artists' canvases1 etc4 ,several cases are reported among railway employees engaged in the painting of bridges1 girders1 and signal-posts4 ,a method for the removal of the dust given off in these processes has not yet been arranged4 ,chipping off of old paint can be effectually replaced by solvent solutions1 in the use of which1 as they are very inflammable1 precautions against naked lights are necessary4 ,in the making of better-class measuring tapes1 the tape1 after passage through the white-lead mixture and drying1 is made to travel through a machine to remove roughnesses1 and subsequently through the fingers of the worker1 protected by leather4 ,dust arises in both the last operations1 and requires to be removed by exhaust ventilation4 ,similar means of prevention are necessary wherever paint is applied1 as in photo-engraving1 and colouring artificial flowers by means of an aerograph instrument4 ,owing to the limited extent to which exhaust ventilation is possible1 reliance must be placed on substitution of wet processes for dry wherever possible4 ,cleanliness of floors requires special attention4 ,although in all painting operations dust is the most potent cause of poisoning1 we would assign to contamination of the hands and the eating of food with unwashed hands a more prominent place as a cause than in any of the other processes involving use of lead or lead colours4 ,in a post-mortem on a sign-painter employed only a few days1 made three weeks after his cessation of employment on account of an attack of encephalopathy1 paint was found thickly adherent under the nails4 ,substitution of colours containing no lead suggests itself as a simple remedy1 but the progress in this direction made so far in the industries mentioned is limited4 ,several important firms manufacturing motor-cars use no lead colours at all2 more than one important railway company 7the outside of the carriages of which has no white colour7 and a few makers of perambulators do the same4 ,it is difficult to obtain knowledge how far leadless are replacing lead colours4 ,in the manufacture of cornice poles 7in which small industry several severe attacks were reported7 the suggestion of a factory inspector to employ lithopone was adopted1 with entire success4 ,a patent graphite has been substituted for orange lead1 with which wooden patterns to form the moulds of articles to be subsequently cast in metal are frequently painted4 ,house-,painting#ce4--,the work of house-painting and plumbing outside a workshop does not come under the ,factory and ,workshop ,act1 #aija1 except to a limited extent under ,section #aje in buildings in course of erection2 and even in that case the requirement of notification of lead poisoning imposed by ,section #gc does not apply4 ,if1 however1 a house-painter is employed for part of his time in mixing paints in a workshop belonging to a builder1 then the question may legitimately be raised as to whether plumbism may not have been due in some measure to such workshop conditions4 ,despite the limited extent to which the ,act applies to lead poisoning of house-painters and plumbers1 seeing that it is industrial in origin many practitioners notify cases1 with the result that the number every year exceeds considerably that from any other lead industry in the country4 ,thus1 the number notified in the ten years #aijj-aiji was #a1igc1 including #chc deaths4 ,the proportion of deaths to persons notified is much higher than for lead industries generally 7#aid per cent41 as compared with #dj per cent474 ,if the proportion of cases to deaths were the same in house-painting as in other industries 7and it is a fair assumption to make71 the number of cases would be #i1dah4 ,when investigation is made into the reported cases1 the pre-dominance of the severer symptoms--paralysis1 brain symptoms1 and chronic plumbism--is brought out4 ,causation of poisoning1 in order of importance1 appears to be3 7#a7 ,dust from sandpapering one surface of paint before applying another2 7#b7 dust from mixing dry white lead with oil2 7#c7 dust arising from paint that has dried on overalls2 7#d7 contamination of food with unwashed hands2 and 7#e7 fumes from burning off old paint4 ,use of ,leadless ,paints4--,opinion still differs as to the feasibility of substituting zinc sulphide or zinc oxide 7or a combination of the two7 for white lead in paints1 in spite of elaborate investigation of the point by commissions of inquiry appointed notably by the ,french1 ,austrian1 and ,dutch ,governments4 ,there is1 however1 general consensus of opinion that for the painting of internal surfaces of houses and of all surfaces which are not exposed to the weather zinc paints have the advantage 7apart from their non-poisonous quality7 over white-lead paint of not changing colour4 ,the technique for applying zinc oxide paint differs much from that for applying white lead4 ,being much less dense1 it requires to be ground with a greater proportion of oil1 and the vehicles and driers necessary for the thinning of the stiff paste are different from those ordinarily used for thinning and mixing white lead4 ,coats of zinc oxide should be applied as thin as possible1 and hence there is the drawback that where three coats of white lead will suffice1 four coats of zinc oxide may be necessary unless the paint is skilfully applied4 ,the best method of applying zinc oxide paint with the brush has to be learnt in order to get the best effect4 ,the ordinary house-painter1 therefore1 accustomed to the use of lead paint1 cannot expect to obtain the same result from zinc paint treated in the same way4 ,and zinc oxides differ in value as pigments according to the methods of production4 ,that obtained by direct roasting of the ore 7franklinite and zincite7 is superior to that prepared by the indirect method of oxidation of spelter4 ,zinc sulphide enters into the composition of many white paints mixed with zinc oxide1 barytes1 and often lead sulphate4 ,its defect in colour is thus concealed1 and it adds to the mixture the important property known to the painter as 8body40 ,under a variety of names1 such as 8,orr's enamel white10 8patent zinc white10 and 8lithopone10 such mixtures have a large sale1 and for many purposes can act as a substitute for white-lead paint4 ,extensive inquiries have been made in recent years in ,continental countries into the effect of use of white-lead paint in producing plumbism1 the processes employed1 and the possibility of substitutes--in ,austria1 from #aijd to #aijg2 in ,germany1 in #aije2 in ,holland1 from #aijc to #aiji2 in ,france1 from #aija to #aiji2 in ,switzerland1 in #aijd2 and in ,belgium1 from #aijd to #aiji4 ,in #aijb the ,french ,government1 by a decree applying to house-painting1 prohibited 7#a7 use of white lead except when ready mixed with oil2 7#b7 direct handling of white lead2 7#c7 dry-rubbing or sand-papering of painted surfaces2 and required 7#d7 provision of the usual means for cleanliness1 including overalls4 ,this decree in #aijd was extended to all kinds of painting with use of white lead4 ,finally1 in #aiji1 a law1 to take effect from #aiad1 was passed prohibiting the use of white lead in paint altogether4 ,in ,belgium1 following on regulations issued under royal decree in #aije1 in which1 among other things1 quarterly periodical medical examination of house-painters was required1 the law dated ,august #bj1 #aiji1 came into force1 prohibiting the sale1 transport1 and use1 of white lead in the form of powder1 lumps1 or small pieces1 and requiring1 if intended for the purpose of painting1 the white lead to be mixed ready ground in oil4 ,dry-rubbing and sandpapering are also prohibited4 ,in the ,german ,empire the work of house-painting is controlled by regulations dated ,june #bg1 #aije1 of which the following are the main provisions3 7#a7 ,prohibition of actual contact with white lead in grinding and mixing1 and adequate protection from the dust so created2 7#b7 mechanical incorporation of the white lead with the oil or varnish1 and prevention of the escape of dust into the workroom2 7#c7 preliminary moistening prior to scraping1 chipping off1 or rubbing down1 dry oil colours2 7#d7 and 7#e7 provision of overalls and washing accommodation1 including soap1 nailbrushes1 and towels 7in erection of new buildings the workmen must be able to wash in a place free from frost72 7#g7 instruction of the workman by the employer as to the risk attaching to the work by supplying him with a copy of the regulations and cautionary notice4 ,further1 where painting operations are carried on in factories or workshops as subsidiary to other processes1 there must be 7#h7 provision of washing accommodation in a special room capable of being heated1 and of a place in which to keep clothing2 7#i7 periodical medical examination at half-yearly periods2 and 7#aj7 prohibition of smoking and consumption of alcohol in the workrooms4 ,the ,austrian ,regulations1 dated ,april #ae1 #aiji1 follow the ,german ,code closely1 but differ in that they 7#a7 prohibit the use of white lead paint for the interior surfaces of houses or of any surfaces not exposed to the weather2 7#b7 affixing of a notice on the can or cask that it contains lead2 and 7#c7 periodical medical examination at quarterly instead of half-yearly periods4 ,at the present time committees appointed by the ,home ,office are inquiring into the coach-painting and house-painting industries in this country4 ,the results of careful and detailed experiments made by the ,white ,lead ,commission appointed by the ,dutch ,government1 which inquired into the subject1 are summarized as follows3 ,i4 ,zinc-white paints are much better able to withstand the action of sulphuretted hydrogen gas than white-lead paints4 ,,ii4 ,zinc-white paints do not withstand the action of sulphurous acid in the atmosphere as well as white-lead paints4 ,as this gas is present in coal-smoke of locomotives1 steamers1 tall chimneys1 etc41 zinc-white paint much exposed to such smoke--for instance1 in railway-stations1 etc4--will soon become corroded1 and cannot then replace white lead4 ,,iii4 ,zinc-white paints applied on zinc1 ,portland cement1 or iron 7the latter having previously been provided with first coats of red oxide of lead or iron71 are able to withstand the action of the open air for a space of five years quite as well as white-lead paints1 and can entirely replace the latter1 provided they are not exposed to the action of vapours containing sulphurous acid4 ,,iv4 ,in the interior of buildings zinc-white paints1 applied on wood1 iron1 zinc1 ,portland cement1 and plaster1 are as good as white-lead paints2 and can entirely replace the latter1 provided they are not exposed much to vapours containing sulphurous acid or to much damp4 ,v4 ,zinc-white paints applied on wood1 if not exposed much to the action of sulphurous acid gas1 will in many cases last during five years in the open air as well as white-lead paints1 and can replace the latter with good results4 ,but in all places where water accumulates1 as on window-sills1 the lower side of cornice-work1 etc41 they will1 even after three or four years1 deteriorate to such a degree that repainting will become necessary for the preservation of the wood2 in this respect1 therefore1 they are inferior to white-lead paints4 ,,vi4 ,zinc-white paints1 such as the ,white ,lead ,commission have used successfully1 cover at least equally as well as the white-lead paints customary in this country4 ,the zinc-white putty used by the ,white ,lead ,commission is quite as serviceable as ordinary white-lead putty4 ,,vii4 ,painting with zinc-white paint1 such as the ,commission used on new woodwork in the open air1 does not cost more than painting with the white-lead paints customary for that purpose4 ,,viii4 ,painting on existing paintwork1 so-called 8repainting10 in the open air1 with zinc-white paints such as the ,white ,lead ,commission used1 costs more than the white-lead paints hitherto in use1 inasmuch as the preparation of the wood painted with zinc-white paints involves greater expense in rendering it fit for the repainting than in the case of wood painted with white lead in rendering it fit for further painting with white lead4 ,in the case of painted wood which is exposed to the open air1 the possibility is1 moreover1 not excluded that1 where such wood is in an unfavourable condition of humidity 7see under ,v471 it may have to be repainted sooner than if it had been painted with white-lead paints4 ,in these circumstances the cost of maintenance of wood painted with zinc-white paint1 and exposed to the open air1 is further increased as compared with wood painted with white-lead paint4 ,,ix4 ,lithopone paints cannot replace white-lead paints in the open air2 they have proved to be quite unfit in this respect4 ,x4 ,for paintwork above water1 first coats of oxide of iron have1 during five years1 proved to be quite as good and serviceable as first coats of red oxide of lead4 ,for coats of paint under water1 oxide of iron cannot be used4 ,coats of oxide of iron paint are cheaper than coats of red oxide of lead paint4 ,when oxide of iron is used for the first coat1 much more technical skill is required for the painting of the covering coats than is the case when red oxide of lead is used for the first coat4 ,shipbuilding#cf4--;,cases arising in shipbuilding are due not so much to mixing the paints or red-lead paste as to the dust produced in sandpapering the coats of white paint applied in cabins1 etc41 in chipping and scraping off old red-lead paint1 often in confined spaces such as double bottoms1 tanks1 bilges1 etc4 ,splashing from injecting red lead between plates1 fumes from burning off old paint1 and fumes from paint while using it in confined spaces1 are mentioned in reports4 ,several attacks have occurred to persons engaged in inserting red-hot rivets into holes containing yarn soaked in red lead and oil4 ,lead fumes1 it is suggested1 are given off4 ,the number of cases included under this heading each year has been-- #aijj #cb #aija #bh #aijb #ae #aijc #bd #aijd #dh #aije #cb #aijf #bf #aijg #bb #aijh #ae #aiji #bg #aiaj #ba ,the figures illustrate the difficulty of obtaining a reduction in the attacks when the cause is to be found in conditions not amenable to control by exhaust ventilation4 ,the possibility of effecting some reduction by such precautions as can be adopted is suggested by the diminution 7from #aaj to #fj7 in the number of cases in the ,government dockyards in the six years #aije-aiaj and #ahii-aijd respectively1 as compared with the increase 7from #fg to #hg7 in all other shipbuilding yards4 ,in the ,government dockyards1 among other precautions1 men employed on red-leading appear before the medical officer periodically1 and no man is allowed to do the work for more than two days a week4 ,further1 oxide of iron paint is to be used in the double bottoms1 wing passages1 and other confined spaces on board ships4 ,all men employed as painters are allowed five minutes out of their working time for washing4 ,other ,industries4--,the industries and processes which are gathered together under this head will be seen from the following distribution3 ,industries4 ,cases 7,ten ,years3 #aijj-aiji74 7#a7 ,iron drums and kegs #dg 7#b7 ,harness furniture #bc 7#c7 ,tempering springs #ac 7#d7 ,other contact with molten lead #ajc 7#e7 ,metal sorting #ac 7#f7 ,handling lead and dust from metallic lead #abb 7#g7 ,shot-making #ad 7#h7 ,glass-making #ac 7#i7 ,india-rubber #bc 7#aj7 ,yarn-dyeing #bh 7#aa7 ,copper letters and opal signs #bh 7#ab7 ,other lead compounds #aif 7#ac7 ,miscellaneous #cf --- ,total #fei 7#a7 and 7#b7 have been described under tinning of metals1 as the processes are similar1 and in the year #aiji they were included along with tinning of hollow-ware under the same code of regulations4 ,tempering of steel buffer springs 7#c7cg1 carried on in ,sheffield1 gives rise to poisoning from fumes of molten metal into which the springs are immersed1 and from dust of skimmings1 unless there is efficient hooding and exhaust4 ,a sample of dust collected from a lampshade over a melting-pot was found in the ,government laboratory to contain #dha of metallic lead1 or #eah per cent4 of lead monoxide4 ,in testing the springs under a hydraulic press1 and subsequent straightening by hammering on an anvil1 the thin coating of lead on the surface scales off1 and may be inhaled4 ,other contact with molten metal 7#d7 includes operations which do not differ from several already described1 in which danger is incurred from either fumes and dust in skimming the dross or subsequent handling1 such as manufacture of solder1 coating cables1 filling copper cylinders with molten lead for the purpose of bending them1 and subsequently re-immersing them in the bath to melt out the lead1 tinning of nails1 making lead patterns for fenders 7in which there may be danger1 also1 from use of a wire brush to get rid of adhering sand71 etc4 ,handling lead and dust from metallic lead 7#e7 includes operations such as die-stamping1 stamping tickets and other articles on a leaden slab 7where the danger is akin to1 though probably less in degree than in file-cutting71 examining bullets1 manufacture of metallic capsules1 lining boxes with sheet lead1 lead glazing 7where the danger is essentially that of plumbing work71 etc4 ,it includes also a number of cases which were reported previous to #aije in the markers of testing ranges at a small-arms factory4 ,duckering#ch1 who investigated these cases1 found that the bullets were stopped by dry sand in boxes #h feet long4 ,on entering the sand the bullets became disintegrated1 so that1 after being in use for some time1 the sand contained a large amount of lead1 and had to be removed4 ,in doing this the box was turned over1 and the sand deposited on the floor immediately behind the targets4 ,the lead was then separated by sifting by hand1 and the sand used over again4 ,in these operations much floating dust was produced1 which was inhaled by the markers1 who stood in an open trench immediately in front of and below the targets4 ,metallic ,capsules4--,some cases have occurred from the manufacture of capsules for bottles4 ,the capsule consists of a lead leaf rolled between two leaves of tin4 ,cases arising in the early processes of casting and rolling do not differ from those described as due to contact with molten metal and handling of lead4 ,the most difficult to deal with are those which occur in the final process of cleaning and colouring4 ,before colouring with varnish paint1 the capsule is placed on a rapidly revolving lathe1 and the hand of the worker1 carrying a cloth containing whitening1 is placed lightly on the capsule4 ,a slight amount of dust is inevitably raised1 and this dust1 collected from the bench1 was found to contain from #aae to #bef per cent4 of lead2 while dust which had settled on a beam #i feet from the floor contained #ic per cent4 ,of thirty-one workers employed in cleaning and colouring1 fifteen showed evidence of lead absorption in a blue line on the gums1 and in one there was considerable weakness of the left wrist4 ,similar experience of lead poisoning in this industry has been noted in ,german and ,austrian factories4 ,periodical medical examination at quarterly intervals has been instituted in the principal factory1 with good results1 as it enables those who show early signs of lead absorption to be transferred to other processes4 ,exhaust ventilation has been tried1 but1 except at the few lathes where cleaning alone is done1 without complete success1 in view of the nature of the work4 ,shot-making4--,cases in shot-making arise from the dust given off when sifting the shot into different sizes--an operation which should be carried on in sieves entirely closed in and under negative pressure4 ,dust collected from the glass casing over a sifting machine contained #fjc per cent4 of metallic lead4 ,the sample was free from arsenic4 ,heading of ,yarn dyed with ,chromate of ,lead4--,cotton yarn is dyed 7#aj7 on a considerable scale with chromate of lead1 chiefly for ,oriental markets2 and it is the orange chrome--that most heavily weighted with lead--which is most in demand there4 ,the orange chrome colour is obtained by dipping hanks of yarn into solution of lime1 and then into acetate of lead4 ,the process is repeated a second time1 after which the chromate is formed by dipping in bichromate of soda1 and finally boiling in lime-water#ci4 ,in production of yellow chrome colour1 the yarn is treated only once in a bath of lead acetate4 ,other colours made are lemon chrome and 7by addition of an indigo bath7 chrome green4 ,the early processes of dyeing rarely give rise to poisoning1 but the strong solution of bichromate of soda readily causes characteristic ulceration of the skin--8chrome holes40 ,danger arises from dust in the process of heading or 8noddling10 as it is sometimes called1 of the dried yarn over posts4 ,the hanks of yarn are tugged and shaken by women as a rule1 and in the case of orange chrome very considerable quantities of dust are liberated4 ,we have been told that a hank of this kind of yarn does not commend itself to an ,oriental buyer unless1 when shaken1 dust is visible4 ,the industry was certified as dangerous in #ahie1 in view of serious illness and death in ,glasgow and ,manchester1 and special rules were made to apply1 not only to the heading operations1 but also to the winding1 reeling1 and weaving1 of the dyed yarn--processes in which cases of poisoning are very rare4 ,detailed inquiry was made in #aijf in eleven factories where yarn was dyed on a considerable scale by means of chromate of lead--in eight mainly for export to ,india1 and in three for the home market4 ,yarn dyed for the home market gives off less dust when headed1 as the material undergoes additional washing in water and in dilute acid2 and it is also sometimes passed through a sizing of starch1 which fixes the chromate of lead to the yarn more securely4 ,proof of the greater danger from orange chrome is found in the fact that ,dupr was able to wash #a pound of dust 7#jbi per cent47 from #cde pounds of heavy orange yarn1 and only #a pound 7#jjc per cent47 could be washed from #c1cjj pounds of light yellow or green yarn4 ,in none of the factories were the workers engaged solely on the dangerous yellow and orange chrome-dyed yarn4 ,in some the work may last an hour or two every day1 in others for an hour or two every day in alternate weeks1 or for one week in every three or four weeks1 and perhaps in a dozen factories the work may not be done more frequently than half a day a month1 or even one in three months4 ,particular attention was paid to the nature of the exhaust ventilation at the 8heading0 posts1 as this is the most important point in the protection of the workers4 ,it was provided in eight out of the nine principal yarn-dyeing factories4 ,the exception was one where the work was said to be solely for the home market4 ,in one a #b foot #f inch ,blackman fan was placed in the wall without connection of the 8heading0 posts with it by means of ducts and hoods4 ,in four1 hoods and ducts of wood1 square in section1 with right-angle bends1 had been locally applied to the posts4 ,in other four1 hoods and ducts were of metal1 circular in section4 ,the velocities in feet per minute 7obtained with a ,davis self-timing anemometer7 were taken at the opening into the branch duct behind or under the post4 ,the value of anemometric tests in detecting blockages or interference in the ducts is evident from the table on p4 #cjj4 ---------------------------------------- -------------- 7#a7 7#b7 7#c7 7#e7 7#f7 7#g7 7#h7 7#aj7 ---------------------------------------- -------------- ,fan4,fan4 ,fan4 ,fan4 ,fan4,fan4 ,fan4 ,fan4,fan4,fan4 ,fan4,fan4 #bdj #hbj #ccj ,nil#a1bjj #dbj #dej #baj #ghj #egj #gjj #hej #dej #dej #bj #dbj #eaj #baj #egj #gjj #dhj #bgj #dej #bgj #ghj #cfj #dbj #cij #ffj #edj #dij #hej #dhj7gej7 #dbj #bgj #cfj #dbj #dcj #edj #egj #egj #dhj #ccj ,nil #bej #bgj #abj #dbj #eaj #edj #ecj #dej7ddj7 ,nil #cjj #cjj #abj #dij #edj #edj #cbd #cbj #cjj #ahj #cej #dhj #dej #cjj #cjj #dej #bhj7dbj7 #bej #aej #bij #dhj #dbj #cjj #dej #be #acj #cej #dcj #cij #eaj #dbj #be #bbj #ahj #dbj #cfj #dfj #djj #cfj #cjj #bdj #dbj #bdj #bhj #dej #dhj ,nil #baj #cij ,nil #baj #cij ,nil ,nil ---------------------------------------- -------------- 7#a7 ,the draught here was obtained from the main chimney-shaft4 ,the small velocities at the end post1 it was subsequently found1 arose from the fact that the double heading post was connected by means of a very small duct to the end of the large duct which served the other posts4 7#b7 ,wooden duct connected up with fan4 ,the area of the openings into the duct could be enlarged or diminished by means of a shutter4 ,the figures in brackets were those obtained when the shutter was fully opened4 7#c7 ,in this factory originally a #b foot #f inch fan was simply placed in the wall4 ,subsequently they were boxed in and ducts of wood brought within a foot of the noddling bar4 ,four of the branch ducts were found to be blocked4 7#e7 ,wooden ducts and hoods behind bar both close to the fan4 7#f7 ,circular metal ducts with curved angles1 and placed about #h to #aj inches behind post2 all connected up with a #d foot #f inch fan4 ,the small velocities 7#abj feet7 at two posts was due to loose connection of the branch ducts allowing air to be drawn in at the foot4 7#g7 ,metal duct distant about #b feet from the post1 and situated immediately below and not behind the bar4 ,dust was prevented from rising above the post by a glass screen1 the projection of which also prevented the worker from coming too near to1 or getting his head over1 the post4 7#h7 ,metal ducts1 #i inches in diameter4 ,evidence of ill-health was greatest here1 notwithstanding good draught1 because the branch ducts were not brought close enough to the point where 8heading0 was done1 but were distant #ae inches from the centre of the post1 and 8noddling0 was done at a distance of #b feet from the duct1 one man standing between the draught and the bar4 7#aj7 ,draught arranged as in 7#g71 below the bar1 without protection of the worker by a glass screen4 ,regulations now apply to the industry4 ,so clear is it that locally-applied exhaust ventilation is of paramount importance in prevention of poisoning1 that1 however intermittent the operation of 8heading10 exemption from this requirement cannot be permitted4 ,determination periodically by the occupier of the speed of the draught at each exhaust opening should prevent blockage of ducts4 ,the regulations do not apply to the winding of1 and weaving with1 yarn dyed with chromate of lead4 ,rarely in the spinning and weaving factories of ,blackburn does the amount of the particular yarn in question constitute as much as #e per cent4 of the total quantity of coloured yarn used4 ,section #gd1 #aija1 is sufficient to meet the isolated cases where injury to health arises4 ,the habit of biting chrome-dyed thread has given rise to lead poisoning4 ,nor do the regulations apply to treatment of calico or cloth into which lead may enter4 ,such poisoning as may occur must be practically confined to persons employed in the paint-mixing house4 ,manufacture of ,india-rubber4#i--,litharge1 massicot1 red lead1 and sulphide of lead1 are generally mixed with rubber4 ,litharge is regarded not only as a valuable filler for rubber1 but has the faculty of hastening vulcanization4 ,all dry-heat goods depend upon it where a dark or black effect is wanted4 ,every year a few cases are reported in the process of mixing the batches in the weighing room of the rubber factory1 or more frequently at the hot calender rolls1 where the batch of dry powder containing the lead compound is gradually distributed by hand on to the rubber so as to effect an intimate mixture4 ,the heated air over the rollers causes dust to rise4 ,according to the purpose for which the rubber is wanted1 the quantity of litharge in the batch varies4 ,in one factory of fourteen men employed at the calender rolls1 ten showed a blue line1 five were markedly anmic1 one had weakness of the wrists1 and two weakness of grasp#dj4 ,only one case has been reported since exhaust ventilation was applied locally over each calender roll4 ,in a rubber tyre factory five cases followed one another in quick succession1 all in persons employed on the rolls4 ,there should be no hesitation in requiring exhaust ventilation wherever employment in mixing the batches or at the rolls is constant4 ,in general1 however1 the work in weighing out is intermittent1 and reliance is placed on the wearing of a respirator4 ,no attempt has been made to enumerate all the industries and processes in which lead poisoning may arise4 ,the task would become wearisome1 as they are so numerous4 ,nor is it necessary to give details of all that are known1 as it is doubtful whether there can be any different in nature or requiring different treatment from the many which have been described4 ,,references4 #a ,special ,report on ,dangerous or ,injurious ,processes in the ,smelting of ,materials containing ,lead1 and in the ,manufacture of ,red and ,orange ,litharge and ,flaked ,litharge1 by ,e4 ,l4 ,collis1 ,m4,b4 ,cd4 #eaeb4 #aiaj4 ,wyman and ,sons1 ,ltd4 ,price #f;d4 #b ,annual ,report of the ,chief ,inspector of ,factories for #aija1 p4 #bac4 #c ,ibid41 p4 #bdb4 #d ,ibid4 for #aijf1 p4 #bgb4 #e ,h4 ,o4 ,,hofman3 ,metallurgy of ,lead4 #aijf4 #f ,annual ,report of the ,chief ,inspector of ,factories for #aijj1 p4 #dch4 #g ,ibid4 for #aiaj1 p4 #aed4 #h ,special ,report above1 p4 #ae4 #i ,,layet3 ,quoted by ,oliver in ,dangerous ,trades1 p4 #bhh4 #aj ,,dixon ,,mann3 ,forensic ,medicine and ,toxicology1 p4 #dgg4 #aa ,,sommerfeld3 ,bekmpfung der ,bleigefahr1 p4 #bbj4 #ab ,,sommerfeld3 ,quoted by ,silberstein below1 p4 #beg4 #ac ,,silberstein3 ,die ,krankheiten der ,buchdrucker1 in ,weyl's ,handbuch der ,arbeiterkrankheiten1 p4 #beg4 ,gustav ,fischer1 ,jena1 #aijh4 #ad ,,tatham3 ,decennial ,supplement to ,sixty-fifth ,annual ,report of the ,registrar-,general4 ,cd4 #bfai4 #ae ,third ,interim ,report of the ,departmental ,committee on ,certain ,miscellaneous ,dangerous ,trades4 ,c4 #ijgc4 #ahih4 ,report on the ,draft ,regulations for ,file-,cutting by ,hand1 by ,chester ,jones4 ,cd4 #afeh4 #aijc4 #af ,annual ,report of the ,chief ,inspector of ,factories for #aijd1 p4 #abe4 #ag ,ibid4 for #aijf1 p4 #bgc4 #ah ,special ,report on ,dangerous or ,injurious ,processes in the ,coating of ,metal with ,lead or a ,mixture of ,lead and ,tin1 by ,miss ,a4 ,m4 ,anderson1 ,h4,m4 ,principal ,lady ,inspector of ,factories1 and ,t4 ,m4 ,legge1 ,m4,d41 ,h4,m4 ,medical ,inspector of ,factories2 together with a ,report on an ,experimental ,investigation into the ,conditions of ,work in ,tinning ,workshops1 and ,appendices1 by ,g4 ,elmhirst ,duckering1 one of ,h4,m4 ,inspectors of ,factories4 ,cd4 #cgic4 ,london3 ,wyman and ,sons1 #aijg4 ,annual ,report of the ,chief ,inspector of ,factories for #aijb1 pp4 #bif-cah4 ,report on ,draft ,regulations on the ,tinning of ,metal ,articles1 by ,e4 ,t4 ,h4 ,lawes4 ,the ,cause of ,lead ,poisoning in the ,tinning of ,metals1 by ,g4 ,e4 ,duckering4 #ai ,the ,health of ,brass ,workers1 by ,t4 ,m4 ,legge4 ,annual ,report of the ,chief ,inspector of ,factories for #aije1 pp4 #chh-cig4 #bj ,ibid4 for #ahih1 pp4 #aai-abc2 and many references in later ,annual ,reports4 #ba ,the ,bischof ,process for the ,manufacture of ,white ,lead1 by ,professor ,sir ,william ,ramsay1 ,k4,c4,b41 ,d4,sc4 #aijf4 #bb ,report of the ,departmental ,committee on the ,use of ,lead1 and the ,danger or ,injury to ,health arising from ,dust and ,other ,causes in the ,manufacture of ,earthenware and ,china3 vol4 i41 ,report2 vol4 ii41 ,appendices4 ,cd4 #ebgg-h4 #aiaj4 ,lead ,compounds in ,pottery3 ,report to ,h4,m4 ,principal ,secretary of ,state for the ,home ,department on the ,employment of ,compounds of ,lead in the ,manufacture of ,pottery2 their ,influence upon the ,health of the ,workpeople2 with ,suggestions as to the ,means which might be adopted to ,counteract their ,evil ,effects1 by ,professor ,t4 ,e4 ,thorpe1 ,,ll4,d41 ,f4,r4,s41 ,principal of the ,government ,laboratory2 and ,professor ,thomas ,oliver1 ,m4,d41 ,f4,r4,c4,p41 ,physician to the ,royal ,infirmary1 ,newcastle-on-,tyne4 ,london3 ,eyre and ,spottiswoode1 ,february1 #ahii4 ,price #e;d4 #bc ,work of the ,government ,laboratory on the ,question of the ,employment of ,lead ,compounds in ,pottery1 by ,professor ,t4 ,e4 ,thorpe4 ,cd4 #fgi4 #aija4 #bd ,h4 ,r4 ,rogers3 ,report of a ,series of ,experiments for ,determining the ,amount of ,lead in the ,glaze of ,finished ,ware1 based on the ,method described by ,sir ,henry ,cunynghame1 ,k4,c4,b41 in his evidence before the ,departmental ,committee on the ,use of ,lead 7see #bb1 above74 #be ,see #bb1 above1 pp4 #ic1 #id4 #bf ,c4 ,r4 ,,pendock3 ,unpublished ,report4 #bg ,special ,report on ,dangerous and ,injurious ,processes in the ,enamelling and ,tinning of ,metals1 by ,miss ,a4 ,m4 ,anderson and ,t4 ,m4 ,legge1 in ,annual ,report of the ,chief ,inspector of ,factories for #aijb1 pp4 #bif-cah4 #bh ,annual ,report of the ,chief ,inspector of ,factories for #aiaj1 p4 #aed4 #bi ,zeitschrift fr ,gewerbehygiene1 ,unfall ,verhtung und ,arbeiter-,wohlfahrtseinrichtungen1 ,january1 #aijb4 #cj ,annual ,report of the ,chief ,inspector of ,factories for #aija1 pp4 #bba-bbi4 ,die in electrischen ,akkumulatoren ,fabriken beobachteten ,gesundheitsschdigungen4 ,arbeiten aus dem ,kaiserlichen ,gesundheitsamte1 by ,dr4 ,wutzdorff4 #ahih4 #ca ,third ,interim ,report of the ,departmental ,committee appointed to inquire into and report upon ,certain ,miscellaneous ,dangerous ,trades1 pp4 #af-ai4 ,c4 #ijgc4 #ahih4 #cb ,d',,arcy ,,ellis3 ,brit4 ,med4 ,journ41 vol4 ii41 pp4 #djf-djh1 #aija4 #cc ,report on the ,manufacture of ,paints and ,colours containing ,lead1 as affecting the ,health of the ,operatives employed1 by ,t4 ,m4 ,legge1 ,m4,d4 ,cd4 #bdff4 #aije4 ,painters' ,colours1 ,oils1 and ,varnishes1 by ,g4 ,h4 ,hunt1 ,griffin1 p4 #ceg4 #aija4 #cd ,annual ,report of the ,chief ,inspector of ,factories for #aije1 pp4 #cff-cfh1 and references in other ,annual ,reports4 #ce ,report of the ,departmental ,committee appointed to inquire into the ,dangers attendant on ,building ,operations1 ,appendix ,,ix41 pp4 #ahd-ahg4 ,cd4 #chdh4 #aijg4 ,painters' ,colours1 ,oils1 and ,varnishes1 by ,g4 ,h4 ,hunt1 ,griffin4 #aija4 #cf ,annual ,report of the ,chief ,inspector of ,factories for #aiaj1 pp4 #age-agf4 #cg ,ibid4 for #aijf1 pp4 #bgb1 #bgc4 #ch ,annual ,report of the ,chief ,inspector of ,factories for #aije1 pp4 #cfh1 #cfi4 #ci ,dangerous ,trades ,committee's ,final ,report1 ,c4 #ieji1 pp4 #bf-cj4 ,,alex4 ,,scott3 ,minutes of ,evidence of ,various ,lead ,industries ,committee1 #ahid1 ,c4 #gbci-a1 pp4 #aje-ajh4 ,j4 ,s4 ,,clayton3 ,industrial ,lead ,poisoning among ,yarn ,workers4 ,brit4 ,med4 ,journ41 vol4 i41 p4 #caj1 #aijf4 #dj ,annual ,report of the ,chief ,inspector of ,factories for #aija1 p4 #bca4 ,,index ,abortion caused by lead1 #ce ,absorption of lead3 cutaneous1 #be2 from lung1 #bc2 gastric1 #ai2 intestinal1 #ba1 #bb2 in liver1 #bd2 mechanism of1 #bj2 prevention of1 from stomach1 #bc ,accumulators4 ,see ,electric accumulators ,acetate of lead1 poisoning by1 #id ,acetic acid1 solvent action of1 on lead oxide1 #ae ,acid lemonade1 #ahe ,acidity1 gastric contents1 #ae ,action of lead3 on gold and silver1 #c2 on water1 #c ,acute encephalopathy1 #ed1 #ie ,acute lead poisoning1 #aaj1 #aaa ,acute nephritis1 #fj1 #aca ,aerographing1 #bgb1 #bhj tiology of lead poisoning1 #g ,age as affecting lead poisoning1 #ce1 #bci ,akremnin soap1 #bch ,albuminate of lead1 preparation of1 #ag ,albuminuria1 #abh ,albuminuric retinitis1 #afj ,alcohol3 as predisposing cause1 #cg1 #fd2 gastritis and plumbism1 #fd2 in experimental poisoning1 #he2 similar effect to lead on kidney1 #aca ,alteration in blood-corpuscles in lead anmia1 #acc ,alternation of employment1 #cd1 #bea ,amaurosis1 #gj1 #afj ,amblyopia1 #gf ,amenorrha1 #cf ,anmia1 #ci1 #aab1 #acb1 #acf1 #bbg2 treatment of1 #aij ,anemometers1 #bai ,antibrachial paralysis1 #add1 #adh ,antimony1 effect of1 on lead fume1 #aii ,appointed surgeon1 #aab1 #bba ,aran-,duchenne paralysis1 #adi ,armit1 nickel poisoning1 #aa ,arsenic3 ,cloetta's experiments1 #bd2 excretion of1 in fces1 #bd ,arterio-sclerosis1 #aaf ,arthralgia1 #ej1 #afa ,arthritis1 #dj ,artificial gastric juice1 action of1 #ag ,atrophic nerve changes1 #fi ,attack rate from lead poisoning 7table71 #ee ,autopsy1 points to be noted in1 #afb ,bacup epidemic1 #d ,basophile granules1 #gg1 #acc1 #ace1 #agi ,baths1 #bch ,blood3 action of lead salts on1 #b2 in lead poisoning1 #gj1 #gh1 #acd1 #agi2 pressure1 #aaf1 #ahj2 vessels1 #fh1 #gj1 #ge ,blue line1 #abb1 #abc1 #abh1 #bbf2 experimental production of1 #da1 #abd2 from diachylon1 #ac ,brachial paralysis1 #adh ,brain1 analysis of1 #if ,brass1 presence of lead in1 #bfc ,brassworkers and plumbism1 #ea1 #bfc ,breathing experiments1 #ha ,bright's disease and lead poisoning1 #fj ,burtonian line4 ,see ,blue line ,carbon in lung1 #aa ,card system1 use of1 #ahf ,central nervous system1 #fi1 #aeg2 treatment1 #aif ,cerebral symptoms1 #ea1 #aeg ,certifying surgeons1 reports of1 #de1 #bba ,chandelier fitters1 poisoning among1 #bfd ,channels of lead absorption1 #h ,chemical analysis of brain1 #ie ,chemical characters of lead salts1 #d ,chemical diagnosis1 #aff ,chemical examination of organs1 #afc ,chemistry of lead1 #b ,choroidal atrophy1 #afa ,chromate of lead in yarn-dyeing1 #bih ,chrome colours1 #bhg ,chronic colic1 #aai ,circulatory system1 #ge1 #acg ,cirrhosis of kidney1 #gd ,coach-painting1 #bhh2 dust in atmosphere breathed1 #bje2 leadless paints1 #bij2 reported cases from1 #bhi2 sandpapering in1 #bhi ,colic1 #aaf1 #aag1 #aah1 #aai1 #ahh1 #aij2 differential diagnosis1 #ahh2 treatment of1 #ahg ,colloidal lead1 #e ,colon1 palpation of1 #abf ,colours1 #bhe ,comparative mortality1 #ei ,conjunctiva in lead anmia1 #acb ,constipation1 #aae ,copper extraction1 plumbism in1 #bdf ,cutaneous absorption1 #be ,death certificates in plumbism1 #eg ,degeneration of blood vessels1 #fh ,determination of lead in urine1 #afi ,diachylon1 #ac ,diagnosis3 from chemical analysis1 #aff2 of lead colic1 #abj1 #ahh ,diarrha1 #aae ,differential count in lead anmia1 #acd1 #acg1 #ahj ,digestion experiments1 #af1 #ag ,drink for lead-workers1 #ahf ,drugs in lead colic1 #ahi ,duration of employment and plumbism1 #eb ,dust1 lead3 amount of1 in air breathed1 #aii1 #bjg2 chief cause of plumbism1 #aj2 8laying10 difficulties of1 #aa2 rate of settling1 #g2 respirators for1 #bjg ,dysmenorrha1 #cf ,earthenware3 and china1 #bgj2 attack rate1 #ef2 decorative processes1 #bgb2 dust in atmosphere1 #bjd1 #bjf2 glaze processes1 #bgb2 leadless glaze1 #bgd2 low solubility glaze1 #bgd2 ,potteries ,committee on1 recommendations of1 #bge2 reported cases in 7table71 #bga ,electric accumulators1 #bha2 reported plumbism in1 #bhc2 ventilation in1 #baf ,electrical reactions1 #aea1 #aec1 #aed ,electrical treatment1 #aid ,electro-chemical tests1 #afh ,electrolytic estimation of lead1 #agd2 reactions1 #e ,enamelling 7vitreous71 #bgh2 aerographing in1 #bhj2 use of leadless colours in1 #bgh ,encephalitis1 case of chronic1 #ga ,encephalopathy1 #ed1 #fh1 #ga1 #aeg ,estimation of lead3 in digestion1 difficulties of1 #ah2 in urine1 #afi1 #agj1 #age ,excretion3 of arsenic1 #bd2 of lead salts1 #cb1 #abg1 #abh ,excretory system1 #gb ,exhaust ventilation4 ,see ,ventilation ,experimental lead poisoning3 pathology of1 #ha2 post-mortem findings1 #ia2 symptoms1 #fi1 #hi1 #ajc ,experimental arsenic poisoning1 #bd ,experimental results1 summary1 #ajd ,eye changes1 #gf1 #aej1 #aeh ,facial nerve1 paralysis of1 #aie ,fces3 examination for lead in1 #ahb2 lead in1 #cb1 #fd ,family susceptibility1 #cj ,fans4 ,see ,ventilation ,faradism for paralysis1 #aie ,file-cutting1 #bef2 atrophy of muscles in1 #eb1 #beg2 reported cases in1 #beh ,file-hardening1 #beh2 lead fume from1 #bjj1 #bja2 use of fused metallic salts for1 #beh ,forms of paralysis1 #ed1 #adb ,fritted lead3 action of water on1 #hi2 poisoning1 #cd1 #ig2 solubility test1 #ad ,fume 7lead7 in atmosphere breathed1 #aih1 #bjg ,gastric absorption1 #ai1 #ba1 #bb ,gastric digestion1 artificial1 #ag ,gastric juice1 action on lead salts1 #ae1 #af ,gastritis in plumbism1 #fe ,gastro-intestinal absorption1 #ab1 #ac1 #fd ,generalized paralysis1 #aea ,glass-cutting1 #bhc ,glaze1 #bgb2 leadless1 #bgd2 low solubility1 #bgd ,gout1 #ch ,hmatoporphyrin1 #ahj1 #ahb ,hmoglobin1 #aac1 #acb ,hmorrhages in plumbism1 #gf ,hmostatic action of lead salts1 #b ,hair lotions1 poisoning from1 #ac ,harness furniture1 tinning of1 #bei ,headache1 #abj ,health ,register1 #bbh ,heart1 #aci1 #aic ,heart symptoms1 #aic ,heat1 exhaust by1 #bjh ,histological examination of lead tissues1 #afc1 #agf ,histology3 of experimental poisoning1 #ib2 of nervous system1 #fg ,house-painting1 #bia2 regulations for1 #bic2 reported plumbism in1 #bia ,hunter1 ,john1 8dry bellyache0 from rum1 #a ,hypersthesia1 #afa ,immunity1 #bg1 #bi1 #aac ,incipient symptoms1 #aab1 #bbb ,india-rubber1 manufacture of1 #cja ,inhalation experiments 7table71 #aja ,inoculation experiments1 #hc1 #hh1 #ii ,instruction of worker1 #bdj ,interstitial nephritis1 #acj ,intestinal absorption1 #bb1 #id ,intestinal staining1 #ba1 #id1 #abe ,iodine in plumbism1 #aib ,ionization in paralysis1 #aie ,iron drums1 tinning of1 #bfj ,italians and lead poisoning1 #cj ,kidney3 changes1 #gc1 #gd1 #abi2 excretion of lead by1 #abh2 interstitial hmorrhages1 #acj ,lactic acid1 solvent action of1 #ae ,large intestine and lead absorption1 #ba ,lavatories1 #bce1 #bch ,lead3 compounds1 #g2 fume and dust in atmosphere1 #aih-bjg2 in urine1 #abi1 #afg2 melting-point1 #b1 #aii ,lead bed in file-cutting1 #beg ,lead burning1 #bfb2 in electric accumulators1 #bhc ,lead chloride in tinning1 #bjj ,lead dust3 minimal toxic dose1 #ca1 #bjg2 rate of settling1 #g2 size of particles1 #ab ,lead fume in tinning1 #bjb ,lead oxide1 danger from skimming1 #bjj ,lead piping1 #bea ,lead poisoning3 acute1 #aaj2 mortality1 #eg2 entry of poison1 #h ,lead silicate1 #cd ,lead smelting3 and silver refining1 #bdb2 analysis of fumes in1 #bdf2 cupellation process1 #bdf2 ,huntingdon-,heberlein process1 #bdc2 in blast furnace1 #bdc2 ,parkes's process1 #bdd2 ,pattinson process1 #bde2 reported plumbism1 #bdh ,leadless glaze1 #bgd ,leadless paints1 #bia ,lead salts3 action on blood1 #b2 action of gastric juice on1 #af1 #ag ,lemonade1 sulphuric acid1 #ahe ,letterpress printing4 ,see ,printing ,litharge1 manufacture of1 #bej ,lithopone1 #bia1 #bib ,litho-transfers1 #bgg ,liver1 absorption by1 #bd ,loss of fat in plumbism1 #aab ,lumbago1 #aae1 #aib ,lung3 absorption by1 #ih2 phagocytic absorption of lead1 #bc ,meal-rooms1 requirements of1 #bcd ,mechanism of lead absorption1 #bj ,medical examination1 periodical1 #aae1 #bba-bbi ,medical ,health ,register1 #bbh ,medical practitioners and notification1 #dd ,melting-point of lead1 #b1 #aii ,menorrhagia1 #cf ,mental symptoms1 #aad1 #aba1 #aeh ,metallic capsules1 #big ,metallic taste1 #abg ,micro-chemical tests1 #afg ,molten lead1 contact with1 #big ,mortality figures1 #ei ,motor-cars4 ,see ,coach-painting ,muscles paralyzed in experimental poisoning1 #add ,muscular system1 affections of1 #aad-afa ,nephritis1 #aib ,nervous symptoms1 #ff1 #fg1 #adj2 treatment1 #aic ,neuritis1 peripheral1 #ff1 #fg ,nickel carbonyl poisoning via lung1 #aa ,normal lead1 #cc ,notification of plumbism1 #dd dema of brain1 #aei ,olive oil in colic1 #ahi ,ophthalmoscopic examination1 #afj ,oral sepsis1 #ch ,orange chrome1 #bii ,organic mixtures1 lead in1 #agc ,organic compounds of lead1 #e ,organs of generation1 effect on1 #cf ,overalls and head coverings1 #bcj ,oxides of lead1 #c1 #bdi ,painters and lead poisoning1 #ajg4 ,see also ,house-painting ,paints3 and colours1 manufacture of1 #bhe2 leadless1 #bi1 #bia ,pancreatic digestion1 action of1 #ag ,paralysis3 in animals1 #ad2 electrical reactions in1 #aha2 forms of1 #fd1 #ff1 #adb2 general1 #aea2 in file-cutters1 #aeb2 insidious onset of1 #aad2 of special sense organs1 #aej2 prognosis of1 #aig2 statistics of1 #ec ,parotitis1 #abg ,pathology of lead poisoning1 #fb 8,pentarcomb0 exhaust1 #bag1 #bed ,peptonate of lead1 #ah ,peptone1 solvent action of1 #ai ,perambulators1 painting of1 #bij ,perihepatitis1 #bfd ,peripheral neuritis1 #bff ,peritonitis1 saturnine1 #fe ,peroneal paralysis1 #adi ,phagocytosis of lead particles1 #bj ,phthisis3 in printing1 #bef2 not a sequela1 #fj ,physiology of digestion1 #af ,plumbing1 #bfa ,plumbism1 reported cases 7#aijj-aiji71 #df1 #dg ,plumbo-solvency of water1 #d ,porcelain enamelling1 #bgh ,post-mortem signs1 #ia1 #afa ,potassium iodide1 action of1 #cb1 #aia ,pottery4 ,see ,earthenware ,predisposing causes1 #cf1 #db ,presaturnine state1 #ahd ,preventive measures3 age of employment1 #bci2 baths1 #bch2 cloakroom1 #bca2 exhaust ventilation1 #bjg2 floors1 #bdj2 food1 #hf2 head coverings1 #bca2 instruction of worker1 #bdj2 meal-room1 #bcd2 overalls1 #bcj2 periodical examination1 #bba2 separation of processes1 #bci2 washing accommodation1 #bce ,printing3 compositors' work1 #bee2 linotype machine1 #bjj1 #baa1 #bag1 #bec2 reported cases from1 #beb2 stereo-casting1 #bed2 type-casting1 #beb ,prodromal symptoms3 of colic1 #aah2 of paralysis1 #ada ,prognosis in lead poisoning1 #aig ,progressive spinal muscular atrophy1 #fh ,pulse-rate1 alteration of1 #gf1 #aae1 #aah ,purgatives in lead colic1 #ahh ,putty powder1 #bhc ,pyorrha alveolaris as predisposing cause1 #dj1 #abd ,qualitative tests1 #aff ,quantitative estimation of lead1 #agj ,reactions of degeneration1 #aeb ,red lead3 manufacture of1 #bdi2 reported attacks in1 #bdi ,relative toxic dose of lead compounds1 #aje ,repairs in factory as cause of plumbism1 #aj ,respirators1 inefficiency of1 #bag ,respiratory absorption1 #i ,rheumatic pains1 #aba1 #afa1 #aib ,safes1 painting of1 #bij ,salivary glands and excretion of lead1 #abe 8,selective0 action of lead on nerves1 #adg ,sequel of lead poisoning1 #eg1 #fj ,sex as affecting susceptibility1 #ce ,sheet lead1 #bda ,shipbuilding1 #bie2 reported plumbism1 #bie ,shot-making1 #bih ,silicates of lead1 #cd ,silver refining4 ,see ,lead smelting ,size of particles of lead compounds1 #ab1 #cd ,skin1 colour of1 #acb ,smelting of lead4 ,see ,lead smelting ,solar plexus1 #fe ,soldering1 #bfa ,solubility3 of lead salts1 #e1 #ae1 #af1 #ag2 test for fritted lead1 #ad ,solvent action of peptone1 #ai ,spastic paraplegia1 #fh ,spiegeleisen1 poisoning in manufacture of1 #bdf ,spring tempering1 fume from1 #bja1 #bif ,stained-glass painting1 #bhe ,statistics of plumbism1 #dd1 #de ,susceptibility1 #bg ,tape measures1 painting of1 #bij ,tea lead1 #bea ,temperature in lead poisoning1 #aah ,tempering files1 #bjj ,terne plates1 #bfj ,tests for lead1 #afg ,tetramethyl diphenyl test1 #afi ,thorpe test1 #bge ,tiles4 ,see ,earthenware ,tinning3 of hollow-ware1 #bei2 of harness furniture1 #bei2 of irondrums1 #bfj2 dust in1 #bjc2 lead chloride fume in1 #bjb-bjc2 repeated attacks in1 #bfa ,tolerance of lead1 #bh1 #aac ,toxic dose3 of lead acetate1 #aaj2 of lead carbonate1 #aaj2 of lead dust1 #ca1 #bjg2 of fritted lead dust1 #hh1 #ig2 of white-lead dust1 #he ,treatment of acute lead poisoning1 #aaa1 #ahd ,tremor1 #adb1 #aef ,turpentine poisoning1 experimental1 #ajh ,type metal1 #bjb ,urine3 acidity1 #aha2 chemical examination of1 #ahj2 determination of lead in1 #afg2 lead in1 #cb1 #gc1 #afi2 phosphates1 #aha ,vaso-motor changes1 #fe1 #gf1 #adj ,ventilation 7exhaust71 #bjg-bbj2 by fans1 #baj2 by heat1 #bjh2 composing boxes1 #bee2 essential points1 #bjh2 in earthenware1 #bgc2 in electric accumulators1 #baf1 #bhb2 in enamelling1 #bgh2 in glass-cutting1 #bhd2 in india-rubber1 #cjb2 in lead smelting1 #bde2 in litharge1 #bea2 in paints1 #bae1 #bhf2 in printing foundry1 #bed2 in red lead1 #bej2 in spelter1 #bdi2 in tinning1 #bei2 in vacuum cleaning1 #bah2 in white lead1 #bad1 #bfh2 in yarn-heading1 #cjj2 smoke-test1 #bah ,volatility of lead1 #b ,washing accommodation1 #bce ,wasting in lead poisoning1 #aac1 #aae1 #ade ,water1 action on lead1 #c1 #d ,white lead3 ,brimsdown process1 #bfi2 casual labour in1 #bfi2 cause of dangers in1 #bff2 chamber process1 #bfh2 diminution in reported cases1 #bgj2 ,dutch process1 #bfe2 precipitation process1 #bfi2 ventilation in1 #bad ,works' medicines1 #ahe ,wrist-drop4 ,see ,paralysis ,yarn-dyeing with chromate of lead1 #bih ,zinc3 action on kidney1 #acj2 paints1 #bib1 #bid ,,billing ,,and ,,sons1 ,,ltd41 ,,printers1 ,,guildford ,transcriber's ,notes ,the text used in this document is the one used in the source document1 except as mentioned below4 ,in particular1 non-,english words and phrases and titles and author names of references1 and summations and other calculations in tables have not been corrected1 unless mentioned below4 ,table numbering 7or the lack thereof7 has not been standardised4 ,depending on the hard- and software used to read this text and their settings1 not all elements may display as intended4 ,page #a1 #f3 ,stockhusen is probably an error for ,stockhausen4 ,page #ch1 the reference to ,goadby#ac points to a publication by ,garrod4 ,page #eb3 hyperthenar eminence may be an error for hypothenar eminence4 ,page #fd1 444 se recontrant d'une manire diffuse 4443 possibly an error for 444 se rencontrant d'une manire diffuse 4444 ,page #gj1 bottom row of ,table ,,ix3 possibly the first column should read ,average age at death4 ,page #bbj1 ,literature reference #e3 there is no footnote marker in the text4 ,changes made ,tables and illustrations have been moved out of text paragraphs4 ,some of the tables have been re-arranged or split for legibility2 ditto marks and the word ,ditto have in several places been replaced with the dittoed text4 ,some obvious minor typographical and punctuation errors have been corrected silently4 ,page #c3 444 mascicot and litharge 444 changed to 444 massicot and litharge 4444 ,page #dg1 ,table ,,iii bottom part3 value for #aiaa in the row ,other industries changed from #h to #hh 7based on the totals given74 ,page #fa1 ,footnote #b3 ,dr4 ,john ,tathan changed to ,dr4 ,john ,tatham4 ,page #ge3 ,pfleuger changed to ,pflueger4 ,page #gf3 ,seiffert changed to ,seifert4 ,page #gi1 references #af and #bg3 ,bleilhnung changed to ,bleilhmung2 reference #di3 les ,maladies du ,pois et ,reins changed to les ,maladies du ,foie et des ,reins4 ,page #hh3 eutetic entangling changed to eutectic entangling4 ,page #acg3 ,the footnote under second table 7,furniture-,makers--,sand-,paperers7 has been copied to under the first table 7on ,lead ,sulphate ,workers7 for clarity4 ,page #aea3 ,electrical ,reactions4 changed to ,electrical ,reactions4 ,page #afi3 magnese changed to manganese4 ,page #bbj3 ,leclere de ,pulligny changed to ,leclerc de ,pulligny4