,transcriber's notes3 ,this plain text e-book contains tables1 equations and chemical formulae1 some of which cannot be rendered very realistically in plain text format - the html version is stongly recommended1 viewed with a standard web browser4 ,italic script is denoted by underscores and bold by 99asterisks994 ,subscripted text is enclosed within and preceded by an underscore1 e4g4 ,ca7,,oh7#b4 ,superscripted text is likewise enclosed but preceded by 1 e4g4 #aj-eb4 ,the text of the book has mostly been preserved in its original form1 including inconsistent italics1 capitalisation1 and hyphenation4 ,however1 some defects have been corrected silently1 such as missing_/inconsistent punctuation1 parentheses and spacing1 and an erroneous has been replaced by in a fraction in footnote #fi4 ,tables have been formatted to match the originasl1 but a large table that was originally split over four pages 7pp4 #ih-aja71 has been condensed into two sections4 ,footnotes have been numbered and positioned below the relevant paragraphs1 and some illustrations have been moved closer to the relevant text4 ,the following typographic corrections have been made3 mutiplied multiplied ,kothbeize ,kothbeizen of on phenolphtalein phenolphthalein hydroxylion hydroxyl ion ,ca7,,oh#b7 ,ca7,,oh7#b pepsine pepsin bibliographic xref 7#i7 7#ai7 ,the following inconsistent spellings have not been altered3 ,frankfort a_/,m - ,frankfort o_/,m ,zenckeri - zenkeri ,casenin - ,caseuin ,kentniss - ,kenntnis - ,kenntniss resistant - resistent c4c4 - c4cm4 urea - ure ae - ,,the ,,puering1 ,,bating ,,drenching ,,of ,,skins ,scientia et potentia humana in idem coincidunt1 quia ignoratio caus destituit effectum4 ,natura enim non nisi parendo vincitur3 et quod in contemplatione instar caus est1 id in operatione instar regul est4 ,knowledge and human power are synonymous1 since the ignorance of the cause frustrates the effect2 for nature is only subdued by submission1 and that1 which in contemplative philosophy corresponds with the cause1 in practical science becomes the rule4--,,bacon1 ,aphorism ,,iii4 ,,the ,,puering1 ,,bating ,,drenching ,,of ,,skins ,,by ,,joseph ,,turney ,,wood ,,director ,,of ,,turney ,,brothers1 ,,limited1 ,,nottingham2 ,,examiner ,,in ,,leather ,,tanning1 ,,dressing ,,of ,,skins1 ,,and ,,leather ,,dyeing ,,to ,,the ,,city ,,and ,,guilds ,,of ,,london ,,institute2 ,,member ,,of ,,the ,,international ,,association ,,of ,,leather ,,trades ,,chemists1 ,,etc4 #cc ,,illustrations ,illustration ,london ,e4 ,f4 ,n4 ,,spon1 ,ltd41 #eg ,,haymarket ,new ,york ,,spon ,,chamberlain1 #abc ,,liberty ,,street #aiab ,,dedicated ,,to ,,sir ,,john ,,turney ,,the ,,veteran ,,of ,,the ,,light ,,leather ,,industry ,,in ,,grateful ,,acknowledgment ,,contents ,,page ,,list ,,of ,,illustrations ix ,,preface xi ,i4 ,,description ,,of ,,the ,,puering ,,and ,,bating ,,process #a ,,ii4 ,,the ,,chemistry ,,of ,,bating #bc ,,iii4 ,,the ,,physics ,,of ,,bating #ee ,,iv4 ,,the ,,bacteriology ,,of ,,the ,,bate #hg ,v4 ,,action ,,of ,,enzymes #abg ,,vi4 ,,original ,,papers ,,on ,,bating #adg ,,vii4 ,,artificial ,,bates #agh ,,viii4 ,,patents #aic ,,ix4 ,,drenching #bcc ,x4 ,,original ,,papers ,,on ,,drenching #bdf ,,xi4 ,,bibliography #bhb ,,conclusion #bib ,,index #bie ,,illustrations ,,fig4 ,,page #a4 ,curve showing removal of lime by washing #f #b4 ,cubical 8truck0 for measuring skin facing #h #c4 ,puer wheel #ac #d4 ,front elevation of puer wheel #ac #e4 ,end elevation and section of puer wheel #ad #f4 ,sir ,john ,turney's scudding machine facing #ag #g4 ,curves of ash contents during puering #ch #h4 ,diagram of volumenometer #fb #i4 connexions of electrometric apparatus #gf #aj4 ,electrometric apparatus #gh #aa4 ,apparatus for measuring degree of falling #hc #ab4 ,curves obtained by measuring apparatus #he1 #hf #ac4 ,improved apparatus for measuring degree of falling #hf #ad4 ,various forms of bacteria in puer liquors facing #hh #ae4 ,b4 coli commune #hh #af4 ,b4 erodiens 7,becker7 #ig #ag4 ,plate culture from fresh puer #ig #ah4 puer wheel #ajc #ai4 ,b4 putrificus #ajc #bj4 ,organisms in pigeon dung1 #ajjj #ajd #ba4 ,pure culture of bacillus 7d7 from sweated skin facing #ajf #bb4 7e7 #ajf #bc4 ,b4 butyricus 7,hueppe7 #aab #bd4 ,spirillum volutans 7,kutscher71 stained to show flagell #aab #be4 unstained preparation #aab #bf4 ,curves showing rate of hydrolysis #abi #bg4 ,organisms in bran drench1 #ajjj #bdj #bh4 ,chains of bran bacteria1 #ajjj #bdj #bi4 ,bran fermentation1 advanced stage #bda #cj4 ,b4 furfuris1 facing #bfi #ca4 ,b4 furfuris1 #bfi #cb4 ,cultures of in glucose gelatin #bfh #cc4 ,gas curve 7,b4 furfuris7 #bgg ,,preface ,the present volume is the outcome of a desire to preserve the numerous notes which ,i have made during over twenty years' work at the practical and scientific study of bating4 ,it has been my wish to complete the investigation of this important process in leather manufacture1 for1 as ,lord ,allerton has paradoxically remarked3#a 8,good leather is made before the skins go into the tan liquor at all10 but owing to circumstances having drawn me more and more to the commercial side of the business1 ,i have been compelled to abandon this project4 #a ,report of ,first ,conference of ,leather ,trade ,chemists1 #ahig1 p4 #adf4 ,when learning the trade as an apprentice every fault in the leather was attributed to this part of the work1 and the troubles and miseries of the 8puer shop0 first caused me to take up the study of puering4 ,i was determined to know the causes underlying the process4 ,puering is not only a filthy and disgusting operation1 but is prejudicial to health1 and in the nature of it is attended by more worry and trouble than all the rest of the processes in leather making put together4 ,by giving a rsum of the work done up to the present time1 ,i hope to be of assistance to the younger generation of ,tanning ,chemists1 to some of whom is reserved the privilege of carrying on the work4 ,i think it may now be said1 at any rate1 that the solution of the problem of constructing an artificial bate on scientific principles1 which will replace the present crude methods1 is well within sight4 ,the principal obstacles are1 on the one hand1 the inertia of ,english manufacturers2 on the other hand1 the class of labour employed in puering is not of the highest order of intelligence4 ,innovations in most things are resisted1 partly because they necessitate changes in the method of working1 and partly because of the innate conservatism of human nature4 ,it is certainly a significant fact that although most of the pioneer work on this subject was done in ,england1 the practical side has been taken up in ,germany1 and by freely spending money on large trials in the works they have enabled the manufacture of artificial bates to be developed on a commercial scale4 ,in #ahhf1 while studying ,chemistry under ,professor ,frank ,clowes1 ,i began to examine microscopically the various liquors of a light leather factory1 and more especially the bran drenches4 ,at that time ,i knew nothing of bacteriology1 for the simple reason that little but pathological work in this line was being done in ,england4 ,through the kindness of ,professor ,clowes1 ,i obtained an introduction to ,mr4 ,adrian ,brown 7now professor at the ,university of ,birmingham71 and in his laboratory at ,burton-on-,trent ,i saw the first pure cultivations of ,bacterium ,aceti which he had isolated1 and of which he had completely studied the chemical action4#b ,i had there an opportunity of seeing the methods and apparatus employed4 ,i also had the benefit of ,mr4 ,brown's advice in commencing a systematic study of the process of drenching4 ,professor ,percy ,frankland1 then at ,dundee1 advised me further as to the microscope and other matters4 ,my warmest thanks are due to these friends for directing me in the right way4 #b ,jour4 ,chem4 ,soc41 ,mar4 #ahhf4 ,as a result of my first investigations1 on ,december #aa1 #ahhi1 ,i read a short paper entitled 8,methods of ,bacteriological ,research--with some account of ,bran ,fermentation10 before the ,society of ,chemical ,industry4 ,the way in which this paper was received led to a further research into the nature of bran fermentation in conjunction with ,mr4 ,w4 ,h4 ,willcox1 ,b4,sc4 7now ,senior ,analyst to the ,home ,office71 by which the action of the bran drench was thoroughly investigated1 and the results published in the ,journal of the ,society of ,chemical ,industry1 ,may #ca1 #ahic4 ,this was followed1 on ,june #cj1 #ahig1 by a paper 8,on a ,pure ,cultivation of a ,bacillus ,fermenting ,bran ,infusions10 also in conjunction with ,dr4 ,willcox4 ,in #ahih1 in reply to a publication of ,director ,eitner1 of ,vienna1 ,i published in the ,leather ,trades' ,review 7,november #ae71 a rsum of the whole subject1 entitled 8,the ,rationale of ,drenching40 ,already1 in the first paper above named 78,methods of ,bacteriological ,research071 ,i had called attention to the bacteria of the bate prepared from dogs' dung1 and in a paper entitled 8,fermentation in the ,leather ,industry10#c developed this aspect of the subject1 and first pointed out the influence of enzymes in bating4 ,i therefore decided to study the phenomena occurring in the bate in the same way as ,i had studied drenching4 #c ,jour4 ,soc4 ,chem4 ,ind41 #ahid4 p4 #bah4 ,the work was begun in #ahie1 and1 as it was likely to occupy an indefinite time1 the first instalment1 entitled 8,notes on the ,constitution and ,mode of ,action of the ,dung ,bate in ,leather ,manufacture10 was published ,november #cj1 #ahih2 while 8,further ,notes on the ,action of the ,dung ,bate0 was published on ,november #cj1 #ahii4 ,in these papers ,i indicated the lines on which a culture of bacteria might be practically applied to the bating of skins1 and gave the composition of a liquid which1 while acting as a nutrient medium for the bacteria1 contained at the same time most of the active chemical compounds of dog dung4 ,meanwhile1 ,dr4 ,popp and ,dr4 ,becker1 in ,frankfort a_/,m1 were investigating independently the bacteria of dog dung1 and conceived the idea of employing them commercially4 ,my dear friend ,franz ,kathreiner1 of ,worms1#d put me in communication with these gentlemen1 and we were thus enabled to work in conjunction4 ,as a result of our combined labours1 an artificial bate1 called 8,erodin10 was put upon the market4 ,this will be fully treated of in the chapter on ,artificial ,bates4 #d ,died1 ,april #aije4 ,i shall give first a short account of bating1 and then sum up as briefly as possible the present state of our knowledge of the process1 afterwards giving an account of the more important of the various patents which have been taken out for artificial bates4 ,although the book is divided into separate sections for convenience1 it is obvious that we cannot separate chemistry from physics1 nor bacteriology from chemistry1 nor enzyme action from all three4 ,my own papers are printed as read4 ,the ,bibliography does not profess to be complete1 but includes most of the works consulted4 ,no one realizes more than ,i how incomplete the work is1 and how much research still remains to be done in order to complete it4 ,thanks to the efforts of the ,leather ,industries ,department of the ,university of ,leeds1 and the ,technical ,college of the ,leather ,sellers' ,company1 ,bermondsey1 the era of ,rule of ,thumb is passing1 and there is little doubt that the work that is being done in these institutions will be translated into practical use in the factories by the coming generation4 ,i wish to express my special thanks to ,mr4 ,,douglas ,j4 ,,law1 and to ,dr4 ,h4 ,j4 ,s4 ,,sand for assistance in preparing the notes for publication1 to ,dr4 ,j4 ,,gordon ,,parker1 ,director of the ,leather ,sellers' ,technical ,college1 ,london1 for the description of the bating of hides1 and to ,,professor ,,kr,l1 of ,prague1 for some of the photographs of bacteria4 ,,joseph ,t4 ,,wood4 ,nottingham3 ,january #aiab4 ,,puering1 ,,bating1 ,,and ,,drenching ,,of ,,skins ,,chapter ,i4 ,,the ,,puering ,,and ,,bating ,,process4 8,beizen sind ,stoffe die mit dem ,kalk nicht nur ein chemische ,verbindung einzugehen im ,stande sind1 wodurch derselbe lslich und somit vollstndig unschdlich wird1 sondern auch den gegenseitigen festen ,schluss der einzelnen ,wandungen der ,zellenelemente mechanisch lockern1 den ganzen ,bau der ,haut in sich nachgiebiger machen und so die ,verschiebbarkeit der einzelnen ,hautgebilde erhhen40--,j4 ,c4 ,h4 ,,lietzmann1 #ahfb4 8,bates are materials which are not only able to enter into chemical combinations with the lime1 whereby it becomes soluble1 and is thereby rendered completely harmless1 but they also mechanically loosen the cementing substance of the separate cell elements1 and render the whole structure of the hide more pliable1 and thus increase the mobility of the various parts40 ,the object of bating or puering is to render the skins1 and the resulting leather1 soft and supple4 ,skins which have undergone the liming process1 must be thoroughly freed from lime before going into the tan liquors1 and1 for light and soft leathers1 they must be reduced or 8brought down10 so that the elasticity or resilience of the skin fibres is got rid of1 and the skin1 when tanned1 can be stretched without springing back4 ,this is usually done in the case of light leathers1 by passing the skins through a bate or puer1 composed of an infusion of dogs' dung in water at a temperature of #ce to #dj ,c41 until the required result is obtained4 ,this condition is known to the workman by the feel of the skin4 ,a good indication is1 that the skin when 8down0 retains the impression of the thumb and finger if squeezed4 ,a properly puered skin1 when dropped on the floor1 will also be perfectly flaccid1 the folds lying closely together4 ,it may1 however1 be said that it is only by experience and a kind of instinct that the exactly correct condition of the skin can be judged4 ,i know of no very early works on leather manufacture giving an account of bating4 ,it was a 8secret process10 and the results obtained depended almost entirely upon the judgment of the operator2 and this judgment was frequently in error1 owing to the fact that he did not understand what took place in the bate4 ,the earliest account ,i have been able to find is in a book#e in the possession of ,mr4 ,seymour-,jones1 of ,wrexham1 entitled 8,the ,art of ,tanning and ,currying ,leather1 with an ,account of all the ,different ,processes made use of in ,europe and ,asia for ,dying ,leather ,red and ,yellow1 ,collected and ,published at the ,expense of the ,dublin ,society1 to which are added ,mr4 ,philippo's ,method of ,dying the ,turkey ,leather as approved of by the ,society for the ,encouragement of ,arts1 etc41 and for which he had a ,reward of #ajj1 and their ,gold ,medal1 for the ,secret4 ,also the ,new ,method of ,tanning invented by the late ,david ,macbride1 ,m4,d41 ,london4 ,reprinted for ,j4 ,nourse1 on the ,strand1 ,bookseller to ,his ,majesty1 #aghj40 #e ,there is a copy in the ,british ,museum and also in the ,patent ,office ,library4 ,in the chapter entitled 8,alumed ,calf ,skins for ,bookbinding0 7p4 #ach71 after the limed skins have been fleshed1 the writer continues-- 8,to alum them1 put into a large vat1 three or four pails of dogs' turd 7this dogs' turd is called alum72 on this they fling a large pail of water to dilute it2 this done1 the workman goes into the vat1 and1 with his wooden shoes1 tramples it1 filling the vat half full of water4 ,the alumer1 on his part1 pours water out of his boiler into this vat1 mixing it with the cold water1 after which he flings in the skins1 stirring them and turning them for some moments with great sticks40 ,the work is described pretty much as now practised1 the puer tub being kept at a uniform heat by constantly taking out liquor1 heating it1 and returning it4 ,but neither these goods1 nor morocco1 are put through a 8drench0 after the puer1 as we do now2 they are scudded on the flesh1 and well washed several times in clear water before being tanned4 99,morocco ,leather99 7p4 #bjd74--,the dry skins are soaked three or four days1 8pared0 on the beam1 and unhaired in weak lime pits one month4 ,at ,nicosia they put the skins into lime1 reduced to powder1 for twenty days in summer1 or twenty-five to thirty in winter2 out of the lime1 the skins are well washed and drained4 ,the author continues-- 8,the river work finished1 the skins are put into the dogs' confit1 or mastering2 for every four dozens of skins they add one bucket of dogs' excrement1 containing fourteen or fifteen quarts1 which is worked up with their hands into a kind of pap and well diluted4 ,the skins are flung in1 stirred and worked in the mastering for some minutes1 then turned and left to rest4 8,they remain about twelve hours in the mastering1 which opens them1 and takes off the rawness1 disposes them to relax1 fill and ferment4 ,this excrement1 by its alkaline parts1 also cleanses them and takes out the grease1 which would hinder them from taking the colour4 ,i shall hereafter speak of bran mastering4 8,at ,diarbekir1 they make use of these masterings in a different way4 ,whilst the skins are drying1 they fill great hollows made in the earth1 like our lime pits1 with dogs' dung1 which is diluted to the consistence of honey1 or of thin pap1 in which they soak the skins for eight days in winter1 and three in summer1 treading them each day with the feet4 ,they are taken out of this fecal matter1 and well washed with fresh water1 after which another mastering is made with bran diluted with water1 in which the skins are soaked six days in winter1 and three in summer1 observing to tread them each day with the feet1 the same as in the dogs' mastering2 they are then taken out1 washed in fresh water1 and prepared for dyeing40 ,from these primitive methods the majority of tanners1 even of the present day1 have departed but little1 except that1 instead of stirring the goods and liquor with a stick1 a paddle is used1 and the process thus shortened considerably4 ,before describing the operation of puering1 it will be best to describe the preliminary washing of the skins1 because1 although limed skins may be entered direct into the puer and brought down quite satisfactorily1 in this case more puer and more time are required1 hence it is usual to get rid of the bulk of the lime by washing them in water before putting them into the puer4 ,in some cases very dilute hydrochloric or other acid is used1 in order to shorten the time of watering4 ,it is now well known that lime cannot be entirely removed from skins by washing in water1 no matter how long the washing be continued4 ,a limed skin containing #df per cent4 ,ca,o1 calculated on the dry weight1 was found to contain after washing-- ---------------------------------------- ---- ,time of ,per cent4 ,ca,o on ,per cent4 lime washing dry skin removed ---------------------------------------- ---- #a hour #cje #cd #b hours #bbj #eb #c #age #fb #f #aee #ff #g #aee #ff #bd #aej #fg ---------------------------------------- ---- ,illustration3 ,fig4 #a4 ,if the washing be continued1 a less amount of lime is removed in each successive period of time1 so that it is evident a point is soon reached at which it becomes a waste of time to continue the washing4 ,in practice this point is reached in about two hours4 ,the progress of the washing is best shown by the curve in the diagram 7,fig4 #a71 in which the ordinates represent the percentage of lime 7,ca,o7 in the dry skin1 and the absciss time in hours4 ,it will be seen that the character of the curve is a hyperbola2 such a curve only approaches a line 7representing in the example chosen about #a-a_/b per cent4 of lime7 asymptotically--in other words1 it is impossible to wash out all the lime except by an infinite number of changes of water1 since each washing removes a less amount than the previous one4 ,the above is a typical case of the washing of limed grains from the splitting machine in the manufacture of skivers4 ,these contain from #d to #e per cent4 of lime on the dry skin1 and1 after washing in water in a paddle for six hours1 analysis shows them to contain still about from #ae per cent4 to #ai per cent4 of lime 7,ca,o74#f #f ,some further analyses of grains at ,trent ,bridge gave the following results3-- ,water ,ca,o ,ca,o on dry skin ,grain from splitting machines #gfc #aad #dh ,the same after washing #bd hrs4 #hfj #jbb #aeg ,the same after puering -- -- #jhj ,another grain #gig #ajf #ebj ,the same after deliming as completely as possible with -- -- #jde ,h,cl ,skin in natural condition #fdj -- #jabe ,m4 ,c4 ,lamb has found in sheep grains split for skivers the following amounts3-- ,ash ,ca,o ,ca,o in ,ash ,grain from splitting machine #ic #cb #cdh ,the same after washing #da #ae #cea ,the same after puering #ca #ji #bia ,the same after bran drench #ag #jee #cbd ,the figures are all percentages calculated on the dry weight of the skin4 ,munro ,payne 7,tanners' ,year ,book1 #aije1 p4 #ge7 gives the following amounts of lime as ,ca7,,oh7#b in limed hides1 calculated on dry weight at #bab ,f43-- ,direct from limes max4 #chei per cent4 min4 #bhcf ,limed for buff #dfba ,limed for tanning #cgfei ,ditto after bating #jfhi ,calf limed #bfja ,calf bated #jabae ,goat limed #efac ,goat bated #abfh ,the effect of washing depends on the character of the water 7hard or soft71 and also on its temperature4 ,hard waters should have a small quantity of clean lime added to them before entering the goods1 in order to remove dissolved ,,co#b1 which1 by carbonating the lime on the surface of the skins1 renders the grain harsh and the subsequent puering difficult4 ,with regard to temperature1 it is preferable to employ cold water until the bulk of the lime is out1 since this dissolves more lime than warm water4 #ajj c4c4 of saturated lime water1 at #aj ,c41 contains #jacd grm4 ,ca,o4 #ajj c4c4 at #dj ,c4 contains #jaaai grm4 ,ca,o4 ,moreover1 a comparatively small rise of temperature causes a considerable decomposition in a fully limed skin1 by which the skin substance is rendered more soluble1 and consequently lost for the purposes of the tanner4 ,for a fully limed skin the limit of temperature is about #hb ,f4 7#bh ,c471 whereas a skin free from lime or alkali may be submitted to a temperature of #abj ,f4 7#di ,c47 without damage to the fibre4 ,lamb prefers a short washing of half an hour in water at #ce to #ch ,c41 for the reason that the increased temperature causes the goods to become more flaccid1 but this condition is attained at the expense of the loss of skin substance we have mentioned4 ,illustration3 ,fig4 #b4--;,cubical ,truck4 ,in order to save time and water1 the following method is adopted4 ,the goods are measured by means of a cubical truck on wheels 7,fig4 #b72 it holds #bej kilos of wet skins 7#eej lb474 ,four of such trucks are placed in a wash wheel1 and a stream of water from a #a-;in4 pipe turned on4 ,the goods are run from three-quarters of an hour to one hour2 the water is then stopped1 and #djjj c4c4 of commercial hydrochloric acid 7#ah ,b47 is run in slowly1 in a very diluted state1 through a perforated lead pipe4 ,after all the acid has run in1 the wheel is run for half an hour1 then water turned on again for half an hour in order to wash away the calcium chloride produced4 ,during this last washing1 hot water is admitted at the back of the wheel through a perforated pipe1 in order to raise the temperature of the goods1 so that they do not enter the puer wheel in a cold condition1 and thus lower the temperature of the puer liquor4 ,the goods are now ready for puering4 ,the chemical action of the acid is a very simple one1 and is expressed by the formula-- ,ca7,,oh7#b #b;,h,cl ,ca,cl#b #b;,h#b,o #gd #gca #aaji #cfg #g ,from the molecular weights it will be seen that #gd grm4 of calcium hydrate1 equivalent to #ef grm4 of lime 7,ca,o71 require #gc grm4 of ,h,cl gas for neutralization4 ,this quantity of gas is contained in #bfe grm4 of commercial hydrochloric acid of #ah ,b41 or about #bcj c4c4--that is1 for #ajj grm4 ,ca,o1 #daj c4c4 of #ah ,b4 acid are required2 hence for the #ajj kilos wet grain containing #djj grm4 ,ca,o1 #afdj c4c4 of acid are required for complete neutralization4 ,it is impracticable to use this amount of acid1 for the reasons stated above4 ,it will be noted that the quantity of acid used is only about one-tenth of that required to neutralize completely the lime in the skin4 ,if a greater amount of acid be used the skins begin to absorb acid before the lime in the interior is neutralized2 but1 provided the lime on the surface of the skins is removed1 that remaining in the interior is forced out during the course of the bating process 7see ,chapter ,,iii474 ,if more acid were used1 then it would require to be added so slowly that time would be wasted unnecessarily in doing the work4 ,with regard to the use of other acids for deliming1 ,lamb considers formic acid preferable to hydrochloric1 and states that the removal of lime is more effectively accomplished by its use4 ,he attributes a pulling down action to the calcium formate produced1 so that less formic acid is required than would be equivalent to hydrochloric1 merely regarded as a solvent for lime4 ,we shall refer to this point again in ,chapter ,,ii4 ,it may be stated here that the author has obtained better results by the use of a mixture of formic and acetic acid1 in equal proportions1 than from either acid alone1 but that the cost of working is considerably greater than with hydrochloric acid4 ,lactic acid is in fairly common use as a deliming agent4 ,in practice #a per cent4 lactic acid 7#ej per cent4 strength7 calculated on the wet weight of pelt1 is used1 added gradually in small quantities4 ,this does not remove the whole of the lime1 but sufficient for the skins to puer quickly4 ,some tanners measure their acid per dozen skins4 ,in a case which came under my notice1 #abjj c4c4 #ij per cent4 formic acid were being used for ten dozens medium goat skins at a temperature of #ce ,c41 time #a-a_/d hours4 ,the following table1 due to ,professor ,h4 ,r4 ,procter1#h gives the cost of dissolving #a lb4 of lime at present approximate prices of the various acids4 ,the dissociation constant ,k shows their relative 8strength20#i the equivalent1 ,eq41 the weight in lb4 of #ajj per cent4 acid required to dissolve #bh lb4 of lime4 ,ordinary wet limed hides1 unhaired and fleshed1 contain only about #d lb4 lime per #ajjj lb4 wet weight4 #h ,tanners' ,year ,book1 #aiaa1 p4 #ei4 #i ,see ,chapter ,,iii4 ,,cost ,,of ,,acids ,,to ,,remove #a ,,lb4 ,,lime4 ---------------------------------------- ------------------- ,cost ,strength ,cost for ,acid ,eq4 ,k per cwt4 per cent4 #a lb4 ,ca,o ---------------------------------------- ------------------- s4 d4 d4 ,hydrochloric #cfe say #bjj #c #c #cae #ad ,sulphuric #dij #d #j #iej #jh ,oxalic #fcj #ja #cj #d #iij #ha ,formic #dfj #jjbad #ce #j #hgd #gj ,lactic #ijj #jjach #bf #j #dig #ahj ,acetic #fjj #jjjah #ah #j #djj #ajj ,butyric #hhj #jjjaae #ba #j #hbh #hj ,boracic #fbj #jjjjjjjja #bg #j #iij #fe ---------------------------------------- ------------------- ,it will be seen from the above table that sulphuric is the cheapest acid to use2 but1 owing to the insoluble nature of the calcium sulphate1 it is best to use hydrochloric acid4 ,procter has suggested using a mixture of sulphuric acid and common salt in molecular proportions1 so as to avoid the iron which is generally present as an impurity in commercial hydrochloric acid4 ,the author has tried this1 and found it perfectly satisfactory4 ,for a complete discussion of chemical deliming1 see ,procter's 8,principles of ,leather ,manufacture10 chapter xiii4 ,quite recently butyric acid1 which is now being manufactured on a commercial scale by the process of ,dr4 ,effront 7,brussels71 has come into use for deliming4#aj and is likely to become a useful acid1 as it can be manufactured cheaply4 ,according to ,parker1 it dissolves less skin substance than formic1 acetic or lactic acids1 which observation is confirmed by ,thuau4 ,the quantity required per #ajj lb4 of ordinary washed sheep skin is about #a_/b lb4 of the #hj per cent4 acid4 ,it is used in exactly the same way as other acids1 i4e4 it should be added in small quantities1 suitably diluted1 at successive intervals of time4 #aj ,see also ,l',acide ,butyrique dans la ,tannerie1 ,urbain ,j4 ,thuau1 ,le ,cuir1 ,aug4 #aiaj4 ,also ,collegium1 #aiaj1 pp4 #cdg1 #cfc4 ,acid salts are also used for deliming1 and ,procter suggested sodium bisulphate ,na,h,s,o#d 78,principles10 p4 #aee74 ,more recently1 sodium bisulphite 7,na,h,s,o#c7 has been recommended2#aa the skins are tumbled for half an hour with a dilute solution1 which combines with the lime according to the following equation-- 7#a7 ,ca7,,oh7#b ,na,h,s,o#c ,ca,s,o#c ,na,o,h ,h#b,o if sulphides are present the reaction is-- 7#b7 ,na#b,s #b,na,h,s,o#c ,h#b,s #b ,na#b,,so#c #aa ,le dchaulage des ,peaux en tripe1 ,ettore ,guisiana 7,turin71 ,coll4 #aiaj1 p4 #ad4 ,after this treatment the theoretical quantity of hydrochloric acid1 diluted with plenty of water1 is run in through the axle of the tumbler1 and the skins run another half hour4 ,the reactions are-- 7#a7 ,ca,s,o#c #b;,h,cl ,ca,cl#b ,,so#b ,h#b,o 7#b7 ,na#b,,so#c #b;,h,cl #b,na,cl ,,so#b ,h#b,o ,the sulphurous acid evolved in this way slightly swells the skins1 and also removes stains due to the alkaline polysulphides2 it is also said to remove salt stains4 ,illustration3 ,fig4 #c4--,puer ,wheel1 with ,cover ,removed4 ,illustration3 ,fig4 #d4--;,elevation of ,puer ,wheel 7back74 ,a more interesting process1 introduced by ,dr4 ,gr4 ,eberle#ab as a bating process1 but which is really a deliming process1 consists in using organic acids in the form of their anhydrides1 lactones1 or lactides4 ,during the process these anhydrides1 lactones1 or lactides1 are gradually decomposed with formation of the free acids1 which in a nascent condition unite directly with the lime in the skins4 ,the anhydrides of acetic1 propionic1 butyric and lactic acid have been tried1 the lactone of -oxybutyric acid ,,ch#b ,,ch#b ,o1 and the lactide of lactic acid4 _/ ,,ch#b ,,co #ab ,verfahren zum ,beizen von ,haten1 ,ledertechnische ,rundschau1 ,no4 #bd1 #aiaj4 ,coll4 #aiaj1 p4 #cgb4 ,after washing and deliming1 the goods1 warmed to a temperature of #ij to #ajj ,f41 are now measured in the truck above described1 and put as quickly as possible into the bating paddle4 ,this is constructed to carry two trucks4 ,the figures 7,figs4 #c1 #d and #e7 show a modern paddle adapted for puering light skins1 such as goat1 sheep1 splits 7grains71 either with dung or with an artificial bate4 ,illustration3 ,fig4 #e4--;,end ,elevation of ,puer ,wheel4 ,the inside dimensions are3 length1 #d ft4 #f in42 width1 #d ft42 depth1 #b ft4 #f in4 ,a copper pipe of two coils is provided at the back1 through which steam is passed for maintaining the temperature of the wheel--the goods are prevented from coming in contact with this pipe by a perforated board4 ,another steam pipe1 jointed so that it may be turned in and out of the paddle1 is provided for heating up the wheel to the required temperature before beginning the bating4 ,this pipe is not shown in the drawing4 ,the thermometer can be read while the paddle is in motion4 ,a suitable speed to keep the goods in motion is twenty revolutions per minute4 ,the whole wheel is covered in1 for the purpose of preserving the heat1 and also to exclude light and air1 which are prejudicial to the action of the bacteria4 ,such a paddle1 or wheel1 has a capacity of #bjj gallons liquor1 or #ijj litres1 and will bate #be dozens of average grains1 weighing in the wet state #aajj lb4 or #ejj kilos4 ,the dog dung1 which is usually obtained from hunting kennels1 and of which the composition is given in ,chapter ,,ii41 is simply diluted with water in the paddle2#ac five buckets1 weighing about #afe lb41 are required for the above quantity of goods4#ad #ac ,when the puer is dirty it should be diluted with water and strained through a bag1 or the diluted puer may be put into a tub and the heavy grit and dirt allowed to fall to the bottom of the vessel4 ,puer from hunting kennels is usually clean enough to use without this process4 #ad ,the quantities of puer used vary considerably in different works4 ,at ,trent ,bridge1 #aj to #ae lb4 of wet puer from hunting kennels are used per #ajj lb4 of wet pelt4 ,in a ,german works1 #ae kilos of fairly dry dog dung are used per #ajj kilos of pelt 7,blsse74 ,in an ,american works1 two buckets 7one bushel7 wet dog dung were used to puer #aj dozens of #h lb4 calf skins4 ,this is equal to about #fb lb4 of puer to #ajj lb4 of skin1 which seems an excessive quantity4 ,in an ,italian works1 two kilos dry dung were used to #bj skins of sheep1 equivalent to about four kilos per #ajj4 ,in an ,english tannery1 #ajj hides for harness leather required four bushels by measure of pigeon dung1 costing #as4 #f;d4 per bushel 7one bushel equals eight gallons74 ,the amount used depends on the state of the goods1 the prevailing weather1 and1 further1 on the quality of the puer4#ae ,when the temperature is maintained at #dj ,c41 ordinary limed goods1 which have been washed1 come down in from one to three hours4#af #ae ,a ,german firm1 who supply dry dog and pigeon dung for bating purposes1 recommend that the material should be spread in a warm room at #cj ,c41 and moistened up to #hj per cent4 of its weight with an infusion of oat straw1 and continuously turned over until completely softened4 ,other materials may be used for the fermenting fluid in place of the oat straw infusion1 such as broth made from waste fleshings1 whey1 or even a simple inorganic solution1 such as is used for cultivating bacteria1 consisting of-- #b parts potassium phosphate4 #a part magnesium sulphate4 #a part calcium nitrate4 #ae part calcium chloride4 #ajj parts water4 ,this procedure is neither more nor less than an application of the principles of bacterial cultivation and propagation1 shown to be practically useful in the bating process by ,professor ,h4 ,becker1 of ,frankfort1 and by the ,author in various publications 7see ,chapter ,,vii474 #af ,there is considerable variation in the length of time required to bring down the skins4 ,lamb states that half an hour is frequently sufficient1 but at ,trent ,bridge #b-c hours are generally required4 ,the causes of the variation are not altogether clear1 but depend partly on the previous history of the goods 7fellmongering1 liming1 etc471 and partly on the water used4 ,during puering1 the lime soaps in the skin are decomposed1 and the fat set free--in an estimation of the fat1 #jaea per cent4 on the wet skin was found before puering1 and #bdh per cent4 after puering4 ,the fat thus set free can be removed to a great extent by scudding2 but in modern practice this is not pushed to extremes1 as the grain is liable to be damaged by excessive scudding4 ,the fat is afterwards removed from the dry leather by means of benzine or other solvent1 employed in a suitable apparatus4 ,illustration3 ,fig #f4--,sir ,john ,turney's ,scudding ,machine for ,sheep ,grains4 99,scudding499--,when the goods are 8down10 they are ready for scudding4 ,this operation in the case of grains is performed either by hand over the beam1 or by means of a special scudding machine4 ,the scudding machine figured 7,fig4 #f7 was invented by ,sir ,john ,turney in #ahhj1ag and is the only type of machine which will safely scud split skins4 ,it will readily be understood that the usual type of scudding machine1 in which a spiral knife is used1 would tear the delicate structure of the grain4 ,the ,turney scudding machine works with hard1 circular brushes1 which revolve against a wooden roller carrying the skin4 ,at the same time a continuous stream of water1 at a temperature of #aaj ,f41 is sprayed upon the skins from a perforated pipe4 #ag ,the original ,turney scudding machine1 was invented in #ahga1 and patented in that year4 ,the specifications are numbered #acea1 and #ccaj1 #ahga4 ,it was also patented in ,america4 ,specification ,no4 #aca1dhj1 dated ,september #ag1 #ahgb4 ,improvements in apparatus for cleaning and scouring hides and skins4 ,after scudding1 the skins are washed in cold water for about ten minutes4 ,this checks the action of the puer1 and also washes away any loose dirt4 ,they are then ready to pass on to the drench 7,chapter ,,ix471 or to the pickling process1 or direct to the tan liquor1 according to the kind of leather required4 99,the ,bating of ,hides for ,harness or ,dressing ,purposes499--,the hides intended for harness leather1 or for dressing purposes1 are usually bated with hen or pigeon manure4 ,the exact process varies in different tanyards1 being dependent upon the condition of the pelt prior to bating1 as to whether it is bated directly after fleshing or receives a preliminary deliming4 ,the process is also dependent upon the amount of bating action required for the specific purpose prior to tanning1 but the following three methods are in actual use1 and may be taken as typical methods3-- ,harness ,backs4--,about a hundredweight of hen manure is put into a suitable tub or vat capable of holding about fifty gallons2 some thirty gallons of water1 at a temperature of about #ajj ,f41 is poured on to the manure1 and the whole is thoroughly stirred up by means of a wooden stick or plunger1 working the manure about in order to mix it to a consistence of thin soup4 ,the vat is now stored in a warm place1 so that the temperature is kept about #gj ,f4--it is customary to store this in the boiler-house1 or some similar warm room4 ,it should be stirred two or three times a day1 until it begins to show signs of working2 two days is generally sufficient for this4 ,a pit is now prepared1 with the necessary amount of water2 and1 by the aid of a steam pipe1 or other similar means1 the temperature of the water is raised to #gj1 and the contents of the bate tub are now added4 ,this should be poured into the pit through a sack1 or a canvas filter1 so as to keep back stones1 solids1 feathers1 and other extraneous matters4 ,the pit is now thoroughly plunged1 and the goods entered2 these should be handled up three to four times a day for two days4 ,at the end of two days the goods are usually scudded1 by working the back on an ordinary unhairing beam with an unhairing knife4 ,they then go into a fresh pit containing a new solution of bate made up in the same manner1 and1 when sufficiently bated1 which generally takes about three days1 the goods are removed from the pit1 scudded again by working them over with a slate scudding tool1 when they are ready for tanning4 ,some tanners give them a bath of boracic acid prior to their going into the tanning liquor2 this has the effect of materially brightening the colour4 ,the second pack of harness backs go into the same liquor--which must be re-warmed to a temperature of #gj--;in which they are handled as before for about two days1 and are finished off in a new liquor made as above described4 ,it will be understood1 therefore1 that in a tanyard1 working regularly1 the pack of backs go first into an old bate for two days1 and are then finished off in a freshly made one2 so that each pack gets two days in an old pit1 and one or more days in the new4 ,the bate in the tub may also have a second water1 or be strengthened4 ,dressing ,hides4--,for these goods a somewhat stronger bating effect is required1 and pigeon manure is therefore frequently used4 ,the preparation of the bating liquor is as described above1 both as regards quantity and temperature of the water and time of maceration4 ,the whole process may be carried out exactly as described for harness backs1 but the following is an illustration of another method in practical use4 ,imagine four ordinary bating pits1 worked in a round4 ,the first pit is very old1 having had three packs of hides through it2 the second having had two packs1 and the third one pack2 and the fourth is made new4 ,the goods1 after unhairing and fleshing1 and washing1 are put into the first pit quite cold1 are handled in this three times on the first day1 and afterwards put into the second pit1 the temperature of the second pit having been previously raised to #fe--the cold pelt going into this pit reduces the temperature to about #fj4 ,they are handled in this pit twice1 and remain overnight2 and the third day they go into the third pit1 the temperature of which is raised to #gj before the goods go in4 ,they are raised1 scudded thoroughly on the grain1 and new liquor is made from new bating liquor prepared as described above2 the goods are now entered1 handled at least twice a day1 and1 if insufficiently bated1 are left overnight4 ,by the next day they will probably be sufficiently 8down0 to permit of them going on to the scudding beam and thence on to tanning4 ,in the event of any hide being insufficiently bated--in other words1 if the 8bone0 has not completely disappeared in the inner part of the hide--they are returned once more for three or four hours1 the temperature of the pit being raised to #gj with a steam coil4 ,by this system1 which is known as a system of 8sets10 it will be noticed that the pits are worked in a round of four2 the first pit1 or oldest1 being used more or less as a wash pit1 the actual bating taking place in the second1 third and fourth pits4 ,no pit has more than four packs passing through it1 and the temperature never rises above #gj1 or1 at the outside1 #ge4 ,the reason of the comparatively low temperature is due to the fact that in pit bating1 if the temperature is raised above #ge1 the grain of the hide becomes affected before the internal 8bone0 is sufficiently soft1 which results in a tender grain1 which considerably affects the resulting staining or dyeing which the leather usually receives before it is put on the market4 ,the ,third ,process4--,this process is suitable for either harness or dressing hides1 and differs from the above-described process only in the fact that instead of bating the hides in pits1 a latticed drum is used in order to keep the hides in constant motion4 ,this consists of a large pit1 in which a latticed drum revolves two-thirds immersed in the liquor4 ,the bate liquor is made up as usual1 and the temperature of the liquor raised to #ge or #hj ,f42 the hides are then placed in the latticed drum1 which revolves at from four to six revolutions per minute1 and1 if the goods are put in the drum in the morning1 and if the temperature is kept at about #gj ,f41 the hides are generally sufficiently bated by evening4 ,they may then be taken out of the drum1 scudded1 and left suspended in boracic acid overnight1 and can then be taken to the liquor next morning4 ,where there is considerable motion1 even the heaviest hides will stand a temperature of #ge1 and even #hj4 ,some tanners who use the latticed drum method1 do not place their hides in the drum until the afternoon2 they are drummed for about an hour in the cold bate1 and left overnight2 next morning the temperature of the bate is raised to #ge1 and the drum started2 they are then removed from the drum towards the afternoon1 when sufficiently 8down0 to admit of them passing forward into the next process4 ,the above are three typical methods in common use in ,england1 but many modifications of these processes exist4 ,everything depends upon the amount of lime in the hide1 on the number of haulings or handlings given to the goods1 and the temperature or the conditions under which the hides are bated1 so that no hard-and-fast lines can be laid down4 ,much also depends upon the method of liming used1 prior to the bating4 ,it must be borne in mind that the bating of hides1 and even of kips1 differs materially from the bating of goat and sheep skins1 as one has to deal with double or even treble the substance4 ,if the bate is worked at a temperature of even #gj or #ge1 there is the danger of the grain being seriously affected before the bate has penetrated to the interior of the pelt1 unless the goods are kept in constant motion4 ,instead of a latticed drum1 large paddles are used in some factories4 ,if the pit is large enough the paddle causes both hides and liquor to revolve1 and thus gives the required movement necessary for a regular and even 8bating effect0 to be obtained4 ,,chapter ,,ii4 ,,the ,,chemistry ,,of ,,bating4 8,and now1 as we cannot understand the frame of a ,watch1 without taking it into pieces2 so neither can ,nature be well known1 without a resolution of it into its beginnings1 which certainly may be best of all done by ,chymical ,methods0--,,jos4 ,,glanvill1 #affh4 ,professor ,h4 ,r4 ,,procter1 in his 8,principles of ,leather ,manufacture10 #aijc1 p4 #aec1 has given a very complete account of chemical deliming1 and also of the bating and puering processes4 ,meunier and ,vaney1 8,la ,tannerie10 #aijc1 give a general review of our knowledge of these processes up to that date4 ,these accounts are extremely useful1 but treat the subject in a general manner4 ,i propose to treat of the particular case of puering by means of an infusion of dogs' dung in water1 as ,i believe this will give an insight into all the other bating processes4 ,so far as the purely chemical action of the bate goes1 it consists in the solution of the lime contained in the skins1#ah thus setting free a certain portion of skin substance which was combined with the lime1 and the subsequent solution of more or less of this skin substance4 #ah ,limed sheep grains1 or ,pelts1 which have been limed for splitting1 contain from #c per cent4 to #f per cent4 ,ca,o on the dry skin 7see footnote1 p4 #g71 and about #hj per cent4 of water4 ,in a typical case of a fully limed grain1 the lime was found to be distributed as follows3-- ,free uncombined lime 7,ca,o7 #ag per cent4 on the dry skin ,ca,o combined with skin #be ,ca,o as carbonate1 or other salts #ad ----- #ef ,thus1 #ge per cent4 of the total lime in the skin was in the caustic state4 ,if the skin be cut during the progress of the bating operation1 and a solution of phenolphthalein applied to the cut surface1 the course of bating may be followed1 and it will be found that the caustic lime disappears from the skin in a very short period of time1 accompanied by the sudden collapse of the fibres4 ,we shall treat of this more fully in ,chapter ,,iii4 ,after puering1 the lime 7,ca,o7 contained in the skin1 amounts to #je to #ji per cent41 calculated on the dry skin4 ,this lime is in a perfectly neutral state1 and is more or less in combination with the fibre of the skin4 ,the exact state in which the lime exists in the skin after puering is not known1 and would form a very interesting subject for research4 ,if a fresh puer be made and boiled for half an hour1 then allowed to cool to #ie ,f41 it will be found to remove the lime from the skin in a very similar way to an ordinary bate1 but it has not so rapid a reducing action as an unboiled bate4 ,in this case both bacteria and enzymes are destroyed1 so that the action may be put down to the chemical constituents of the bate4 99,chemical ,composition of the ,puer499--,the mineral constituents of the fces1 both in dogs and human beings1 are well known1 owing to the study of the processes of digestion and nutrition in physiological laboratories2 but the organic constituents are yet little known1 and the sum of the weight of those at present estimated is far from the total of these matters present4 ,it is a mistake to suppose that the fces represent the residue only of the food taken4 ,strassburger#ai estimates that bacteria alone account for nearly one-third of the dry matter4 ,in addition1 the intestinal mucous membrane is an important excretory channel for lime1 magnesia1 iron and phosphoric acid1 as has been shown by analyses of fces from men and dogs1 during prolonged fasting4#bj ,even when no nitrogenous food is eaten1 the dry fces always contain from #d to #h per cent4 of nitrogen2 in a dog fed on meat it amounts to #fe per cent4 #ai ,schmidt1 and ,strassburger1 ,die ,fces des ,menchen 7,hirschwald1 ,berlin71 #aija4 #bj ,lambling1 ,prcis de ,biochimie1 #aiaa1 p4 #bba4 ,in making a chemical analysis of the fces1 the mineral matter is estimated in the ash in the usual way for ash of organic substances1 with special precaution1 on account of the phosphates present4 ,the material is first charred1 the salts removed by acetic acid2 the acetic acid solution is then decanted1 the residue washed with distilled water1 and the combustion then completed4 ,the acetic solution and washings are added to the final ash1 the whole evaporated to dryness1 and gently ignited to decompose the acetates4 7,cf4 ,bull4 #df1 ,u4,s4 ,dept4 of ,agriculture1 ,washington1 #ahii47 ,in estimating the fats1 the dry puer is ground up with sand1 then extracted with ether in a ,soxhlet4 ,the fats are present in four states3--#a1 neutral fats2 #b1 free fatty acids2 #c1 alkali soaps1 soluble in ether2 #d1 small quantities of lime and magnesia soaps remaining in the residue in the ,soxhlet4 ,for details as to the separation and estimation of these1 ,lewkowitsch's 8,oils1 ,fats and ,waxes0 7,macmillan7 should be consulted4 ,the separation and estimation of the organic constituents in the puer1 is one of the most difficult problems of physiological chemistry1 and to include the methods used would demand a special treatise beyond the scope of the present volume4 ,hoppe-,seyler's 8,physiological ,chemistry10 and ,allen's 8,commercial ,organic ,analysis10 vol4 iv41 may be consulted2 and there is a mass of useful information in ,dr4 ,ren ,gaultiers' 8,prcis de ,coprologie ,clinique0 7,paris1 ,baillire et ,fils1 #aijg74 ,it is proposed to give here the results of a number of analyses of dog dung made by the author and others1 and to discuss the action of the various bodies upon the skins4 ,many more experiments and much research requires to be done1 before the complete action of the bate is clear1 but only by the method of experiment with the various bodies present can the problem eventually be solved4 ,analysis of raw puer from hunting kennels 7,quorn7 showed the approximate composition of #ajjj grm4 of raw puer1 containing #aej grm4#ba of dry matter to be as follows3-- #ba ,another sample contained #acf grm4 dry matter4 ,grammes ,sodium chloride and sodium sulphate #ba ,sodium ammonium phosphate #adj ,earthy phosphates1 principally ,ca#c7,,po#d7b #ccf ,ferric phosphate #jhg ,calcium sulphate #aid ,silicic acid #cdj ,calcium in solution as ,ca,o #adb ,total ,p#b,o#e in solution #djj ,non-volatile acids 7as lactic7 #cjj ,volatile acids 7as acetic7 #bbj ,amines 7as ammonia7 #fbj ,enzymes #cff ,nitrogenous bodies not included in the above1 consisting of complex amido-acids1 leucin1 tyrosin1 xanthin1 and other purine bases1 indol and skatol #agjj ,organic matter1 cellulose1 etc4 mostly insoluble1 including fats and soaps #gjjj ,on the dry matter the amounts extracted by various solvents were3-- ,per cent4 ,water #bdjc ,alcohol #bbbg ,,cs#b #aeeg ,c#b;,h,cl#c 7,tri-chlorethylene7 #adde ,petrol4 ether #acbc ,no carbohydrates 7sugars7 capable of reducing ,fehling's solution were found in the puers examined4 ,the ash#bb of the dry fces from dogs fed on a flesh diet varies from #bj to #cdbg per cent41 with the following percentage composition3-- #bb ,gaultier4 ,see also analysis given in ,chapter ,,vi4 ,silica #gjd ,,co#b #dfb ,,so#c #gcg ,fe#b,o#c #dbb ,ca,o #bebi ,p#b,o#e #bfda ,mg,o #aeeb ,cl #aej ,alkali #eec ,in a dog weighing #cj kilos41 fed on a mixed diet of #ejj grm4 meat and #bjj grm4 starch1 #ghf grm4 dry fces were obtained containing #bcgf per cent4 ash of the following percentage composition3-- ,ca,o #bbc ,p#b,o#e #bed ,fe#b,o#c #ajf ,mg,o #ih ,,so#c #ej ,cl #jb ,alkali #aa ,insol4 in ,h,cl #bah ,it is obvious that the composition of the fces will vary with the food given1 and in this connexion it may be stated that the puer used was obtained from dogs fed on a mixture of boiled horseflesh and oatmeal porridge1 about equal quantities4 ,sometimes charcoal and cabbage are mixed with the food1 in this case the puer is very dark coloured4 ,the dark colour so produced is to be carefully distinguished from the dark colour caused by decomposition of the puer4 ,we cannot leave out of account the urinary products1 which1 in the case of dung from hunting kennels1 are always present1 though in varying quantities4 ,the total nitrogen in #aebj c4c4 of urine was found#bc to be #aei grm4 #bc ,abderhalden1 ,physiological ,chemistry4 ,each #ajj grm4 total nitrogen was distributed as follows3-- ,urea #hei ,,nh#c #da ,creatinine #cc ,uric acid #je ,n in other compounds #eg ,the inorganic compounds were3-- ,per cent4 ,sulphur 7as sulphate7 #cca ,p#b,o#e #cih ,cl #fcj ,the urine of carnivora is acid1 that of herbivora is neutral or alkaline4 ,urea1 which is the chief nitrogenous constituent1 is very quickly fermented by several species of bacteria1 and entirely decomposed into ammonium carbonate1 so that it is this latter body which acts in the bate4 ,uric acid exists in the urine of the carnivora1 but the quantity is small compared with the urea4 ,herbivora excrete1 mostly1 hippuric acid ,,nhc1 ,h#e,o _/ 7benzoyl-glycocoll1 ,,ch#b 71 ,,cooh and this difference may account to some extent for the difference in bating property1 that of the excreta of herbivora being very small as compared with the carnivora1 such as the dog4 ,in this respect there are differences which are difficult to account for2 for instance1 the excreta of the lion1 fed entirely on a meat diet1 was not found to have such a powerful bating effect as ordinary dog puer4 ,even after keeping for several weeks1 to allow the bacterial flora to develop1 the result was the same4 ,the analysis of the lion's dung gave the following results3-- ,per cent4 ,water #eib ,ash #baa ,lime 7,ca,o7 #ajc ,phosphates 7,p#b,o#e7 #ajfg ,organic matter #aig ,dog dung contains some non-volatile bases of the purine group1 such as xanthin 7,c#e;,h#d,n#d,o#b7 and guanin 7,c#e;,h#e,n#e,o71 but the action of these bodies in the bate1 has not been studied4 ,it is also extremely probable that these and similar bodies are formed during the bating by a process of auto-digestion of various proteids4#bd ,the quantity of fat in dry puer1 amounts to #aj-aa per cent4 ,cholesterol was present4#be ,part of the fat is in the form of lime and magnesia soaps1 but part in the form of an emulsion1 which probably plays an important part in the puering process4 ,the function of the fatty constituents of puer is one of the problems on which further research is necessary4 #bd ,cf4 ,mann4 ,chemistry of the ,proteids1 #aijf1 p4 #dcb4 #be ,the cholesterol was obtained by extracting the dry puer with ether1 saponifying with alcoholic potash4 ,shaking out the unsaponifiables with ether1 evaporating to dryness4 ,the residue was taken up with absolute alcohol1 decolorized with animal charcoal4 ,on cooling1 characteristic crystals of cholesterol separated4 ,hoppe-,seyler finds from #a per cent4 to #d per cent4 cholesterol in fces4 ,see also ,gaultier1 ,coprologie ,clinique1 p4 #afj4 ,the colouring matters of the puer are nearly all derived from bile products4 ,most of them are found in the petroleum extract1 which contains far more of the colouring matters than the chloroform extract4 ,the following bile colouring matters have been prepared by ,merck1 of ,darmstadt3 bilihumin1 biliprasin1 bilirubin1 bilifuscin1 biliverdin4#bf ,so far as has been ascertained by the author1 their effect in the bating is nil1 but1 in so far as they impart colour to the pelt1 they are detrimental4 #bf ,for qualitative tests for the colouring matters1 see ,gaultier1 ,prcis de ,coprologie ,clinique1 p4 #aei4 ,experiments on the action of bile are given in the paper reprinted in ,chapter ,,vi4 ,recently ,eberle#bg has proposed to add a proportion of gall juice 7bile7 to a bate containing pancreatic enzymes1 with a view of energizing the latter4 ,this part of the subject will be dealt with in ,chapter ,v4 #bg ,english ,patent1 #babjb1 #aiji4 ,see also ,chapter ,,viii4 99,the ,reactions of the ,puer499--,the organic acids are present principally in the form of the sodium or calcium salts4 ,the intestinal juices contain sodium carbonate1 but this is neutralized by lactic acid found in the intestines1 so that the excreta usually have an acid reaction4 ,the reaction of a fresh puer liquor is faintly acid to litmus1 but this acid is immediately neutralized by the introduction of the skins1 so that the rest of the bating process takes place in a neutral or alkaline medium1 and the quantity of lime removed by the free acids is probably small4 ,the acidity of a filtered puer liquor made up freshly and titrated with ,n_/#e soda1 and phenolphthalein as indicator1 was found to equal #aj c4c4 ,n_/#a acid per #ajjj c4c4 of bate4 ,in the volume of liquor used1 namely1 #ijj litres1 this would neutralize only #bej grm4 of lime 7,ca,o74 ,the determination of the exact acidity or alkalinity of puer liquors by ordinary methods with indicators is not easy1 as the end reactions are not sharp4 ,the liquor above described was alkaline to methylorange and litmus1 although acid to phenolphthalein1 and the results also vary somewhat1 according to the quantity of bate used for titration1 and according to the strength of the acid or alkali used4 ,the method used1 both at the ,trent ,bridge laboratory and ,messrs4 ,doerr and ,reinhart's laboratory at ,worms1 is as follows3-- ,the puer liquor is filtered through a ,schleicher and ,schulls hard filter1 ,no4 #fjb1 #ah-a_/b cm4 diam42 #ej c4c4 are taken1 #d drops of phenolphthalein solution 7#aj gr4 dissolved in #cjj c4c4 alcohol7 added1 and titrated with ,n_/#e acid or alkali as the case may be4 ,if the acidity be determined by adding excess of alkali and titrating back1 a larger amount of acid is found than by direct titration4 ,in the above-mentioned case1 an indirect titration showed an acidity equal to #ah c4c4 ,n_/#aj acid per #ajj c4c4 of liquor4 ,on adding the alkali to a fresh filtered puer liquor1 a flocculent precipitate is produced1 which appears to be due to the decomposition of proteid compounds of weak organic acids1#bh the alkali uniting with them and setting the proteids free4 ,as these compounds are undoubtedly decomposed by the lime in the skins1 it seems probable that the acidity available for neutralizing lime may be greater than that shown by direct titration4 #bh ,probably syntonin1 or bodies of a similar nature 7see ,allen4 ,comm4 ,org4 ,anal4 iv4 p4 #d74 ,the supposition is supported by the fact that solutions of puer have a slight laevorotatory action on polarized light4 ,see also note on ,van ,liers paper1 ,coll4 #cgf1 #aiji1 p4 #hbc4 ,a method which was suggested by me for the estimation of the acidity of tan liquors may be applied also to the examination of the bate liquors1 namely1 the method by which the electric potential between a hydrogen electrode dipping into the bate liquor1 and a standard calomel electrode1 is used to determine the neutral point 7for details see ,chapter ,,iii471 using the potentiometer devised by ,dr4 ,h4 ,j4 ,s4 ,sand4#bi #bi ,see paper entitled1 8,the ,employment of the ,electrometric ,method for the ,estimation of the ,acidity of ,tan ,liquors10 by ,h4 ,j4 ,s4 ,sand1 ,ph4,d4 ,d4,sc41 and ,d4 ,j4 ,law1 ,b4,sc4 ,f4,i4,c41 ,j4,s4,c4,i4 #aiaa1 p4 #c2 also ,part ,,ii41 by ,wood1 ,sand and ,law1 ,j4,s4,c4,i4 #aiaa1 p4 #hgb4 ,puer liquors1 titrated in this manner with ,n_/#aj soda or ,h,cl until a potential of #jfi volts is reached 7at which point phenolphthalein turns from colourless to red71 gave the following results per #ajj c4c4 filtered liquor4 ---------------------------------------- --------------------- ,alkali ,no4 ,description of ,reactionc4c4 ,n_/#aj or ,required for ,liquor ,acid ,neutralization ---------------------------------------- --------------------- #a ,new puer ,acid #gd alkali before goods #b ,the same after ,alkaline #jeg acid goods #c ,new puer ,acid #ha alkali before goods #d ,the same after ,alkaline #cbe acid goods #e ,used puer after,alkaline #ejj acid goods #f ,spent puer ,alkaline #ff acid ---------------------------------------- --------------------- ,determinations made in this way are more accurate than the colorimetric method above described4 ,puer liquors after use are found by the electrometric method generally on the alkaline side1 whereas such liquors show neutral to phenolphthalein owing to some action of the bate constituents on the indicator4 ,,puer ,,liquors ,,in ,,electrometric ,,apparatus4 ---------------------------------------- --------------------- c4c4 of c4c4 of ,p4,d4 ,n_/#aj ,,koh ,p4,d4 ,n_/#aj ,h,cl ,before required ,after required ,no4 ,skins for ,skins for ,description of ,liquor #ej c4c4 #ej c4c4 volt liquor to volt liquor to #jfi volt #jfi volt ---------------------------------------- --------------------- ,a#a #jfbb #aie 44 44 ,new puer ,a#b 44 44 #jgdg #ai ,a#a after #b packs skins ,b#a #fjg #cg 44 44 ,new puer ,b#b 44 44 #ggj #ca ,b#a after #c packs skins ,c#a #ehj #dc 44 44 ,new puer ,c#b 44 44 #gfb #bh ,c#a after #b packs skins ,d#a #ehj #eb 44 44 ,new puer ,d#b 44 #jh #fhj 44 ,d#a after #a pack skins 7still on the acid side of #jfi7 ,e#a #egj #fb 44 44 ,d#b #d buckets more puer ,e#b 44 44 #gbj #jh ,e#a after #a pack skins ,f#a #faj #cj 44 44 ,new puer ,f#b 44 #je #fhj 44 ,f#a after #a pack skins 7still on the acid side of #jfi7 ---------------------------------------- --------------------- ,the potential at the neutral point1 using an auxiliary electrode filled with ,n_/#a potassium chloride1 was #jfi volts4 ,potentials below this point1 therefore1 indicate an acid reaction1 and1 conversely1 potentials above #jfi volts indicate an alkaline reaction4 ,the apparatus is thus very useful in following the course of the bating process4 ,the initial potential also enables the hydrion concentration of the bate liquor to be determined directly 7see ,chapter ,,iii474 ,it was found that during the bating of a pack of skins the hydrion concentration of the liquor diminished from #aj-eb to #aj-gd normal4 ,such acidities as are found by this method1 e4g4 #g-h c4c4 ,n_/#aj acid per #ajj c4c41 are too great if made up by taking a solution of the free acids4 ,the ionization must be almost entirely repressed by the presence of sufficient neutral salts of the same acids in the bating liquid1 in order to obtain a similar result to the puer4 ,the table opposite gives the values found for a series of puer liquors1 made with dog manure from hunting-kennels4 ,the reaction of puer liquors 7expressed in c4c4 of ,n_/#a alkali or acid per #ajjj c4c4 of bate71 in a series in which the washed goods were run for one hour in old puer1 out of which goods had been taken1 and then transferred to a freshly-made puer1 was as follows3-- ---------------------------------------- ,bate ,before ,goods ,after ,goods ---------------------------------------- ,old puer ,neutral #bh c4c4 acid ,fresh #aj c4c4 alkali ,neutral ,old puer ,neutral #dj c4c4 acid ,fresh #aa c4c4 alkali ,neutral ---------------------------------------- ,these figures were obtained by the ordinary colorimetric method described on p4 #cb4 ,adding together the alkalinity of the bate run away1 and the acidity of the new bate which is neutralized1 the total for #a and #b #ch c4c4 ,n_/#a acid1 and for #c and #d1 #ea c4c4 ,n_/#a acid4 ,multiplying by #haj 7volume of bate less volume of dry skin71 we find that the skins have neutralized #cjgh and #daca litres ,n_/#a acid respectively4 ,since one litre of ,n_/#a acid will neutralize #bh grm4 of lime1 it follows that the lime removed by the bate was in one case #hfb grm41 in the other case #aaeg grm4 ,the #ejj kilos1 of wet washed grains introduced into the paddle contain approximately #je per cent4 of lime ,ca,o1 equivalent to #bejj grm4 altogether4 ,as will be seen from the figures given in table1 p4 #ce1 the free acids present in the fresh bate are only capable of neutralizing #aj #haj c4c4 of normal alkali1 and this is equivalent to #bbe grm4 of ,ca,o1 or #i per cent4 of the total lime4#cj #cj ,eitner1 ,der ,gerber1 #eff1 p4 #gg1 states that little or no neutralization of lime by acids or acid salts takes place in the bate4 ,in addition to this1 a considerable amount of lime is removed from the skins which is not found afterwards in solution1 but which is precipitated in an insoluble form during the course of the bating process4 ,in an experiment to determine the amount of this insoluble lime1 the following figures were obtained3-- ,,lime ,,in ,,puer ,,liquor1 ,,grams ,,per ,,litre ,ca,o4 ,before ,skins ,after ,skins ,soluble lime #jai #jdhe ,insoluble lime #jac #jdhe ---- ----- #jcb #jigj ,it will be noted that the amount of insoluble lime has increased to a greater extent than the soluble lime1 showing that part of the lime from the skins has been precipitated in an insoluble form4 ,the increase of lime in the solution is #jbie grm4 per litre of soluble lime1 and #jcee grm4 per litre of insoluble lime1 a total increase of #jfej grm42 that is1 the ratio of soluble lime to insoluble lime in the original puer is #adf 3 #a4 ,in the used puer it is #a 3 #a1 so that in the above case more than half the lime removed from the skins 7#ede per cent47 has been precipitated in an insoluble form1 some of it in the form of calcium phosphate1 and the remainder probably in the form of calcium oxalate4 ,crystals of calcium oxalate may be seen under the microscope in the puer residues4 ,the oxalic acid is produced by bacterial action1 as has been shown by ,zopf#ca and ,banning#cb2 but it is difficult to estimate it in the bate1 and a reliable analytical method of doing so requires devising4 #ca ,ber4 ,deutsch4 ,botan4 ,ges4 #aijj1 xviii4 #cb1 ,j4,s4,c4,i4 #aijj1 #chf4 #cb ,centr4 ,bakt4 ,parasitenk1 ii4 ,abt4 viii41 #cic1 etc41 ,j4,s4,c4,i4 #aijb1 #aaea4 ,a further #cj per cent4 to #dj per cent4 of the lime in the skins is removed by the chemical action of the complex amines of the organic acids1 and by the mechanical effect of the paddle or drum1 so that the final result is more or less as follows3-- ,per cent4 ,lime neutralized by free acids #i ,lime dissolved by complex amines #be ,lime precipitated #cj ,lime remaining in the skins #cf --- #ajj ,the lime remaining in the skins is not in the caustic state1 but principally in the form of neutral salts 7see footnote to p4 #bd74 ,illustration3 ,fig4 #g4 ,some of these neutral salts appear to be absorbed by the skin during the course of the bating1 for1 on examining pieces of the same skin at frequent intervals during the operation1 and determining the ash1 it was found that a minimum point for ash content was reached in about ten minutes1 after which the ash actually increased4 ,the results are shown in the following table1 and also graphically by the curves1 ,fig4 #g--;in which ,a is a 8grain0 previously washed as free from lime as possible2 ,b1 an unwashed 8roan40 ,the effect of the absorption of inorganic matter is very noticeable in both cases4 ,a part of the effect only is apparent since a certain amount of skin substance passed into solution4 ,,variation ,,of ,,ash ,,percentage ,,during ,,puering4 ---------------------------------------- --------- -- ,ash1 per cent4 on ,dried ,skin ---------------------------------------- -------- ,time of ,puering ,washed ,delimed ,limed ,roan 7,b7 in ,minutes ,grain 7,a7 ---------------------------------------- -------- #j #bhh #gjc #e #bia -- #aj #cbj #ced #ae #dhj -- #bj #djh #dbd #be #dbi -- #cj #dhe #eai #ce #dei -- #dj #dgj #ede #de #dfj -- #ej #dde #efg #ee #ddb -- #fj -- #ejj ---------------------------------------- -------- ,the following analyses give the amount of lime in solution before and after the bating of the skins1 in grams per litre of filtered puer liquor3-- ---------------------------------------- ------------------ ,no4 ,bate ,before ,goods,after ,goods,increase of ,ca,o ---------------------------------------- ------------------ #a ,fresh puer #jajh #jfb #jeab #b #jcd #jgb #jch #c #jbj #jeb #jcb #d #jai #jdi #jcj #e ,old puer #jed #jhd #jcj #f ,old puer1 goods #jih #ach #jdj not washed4 #g ,french puer #jcjh #jedh #jbd shop4 ---------------------------------------- ------------------ ,the limit of the quantity of lime in solution in a normal puer1 in the form of calcium salts1 appears to be about #a grm4 per litre4 ,if more lime be presented to the liquor1 the goods stop coming down4 ,if now fresh dung be added1 they will continue to come down1 but the quantity of lime in solution does not increase2 the excess of lime is precipitated1 partly as phosphate and partly as oxalate1 in the way stated above4 ,the type of reaction by which the lime is dissolved is similar to that occurring between ammonium chloride and lime1 and is expressed by the formula-- #b,,nh#d;,cl ,ca7,,oh7#b ,ca,cl#b #b,,nh#c #b;,h#b,o and in the case of the calcium carbonate in the skins-- #b,,nh#d;,cl ,ca,c,o#c ,ca,cl#b 7,,nh#d7b;,,co#c1 so that every molecule of lime neutralized1 liberates two molecules of ammonia4 ,jean states that the production of ammonia progresses regularly during the puering1 and that when the free ammonia reaches #jb grm4 per litre the bate is unfit for further use4 ,but if the excess of ammonia be neutralized by the addition of phosphoric acid1 which also precipitates the lime brought in by the skins1 the bate may be kept in constant use for some time4 ,jean found #jjf grm4 ,,nh#c per litre in the puer as made up for use1 and1 after one lot of skins had been put through1 #jjhf grm4 per litre2 after two lots of skins1 #jace grm4 per litre4 ,in ordinary puer wheels1 as used at ,trent ,bridge1 we find-- 7a7 7b7 ,before goods #jjhaf #jjhej grm4 ,,nh#c per litre ,after #jjhcc #jjgii so that there is little or no difference before and after puering in this case4 ,part of the ammonia formed escapes into the air2 a further portion unites with the acids which are being formed by the action of bacteria in the bate 7see ,chapter ,,iv471 and it is also probable that part combines in some way with the calcium salts in the bate4 ,the actual reactions taking place are of course much more complicated than this simple case1 because1 instead of ammonia and ammonium chloride1 we have a number of complex salts formed by combination of organic acids with substituted ammonia derivatives1 such as methylamine1 ethylamine1 etc4 ,the chief of these are ethylamine and methylamine butyrates1 and lactates1 and probably propionates1 although ,i have not been able to separate the latter4#cc #cc ,fitz 7,berichte1 #ahgf-ahhd1 see ,herfeldt1 ,j4,s4,c4,i4 ,may #ca1 #ahie71 has shown that lactates in dung are decomposed by bacteria1 the chief product being propionic acid4 ,the reaction with the butyrate is represented by the equation-- #b;,c#b;,h#e,,nh#b;,c#c;,h#g;,,cooh ,ca,o #b;,c#b;,h#e,,nh#b ,c#c;,h#g;,,coo ,ca ,h#b,o _/ ,c#c;,h#g;,,coo by which it will be seen that the amine is set free just in the same way as ammonia in the equation on p4 #dj4 ,in order to ascertain if the action of the amines was the same as that of salts of ammonia1 ,i prepared the following compounds and tested their action on skins at #cg ,c41 a control piece of the same skin being kept in water at the same temperature4 ,the time in each case was one hour4 ,all the solutions were neutral4 #a4 ,ethylamine lactate3 skin swells slightly1 not 8down0 equal to puer4 #b4 ,ethylamine propionate3 skin moderately fallen1 not equal to puer4 #c4 ,ethylamine butyrate3 about the same as ,exp4 #a4 #d4 ,trimethylamine butyrate3 very similar action to ,exp4 #c and to ammonium butyrate4 ,the results correspond very closely with those obtained in previous experiments with various salts of ammonia 7see ,chapter ,,vi471 and justify us in assuming that in all essential respects the action is similar4 ,the free amines enter into fresh combinations with acids which are produced by bacterial action1 and this process goes on until all the nutrient material is exhausted4 99,the ,role of ,phosphates in the ,bate499--,there is no doubt that the phosphates in the bate play an important part1 but exactly in what manner they act is not yet known4 ,one of the principal effects is the part they play as 8buffers10 in preventing brusque changes of the hydrion concentration during the bating process4 ,this has been pointed out by ,soerensen in the case of enzyme reactions4 ,the phosphates in dung are mixtures1 which are capable of fixing both acids and bases2 and so the small quantities of these bodies1 which are produced by the splitting up of the organic matter1 are taken up or released as the case may be4 ,the chemistry of the phosphates is one of the most complicated branches of inorganic chemistry1 and1 as a consequence1 the determination of the constitution of the various phosphates in dung is an extremely difficult matter1 and demands a lengthy research4 ,for instance1 besides the salts directly derived from the three phosphoric acids1 ,,hpo#c1 ,h#c,,po#d and ,h#d,p#b,o#g1 phosphates exist which are probably derived from hypothetical di-1 tri-1 or meta-phosphoric acid1 n,,hpo#c1 and a few salts have been isolated1 which are perhaps derived from the hypothetical acids ,p#d,o#g7,,oh7#f and ,p#aj,o#ai7,,oh7#ab 7,watt's ,dict41 art4 8,phosphates074 ,including the double salts1 there are more than #af different calcium salts of phosphoric acids4 ,the normal lime salt ,ca#c7,,po#d7b is very slightly soluble in water1 but its solubility is increased by the presence of various organic substances such as exist in dung1 and part of the soluble phosphates found in the bate are undoubtedly nothing more than this salt in solution4 ,this fact has been utilized in the manufacture of the artificial bate ,erodin 7see ,chapter ,,vii474 ,the phosphoric acid in the puer is partly precipitated by the lime in the skins1 and hence diminishes during the bating process4 ,in some cases practically the whole of the phosphoric acid disappears from the solution4 ,the following experiment will give an idea of the amount of lime precipitated as phosphate4 ,a filtered puer liquor was analysed for lime and phosphoric acid1 before and after the skins were passed through4 ,the results were1 in grm4 per litre-- ,before ,after ,soluble lime as ,ca,o #jcfd #jedj ,p#b,o#e #jdbd #jcbh ,increase of lime1 #jagf grm42 diminution of ,p#b,o#e1 #jjif grm4 ,calculated to calcium phosphate ,ca#c7,,po#d7b1 this amount of phosphoric acid has combined with #jaad grm4 ,ca,o4 ,assuming that the ratio of soluble to insoluble lime is the same as given1 p4 #cf1 then the lime is distributed as follows3-- ,grm4 ,increase of soluble ,ca,o #jagf insol4 ,ca,o #jbaj ,lime as ,ca#c7,,po#d7b #jaad ,hence oxalate 787 #jjif ,that is1 of the lime precipitated1 #ed per cent4 is phosphate1 #df per cent4 oxalate4 ,in another puer containing before use #jchc grm4 ,p#b,o#e per litre1 only traces of phosphates were found in solution after goods had been puered in the liquor1 and in some analyses by ,jean 7#ci7 the following figures were obtained3-- ,,grams ,,of ,,phosphoric ,,acid ,,per ,,litre4 ,fresh dung after four days' maceration #jjhb ,bate after one pack of skins #jjcf ,bate after two packs of skins #jjah ,although these figures are less than those found at ,trent ,bridge1 they confirm the fact that the soluble phosphates diminish during the bating process4 ,the phosphates in solution thus diminish during the bating1 and are found in the insoluble matter which separates out4 ,a small portion of the lime remaining in the skins is also converted into phosphate by the action of the bate4 ,in an experiment to determine this1 a portion of the same skin was taken before and after puering4 ,the pieces were dried1 ashed1 the ash dissolved in dilute nitric acid1 and the phosphates precipitated by ammonium molybdate4 ,in the skin before puering no phosphates were present1 but in the skin after puering there was a small amount1 though not sufficient to weigh4 ,the action of ammonium phosphate on the lime in the skin is very small4 ,a skin was treated with a #ja per cent4 solution of ammonium phosphate at #ajj ,f4 for one hour4 ,the ,ca,o in the dry skin was estimated1 and found to be-- ,per cent4 ,before the experiment #aic ,after #ade ,a considerable amount of calcium phosphate was found in the skin after the experiment4 ,other chemical compounds existing in the puer1 or formed by the action of bacteria 7principally ,b4 coli commune1 see ,chapter ,,iv471 are indol1 skatol and a number of aromatic oxyacids1 principally para-oxyphenyl-propionic acid1 a little para-oxyphenylacetic acid and skatol carbonic acid4 ,in addition1 tyrosin1 leucin1 tryptophan and mercaptans have been separated4#cd #cd ,rettger1 ,amer4 ,jour4 of ,physiol41 viii4 p4 #bhd2 ,koch's ,jahresbericht1 #aijc1 p4 #aab4 ,with these bodies no experiments on skin have been made1 so far as ,i am aware1 except with indol and skatol4 ,kathreiner found that these had a slight reducing action on skin1 so that one may say they play some part in the puering4 ,the action of the bile salts1 glycocholate and taurocholate of soda1 also needs investigation4 ,these have an indirect effect in the puer1 as they favour the development of some species of bacteria 7chiefly coli7 and hinder the growth of others4 ,some action has also been ascribed to sulphuretted hydrogen1 but in the puer liquors which ,i have examined no ,h#b,s was found1 either before or after the skins were entered4 ,it will be seen that the ammonia compounds in the bate are not of themselves particularly fitted for the purpose of removing lime#ce from the skins1 but owing to bacterial action 7which we shall treat of in ,chapter ,,iv471 acids are produced which combine with the ammonia1 and in this way the small quantity of these compounds originally present is continually being regenerated while the bating is in progress4 ,ammonia is set free by the lime in the skins4 ,it is then neutralized by acids produced by bacteria1 and thus acts as a carrier for the acids1 and the bate remains in a nearly neutral condition4 ,as the lime increases in the liquid the action of the bacteria diminishes1 and finally the alkalinity becomes too great to allow the bacterial or chemical action to proceed further4 #ce ,deliming with acids when carefully done takes out more lime than the puer1 without in any way injuring the skin1 but when tanned with sumac the bellies and axilla are harsh1 and of a browner colour than in a puered skin4 ,analysis showed no more lime in the brown portions than in the centre of the skin1 where the colour was quite bright and satisfactory4 ,it will be noted that the concentration of the active salts in the bate is extremely small4 ,if the amine compounds be assumed to consist of ethylamine butyrate or lactate1 the concentration of the solution is approximately #a grm4 per litre2 it is important that the concentration of salts should not greatly exceed this amount4 ,i have found by experiment with ammonium chloride solutions1 that the best reducing action is provided by a concentration of #jg to #a grm4 ,,nh#d;,cl per litre2 if the concentration be raised to #b or #c grm4 per litre1 the skins become 8leathery0 and do not fall properly4 ,the alkalinity must not be greater than #c-e c4c4 ,n_/#aj per #ajj c4c4 bate1 for the bate to work at its best4 99,solution of ,skin ,substance during the ,puering499--,the determination of the total skin substance dissolved by the puer is best done by ,kjeldahl's method before and after the goods4#cf #cf ,vide ,procter1 ,l4,i4,l4,b41 #aijh1 p4 #fd4 ,the difference in the total nitrogen found multiplied by #ef gives the amount of skin substance dissolved by the bate1 assuming the amount of nitrogen in the dry ash-free skin to be #agh per cent4 ,if very great accuracy be required1 a small correction for nitrogen1 brought into solution from the puer itself1 is necessary4#cg ,this correction must be ascertained for the particular puer used by actual experiment4 #cg ,in a blank experiment to determine this1 #jjdgf grm4 ,n per litre was found to be brought into solution from the puer4 ,the following figures give the results in grams per litre obtained in the puering of sheep grains4 #ej c4c4 of the filtered puer liquor are slightly acidified with sulphuric acid1 evaporated nearly to dryness and ,kjeldahled in the usual way4 ,mean ,total nitrogen before skins #jbfcb #jbfjd #jbegf after #jdibh #jdhdd #jdgfj ,difference -- #jbbdj ,equivalent to #abed grm4 skin substance per litre4 ,this was somewhat over a kilogram of skin substance for the paddle in question1 and equal to #a per cent4 of the dry ash-free skin4 ,as to the differentiation of the dissolved skin substance into albumoses1 peptones1 monamino acids1 diamino acids1 ammonia1 etc41 a modification of ,stiasny's method#ch for the examination of soaks and old limes may be used4 #ch ,stiasny1 ,on ,old ,limes4 ,collegium #aiaj1 p4 #aha4 ,the method is based on the fact1 discovered by ,schiff1 that formaldehyde reacts with amino acids1 forming methylen-amino acids1 which are distinctly acid and allow a sharp titration with phenolphthalein as indicator1 while the amino acids themselves react almost neutral4 ,soerensen has worked out a method on this basis for the determination of different amino acids1 and for tracing the course of hydrolysis of albuminous matters4 ,instead of using phenolphthalein as an indicator1 the electrometric apparatus of ,sand 7see p4 #gf7 is employed4 #ej c4c4 of the filtered puer liquor are put into a beaker1 the hydrogen electrode is immersed in the liquor1 and the potential difference 7,p4,d47 observed2 this gives the hydrogen ion concentration of the solution4 #aj c4c4 of neutral formaldehyde solution 7#dj per cent47 are added1 and the ,p4,d4 again observed2 it will be found to diminish rapidly1 but soon becomes constant1 indicating that the reaction is a quick one4 ,the increase of acidity1 as shown by the lowering of the potential difference1 is due to the acidity developed by the combination of the formaldehyde with the amino acids forming methylen-amino acids of appreciable hydrion concentration4 ,the amount of such acids is estimated by titrating with ,n_/#aj caustic soda solution until the ,p4,d4 rises to the same voltage as that originally found4 ,the following figures were found in an experiment3-- ,original ,puer ,the same ,liquor ,after ,goods 7volts7 #jfa #jfi after #aj c4c4 formalin #jec #jed ,n 7,kjeldahl71 grm4 per litre #jcacf #jeicf ,increase of ,n -- #jbhjj ,n_/#aj soda for #ej c4c4 to original voltage #gj #aaf c4c4 increase ,n_/#aj soda -- #df #a c4c4 ,n_/#aj soda mg ,n -- #cje ,a preferable method is to add decinormal acid or alkali to the original liquor until the ,p4,d4 of #jfi is reached1 at which point the liquor will be neutral to phenolphthalein1 and1 after adding formaldehyde1 to titrate with ,n_/#aj soda until the ,p4,d4 of #jfi is again reached4 ,the factor which connects the amount of decinormal soda required for the titration1 after the addition of formaldehyde1 with the total nitrogen as determined by ,kjeldahl's method1 will afford information as to the extent of the hydrolysis undergone by the proteid matter1 in the same manner as ,stiasny 7loc4 cit471 has proposed to differentiate the dissolved proteid matter in lime liquors4 ,as hydrolysis proceeds the percentage of nitrogen in the molecule increases1 being at its maximum in the ultimate nitrogenous product ammonia2 the factor1 therefore1 becomes less as hydrolysis becomes more advanced4 ,for ammonia #a c4c4 ,n_/#aj soda #ad mg4 ,n hydrolized gelatin#ci #bi ,witte peptone completely hydrolized#ci #cf lysin #bh arginin #ef histidin #db #ci ,stiasny4 ,collegium #aiaj1 p4 #ahd4 ,we may conclude that the skin substance dissolved in the puer liquor is hydrolized almost as completely as gelatin is by boiling with sulphuric acid4 ,i have previously pointed out that dilute acids dissolve a certain amount of skin substance 7see p4 #aeg71 and in this connexion1 ,dr4 ,georges ,abt has given me the results of some experiments1 on the solubility of skin in various organic acids1 which he made in ,vienna4 ,pieces of skin1 weighing #dj grm4 in the wet state1 were allowed to remain for one month in ,n_/#aj solutions of the acids4 ,the ,n was then determined1 by ,kjeldahl's method1 with the following results1 expressed as per cent4 of the wet skin dissolved3-- ,per cent4 ,acetic acid dissolved #jfde ,lactic #bbg ,butyric #jegg ,formic #adg ,it will be seen that butyric acid dissolved the least amount of skin1 lactic acid dissolving close upon four times as much4 99,scud499--,a certain amount of skin substance comes away in the 8scud40 ,this is the liquid squeezed out of the skin by the pressure of the scudding knife after puering4 ,the liquid has the same composition as the puer liquor out of which the goods have been taken1 and in addition contains large quantities of pigment granules1 wool roots1 and some skin substance1 which together constitute the so-called 8filth0 of the skin4 ,analysis of a scud from ,english sheep grains showed only #jafd per cent4 ,n1 equivalent to about #a per cent4 skin substance 7#iae grm4 per litre74 ,fat1 #gi grm4 per litre4 ,eberle and ,krall have recently#dj analysed the fatty matter which adheres to the men's knives in scudding lamb skins for gloving work4 ,they obtained the following results3-- #dj ,ueber die ,zusammensetzung des beim ,beizen von ,lammfellen mit ,hundekot abfllenden 8festen ,schmutzes03 ein ,beitrag zur ,beizenfrage4--,coll41 #aiaa1 p4 #dde4 ,per cent4 ,water #big ,fat #dbj ,fatty acids combined with lime #ff ,albuminous matter soluble in water #ch ,hair and insoluble albuminous bodies #add ,ash 7containing #eg per cent4 ,ca,o7 #ce ,the fat had a-- ,melting-point #dj-dd ,saponification number about #aba ,iodine number #caf ,hehner value #iai ,acid value #ic ,dr4 ,fahrion found1 in a sample of the fat extracted with ether3-- ,per cent4 ,iodine number4 ,unsaponifiable #dgf #bgc ,fatty acids 7sol4 in petrol ether7 #cic #cjb ,oxy acids 7sol4 in ether7 #ace #acd ,the figures obtained for the fat therefore agree closely with those for wool fat4 99,action of the ,bird-,dung ,bate499--,the depleting action of the pigeon- and hen-dung bate is very similar to that of the puer1 or dog-dung bate2 but the bating process with these materials1 as we have seen 7p4 #ah71 is carried out at a lower temperature1 and is consequently more prolonged4 ,the principal difference between the two bates appears to be a chemical one1 due to the fact that bird dung contains all the urinary products which are present only to a small extent in the dung of mammals4 ,in birds uric acid is the chief stage in nitrogenous katabolism1 the mechanism of its formation being a process of synthesis in the liver 7,halliburton74 ,urea is also present in considerable amount1 and does not appear to be so easily decomposed as the urea in animal urine4#da ,as we shall show in the next chapter1 urea1 and probably also urates1 greatly facilitate the permeability of gelatine1 and to this fact may be ascribed the more gradual action of bird-dung bates4 ,if we attempt to bate hides with dog-dung1 the grain of the hide is found to be attacked and destroyed before the bate has penetrated to the interior of the hide4 ,on the other hand1 a bird-dung bate may be used at a temperature of #ch to #dj ,c4 for the puering of skins destined for light leather1 but its action is not so favourable as that of the puers4 #da ,urea is present to the extent of #e per cent4 in samples of ,peruvian guano4 ,,composition ,,of ,,bird ,,excreta4 ---------------------------------------- ------------------- ,pigeon ,hen ,duck ,goose ---------------------------------------- ------------------- ,moisture #ehcb #efjh #fjhh #dffe #ggjh ,organic matter #bhbe #aief #aibb #cfab #acdd ,phosphates #bfi #bed #ddg #cae #jhi ,carbonate and sulphate #age #cjh #ghe #cja of calcium #bid ,alkaline salts #aii #jhb #aji #jcb ,silica and sand #gjj #agib #ffi #ajge #efe ---------------------------------------- ------------------ #ajjjj #ajjjj #ajjjj #ajjjj #ajjjj ---------------------------------------- ------------------ ,containing nitrogen equal to ammonia #age #aba #jgd #jhe #jfg ---------------------------------------- ------------------ ,macadam#db states that pigeon dung is the most concentrated4 ,hen manure contains the largest proportion of phosphates1 and is followed by duck droppings4 ,that of the goose is the least valuable4 ,the preceding table is taken from his paper4 #db ,manures1 ,natural and ,artificial1 ,w4 ,ivison ,macadam4 ,jour4 ,soc4 ,chem4 ,ind4 #ahhh1 p4 #gi4 ,procter#dc quotes the following1 as a mean of #dj analyses of pigeon dung by ,schulze3-- #dc ,principles of ,leather ,manufacture1 p4 #agi4 ,per cent4 ,water #bajj ,nitrogen #bec ,phosphoric acid #agi ,potash #adf ,he remarks that the action of bird dung is more penetrating1 but less softening and loosening than that of dog dung1 and this effect may be explained by what has been said above4 ,unfortunately1 far less work has been done on the bird-dung bate than on the puer1 and there is a wide field open for research in this direction4 ,,chapter ,,iii4 ,,the ,,physics ,,of ,,bating4 8,the most important aspect of any phenomenon1 from a mathematical point of view1 is that of a measurable quantity40 --,,maxwell4 ,it is impossible in the space of a short chapter to give an adequate explanation of the physical changes taking place during the puering process4 ,an outline only can be given1 and perhaps a few signposts to indicate for those interested1 in what direction further work can be usefully done4 ,it is obvious that if more be attempted1 a treatise on physics and physical chemistry would be required2 such a work is beyond the scope of the present volume4 ,it is to be hoped that the whole of the questions dealt with here1 including the physical chemistry of skin and of the whole tanning process1 will shortly be fully treated by the master hand of our greatest tanning chemist1 ,professor ,h4 ,r4 ,procter4 ,since tanning1 in the earlier stages1 is for the greater part a physical absorption1 or colloidal co-precipitating action1#dd the physical state of the skin fibre1 or condition of the skin before it enters the tanning liquor1 is of the greatest importance4 ,in fact1 the whole of the operations to which the skin is subjected previous to tanning are directed towards changing its physical state1 and the chemical changes undergone are small and principally hydrolytic4 #dd ,stiasny1 ,kritische und ,experimentelle ,beitrge zur ,aufklrung der ,gerbvorgnge4 ,collegium #aijh1 p4 #aag4 ,wood1 ,compounds of ,gelatin and ,tannin4 ,collegium #aijh1 p4 #did4 ,the two most important physical influences over which we have control are pressure and temperature4 ,the pressure during puering is practically constant1 viz4 the atmospheric pressure1 but1 as we shall see later1 a diminution of pressure is favourable to falling or depletion4 ,it would1 therefore1 be interesting to conduct experiments on puering in vacuo1 or under reduced pressure4 ,before considering the effect of temperature and the changes in the volume of the skin during puering1 it will be well to consider the properties of the skin and the puer liquor4 ,in the skin prepared for tanning1 practically all the keratin and epidermis and soluble matters are got rid of1 and we have a mass of fibres which are composed of collagen1 a proteod1 which by prolonged boiling with water is converted into gelatin4 ,neither the chemical formula nor the molecular weight of collagen is known with certainty1 but1 from a series of ultimate analyses1 the change of collagen into gelatin is represented by ,hofmeister#de by the following equations3-- #de ,allen1 ,comm4 ,org4 ,analysis1 iv4 p4 #dei4 ,c#ajb;,h#adi,n#ca,o#ch ,h#b,o ,c#ajb;,h#aea,n#ca,o#ci collagen gelatin from which it will be seen that he assigns a molecular weight of #bdaf to collagen1 and #bdcd to gelatin4 ,other considerations1 however1 make it probable that the molecular weight is double the above figures4 ,gelatin is a typical colloid1 and we may consider that skin is practically a colloid with a structure 7a very important point1 as we shall see later71 but behaving in many ways as gelatin4 ,the puer solution is to a large extent colloidal4 ,therefore1 both the skin and the puer are in the colloidal state4 ,in the typical crystalloid solution of an electrolyte1 the dissolved body is separated into its molecules1 and to a large extent into individual ions1 while1 in the colloid state1 the units of distribution are either large and often conjugated molecules1 or more frequently minute particles composed of many molecules united by cohesive attraction4#df ,in the case of the skin the molecules are not free to move1 but are held in place by the structure of the skin1 and the fibres thus act as semi-permeable membranes1 with capillary spaces between them1 in which water and other fluids are merely held by capillary attraction4 #df ,procter1 ,colloidal ,chemistry4 ,brit4 ,assoc4 ,rep4 #aijh4 ,if filtered puer liquor is put into a vessel closed by a membrane of skin1 and the whole immersed in clear lime water1 the puer solution becomes turbid in a short time1 but the outer solution remains clear1 showing that the skin is permeable to the lime solution 7crystalloid71 but not to the puer solution 7colloid74 ,it was observed1 however1 that the acids contained in the puer diffused through the membrane2 this was shown by the addition of a few drops of phenolphthalein to the lime solution1 when the pink colour disappeared after a short time in the neighbourhood of the skin4 ,these phenomena are due to osmosis4 ,it is the fundamental property of all animal membranes1 to allow some substances to pass through them more easily than others4 ,in many cases1 such membranes1 while freely permeable to water1 are practically impermeable to certain substances in solution1 and play the part of sieves in directing and controlling the diffusion4 ,in the case of skin the phenomena are complicated by the fact that the skin combines chemically with many substances in solution1 and thus we do not always know what part to assign to chemical combination and what to the osmotic phenomena4 ,procter has shown 7,colloid4 chem4 ,beihefte #aiaa1 ii41 pp4 #bdc-bhd7 that1 while gelatin is very permeable as such to solutions of acids and salts1 there may be formed in the presence of excess of acid a hydrolysable chemical complex of the nature of a salt1 in which the gelatin functions as base1 and which is probably less permeable to acids and their salts than the neutral gelatin4 ,the conditions would then be similar to those which obtain when solutions of an acid and its salt are separated by a movable membrane1 which is permeable for the acid and water but not for the salt solution4 ,from the organized structure of the skin surface1 it is unlikely that osmosis takes place between the skin itself and the outer solution1 with the two surfaces of the skin as semi-permeable membrane4 ,osmotic action is most likely to occur in the interior of the skin1 between the skin fibres themselves and the interfibrillar spaces4 ,the colloids in the puer solution1 which constitute a large proportion of its material1 cannot1 from their nature1 penetrate the skin4 ,this may be shown by the above-mentioned experiment4 ,from this it is reasonable to assume that the lime is not actually dissolved from the interior of the skin by the puer acids1 but that solution takes place for the most part after it has diffused out into the puer solution4 ,it is probable1 however1 that part of the bodies of acidic character present in the puer are capable of penetrating the skin fibre1 as has been explained above4 ,the intensity of the osmotic action of puer upon skin must depend upon the quantity of substances contained in it1 to which skin substance acts as an impermeable membrane1 and which on that account induces an osmotic pressure between the outer puer solution and the solutions held in the skin fibre4 ,the effect of puering does not necessarily imply the actual expulsion of water from the skin--in fact1 well puered skin may quite possibly contain as much water as it did in the swelled condition4 ,the difference consists in the manner in which the water is held in the skin1 and its freedom to move from parts which are submitted to pressure4 ,in the swollen skin1 the fibres may be conceived as swollen by the water and holding it in the same manner as a gelatin jelly2 after puering1 the fibres are 8fallen10 and the water1 hitherto held by them1 surrounds them in the liquid form4 ,the osmotic pressure#dg of a solution of concentration c1 temperature ,t1 and pressure p1 is the difference of pressure exerted on both sides of a semi-permeable membrane in thermodynamic equilibrium1 having on the one side the solution under the above condition1 and on the other side the pure solvent under the pressure p#j of its own saturated vapour4 ,on this definition the osmotic pressure of a normal solution is over #bb atmospheres1 or #ccj lb4 per sq4 in42 and since a saturated lime solution is about #a_/bj normal1 its osmotic pressure is about #aa atmospheres1 or #af lb4 per sq4 in4--this represents the force causing the lime to diffuse into water in which the skin is placed4 ,the puer solution being of a colloidal nature1 exerts practically no osmotic pressure1 and since it contains substances capable of entering into combination with lime1 the latter is removed from the surface very quickly4 ,the curve representing the removal of lime by water has been given in ,chapter ,i41 p4 #f4 ,that for puer is not of such a simple character 7see ,fig4 #g1 p4 #ch71 but it will be seen that the greater part of the lime is removed during the first #aj minutes4 ,the curve is plotted for percentage of ash1 since the lime is no longer in a caustic condition but in the form of salts4 ,it is remarkable that the percentage of ash1 after reaching a minimum1 increases considerably4 ,this phenomenon still requires investigation4 #dg ,m4 ,planck1 ,zeit4 f4 ,phys4 ,chem4 xlii4 p4 #ehd 7#aijc74 99,density of ,skin499--,coming to the consideration of the volume of skin and its changes during puering1 we know that the volume v is the reciprocal of the density1 i4e4-- v #a_/1 and therefore #a_/v4 ,carini#dh has carried out exhaustive experiments on the density of skin during tanning1 but1 so far as ,i am aware1 little or no work has been done as to the effect of puering on the density of raw skin4 #dh ,sull' appliccazione della bilancia idrostatica per il controllo della concia delle pelli1 ,milan1 #aijc4 ,the usual methods of determining density are well known1#di and consist in weighing the body first in air1 then in water or other liquid4 ,if m be the weight of the body1 and it loses the weight w when weighed in water-- m_/w4 #di ,see ,kohlrausch1 ,an ,introduction to ,physical ,measurements1 #ahid1 p4 #dc4 ,see also1 ,weighing ,hides in ,water1 ,c4 ,e4 ,parker and ,g4 ,h4 ,russell1 ,tanners' ,year-,book #aije1 p4 #de4 ,for experiments on skin1 instead of weighing in water it has been found more convenient to use a simple volumenometer1 which was devised by ,mr4 ,douglas ,j4 ,law 7see ,coll4 #aiaa1 p4 #bcj47 ,illustration3 ,fig4 #h4--,volumenometer for ,raw ,skin4 ,the apparatus 7,fig4 #h7 consists of the two vessels ,a and ,b1 connected by means of thick rubber tubing to the burette ,c1 of which the top is enlarged to a bulb4 ,the bottle ,a1 which was specially made for us by ,messrs4 ,townson and ,mercer1 ,london1 is of about #a litre capacity1 and the wide mouth is closed by a stopper1 accurately ground to fit the neck1 and extending down to the bottom of the neck4 ,the upper part of the stopper is elongated to a tube1 which is closed by the tap ,g4 ,the vessel ,a is also fitted with a tap ,e4 ,the vessel ,b serves as a reservoir1 and is used to adjust the level of the liquid in the burette ,c by means of the tap at ,f4 ,to find the volume of a piece of skin1 the method of procedure is as follows4 ,the bottle ,a is filled with water up to the neck1 and the stopper ,d1 carefully greased1 is inserted4 ,the tap ,e is then closed1 and the burette is filled with water4 ,then1 with the taps ,g and ,e open1 the bottle ,a is filled with water up to ,d by raising the burette4 ,g and ,e are then closed1 and by opening the tap ,f the level of the water in the burette is adjusted to zero when ,f is again closed4 ,g and ,e are then opened again1 and1 by lowering the burette1 the water in ,a is allowed to fall below the level of the neck of the bottle4 ,e is then shut1 the stopper ,d removed1 and the piece of skin is carefully introduced1 avoiding air bubbles4 ,the stopper ,d is then replaced with the tap open1 and1 by opening ,e and raising the burette1 the water is allowed to come up to the stopper ,d again4 ,the taps ,g and ,e are then closed1 and the volume of the piece of skin read off directly from the burette scale4 ,volumes up to #ej c4c4 are measurable as described above1 but larger volumes may be measured if a known volume of water is run from the burette into the reservoir before introducing the skin4 ,by using various solutions in the apparatus instead of pure water1 the real swelling or contracting effect of these upon the skin may be observed4 ,the skin is introduced into the bottle ,a1 and the solution adjusted to ,g1 which is then closed2 then1 by leaving the tap ,e open1 the real swelling or contraction of the skin is measured by the rise or fall of the liquid in the burette4 ,petroleum or other liquid may be used instead of water2 in some cases1 the use of petroleum is more advantageous4 ,the density of dry gelatin as determined by ,ldeking is #adab1 which is not greatly different from that of skin4 ,carini gives the following figures for ox-hide3-- ,skin with hair #adej depilated with lime #adbe depilated with sodium sulphide #adda but does not give details how these figures were obtained1 and if corrected for ash and fat4 ,the density of limed and puered sheepskin1 determined by drying the skin over sulphuric acid until the weight was constant1 then determining the volume in petroleum1 gave the following results3-- ,limed skin #abcce ,puered #abeij ,i4 ,by determining the volume of the wet skin in the volumenometer1 and the per cent4 of water on drying the skin1 the calculated densities were-- ,limed skin #adch ,puered #acjj ,,ii4 ,correcting for ash and fat1 the dry ash-free skins had the densities-- ,limed skin #acig ,puered #acce ,,iii4 ,the density of the wet limed skin was #ajfc1 but the density calculated from the results 7,i47 above is #ajdge2 from this1 it is evident the fibres of the swollen limed skin undergo compression on swelling1 or that the water contained in them is in a state of compression1 in the same way as gelatin swollen with water occupies a less volume than the sum of the volumes of gelatin and water4 ,ldeking#ej found for #aj per cent4 gelatin jelly #ajfi2 calculated was #ajda4 ,he attributed the whole of the compression to the water1 so that #a c4c4 of water in a #aj per cent4 gelatin jelly occupied a volume of #jifjfi c4c4 ,see also par4 #d p4 #fh4 #ej ,wiedemann's ,annal d4 ,physik1 xxxv4 p4 #ceb 7#ahhh74 ,it may be of interest to give the figures used in the preceding lines in tabular form4 ---------------------------------------- --------------------- ,limed skin,puered skin ---------------------------------------- --------------------- ,density of wet skin #ajfc #ajec ,per cent4 of water found #hjfc #ghb calculated #giej #gii of ash on wet skin #aga #aag of fat #jaea #bf ,density of dry ash-free skin substance #acigj #accef ---------------------------------------- --------------------- ,in addition to the diminution of the density of the skin by puering1 the increase of fat is very marked4 ,the percentage of water referred to the wet skin may be calculated from the formula 77v#b - v#a7_/7a - v#a77 x #ajj where v#a specific volume of the dry skin4 v#b specific volume of the wet skin4 ,the specific volume of the dry skin 7v#a7 may be calculated from the specific volume of the wet skin 7v#b71 the percentage of water 7w7 being known by the following formula3-- v#a 7v#b - 7w_/#ajj77_/7a - 7w_/#ajj771 and by comparing the volume thus obtained with the volume determined by direct experiment1 the amount of contraction is ascertained4 ,in the case we have been considering 7viz4 limed skin with #hj per cent4 water7 v#b calculated #jiee v#b found #jida ,the specific volume of the dry skin v#a calculated #jfiee v#a found #jhaab ,the difference for the dry skin is surprising1 and considerably greater than anticipated1 but has been verified by a large number of experiments4 ,it may be remarked that the exact determination of the density of skin by drying out pieces is liable to error on account of the non-homogeneity of the pieces4 ,there appears to be some chemical combination between the water and the skin very similar to that between water and alcohol1 and although the figures obtained in the above experiments by this method are accurate1 it is not certain that they represent the true density4 ,it is possible that the interior of the skin may still contain some moisture1 and1 in order to arrive at absolute certainty1 it would be necessary to powder the skin1 and ascertain its density in a finely divided condition4 ,when this is done1 the results obtained are very much more concordant than when pieces of skin are used4 ,the following results were obtained for the density of dry hide powder 7as used for analysis by the ,i4,a4,l4,t4,c473-- ,in petroleum ether #abefh ,in carbon tetrachloride #abegj ,in alcohol #abehj ,mean #abegb ,this is equivalent to a specific volume v#a #jgied4 ,the density of the powdered skin may also be determined in the air volumenometer 7,say2 ,kopp4 ,kohlrausch ,physical ,measurements1 p4 #ec74 99,swelling and ,falling499--,the skin1 in its living condition on the healthy animal1 is the most supple and perfect of coverings1 and in producing soft leathers it is the object of the tanner to retain this supple condition4 ,to do this1 the swollen fibres must1 as we have seen1 be got back to their natural state4 ,the phenomena of swelling and depletion of skin have been discussed by ,krner1#ea and recently ,prof4 ,h4 ,r4 ,procter#eb has published a paper which goes into the whole theory of colloidal swelling4 ,in order to understand depletion1 which is the opposite of swelling1 it is necessary to consider what takes place when a body like skin is swollen4 ,i am indebted to ,dr4 ,th4 ,krner for the following summary of the phenomena of swelling4 ,there are three types of swelling3 #a4 ,capillary attraction2 #b4 ,endosmose2 #c4 ,molecular imbibition4 #ea ,th4 ,krner1 #aj ,jahres4 ,bericht1 d4 ,deutsch4 ,gerberschule zu ,freiberg1 #ahii1 p4 #cb4 #eb ,procter1 ,ueber die ,einwirkung ,verdnnter ,sauren und ,salzlsungen auf ,gelatine1 ,kolloid ,chem4 ,beihefte1 #aiaa1 ii4 p4 #bdc4 ,the last named is of the greatest importance in tanning4 ,krner 7loc4 cit47 enumerates certain principles governing molecular swelling4 #a4 ,a body capable of swelling1 when put into water1 absorbs a definite quantity of the water up to a maximum1 which cannot be exceeded4 7,c4 ,ludwig47 #b4 ,the maximum of swelling depends upon the chemical composition of the body1 on its cohesion and elasticity1 and on the temperature and interior pressure of the liquid4 7,c4 ,ludwig47 #c4 ,power of resistance to swelling increases from the exterior to the interior1 according to a parabolic law2 i4e4 the external layers of the body attain the maximum swelling sooner than the internal portions4 7,l4 ,mathiessen and ,a4 ,schwarz47 #d4 ,the volume of the swollen body is smaller than its original volume1 plus that of the liquid absorbed4 7,quincke47 #e4 ,swelling is accompanied by development of heat4#ec #ec ,duvernoy1 ,e4 ,wiedemann1 and ,ldeking1 ,wied4 ,ann4 xxv4 #ahhe1 p4 #ade4 ,the production of heat is simply due to the contraction1 and not to any chemical phenomenon1 such as hydration4#ed ,this explains a fact well known to tanners1 viz4 that skins swell in cold water and 8fall0 in warm water4 ,riecke#ee concludes that the degree of swelling1 m#b_/,m 7where m#b mass of water absorbed1 ,m mass of the body swollen71 in a space filled with aqueous vapour1 unsaturated1 is a function of the pressure and temperature4 #ed ,rodewald4 ,thermodynamik der ,quellung1 ,zeit4 f4 ,phys4 ,chem4 xxiv4 #ahig1 p4 #aic4 #ee ,zur ,lehre von d4 ,quellung1 ,wied4 ,ann4 liii4 #ahid1 p4 #efd4 ,the velocity of swelling 7,pascheles7 may be expressed by the formula-- d,q_/dt 7,m - ,q7,k where ,m maximum of swelling1 ,q amount of swelling in the time t1 and ,k a constant4 ,the differential quotient d,q_/dt gives the velocity for each moment1 and it will be seen that the swelling becomes slower and slower as the maximum is approached4 ,thus1 the law of the velocity of swelling is identical with that of the velocity of inversion of cane sugar1 itself an application of the law of masses4#ef #ef ,nernst and ,schnfliess4 ,einleitung in die mathematische ,behandlung der ,naturwissenschaft1 ,mnchen #b ,aufl4 #fg4 ,for every process of swelling1 the constant ,k must be determined experimentally from observation of ,m1 and it may be shown that-- ,k #a_/t log7,m_/7,m - ,q77 whence the value of ,k may be calculated for each series of determinations4 ,on the manner in which water is held in swollen colloid bodies1 three hypotheses have been put forward4#eg #eg ,see also ,colloidal ,chemistry1 ,h4 ,r4 ,procter1 ,m4,sc41 ,brit4 ,assoc4 ,reports1 ,dublin1 #aijh4 #a4 ,the hypothesis that colloids have a structure in the form of a honeycomb4 7,btschli47 #b4 ,the water is absorbed at the surface of colloids in a specially condensed form4#eh #eh ,wilhemy4 ,pogg4 ,ann4 cxix4 pp4 #aba1 #abb4 ,the water forms1 with the swollen body1 a 8solid solution40 7,ngeli47 ,swelling1 and its opposite1 contraction1 are connected with the surface tension between the swelling or contracting bodies and the surrounding solution4 ,with diminished surface tension1 the surfaces of contact between the two become greater1 i4e4 swelling takes place1 with simultaneous diminution of the volume of the whole system1 and vice versa4 ,for the absorption phenomena which occur1 the following relation holds good3 ,when a substance in solution diminishes the surface tension at the dividing surface1 its concentration is increased2 it is absorbed4 ,when a substance in solution increases the surface tension at the dividing surface1 its concentration is diminished4 ,in the system water-hide substance the researches of ,wiedemann and ,ldkeing have shown that swelling is accompanied by evolution of heat4 ,since a rise of temperature is favourable to a system formed by absorption of heat1 it therefore hinders swelling and vice versa4 ,this is confirmed by practical experience1 and most bating operations are conducted at temperatures between #ce and #dj ,c4 ,with regard to the influence of pressure on swelling1 a similar law holds good as for temperature1 which may be expressed as follows4 ,when a chemical system is compressed at constant temperature1 its equilibrium is shifted in that direction by which the reaction is accompanied by diminution of volume4 ,quincke1 however1 has shown what appears to be a paradox1 namely1 that swelling is accompanied by diminution of volume1 i4e4 the swelling substance1 plus the water taken up1 occupies a smaller space than the sum of the two constituents taken together2 therefore1 an increase of pressure must be favourable to swelling1 and conversely a diminution of pressure is favourable to 8falling40 ,we must clearly bear in mind that in all cases of swelling1 it is the entry of water into the system which is the cause of the swelling1 and since puering is a process which acts in a contrary direction1 i4e4 the skin falls1 this means that water is expelled from the system1 skin plus water4 ,by direct determination1 from #c to #h per cent4 of water is expelled during puering4 ,calculations made from density determinations are masked by the fact1 above referred to1 that the density of the skin changes during puering4 ,a fallen skin contains less water than when in the swollen condition1 but the difference between the percentages of water in the skin in the two states is only relatively small1 and obviously insufficient in itself to account for the great difference in the physical properties of the skin in the two conditions4 ,it is evident1 therefore1 that the state in which the water is held in the two stages must be different4 ,it is reasonable to suppose that1 in the case of swollen skin substance1 the whole of the capillary cavities of the organized structure of the skin are completely filled with water1 which1 owing to its incompressible nature1 confers upon the skin elastic and unyielding properties which it always possesses in this condition4 ,the water1 entering the organized cell structure in the first place by osmotic pressure1 is fixed there and confers upon the skin1 in part1 its own property of incompressibility4 ,it is a well-recognized fact that1 during the puering process1 large quantities of the skin substance are dissolved by the action of the enzymes in the bate1 and it is probable that the finer organized structure is first attacked4 ,the walls of the cells which hold the water are partly destroyed1 leaving the skin with1 quite possibly1 the same amount of water contained in it as a whole1 but with the water dispersed at large throughout its interior structure instead of being held in the fibres4 ,the result of this is1 that when a small area of the puered skin is subjected to local pressure the water in the portion undergoing compression is free to move into the adjacent portions of the skin1 and there is no force acting upon it1 except that of capillarity1 to cause it to return to that area when the pressure is removed from it4 ,when a portion of a puered skin is compressed1 the surrounding part is always swollen to an equivalent amount4 ,that this view is1 in the main1 correct is supported by an observation of ,abt 7,paris71 that1 while cell nuclei may be demonstrated in the layers near the epidermis of an unpuered skin1 they are entirely absent from a puered skin1 showing that the puer has completely dissolved the nuclear structure of the cells4 ,the swelling caused by alkalis is of a different nature to the swelling caused by acids4 ,procter has pointed out#ei that alkaline swelling is not repressed by sodium chloride1 even when caused by sodium hydrate1 but is repressed by sufficient concentration of the hydroxyl ion in the outer solution4 #ei ,colloidal ,chemistry1 p4 #ai4 ,mller#fj points out that jellies containing certain non-electrolytes 7glucose1 glycerine1 alcohol7 render the diffusion of soluble matter much slower than pure jellies of the same concentration1 but the presence of urea favours the permeability of gelatin and agar jellies4 ,the differences in the velocity of diffusion of various salt solutions through jellies of the same strength1 are thus not due altogether to the greater diffusibility of the particular salt solution1 but are to be attributed to the influence of the salt on the permeability of the colloidal medium4 ,limed skin treated with a #a per cent4 solution of urea at #dc ,c4 is depleted or 8falls10 but both the solution and the skin remain alkaline4 #fj ,allgemeine ,chem4 d4 ,kolloide1 p4 #ac4 ,pibram#fa has recently shown that the swelling and contraction of muscle are to be ascribed to absorption and expulsion of water from the cells of the muscle2 the rapid changes taking place1 are brought about by changes in the concentration and composition of the liquid components of the muscle4 ,lactic and phosphoric acids are produced with enormous rapidity1 and of relatively high concentration2 during a short period these cause instantaneous changes in the swelling of the muscle cells1 followed by a return to their original state4 ,for the evidence of this the original paper must be consulted1 but it goes to show that the equilibrium of the system--colloids1 electrolytes1 water--depends on the proportions and quantities of each of these constituents4 ,the phenomena we are considering thus conform to the general law of mass action 7,guldberg and ,waage74 #fa ,pibram1 ,die ,bedeutung der ,quellung und ,entquellung fr physiologische und pathologische ,erscheinungen4 ,kolloid ,chem4 ,beihefte1 ii4 p4 #a4 99,influence of ,solid ,matter in the ,bate499--,it was first pointed out by ,wood 7,j4,s4,c4,i4 #ahii1 p4 #iia7 that a filtered puer liquor had less action on the skin than an unfiltered liquor containing much finely suspended matter4 ,on adding an inert solid 7kaolin7 to the filtered bate1 the action was hastened4 ,no doubt much of the colloidal matter1 and with it some of the enzymes1 are removed by filtration1 but nevertheless1 the suspended particles in the bate have some effect on the process4 ,in a most interesting paper1 ,perrin#fb has recently shown1 that the granules in suspension in a colloidal liquid function like the invisible molecules of a perfect gas with a molecular weight of #cc x #aj-i4 ,such granules are endowed with the molecular 7,brownian7 movement1 and therefore may exert a mechanical effect on the fibres of the skin4 ,although the mass of the particles is large#fc compared with molecular dimensions1 they are small enough to penetrate the pores of the skin1 and where puering is carried too far1 may become deposited beneath the fine hyaline layer1 and thus render it cloudy and unsuitable for fine colours4 #fb ,perrin1 ,kolloid ,chem4 ,beihefte1 i4 p4 #bba4 #fc ,a particle of gamboge in a colloidal solution has a mass #aji times that of a molecule of hydrogen4 99,hydrogen ion ,concentration of ,puer ,liquors499--,it has already been shown1 in ,chapter ,,ii41 that fresh puer liquors have a certain acidity 7#g c4c4 ,n_/#aj per #ajj c4c47 at the commencement of the operation1 but that at the end they are alkaline 7#c c4c4 ,n_/#aj per #ajj c4c474 ,if an artificially acid liquor be made by diluting hydrochloric acid until it shows the same number of c4c4 by titration1 it will be found far too 8strong10 and will swell the skins4 ,this brings us to the consideration of what is meant by the strength of acids4 ,procter and ,jones#fd have drawn attention to the point in their paper on 8,acids in ,tan ,liquors40 ,as is well known1 the ionic theory affirms that degree of acidity depends on the concentration of hydrogen ions1 a strongly acid solution being one in which the hydrion concentration is great1 an alkaline solution one in which it is extraordinarily minute1 and if we adopt pure water as our standard of neutrality1 a neutral solution is one in which the hydrion concentration is approximately #aj-g normal4 ,a normal solution of hydrogen ions would contain #a gram of hydrogen ions per litre2 in the case of hydrochloric acid this would equal #ace ,n_/#a ,h,cl4 #fd ,acids in ,tan ,liquors1 ,journ4 ,soc4 of ,chem4 ,ind41 #aiaj1 p4 #aced4 ,sand and ,law1#fe and ,wood1 ,sand and ,law1#ff have described the mode of estimating the hydrogen ion concentration in tan liquors directly by means of the electrometric method1 and this method is especially applicable to the estimation of the hydrogen ion concentration in puer liquors4 ,it can also be used to titrate the liquors1 and we have already given some of the results in ,chapter ,,ii4 #fe ,journ4 ,soc4 ,chem4 ,ind41 #aiaa1 p4 #c4 #ff ,ibid41 #aiaa1 p4 #hgb4 ,the method is based on the theory of ,nernst1 that the difference of potential between a metal plate and the solution of one of its salts into which the metal is dipping1 depends on the osmotic pressure of the free ions of that metal in the solution 7in other words1 on the concentration of the solution74 ,in the case of hydrogen ions1 we use a plate of platinum coated with platinum black and saturated with hydrogen1 and the difference of potential depends1 therefore1 on the concentration of the hydrogen ions in solution4 ,illustration3 ,fig4 #i4--;,diagram of ,connexions of ,electrometric ,apparatus4 ,the accompanying figure 7,fig4 #i7 shows the hydrogen electrode ,i1 and the auxiliary electrode ,,ii1 drawn to scale1#fg on the right1 whereas the electrical apparatus is explained diagrammatically on the left4 #fg ,an improved form of hydrogen electrode devised by ,dr4 ,h4 ,sand may now be obtained from ,universitts-mecanikes ,fritz ,khler1 ,leipzig4 ,it is shown at ,i in ,fig4 #aj4 ,the principle of the method of measurement consists in connecting the two ends ,p and ,q1 of a sliding rheostat to the terminals of a dry cell1 ,d1 and balancing the potential-difference to be measured against the potential-difference between one end1 ,p1 and the slider1 ,s1 by means of a special form of enclosed capillary electrometer1 ,e4 ,the value of this potential-difference is read directly on a delicate voltmeter1 ,v4 ,the connexions1 which are found ready-made in the box1 have been drawn out1 whereas1 those to be made by the operator are shown by dotted lines4 ,the steps to be taken by the latter1 consist first in taking off the capillary electrometer and manipulating it in such a manner1 that on returning it into position the capillary may be partly filled with a thread of mercury and partly with the acid4 ,the terminals1 ,x and ,y1 marked battery and 1 are connected to a dry cell1 and the terminals1 ,z and ,u1 marked cathode and auxiliary respectively1 to the hydrogen and calomel electrode4 ,very careful insulation of the connexion between the terminal marked auxiliary and the calomel electrode is necessary4 ,the hydrogen is passed through the hydrogen electrode until a constant ,p4,d4 between it and the calomel electrode is obtained4 ,this ,p4,d4 is measured by moving the slider up and down until no movement of the mercury in the capillary electrometer is observed on depressing the key ,k marked electrometer4 ,fig4 #aj is a view of the apparatus as set up for the titration of a puer liquor4 ,h is a cylinder of compressed hydrogen2#fh ,i1 the hydrogen electrode1 dipping into the beaker ,c containing the liquor for titration2 b1 the burette1 containing ,n_/#aj acid or alkali2 ,,ii1 the auxiliary electrode1 the capillary of which is also seen dipping into the beaker ,c2 ,p1 the potentiometer box containing the sliding rheostat ,s and electrometer ,e2 ,d1 a dry battery4 ,the acid or alkali is run in from the burette until the voltmeter shows #jfi volts1 indicating that the liquid is neutral or has a hydrogen ion concentration of #aj-g4 #fh ,it is necessary to use pure hydrogen4 ,this may now be obtained commercially from the ,knowles' ,oxygen ,co41 ,wolverhampton4 ,illustration3 ,fig4 #aj4--;,electrometric ,apparatus4 ,the following table shows some results obtained on puer liquors before and after skins have been put through4 p,h has been called by ,sorensen the exponent of the hydrogen ion concentration ,c1 and is defined by the equation p,h log7#a_/;,c7 i4e4 it is equivalent to the logarithm of the reciprocal of the factor of normality of the solution with respect to the hydrogen ions4#fi p,h for pure water or a neutral solution is #g1 corresponding to #jfi volts4 ,the measurements were made on filtered puer liquors1 using a ,n_/#a ,k,cl calomel electrode as auxiliary1 the capillary of the electrode being filled with #ce,n potassium chloride3-- #fi ,the formula for calculating p,h for the ,n_/#a auxiliary electrode used is as follows3-- ,since 7#jbhc #jjege log7#a_/;,c7 volt7 log7#a_/;,c7 p,h 7 - #jbhc7_/jjege potential difference found ,c concentration of hydrogen-ions4 -------------------------------------- ,before goods4 ,after goods4 ---------------------------------- ,no4 ,volts4 p,h ,volts4 p,h ------------------------------------- #a #jefj #dg #jgee #haf #b #jehe #eaf -- -- #c #jfjj #ed #jfeh #fdd #d #jeie #ece #jgaj #gce #e #jfjj #ed #jgbe #gf #f -- -- #jggj #hce ------------------------------------- ,no4 #f was a very old 8spent0 liquor4 ,the mean hydrogen ion concentration before goods was #jehh volt1 i4e4 the concentration was #aj-ecb normal equivalent to #jjjjjjdgi grm4 per litre of hydrogen ions4 ,therefore the value of p,h was #ecb4 ,a solution of hydrochloric acid of the same strength by titration consumed #jg c4c4 ,n_/#a alkali per #ajj c4c4 ,measured by the electrometric apparatus1 it showed #jdaj volt1 corresponding to p,h #ba1 or a hydrion concentration of #jjgi,n4 ,in other words1 the ,h,cl solution has an acidity or strength #afjj times that of the puer liquor4 ,the mean hydrogen ion concentration of the liquors after goods was #jjjjjjjjgf grm4 per litre1 corresponding to #jgae volt and p,h #gab1 i4e4 the liquor was alkaline to a slight extent4 ,for comparison saturated lime-water gave a reading of #aja volt1 corresponding to p,h #abe4 ,the hydrogen ion concentration is of the greatest importance for the proper action of the enzymes in the bate2#gj we shall1 however1 treat of this in ,chapter ,,vii4 #gj ,vide ,srensen1 ,sur la mesure et l'importance de la concentration des ions hydrogne dans les ractions enzymatiques4 ,comp4 rend4 ,lab4 de ,carlsberg1 #hme4 vol4 #a;ere livraison1 ,copenhagen1 #aiji4 99,conductivity of ,puer ,liquors499--,it was thought of interest to examine the electrical conductivity of puer liquors in actual use1 in the hope that the numbers obtained might give some useful indications4 ,it was found that the conductivity increased1 as might be expected from the lime going into solution1 but the difficulties of the method render it of less use than ordinary chemical analysis4 ,the results of a typical liquor are given here as a record-- ,conductivity 7,k7 of liquor before goods #jjjcaf7a_/7ohm cm477 ,conductivity 7,k7 of liquor after goods #jjjdbc7a_/7ohm cm477 ,the difficulty of expressing the complex reactions of puering numerically is1 we have seen1 very great1 for1 as ,minot#ga says1 8with human minds constituted as they actually are1 we cannot anticipate that there will ever be a mathematical expression for any organ or even a simple cell1 although formul will continue to be useful for dealing now and then with isolated details4 ,nevertheless1 the value of graphic methods to every student of science has been immense40 #ga ,minot1 ,address to ,amer4 ,assoc4 for ,advancement of ,science1 ,minneapolis1 ,dec4 #bi1 #aiaj4 ,nature1 #aiaa1 p4 #if4 ,it has long been my endeavour to express quantitatively the degree to which a skin has fallen4 ,my friend ,dr4 ,sand has suggested that this may be done by subjecting a piece of the skin successively to increasing and then decreasing pressures1 and measuring the thickness under each load4 ,experiments carried out with the apparatus described below show that a limed skin treated in this way is first compressed1 and then on releasing the pressure recovers more or less of its former thickness1 according to the amount of plumping it has received1 i4e4 it shows a certain amount of resilience4 ,a well-puered sheep-skin1 on the other hand1 shows no resilience at all1 i4e4 on releasing the pressure the whole of the compression persists4 ,in the case of an ox-hide subjected to a bate of hen-dung1 a slight recovery takes place on releasing the pressure4 ,this accords with the fact that it will never be possible to puer a thick ox-hide so effectively as a thin sheep-skin4 ,a piece of india-rubber1 on the other hand1 is completely resilient1 i4e4 it wholly recovers its thickness on releasing the pressure4 ,the relative thickness of the same skin in the limed and puered conditions under varying loads is also of interest4 ,the process of puering may1 as a rule1 be taken to reduce a limed skin to between two-thirds and one-half of its thickness in the swollen condition4 ,if both limed and puered skin be then subjected to the same load1 the puered skin will at first be compressed very much more than the limed one4 ,this is probably due to the expulsion from it of water1 held simply by capillary attraction4 ,on further increasing the load1 however1 the compression decreases greatly in the case of the puered skin2 with both limed and puered skin increase of compression ultimately becomes practically proportional to increase of pressure1 and is slightly greater with the former than with the latter4 ,the table gives representative results obtained on the same sheep-skin 7roan7 in the limed and in the puered condition4 ,these results are expressed graphically in ,fig4 #ab4 ---------------------------------------- ----- ,load ,thickness in mm per sq4cm4 -------------------------------- in grm4 ,limed skin ,puered skin ---------------------------------------- ---- #j #cde #agh #afg #bj #cdc #aeh #ahe #dj #ccc #adc #aij #fj #cbh #ace #aic #hj #cbb #abc #aii #ajj #cae #aac #bjb #abj #cjh #ajh #bjj #adj #cjc #aje #aih #afj #bie #aja #aid #ahj #bij #ih #aib #bjj #bhc #ie #ahh #cjj #bgc #hh #ahe ,all off #bih -- -- #chj #bfa #hb #agi #fjj #bdc #gf #afg ,all off -- #gf -- ---------------------------------------- ---- difference in thickness of the skin--i4e4 compression under the same load4 ,illustration3 ,fig4 #aa4--;,apparatus for ,measuring ,degree of ,falling m micrometer dial4 ,,jj jaws between which the skin is placed4 b balance-weight attached to cord passing over pulleys p p1 to counterbalance weight of frame f f4 k knife edge supporting pan and weights w4 ,fig4 #aa shows the apparatus#gb that was employed to obtain these results4 ,it consists essentially of a commercial form of micrometer for measuring the thickness of leather4 ,to one of its jaws a pan for weights is attached1 by means of the frame f f1 in such a manner as to secure a perfectly straight pull4 ,the weights of the frame and pan are counterbalanced in the manner shown by a counterpoise b4 ,the delicacy of measurement may be increased by inserting larger jaws in the form of suitably fashioned disks1 but even when this is done the results are to a certain extent vitiated by the rather considerable friction of the micrometer4 #gb ,the apparatus was constructed by ,mr4 ,w4 ,linney1 of the ,university ,college1 ,nottingham4 ,since this apparatus was constructed ,professor ,h4 ,r4 ,procter has informed me that an appliance devised by ,mr4 ,anderson1 of the ,leeds ,university1 for measuring the thickness of leather under varying pressures1 has been in use in the leather industries department for some months for the purpose of measuring the proportion of the permanent to elastic compression4 ,illustration3 ,fig4 #ab4--;,curve obtained by ,measuring ,apparatus4 7,the dotted lines show the pressure on taking off the load47 ,an apparatus free from this fault is shown in ,fig4 #ac4 ,it consists essentially of a counterbalanced lever ,a1 to which the upper jaw ,j is rigidly attached4 ,by means of a sliding weight ,w1 any desired load1 from zero upwards1 may be put on this jaw4 ,the lever carries a very delicate spirit level1 which allows it to be set accurately horizontal in every experiment4 ,the lower jaw is movable vertically between parallel guides1 and its position is controlled by the screw-wheel ,s which bears a divided circle on its circumference4 ,the position of this wheel1 and therefore of the lower jaw1 may be accurately read on the vernier v4 ,in every experiment it is adjusted so as to make the upper lever accurately horizontal4 ,illustration3 ,fig4 #ac4--;,improved ,apparatus for ,measuring the ,degree of ,falling4 7,sand47 ,,chapter ,,iv4 ,,the ,,bacteriology ,,of ,,the ,,bate4 8,omne vivum ex ovo40--,,harvey 7#aegh-afge74 ,when a drop of liquid from a puer wheel in use is examined under the microscope#gc with #a_/ab o4i4 objective1 it is seen to be swarming with bacteria4 #gc ,a good microscope1 with #a_/ab oil-immersion objective and ,abbe condenser1 is necessary for bacteriological work4 ,the new dark-ground condenser made by ,james ,swift and ,son1 ,london1 is extremely useful for examining living bacteria under high magnifications4 ,the majority are short rods 7bacilli71 but other forms1 cocci and spirilli1 are seen in lesser numbers4 ,most of these bacteria move briskly in the liquid2 as the temperature of the slide sinks1 their movements become slower1 and finally cease4 ,the illustration1 ,fig4 #ad1 shows the various forms of bacteria observed by the author in puer liquors #ajjj diam4 ,illustration3 ,fig4 #ad4--,various ,forms of ,bacteria in ,puer ,liquors4 ,the living bacteria are best examined in a drop culture in the following manner4 ,a clean cover-glass1 of the proper thickness for the objective to be used1 is laid upon a black glass plate4 ,with a platinum loop1 previously heated to redness in the flame1 a drop of sterile physiological salt solution 7#jf to #jge per cent47 or sterile broth is placed in the centre of the cover-glass4 ,with a platinum needle a minute quantity of the puer liquor is stirred into the drop4 ,a slide with a depression in the centre is taken1 the edge of the depression painted round with vaseline1 and pressed over the cover-glass1 so that the drop is exactly central4 ,if the whole be now turned smartly over1 the drop will hang central in the hollow space4 ,if the ring of vaseline is continuous1 and the cover well pressed down1 the drop is preserved from evaporation1 and the bacteria may be examined in their natural condition--best on the edge of the drop4 ,for illuminating the drop culture1 the concave mirror is used1 and a small diaphragm without condenser2 whereas1 for stained preparations1 the flat mirror is used in conjunction with the ,abbe condenser4 ,if the cover-glass be carefully removed1 and dried under a bell glass1 the culture may be preserved in a dry condition1 or may be stained and mounted4#gd #gd ,the most recent method is to preserve the slides without cover-glasses3 a drop of cedar oil is placed directly on the preparation1 and1 after examination1 carefully washed off with xylol4 ,care should be taken not to touch the preparation with the fingers4 ,if the dried preparation is on a cover-glass1 it should be held in the fingers 7prepared side upwards71 and passed slowly three times through the flame of a ,bunsen burner4 ,by holding the preparation in this way1 the exact temperature for proper fixation is obtained4 ,a drop of fuchsin stain1 or gentian violet1 is allowed to remain on the preparation for five minutes2 wash off the superfluous dye with water1 and examine1 either in the wet state or after drying and mounting in balsam4 ,illustration3 ,fig4 #ae4--;,b4 ,coli ,commune4 ,stained to show ,flagellae4 ,for a detailed account of the technique of staining and mounting1 the following works may be consulted3-- ,methods and ,formul4 ,p4 ,w4 ,squire4 7,churchill47 ,taschenbuch fr den bakteriologischen ,praktikanten4 ,dr4 ,rudolf ,abel4 7,stubers-,verlag1 ,wrzburg47 ,technique ,microbiologique4 ,nicolle and ,remlinger4 7,octave ,doin1 ,paris47 ,practical ,bacteriology4 ,kanthack and ,drysdale4 7,macmillan1 ,london47 ,the recent researches of ,tissier and ,metchnikoff have shown that the flora of the intestines1 both of men and animals1 consist very largely of anaerobic bacteria4 ,these have been overlooked in previous researches1 owing to imperfect means of studying this class of organisms4 ,indeed1 in one work on the microbes of the alimentary canal of the dog1 no mention was made of them1 whereas they are all very active4 ,most of these organisms1 and the new methods by which they have been isolated1 are fully described in a new work entitled 8,les ,anrobies10 by ,m4 ,jungano and ,a4 ,distaso1 of the ,pasteur ,institute1 ,paris4#ge #ge ,masson et ,cie1 ,publishers4 ,the following bacteria have up to the present been isolated from dung 7mostly dog dung71 and studied in pure cultures3-- #a4 ,micrococcus ureae 7,cohn74 7,pasteur47 #b4 fulvus 7,cohn74 #c4 prodigiosus4 #d4 ureae liquefaciens4 #e4 ,bacterium sulphureum4 #f4 coli commune4 7,fig4 #ae47 #g4 coli anindolicum4 #h4 ,bacterium coli anaerogenes4 #i4 furfuris 7,wood74 7,fig4 #cj47 #aj4 furfuris 7,wood74 7,fig4 #ca47 #aa4 ,bacillus fluorescens putridus4 #ab4 liquefaciens4 #ac4 subtilis4 #ad4 saprogenes 7,herfeld71 three varieties4 #ae4 butyricus 7,hueppe74 7,fig4 #bc47 #af4 putrificus4 7,fig4 #ai47 #ag4 pyocyaneus4 #ah4 janthinus4 #ai4 coprogenes ftidus4 #bj4 pyogenes ftidus 7a variety of ,b4 coli74 #ba4 zenkeri4 #bb4 magnus4 #bc4 spinosus4 #bd4 liquefaciens 7,eisenberg1 ,frankland74 #be4 amylobacter 7,van ,tieghem74 #bf4 acidi paralactici4 #bg4 ,i4 ,isolated from horse manure by ,severin1 #bh4 ,,ii4 ,centr4 ,bl4 f4 ,bakt4 7#b71 i41 #ig4 #bi4 ,,iii4 #cj4 from horse dung 7anaerobic7 ,severin1 ,centr4 ,bl4 f4 ,bakt4 7#b7 iii41 #gjh4 #ca4 from horse dung 7anaerobic71 ,no4 #c1 ditto4 #cb4 oedematis maligni 7,vibrion ,septique1 ,pasteur74 #cc4 mesentericus vulgatus4 #cd4 lactis aerogenes4 #ce4 cavicida 7,brieger74 #cf4 albuminis 7,bienstock74 #cg4 ,bienstockii4 #ch4 tenuis4 #ci4 enteritidis sporogenes 7,klein74 #dj4 lactis acidi 7,ankerschmid1 #aije74 #da4 megatherium4 #db4 cadaveris sporogenes 7,klein7 said to be identical with ,no4 #af4 #dc4 thermophilus4 7,houston74 #dd4 a4 from puer4 ,see p4 #afb4 #de4 b4 #dg4 ,bacillus mycoides4 #dh-fa4 #ad species isolated from dog and pigeon dung by ,prof4 ,h4 ,becker4 ,zeit4 f4 ,offentlich4 ,chemie4 ,heft xxiii4 ,jahrgang ,x4 p4 #ddg1 includes ,b4 erodiens 7,fig4 #af74 #fb4 ,sarcina fimentaria 7,lehmann and ,neumann74 #fc4 ,streptococcus from sewage4 7,houston47 #fd4 brevis4 #fe4 longus4 #ff4 pyogenes4 #fg4 liquefaciens coli4 7,gamgee ,phys4 ,chem4 #b47 #fh4 ,streptothrix from stable manure4 7,severin1 #f47 #fi4 ,spirillum serpens 7,kutscher74 #gj4 tenue #ga4 undula #gb4 volutans 7,figs4 #bd and #be74 #gc4 from pig dung4 ,smith1 ,centr4 ,bl4 f4 ,bakt4 #af1 7#a71 #abd #gd-gf4 ,vibrio1 three species isolated by ,kutscher4 #gg4 ,clostridium butyricum 7,prazmowski71 said to be identical with ,no4 #be4 #gh4 ,streptococcus faecalis4 ,sidney ,martin1 #cg and #ch2 ,ann4 ,rep4 ,loc4 ,gov4 ,board1 #aijg-i2 ,nature1 ,march #c1 #aiaj1 p4 #bb4 #gi4 ,bacillus bifidus4 #hj4 perfringens4 #ha4 bifermentans4 #hb4 funduliformis 7,veillon74 #hc4 capillosus4 #hd4 sporogenes4 #he4 ventriosus4 #hf4 rodella ,,iii4 #hg4 ,staphylococcus parvulus4 #hh4 ,diplococcus orbiculus4 #hi4 ,coccobacillus preacutus4 #ij4 ,coccobacillus oviformis4 #ia4 ,bacillus faecalis alkaligenes 7,petruschky74 7#gi-ij are anaerobic bacteria1 described and figured by ,jungano and ,distaso47 ,it will be surmised from the above list1 to which additions are still being made1 that the flora of the intestines is pretty extensive1 and1 consequently1 the study of the part played by the various species of bacteria is a long and difficult one4 ,the methods of isolating these bacteria1 and the compositions of the media employed1 would demand a treatise on bacteriology2 but1 for general purposes1 a good liquid medium for the cultivation of puer bacteria is a gelatin peptone broth1 made by digesting #aj grm4 gelatin with #f-a_/b grm4 #hj per cent4 lactic acid in #ajj c4c4 water under pressure for three hours1 neutralizing with ammonia1 adding #a grm4 potassium phosphate1 making up to #ajjj c4c41 and filtering4 ,a sterile infusion of fresh dung may be used1 but it is troublesome to prepare and not easy to get uniform in strength or composition4 ,the culture liquids are left slightly alkaline1 an alkalinity equal to #jjfcf per cent4 ,na#b;,,co#c or #ab c4c4 ,n_/#a soda per litre4 ,the amount of alkali may be increased to #jae per cent4 ,na#b;,,co#c without affecting the growth of the bacteria4 ,of solid media1 #aj per cent4 nutrient gelatin1 or in summer #ae per cent41 is good if used at temperatures below #be ,c4 ,for higher temperatures1 up to #ci and #dj1 nutrient agar is required4 ,the best nutrient gelatin for general work is made according to ,klein's formula4#gf ,for media in general1 a most useful compendium is ,abel's ,taschenbuch4 #gf ,klein1 ,e41 ,micro-organisms and ,disease 7,macmillan71 p4 #bb4 ,see also1 ,kanthack and ,drysdale1 ,practical ,bacteriology 7,macmillan #ahif71 p4 #hf4 ,the number of bacteria in fresh fces varies greatly1 but is of the order of #aj1jjj1jjj per grm4 of dry matter1 capable of developing in nutrient gelatin4 ,of this number1 about #ajj1jjj are spore-bearing organisms4 ,this estimate applies to healthy animals2 in a diseased condition1 the numbers vary enormously4 ,dr4 ,a4 ,c4 ,houston found in raw ,london sewage from #c1jjj1jjj to #i1jjj1jjj microbes per c4c41 of which more than one-tenth were gelatin-liquefying organisms4 ,there were only about #cjj spores of aerobic bacteria1 about #ajj1jjj ,b4 coli1 #ajj ,b4 enteritidis sporogenes1 and streptococci1 in one gram of fces4 ,with the object of ascertaining the effect of the various species of bacteria contained in the dung upon skins1 a large number have been isolated1 and the effect of pure cultures in different media has been tried upon skin4#gg ,a number of the results have been published in the ,journal of the ,society of ,chemical ,industry4 ,professor ,h4 ,becker1 who has done a great deal of this part of the work1 is of opinion that the principal organisms concerned in the bating exist in the dog's intestines1 and belong to the group of coli bacteria4 ,these are very widely distributed bacteria1 and are found in the large intestines of mammals1 and1 as a consequence1 in almost all soils1 and in the mud of rivers and lakes4 ,the principal variety is ,b4 coli commune4 #gg ,the subject is not so far removed from direct human interest as one might suppose4 ,for many years ,metchnikoff1 in ,paris1 has been studying the bacterial flora of the human intestines4 ,his theory is1 that old age is caused by the poisonous products of these intestinal bacteria1 and he proposes to counteract the effects of these poisonous organisms1 by introducing into the system large quantities of lactic acid bacteria1 either in the form of tabloids1 or in the form of sour milk cultures4 ,lortet found it1 along with other organisms1 in the mud of the ,lake of ,geneva1 at a spot where the water was chemically very pure4 ,dr4 ,a4 ,c4 ,houston1 the bacteriologist of the ,metropolitan ,water ,board1 enumerates sixteen varieties of this organism1 #hj per cent4 of which produced acid and gas in lactose-peptone cultures1 indol in peptone-water cultures1 and when grown in milk produced acid and clot4 ,the bacterium 7,fig4 #ae7 resembles that of typhoid fever1 and has frequently been mistaken for it4 ,it is1 however1 much more resistent to destructive influences4 ,it is a short bacillus1 possessing flagellae1 by which it moves more or less rapidly4 ,b4 coli forms short rods #jh wide1 #a to #c long4 ,it moves somewhat slowly by means of flagell1 which may be demonstrated by staining with ,loffler's method4#gh ,it grows equally well in absence or presence of air1 that is1 it is a facultative anaerobe4 ,although it will grow at room temperature1 the optimum growth is at #cg ,c4 ,in plate cultures the appearance of the colonies below the surface of the gelatin is quite different from that of the surface colonies4 ,the former are small round colonies1 about the size of a pin head2 the latter spread into a whitish iridescent film1 with irregular edges4 #gh ,for the demonstration of flagell1 the material is taken from a culture on solid media--a young agar culture is best4 ,make a dilution by ,soyka's method 7p4 #ajc71 dry and fix on a cover-glass as described1 p4 #hh1 then proceed as follows3-- #a4 ,mordant with a mixture of #aj c4c4 #bj per cent4 tannin solution1 #e c4c4 cold saturated ferrous sulphate1 #a c4c4 fuchsin or wool-black solution4 ,this solution is put on the preparation1 which is then heated for one minute until steam is given off4 #b4 ,wash under the tap1 then in alcohol4 #c4 ,stain with anilin-water-fuchsin solution1 prepared by dissolving the dye in anilin-water and adding #a per cent4 of a #a per cent4 solution of caustic soda until the liquid begins to go cloudy4 #d4 ,wash off the stain with distilled water4 ,b4 coli does not liquefy the gelatin4 ,when grown in nutrient solutions containing sugars1 it produces much acid1 and at the same time gases are given off1 consisting of ,,co#b and hydrogen4 ,if the growth in this solution be allowed to continue a secondary fermentation ensues1 and the culture eventually becomes alkaline4 ,indol is produced by ,b4 coli1 and may be demonstrated by adding to #aj c4c4 of the culture1 #a c4c4 of a #a_/ej per cent4 solution of pure potassium nitrite2 then adding a few drops of concentrated sulphuric acid1 when1 if indol be present1 a red coloration 7nitroso-indol7 is produced4 ,this bacterium reduces nitrates to nitrites4 ,cultivated in a #a per cent4 solution of peptone1 to which #a_/ajjjj per cent4 of potassium nitrate has been added1 after four hours at #cg ,c41 the presence of nitrite may be shown2 after the growth has continued for seventeen hours1 the nitrite is further reduced to ammonia4 ,among other products of ,b4 coli1 ,harden found lactic1 formic1 acetic1 and succinic acids1 ethyl-alcohol1 ,,co#b and hydrogen4 ,in ,germany1 ,w4 ,lembke and ,h4 ,becker have specially investigated the bacterial flora of the dog's intestines4 ,lembke1 in #ahifgi cultivated the bacteria from the fces of the dog1 fed in various ways--bread1 meat1 and fat diet--and found ,b4 coli constantly present1 although the form of the individuals1 as well as the colonies1 and the intensity of the indol and gas formation1 showed great variations4 #gi 8,beitrag zur ,bakterienflora des ,darmes10 ,archiv f4 ,hygiene1 ,bd4 #bf1 p4 #bic4 ,the other species of bacteria present varied with the kind of food2 this has a great influence on the flora of the intestines1 which was found to be very different when the dogs were fed on bread to what it was when they were fed on meat4 ,lembke describes two other species of bacteria closely resembling ,b4 coli1 one of which he calls ,b4 coli anindolicum1 which1 as the name implies1 gives no indol reaction2 the other1 ,b4 coli anaerogenes1 is non-motile1 possesses no flagell1 and differs from ,b4 coli by the absence of gas production in the fermentation of sugars4 ,besides ,b4 coli1 there are several species of bacteria which liquefy gelatin1 and a number of facultative organisms1 whose presence is more or less accidental4 ,by changing the food1 and introducing with it quantities of foreign organisms1 the composition of the intestinal flora may be changed4 ,by introducing for a considerable period ,b4 coli anindolicum1 ,lembke succeeded in entirely suppressing ,b4 coli commune4 ,on returning to normal feeding1 the foreign organisms in some cases entirely disappeared4 ,the researches of ,dr4 ,h4 ,becker#hj were applied more directly to the use of bacterial cultures for the bating of skins1 and to the elucidation of the bacterial action of dog-dung infusions4 ,he isolated #ed varieties of bacteria from dog-dung1 and tried the action of pure cultures of many of them on a skin4 #hj ,zeit4 f4 ,offt4 ,chem41 ,heft4 xxiii4 ,jahr4 ,x4 p4 #ddg4 ,a list of the various bacteria isolated by ,becker is given in tabular form on pp4 #ih-aja4 ,illustration3 ,fig4 #af4--;,b4 ,erodiens 7,becker74 ,illustration3 ,fig4 #ag4--,plate ,culture from ,fresh ,puer4 ,professor ,becker's ,bacterium ,no4 #ab1 which he has named ,bacillus erodiens 7,fig4 #af71 is undoubtedly a variety of ,b4 coli1 but has a more rapid motion1 and does not coagulate milk1 although it renders it somewhat thick4 ,cultivated in broth it gives off much gas1 consisting of #ab per cent4 carbon dioxide1 #he per cent4 hydrogen1 #c per cent4 oxygen4 ,if glucose be added1 the quantity of carbon dioxide rises to #dj per cent41 and acid is produced4 ,the most rapid growth is at #cg ,c41 and at this temperature a broth culture has a distinct reducing action on skin4 ,according to the medium in which it is grown1 it produces acid or alkali1 and thus comes under the heading of mixed bacteria4 ,in sugar#ha solutions acid is produced1 and in proteid solutions ammonia compounds1 indol1 and evil-smelling gases are given off4 ,thus1 by varying the medium1 the effect produced may also be varied4 #ha ,dr4 ,a4 ,c4 ,houston has been kind enough to make an examination of ,b4 erodiens1 and to ascertain its action on various sugars4 ,it produces fluorescence in neutral-red broth cultures1 acid and gas in lactose cultures1 indol1 and acid1 and clot in milk cultures4 ,it ferments dulcite with production of acid1 but not cane sugar1 adonite1 inulin1 inosite1 salicin1 or raffinose4 ,b4 erodiens does not secrete any tryptic enzymes1 hence its action on the skin is to be attributed either to an intracellular enzyme1 or to its chemical products1 which1 being secreted in situ1 have a more favourable and powerful action than if merely added to the bating liquid4 ,it was for this reason that ,i proposed to use a mixed culture of bacteria1 especially bacteria from the sweating process 7see p4 #aje71 which secrete a mild form of proteolytic ferment1 capable of dissolving the more easily soluble portion of the skin fibres 7or certain constituents71 but not capable of attacking the hyaline layer4 ---------------------------------------- ----------------------------------- ,no4 of ,shape ,growth the ,bac- ,where and ,motility ,growth on ,gelatin on terium ,found ,arrangement ,agar-agar ---------------------------------------- ----------------------------------- #a ,dog ,small rods ,lively ,in the gelatin stab-culture,a white dung of the size the bacteria show a good surface of the ,bac4 growth in the depth4 ,at thelayer is prodigiosus4 surface it forms a small formed on white button4 ,the gelatin inclined is not liquefied4 ,the col- stiffened onies which have reached agar-agar4 the surface of the gelatin- plate spread in the shape of a leaf1 with a mother- of-pearl-like gloss4 #b ,do4 ,small rods of ,do4 ,stab-culture3 ,the germs ,a yellowish- the size of develop along the entire white layer the hay track4 ,small arms extend is formed bacillus4 sideways into the gelatin4 along the ,a white layer is formed on inoculating the surface4 ,the gelatin isstab4 slowly liquefied4 ,gelatin-plate3 ,when they reach the surface1 the col- onies spread out in the shape of a leaf and then are slightly fluorescent4 #c ,do4 ,very small ,do4 ,stab-culture3 ,very good ,a white rods rounded growth in depth4 ,very many deposit is at the arms extend laterally from formed on ends4 the track of the stab into inclined the gelatin4 ,small knots agar-agar4 are formed at the ends of the arms4 ,a thin white coating is formed on the surface4 ,gelatin is not liquefied4 ,gelatin-plates3 ,the colon- ies located deeper down appear as pale-yellow small round disks1 which gradual- ly work up toward the sur- face and there form circu- lar disks which show larger dots in the middle4 #d ,do4 ,small rods as,slow ,the gelatin stab-culture ,heavy white large as hay movementresembles that of the hay deposit on bacilli4 bacillus1 while the growth the entire in the gelatin-plate more surface4 resembles that of the an- thrax bacillus4 ,threads ex- tend from the liquid colon- ies which have been let in1 which threads are at first braided and twisted1 and later on extend straight into the gelatin4 #g ,do4 ,small rods ,lazy ,stab-culture3 ,strongly li- ,white similar to quefying4 ,a white skin unevenly the hay forms on the surface4 ,alongthin layers bacillus4 the liquefied prick are ra-withspurs4 diations into the solid gelatin4 ,gelatin-plate3 ,quickly li- quefying colonies which form a white skin at the top4 #aa ,do4 ,medium-sized ,motile ,stab-culture3 ,a white coat-,a white small rods4 ing is formed on the sur- deposit face4 ,the gelatin is not along the liquefied4 ,the bacteria puncture4 grow well in the depth4 ,the colonies which come to the surface spread out leaf-like with a mother-of- pearl-like gloss4 #ab ,dog ,medium-sized ,lively ,stab-culture3 ,grows evenly ,heavy white dung small rods4 along along the track4 ,ge- deposit2 latin is not liquefied4 ,a glossy4 thin glossy deposit on the surface4 ,gelatin-plates3 ,the lower- lying colonies appear as pale-yellow circular small disks4 ,braids are noticed in some colonies similar to the superficial colonies of ,proteus4 ,strong decaying smell4 #ac ,do4 ,do4 ,motile ,stab-culture3 ,a thin coat- ,white ing forms on the surface4 deposit ,the bacteria grow downward along the bristle-like4 ,small buttonspuncture4 are formed at the ends of the bristles4 ,gelatin-plates3 ,leaf-like1 mother-of-pearl glossy1 spreading4 #ch ,pigeon ,small rods ,lively ,stab-culture3 ,bag-shaped ,yellow and liquefying of the gelatin1 spreading poultry thesame being coloured over the dung4 yellow4 surface of the culture ,gelatin-plates3 ,the deep- medium4 seated colonies are gran- ular1 yellow4 ,those that have forced their way to the surface form white glistening small buttons4 #dj ,do4 ,do4 ,do4 ,stab-culture3 ,a white heavy,white deposit is formed on the irregular surface of the culture me- deposit4 dium2 grows very well along the track4 ,gelatin-plates3 ,leaf-like deposits with line system4 #db ,do4 ,do4 ,do4 ,stab-culture3 ,a white heavy ,do4 ,spreading4 ,very good growth along the prick4 ,gelatin-plates3 ,leaf-shaped deposits with line system4 #dc ,do4 ,large1 ,not ,stab-culture3 ,the gelatin ,white grouped1 motile is slowly liquefied4 ,only puncture grape-like4 slight growth in the depth4in yellow4 ,the culture medium is col- oured chamois colour4 ,gelatin-plates3 ,yellow disks4 #dd ,pigeon ,small rods1 ,lively ,stab-culture3 ,a heavy white,white and quite spreading on the surface4 irregular poultrydifferent ,very good growth along the deposit4 dung4 in size4 prick4 ,gelatin-plates ,leaf-shaped deposits with the line sys- tem4 #de ,do4 ,small rods ,do4 ,stab-culture3 ,a heavy white,very thin spreading on the surface4 deposit4 ,slight growth only in depth4 ,gelatin-plates3 ,leaf-shaped depositwith clear line sys- tem4 ,the entire colonies appear much thinner than those of the preceding numbers4 ---------------------------------------- ----------------------------------- table continued ---------------------------------------- ----------------------------------- ,no4 of ,growth ,growth ,best ,development the ,bac- on in ,growth of ,special ,remarks terium ,potatoes ,milk at-- ,gas ---------------------------------------- ----------------------------------- #a ,the bacter-,milk is #cg ,c ,only slight ,without doubt a var- ium shows not iety of bacterium only a weakchanged ,coli commune4 growth on potatoes4 ,it forms a yellow layer4 #b ,dirty ,milk ,room ,does not occur -- yellowish remains temp4 layer4 unchanged4 #c ,yellowish ,milk is #cg ,c ,very pronounced4 ,culture-medium to deposit caused to ,from fifty cubic which blue litmus at the curdle centimeters of is added turns red4 place of only after broth #fe cubic inocula- it has centimeters gas tion4 been in were produced in the incu- fifteen hours1 of bator for which #ce per cent4 four days4 was oxygen1 #ajg per cent4 carbonic- acid gas1 and #heh per cent4 nitrogen4 #d ,white1 dry1,milk is ,do4 ,does not occur -- spreading4 changed4 ,serum is separated out4 #g ,white1 dry4,strong ,do4 ,do4 -- serum formation4 #aa ,yellowish ,milk ,do4 ,weak ,strongly resembles glossy curdles the bacterium,coli deposit4 commune and differs therefrom only in that the milk curdles quicker4 #ab ,yellowish ,milk #cg;,c ,considerable4 ,five ,if #jbe cubic centi- glossy becomes cubic centimeters meters of broth- covering4 pappy4 of gas will be de- culture are injected veloped from fifty under the epigastri- cubic centimeters um1 the animal is of common broth in taken violently ill4 an incubator during,after four hours the first fifteen violent diarrhea hours and six cubicoccurs4 ,soon the centimeters during mouse can hardly move2 the first forty- looks bristly4 ,on the eight hours1 con- third day the animal sisting of #abab dies4 ,on opening the per cent4 carbonic body a strong putrid acid1 #c per cent4 smell is noticed4 oxygen1 and #hdi ,some of the injected per cent4 hydrogen4bacteria are found in ,the gas obtained the blood4 ,the intes- from a culture- tines are coloured medium containing green and black4 grape-sugar ,the other organs are contains about #dj pale4 per cent4 carbonic acid4 #ac ,glistening1,strong ,do4 ,weak ,in old stab-cultures yellowish4 curdling4 a brown discoloration of the culture-bed is noticed along the length of the stab4 ,differs in the gelatin stab-culture from the common bacterium ,coli communelikewise in the curdling of the milk4 #ch ,yellow ,milk ,do4 ,not noticed -- glistening is not deposits4 changed4 #dj ,white1 ,do4 ,do4 ,weak4 ,is only -- glistening4 noticed in culture- ,only very bed containing slight grape-sugar4 growth4 #db ,sulphur ,no change ,do4 ,strong only in -- yellow1 of the media containing glistening4milk4 grape-sugar4 #dc ,no growth ,do4 ,do4 ,none -- #dd ,weak devel-,curdling ,do4 ,very weak4 ,only in opment4 ,the media containing culture is grape-sugar4 sulphur yellow4 #de ,weak ,milk is ,do4 ,not noticed -- yellowish not deposit4 changed4 ---------------------------------------- ----------------------------------- ,the practical difficulty is to keep such cultures uniform during propagation1 and so far this has prevented their introduction in practice4 ,similar difficulties have influenced the use of pure cultures of yeast in the brewing of ,english beers1 although the use of a single species of yeast is common in the low fermentation breweries on the ,continent4 ,i found in studying the bacteria of dog dung1 that the species existing in the fresh dung1 which developed in ordinary plate cultures1 appeared to belong to four or five species only1 mostly bacilli4 ,at the end of two or three weeks1 the original species had given place to others1 mostly cocci1 in a very similar way to the change which takes place in putrefaction4 ,in fact1 many of the organisms are identical with those which cause putrefaction4 ,it will be seen1 therefore1 that no single species produces the complex chemical and physiological changes which take place1 or the bodies necessary for the bating of skin1 as some observers have supposed2 but the various species succeed one another as the medium changes its reaction and composition1 until finally the organic portion is resolved into the simplest bodies such as carbon dioxide1 ammonia1 and hydrogen4 ,there is thus a moment when the dung is at its best so far as the bating action is concerned1 and this moment is due to the vital activity of bacteria1 and consequently varies according to the temperature and some other influences 7electrical condition of the atmosphere1 etc474 ,one may say it is at its best at about fifteen days in summer1 and one month or more in winter4 ,puer which has been dried1 is not so powerful in its action as that which is immediately made into a paste with water4 ,it appears to lose its 8nature10 partly owing to irreversible dehydration processes1 and partly because some of the bacteria are killed4 ,plate cultures on agar from fresh puer 7,fig4 #ag71 and from a puer wheel in use 7,fig4 #ah71 show the number of bacteria in the puer wheel to be much greater than in the fresh puer4 ,whence it is evident1 that the bacteria continue to develop in the puer and to produce their various products1 enzymes1 etc4 ,we have already considered the action of the chemical products1 and in ,chapter ,v4 we propose to discuss the action of enzymes4 ,illustration3 ,fig4 #ah4--,plate ,culture from ,puer ,wheel4 ,illustration3 ,fig4 #ai4--;,b4 ,putrificus4 99,pigeon-,dung ,bate as used for ,hides499--,the bacteria contained in the intestines of birds and in bird dung have not been studied to the same extent as those of mammals1 so that it is not possible to give anything but a meagre account of them4 ,a microscopical examination of fresh pigeon dung1 collected on a sterile ,petri dish1 showed debris of food1 cellulose1 etc41 among the debris1 a large number of dumb-bell bacteria 7b7 7,fig4 #bj71 and a few motile pairs 7c72 no bacilli were seen4 ,cells of a saccharomyces 7a7 were also observed4 ,from this pigeon dung attenuations were made by a modification of ,soyka's method1#hb and from the fourth attenuation a plate culture was made in ordinary nutrient gelatin4 ,the colonies from this plate were principally of two varieties 7both non-liquefying organisms71 corresponding to the bacteria observed in the original dung4 ,large cultures were made in a ,carlsberg vessel1 as described in ,chapter ,,vi41 and the effect of these cultures tried upon skin4 ,no particular reducing effect was obtained4 #hb ,the modification of ,soyka's method of making attenuations of bacteria is that of ,gnther 7,bakteriologie1 #ahih1 p4 #bjd71 and is carried out as follows3--,on the inner surface of the cover of a sterile ,petri dish 7which is to be used for making the plate culture71 place four drops of sterile broth1 or sterile water2 inoculate the first drop1 by means of a platinum needle1 with the material to be examined2 heat the needle in the flame1 dip it into the first drop1 and1 with the liquid adhering1 inoculate the second drop4 ,proceed in this way1 each time heating the needle1 to the fourth drop4 ,from this fourth drop a tube of nutrient gelatin is inoculated1 and poured on to the plate4 ,the cover is then put on1 and the plate put into the incubator4 ,the drops on the cover do not in any way contaminate the culture4 ,illustration3 ,fig4 #bj4--,organisms in ,pigeon ,dung4 #ajjj4 ,a microscopical examination of a bating pit used for kips1 showed an extraordinary mixture of bacteria1 bacilli1 vibrios1 and monads2 some comparatively large dumb-bell shaped bacteria1 very motile1 were present4 ,the difference between the bating liquor and the fresh dung was very marked1 especially in the variety of species present4 ,cultures made from several colonies isolated from the above bate1 in a nutrient liquid1 consisting of #aj litres water1 and #bj grm4 gelatin1 peptonized by heating under pressure with #aj c4c4 sulphuric acid1 afterwards neutralizing with ammonia1 and adding the soluble matter from #bjj grm4 bone-meal1 had no action on skin4 ,it would be unsafe to say from these two experiments that the bacterial effect of the pigeon-dung bate is negligible1 but we may assume that it is different and not so great as with the dog-dung bate or puer4 ,a complete research as to the various species of bacteria developing in the bird-dung bate is necessary before this question can be answered4 99,general ,considerations on the ,growth of ,bacteria in ,various ,media499--,since the publication of ,further notes on the action of the dung bate 7,chapter ,,vi471 ,i have found that the bating organisms grow better in the special medium1 when it is neutralized with ammonia1 than when it is neutralized with sodium carbonate1 i4e4 the presence of organic ammonium salts is more favourable to the growth of the bacteria than the corresponding sodium salts4 ,i also found that bacteria obtained from other sources than dung1 viz4 from the roots of wool just beginning to 8slip0 in a sweating stove1 were equally effective in causing the skin to fall4 ,now these bacteria produce ammonia1 and it seems clear that they are essential to the chemical part of the process4 ,they also produce proteoclastic enzymes1 which act upon the skin fibre 7see chapter on ,enzyme ,action74 ,the products of the bacteria depend very much upon the composition of the nutrient medium4 ,many organisms grown in media containing sugar or other carbohydrates produce acids1 but1 grown in proteids free from sugars1 they produce alkaline compounds4 ,villon 78,the ,leather ,industry10 #aija1 p4 #djh7 describes a bacterium which he considers to be the special micro-organism concerned in the depilation of skins1 which resembles ,bacillus d 7,wood7 7,fig4 #ba71 but he does not describe the appearance of the cultures2 he states1 however 7p4 #daj71 that this is the only bacterium which can develop in the limes1#hc and that it is the cause of the unhairing in this case also4 ,since the production of ammonia in limes is known to be due to bacterial action1 it is very probable that this bacterium1 which is ubiquitous1 is also of use in the bate1 and a research in this direction would be interesting4#hd #hc ,villon found that ,bacterium pilline developed #jadb per cent4 ammonia in ten days in lime liquors used for unhairing skin4 #hd ,cultures made from old limes have1 however1 not been found effective in bating4 ,some of the fermentations taking place in the dung come under the heading of putrefactive processes 7see p4 #aaf74 ,tyrosin is formed in considerable quantities during putrefactive fermentation1 but is soon further decomposed1 according to ,nencki1 with formation of indol1 ,,co#b and hydrogen4 ,leucin gives valerianic acid1 ammonia1 ,,co#b and hydrogen2 nitrogenous bodies of the aromatic series are also produced4 ,illustration3 ,fig4 #ba4--;,bacillus d4 ,illustration3 ,fig4 #bb4--;,bacillus e4 ,bacillus urea1 ,b4 prodigiosus1 and ,b4 fluorescens putridus1 evolve trimethylamine 7,herfeldt71 and1 as the writer has shown1 this amine has an important action in the puering process4 ,in combination with organic acids1 it removes lime from the skin1 and in addition it favours the growth of bacteria1 such as bacillus d and e 7,figs4 #ba and #bb7 and ,b4 coli4 ,the albumens and peptones of the dung are pretty well decomposed and absorbed before evacuation2 the bacteria subsequently split up the amido acids into fatty acids and ammonia4 ,the fatty acids are then decomposed generally in the form of the calcium salts1 in the manner shown in the table 7p4 #ajh71 for which ,i am indebted to ,dr4 ,e4 ,herfeldt1 of ,bonn4 ,we have already treated of the action of these various products in ,chapter ,,ii41 but it will be seen from what has been said in the present chapter that the chemistry and bacteriology of the puer overlap1 and that it is difficult1 if not impossible1 to separate them entirely4 ,the bacteria are continually manufacturing chemical compounds1 and decomposing others4 ,in this respect it is interesting and instructive to note that ,nencki1 in his classical work 8,the ,chemical ,mechanism of ,putrefaction10#he considers the processes by which the putrefaction of proteids is brought about by bacteria1 to be analogous to those taking place by melting the bodies with potash1 and he holds the view that in the hydration processes brought about by bacteria1 the water plays the same part as the potash4 #he ,journ4 f4 ,prakt4 ,chem41 ,bd4 xvii41 #ahgh2 see also ,stoklasa1 ,cent4 ,bl4 f4 ,bakt4 vi41 p4 #ebf4 ---------------------------------------- --------------------------- ,no4 ,fermenting ,cause of ,fermentation ,authors4 ,substance4 ,fermentation4 ,product4 ---------------------------------------- --------------------------- #a ,calcium ,bacteria from ,calcium carbonate1 ,hoppe-,seyler1 formate sewer slime4 ,,co#b and ,h ,archiv f4 d4 g4 ,physiol4 xii4 #b ,calcium ,calcium carbonate1 acetate ,,co#b and ,,ch7#d7 #c ,calcium ,thin bacillus #a4 ,propionic acid1 ,fitz1 nine lactate and1 as by-products1 papers in ,undergoes acetic acid1 the 8,berichte four succinic acid and der ,deutsch4 different alcohol4 ,chem4 fermentations ,gesellschaft10 ,other species #b4 ,propionic acid #ahgf-ahhd4 of bacteria3 and valerianic short aerobic1acid4 butyric bacteria #c4 ,butyric acid and 7,fitz74 propionic acid4 #d4 ,butyric acid1 according to ,pasteur 7,comptes rend4 #ahfa7 #d ,calcium ,bacteria #a4 ,chief product1 ,schtzenberger1 malate 7not propionic acid2 8,fermentation10 described74 and1 as by-product1 #ahgf4 ,thin bacilli4 acetic acid4 #b4 ,chief product1 succinic acid2 and1 as by-product1 some acetic acid4 #c4 ,butyric acid and ,h4 ,bacteria #d4 ,lactic acid and ,,co#b4 #e ,calcium ,different #a4 ,chief product1 tartrate species of propionic acid2 bacteria4 by-product1 acetic acid4 #b4 ,butyric acid4 #c4 ,chief product1 calcium acetate2 by-products1 ethyl alcohol1 butyric and succinic acids4 #f ,calcium ,small1 thin ,acetic acid in ,fitz4 citrate bacilli large quantities1 along with small quantities of ethyl alcohol and succinic acid4 #g ,calcium ,micrococci #a4 ,calcium acetate1 glycerate along with small quantities of succinic acid and ethyl alcohol4 ,medium-sized #b4 ,formic acid1 bacilli with some methyl alcohol and acetic acid4 ---------------------------------------- ------------------------- ,nencki explains1 for example1 the metamorphosis of leucin by putrefaction in this way3 ,the bacteria decompose the water into hydrogen and hydroxyl1 which act upon the leucin as follows3-- ,,ch#c ,,oh ,,ch - ,,ch#b - ,,ch - ,,cooh ,h ,,nh#c _/ ,,ch#c ,leucin ,,nh#b ,,oh - ,,ch#b 7,,ch#b7d ,,cooh 7oxycaproic acid7 ,the resulting oxycaproic acid is then split up by the second water molecule into methylenglycol and valerianic acid3-- ,,oh ,,ch#b ,,oh ,h ,,ch#b 7,,oh7#b ,,ch#c 7,,ch#b7c ,,cooh 7,,ch#b7d ,,cooh ,the methylenglycol1 which changes into formaldehyde and water1 is now split up into ,,co#b and hydrogen1 as it would be by melting with caustic alkali4 ,,oh ,h ,h4,,oh _/ ,c ,o ,,co #b;,h#b ,h ,h4,,oh ,,oh ,as we shall see in the chapter on the action of enzymes1 the phenomena are of a catalytic nature4 ,any urea present is decomposed1 by the direct action of micrococcus ure1 into ammonium carbonate and ammonium carbamate1 so that it does not play any part in the bating process as usually carried out with dung which has been kept for some time1 but the ammonia produced plays an important part in the chemical action of the bate1 as we have already seen4 ,if1 however1 dung containing the urinary products be used in a fresh condition1 the urea has indirectly a very important influence on the bating1 as it favours the permeability of the skin fibre4 7,see p4 #gb47 ,the fermentation of the cellulose in the dung has not been studied from the bating standpoint1 but it is well known that it is fermented by various species of bacteria1 which have been grouped together under the generic name of ,amylobacter4 ,deherain and ,gayon first showed that the solution and fermentation of cellulose in the form of dead vegetable matter1 which had previously been observed1 also took place in dung4 ,van ,tieghem1 in #ahgi1 showed that the solution of cellulose is caused by bacteria1 whose properties correspond with those described by him as ,amylobacter4 ,tappeiner was able to ferment cellulose by mixed cultures of bacteria from the intestines of oxen--in neutral solution1 ,,co#b1 methane1 ,h#b,s1 aldehyde1 butyric acid1 and acetic acid1 were all recognized4 ,in alkaline solutions1 the principal products were ,,co#b and hydrogen1 together with the same by-products as before4 ,from the researches of ,van ,sennis1 in #ahij1 it seems pretty certain that the fermentation of cellulose is due to the symbiotic action of at least two different organisms ,the decomposition of the cellulose may be explained by considering that first a sugar-like carbohydrate is formed by hydrolysis1 and that this is then split up into equal volumes of ,,co#b and ,,ch#d4 ,it may be noted that the fermentation is anaerobic1 and no doubt1 so far as bating is concerned1 the chief products are the organic acids produced1 principally butyric and acetic acids4 ,van ,sennis nearly always found ,clostridium butyricum associated with this fermentation4#hf #hf ,proc4 ,roy4 ,soc41 lxvii41 #aijj4 ,another group of organisms which have some influence in the bating process1 are the class called by ,beijerinck1 ,granulobacter4 ,they produce butyric acid1 and this acid1 combining with the ammonia compounds of the dung1 forms salts which undoubtedly exert an effect on the lime in the skins1 though its action on the fibre is1 perhaps1 not so great as the compounds of lactic and propionic acids4 ,the most common butyric ferment is the old ,clostridium butyricum1 now known as ,b4 butyricus1 7,prazmowsky71 which is anaerobic4 ,it forms spindle-shaped spores1 hence the name ,clostridium 7from 1 a spindle74 ,another species 7,fig4 #bc71 found in milk by ,hueppe 7#ahhd71 is aerobic1 and ferments lactic acid and its salts to butyric acid1 ,,co#b1 and hydrogen2 it appears to correspond with ,granulobacter polymyxa of ,beijerinck4 ,oxalic acid is known to be produced by some bacteria and the moulds ,penicillium and ,sclerotinia1 and in the white rot of the turnip it is produced by ,pseudomonas2 it is also produced by some saccharomycetes1 such as ,b4 ,hansenii4#hg ,there is reason to believe that its production plays a part in the bate1 as we have already mentioned in ,chapter ,,ii41 but the organisms producing it and their mode of action still remain to be investigated4 #hg ,reynolds ,green1 ,fermentation1 p4 #cej4 ,there are1 of course1 a large number of putrefactive bacteria in the puer1 among these ,b4 putrificus 7,fig4 #ai71 isolated by ,bienstock2 it is a spore-bearing anaerobic bacillus1 and is interesting as specially attacking fibrin4 ,now fibrin is extremely resistant to the action of most putrefactive bacteria1 and it is very probable that specific organisms ferment the different albuminous compounds1 in the same way that the different carbohydrates are each decomposed by specific ferments4 ,very interesting are the various forms of spirilla met with in dung2 ,figs4 #bd and #be show ,spirillum volutans in the unstained condition1 and also stained to show the flagell4 ,it will be noted that the appearance is so different that1 to an inexperienced observer1 they might be taken for different species4 ,the rle played by these organisms still requires investigation4 ,illustration3 ,fig4 #bc4--;,b4 ,butyricus4 7,hueppe47 ,illustration3 ,fig4 #bd4--,spirillum ,volutans4 7,kutscher47 ,stained to show ,flagellae4 ,illustration3 ,fig4 #be4--,spirillum ,volutans4 7,kutscher47 ,unstained ,preparation4 ,i have pointed out previously the importance of the nutrient medium1 or substratum1 in which the bacteria grow1 on the species surviving4 ,in it one can see on a small scale the ,darwinian process of natural selection4 ,there is a great struggle for existence between the various species1 and the circumstances determining the survival of this or that organism are extremely complicated1 and we are yet very much in the dark as to the action of the various chemical compounds contained in the puer1 so that it is unsafe to neglect even those which are present in only small amounts4 ,very minute quantities of certain bodies1 almost too small for detection by chemical means1 are sufficient to cause large differences in the growth of certain organisms4 ,for instance1 ,raulin found that the addition of a trace of zinc to his nutrient liquids increased the crop of the mould ,aspergillus niger more than four times the weight of a crop grown in the same liquid free from zinc4 ,if we inoculate a nutrient material with a pure culture of bacteria1 and the medium is not exactly adjusted to the needs of the particular organism1 it will not thrive1 and will speedily be overgrown by some other species obtaining access from the air4 ,this fact very much discounts the use of pure cultures of bacteria which have been proposed for bating1 although in the case of erodin1 where the medium has been adjusted to suit the organism1 considerable success has been attained4 ,the whole of the enzymes and chemical compounds essential for a perfect bate1 are not present in the dung when it leaves the animal's body1 but these compounds are produced by the continued action of the intestinal bacteria and other organisms which obtain access from the air4 ,the production of the enzymes depends1 too1 upon the composition of the nutrient medium1 since this exerts a selective influence on the species of bacteria obtaining access to it4 ,just as in the spontaneous souring of milk numerous bacteria have free access to it1 yet the lactic ferment is generally so pure that it may be1 and is1 used as a pure culture on a large scale in the manufacture of lactic acid4 ,coming to the action of the bacteria on the skin fibres1 from the work of ,abt and ,stiasny1#hh we may conclude that the substance of the conjunctive fibres is less profoundly decomposed by bacterial fermentation than by the action of lime4 ,the latter dissolves about #b per cent4 of skin substance from a fresh skin1 whereas a puer acting normally dissolves about #a per cent4 #hh ,sensibilit de la peau verte1 et de la peau aprs l'chauffe1 les pelains1 et les confits1 l'gard de la chaux du sel1 et de l'acide actique4 ,georges ,abt et ,edmund ,stiasny1 ,collegium #aiaj1 p4 #a #i4 ,the nuclein of the skin fibres appears to be all removed by the puer1 since ,abt confirms the fact that no nuclei can be seen under the microscope in a puered skin4 ,the actual solution of the skin substance is brought about by enzymes of a tryptic character4 7,see ,chapter ,v47 ,while the main lines of the bacteriology of the dung bate are now pretty well known and understood1 it will be seen that much work still remains to be done as to details1 and this principally with the anaerobic bacteria of the dung1 which have been studied by few investigators4#hi ,i have suggested#ij that such a research might well be undertaken by the bacteriological laboratories of our ,leather ,industries ,schools in ,leeds and ,london4 #hi ,see ,les ,anaerobies1 ,jungano and ,distaso 7,masson et ,cie ,paris1 #aiaj74 #ij ,the ,bacteriology of the ,leather ,industry1 ,j4,s4,c4,i41 #aiaj1 p4 #fff4 99,moulds and ,putrefaction499--,in view of the fact that moulds are of frequent occurrence on dog dung1 a brief mention of them is necessary4 ,so far as our present knowledge goes the researches of ,van ,tieghem1 ,de ,bary1 ,rankin1 ,marshall ,ward1 ,v4 ,h4 ,blackman and others indicate that their action on the essential bating constituents of the dung is a destructive one4 ,they grow usually on acid media1 and in so doing break down the acids present into simple inorganic bodies1 such as ,,co#b and water1 utilizing the carbon and nitrogen for their own growth4 ,although these fungi secrete almost all varieties of enzymes 7,bourquelot71 yet we have no evidence that any of the enzymes contained in dog dung are from this source4 ,in the usual case of dung preserved in pits or casks1 the upper surface only becomes mouldy1 since moulds require a free supply of oxygen4 ,the mycelium penetrates but a very little way into the body of the dung1 and cannot therefore effect any decomposition1 except of the surface layer4 ,the dung exposed to the action of the mould is generally a bad colour1 and is rejected as unsuitable for puering4 ,the following species have been noted and classified as growing on dog dung1 though probably not all of them are specific4 #a4 ,pilaira dimidiata 7,grove74 #b4 ,mucor caninus 7a variety of ,mucor mucedo74 #c4 ,circinella simplex 7,van ,tieghem74 #d4 ,pilobolus crystallinus 7also on cow-dung74 ,certain myxobacteria are found on dung1 among these ,chondromyces1 described as long ago as #aheg by ,berkeley1 and at that time included among the ,hyphomycetes4 ,it was rediscovered in #ahib by ,thaxton1 and owing to his researches the whole class of myxomycetes is now generally considered as a division of ,bacteria4 ,another myxomycete1 ,polyangium primigenum 7,quehl71 forming a red fructification on dog dung1 is figured in the ,encyclopdia ,britannica1 ,,xi4 edition1 vol4 #c1 p4 #afc4 ,the following abstract gives some account of putrefaction1 and may be of use in conjunction with the account of the bacteriology of the bate which has been given4 ,since it was written ,dr4 ,g4 ,abt 7see ,bibliography #ea7 has also given a very full description of putrefactive processes as affecting leather manufacture4 ,the subject is still occupying the attention of a large number of bacteriologists1 and we may expect more light to be thrown on the whole question during the next few years4 ,,abstract ,,of ,,paper ,,on ,,recent ,,advances ,,in ,,the ,,bacteriology ,,of ,,putrefaction4 ,read before the ,nottingham section of the ,society of ,chemical ,industry1 ,january #bd1 #aijf4ia #ia ,reprinted from the ,journal of the ,society of ,chemical ,industry1 ,february #ae1 #aijf1 ,no4 #c1 vol4 xxv4 ,the numbers in brackets refer to the ,bibliography1 ,chapter ,,xi4 ,to those who have to do with the manufacture of leather1 the changes which take place in the skin from the time it leaves the animal are of the utmost interest4 ,the most important of these changes is the natural process of decomposition known as putrefaction4 ,putrefaction may be defined as the decomposition of nitrogenous organic matter by living organisms1 accompanied by the evolution of malodorous gases4 ,the study of it may be divided into two parts--7#a7 the biological1 7#b7 the chemical4 ,the first concerns the organisms which break down the proteid molecule either directly or by means of enzymes2 the second that of the different products of the action of these organisms4 ,it is extremely difficult to separate these two studies4 ,dr4 ,sims ,woodhead 7#ei7 gives a concise account of the earliest researches on the organisms causing putrefaction by ,leeuwenhoek 7#afib71 ,plenciz of ,vienna1 ,mller of ,copenhagen 7#aghf71 ,needham 7#agdi71 ,spallanzani 7#agfi71 ,schwann 7#ahcg71 ,schroeder and ,van ,dusch 7#ahed71 ,tyndall 7#ahgj71 ,lister 7#ahgh74 ,these names show that the history of putrefaction proceeds parallel with the evolution of the microscope and the development of the comparatively recent science of bacteriology4 ,i propose to-night briefly to carry it up to the present day4 ,i need scarcely say that putrefaction is not a specific fermentation like alcoholic or acetic fermentation1 but that it is extremely complex4 ,in any putrefying matter1 such as gelatin or albumin1 a large number of different species of bacteria may be observed as well as monads and infusoria1 and in some cases moulds1 all of which take part in the process4 ,the first stage is a process of oxidation in the presence of air1 in which robic bacteria use up the oxygen present and only simple inorganic compounds are formed1 carbon dioxide1 nitrates and sulphates2 this part of the process is generally without odour4 ,the second stage1 or true putrefaction1 takes place in the absence of oxygen by anrobic bacteria1 and is a process of reduction4 ,it has been shown that there are no bacteria in healthy tissues1 and if a muscle or any organ is taken from an animal under antiseptic conditions it may be preserved indefinitely in a sterile vessel to which filtered air has free access4 ,solid matter is usually liquefied by organisms like ,b4 liquefaciens magnus1 which are invariably present in the air1 and which prepare the way for more specifically putrefactive bacteria1 such as ,proteus vulgaris and ,b4 putrificus1 but if one observes a number of putrefactions of the same kind of matter under natural conditions1 scarcely any two follow the same course4 ,the modern study of putrefaction dates from ,hauser 7#eh71 who1 in #ahhe1 isolated from putrefying flesh the three organisms--,proteus vulgaris1 ,p4 mirabilis1 and ,p4 zenkeri4 ,he studied the action of these in pure cultures1 and came to the following conclusions3-- ,that ,bacterium termo 7,ehr47 is not a single definite species2 various forms and stages of other organisms have been described under this name4 ,the various species of ,proteus go through a wide range of forms during their development in which cocci1 short and long rods1 thread forms1 vibrios1 spirilli1 and spirocht occur4 ,under special nutritive conditions ,proteus goes through a swarm stage1 in which condition it is capable of moving over the surface and in the solid gelatin4 ,the ,proteus bacteria are facultatively anrobic1 they all cause putrefaction2 ,p4 vulgaris and ,p4 mirabilis are the commonest and most active of all putrefactive bacteria4 ,they do not secrete an unorganised ferment1 but decompose albuminous bodies by direct action4 ,they also produce a powerful poison1 of which small quantities injected into animals produce septicmia4 ,tito ,carbone 7#fj7 found amongst the products of ,p4 vulgaris1 choline1 ethylenediamine1 gadinine1 and trimethylamine4 ,mac 7#fa71 criticising ,hauser's work1 considers the cocci form of ,proteus to be spores4 ,bienstock 7#fb7 believes the rle of the ,proteus group somewhat doubtful4 ,he discovered 7#ahhd7 another widely distributed putrefactive organism1 which he called ,bacillus putrificus2 it is a spore bearing1 drumstick shaped bacillus found in fces2 it is anrobic and specially attacks fibrin4 ,now fibrin is extremely resistent to the action of most putrefactive bacteria1 and it is very probable that specific organisms ferment the different albuminous compounds in the same way that the different carbohydrates are each decomposed by specific ferments4 ,a certain number of species of bacteria are able to decompose both carbohydrates and proteids4 ,tissier and ,martelly 7#gj7 call these mixed ferments1 and divide them further into two groups 7#a71 mixed proteolytic ferments1 including ,b4 perfringens1 ,b4 bifermentans sporogenes1 ,staphylococcus albus1 ,micrococcus flavus liquefaciens1 ,proteus vulgaris1 this group decompose albumin by means of tryptic enzymes4 7#b7 ,mixed peptolytic ferments are only able to attack the albumin when it has undergone a preliminary decomposition4 ,this group comprises ,b4 coli1 ,b4 filiformis1 ,streptococcus pyogenes1 ,diplococcus griseus non liquefaciens4 ,the second class of bacteria are those which are without action on carbohydrates1 and only attack proteids2 these consist of the true proteolytic bacteria ,b4 putrificus1 and ,b4 putidus gracilis1 and the peptolytic bacteria1 ,diplococcus magnus anaerobius and ,proteus zenkeri1 which can only decompose peptones4 ,these authors state that ,b4 putrificus is always present in putrefying albumin1 but always accompanied by facultative robes which favour the growth and development of the special putrefactive bacteria4 ,in the putrefaction of meat the reaction is first acid owing to the action of the mixed ferments on the sugars present4 ,in the next stage ammonia is formed by the tryptic enzymes secreted by the robic bacteria1 and so the anrobic organisms are enabled to develop4 ,we can thus understand how it is that putrefaction proceeds more rapidly the more mixed ferments there are present1 although these were formerly supposed to hinder putrefaction from taking place4 ,when meat is exposed to air it is first attacked by the mixed ferments1 ,micrococcus flavus liquefaciens1 ,staphylococcus1 ,bacillus coli1 ,bacillus filiformis1 ,streptococcus and ,diplococcus1 and becomes acid2 at the same time1 the presence of decomposition products of albumin may be detected1 proteoses1 amidoacids1 amines and ammonia2 the latter quickly neutralise the acids1 and in three to four days the meat is alkaline1 and has a faint putrid smell4 ,bacillus perfringens and ,bacillus bifermentans sporogenes now make their appearance2 the latter of these organisms produces amines1 amido-acids and ammonia4 ,in this stage the simple anrobic ferments are able to begin their work1 and real putrefaction sets in2 as this proceeds1 the mixed ferments gradually disappear1 and finally the only organisms remaining are ,bacillus putrificus1 ,bacillus putidus gracilis1 and ,diplococcus griseus non liquefaciens4 ,another organism1 which appears to play an important part in the decomposition of animal bodies1 is described by ,klein 7#fc72 he found that in bodies1 which had been buried from three to six weeks1 bacteria such as ,b4 coli and ,b4 proteus had almost disappeared1 and an anrobic bacterium1 which he calls ,b4 cadaveris sporogenes1 was very active4 ,it is a motile bacillus #b-d long1 with flagell all over its surface4 ,spores are formed at the rounded ends1 giving it a drumstick form4 ,it coagulates milk1 the clot gradually dissolving4 ,it grows on all the usual nutritive media1 but only under strictly anrobic conditions4 ,in a paper1 entitled 8,fermentation in the ,leather ,industry10#ib ,i gave a short account of the progress of putrefaction as it takes place in the animal skin1 and also described some of the organisms ,i had observed in putrefying skin4 ,a small piece of skin was placed in water and allowed to stand at room temperature4 ,during the first two days there was little change1 but on the third day a number of swiftly moving darting monads made their appearance4 ,some of these were propelled by flagell1 but a few had assumed amboid forms4 ,a slowly moving bacillus consisting of a long straight rod1 apparently broken up into cells exactly like the ,vibrio subtilis1 illustrated in the 8,micrographic ,dictionary10 was observed1 accompanied by some species of spirillum4 ,higher organisms present were a ,paramcium and a colourless transparent piece of protoplasm1 shaped like a dumb-bell1 with a slow rotating motion4 ,on the fifth day the number of vibrios and spirilli had greatly increased1 some with a swifter motion than others4 ,there were also many large infusoria present2 one of a peculiar double form1 which appeared to be a development of the dumb-bell shaped piece of protoplasm seen on the third day4 ,on the seventh day the most striking feature was the great increase in the number of vibrios2 the field of the microscope was crowded2 masses of the bacilli could be seen clustered round small particles of the disintegrating skin as if feeding upon it2 there were more infusoria1 many of them short1 boat-shaped monads1 with a trembling motion1 refracting light strongly2 these evidently accompany the putrefaction bacteria1 and assist in the final disintegration4 ,on the ninth day the piece of skin was entirely dissolved4 #ib ,j4,s4,c4,i41 #ahid1 #bah4 ,procter calls attention to the relative putrescibility of the different constituents of skin1 and especially to the rapid putrescence of the lymph and serum4 ,so far as ,i know1 this part of the subject has not been studied at all thoroughly1 and there is a considerable field open to workers in our research laboratories4 ,pure fat is not decomposed by bacteria1 but if albuminous matter is present1 the fat is split up by several species of bacteria and moulds4 ,schreiber 7#gc7 has shown that the presence of oxygen is necessary4 ,as this subject scarcely comes within the category of putrefaction1 ,i refer you to ,schreiber's paper1 and also to an important paper by ,otto ,rahn 7#gd7 recently published4 ,in the putrefaction of vegetable matter the cellulose is attacked by specific organisms1 which have been thoroughly investigated by ,omeliansky 7#ge74 ,he has shown that the fermentation of cellulose is an anrobic process1 caused by two species of bacteria belonging to the class of butyric ferments4 ,morphologically the organisms closely resemble one another1 but one of them decomposes the cellulose with evolution of hydrogen1 the other with evolution of methane2 in both cases considerable amounts of acetic acid and normal butyric acid are produced4 ,i have previously stated that monads and infusoria take part in the process of putrefaction1 but ,i do not know that their action has been studied in the same way as that of bacteria4 ,the life history and morphology of some of these monads was studied in #ahga to #ahge by ,dallinger and ,drysdale 7#gf74 ,these authors1 in their researches into the life history of the monads found in a putrefying infusion of cod's head1 came to the conclusion that 8bacteria are not the only or even 7in the end7 the chief organic agents of putrefaction1 for most certainly in the later stages of a disintegration of dead organic matter the most active agents are a large variety of flagellate monads40 ,dallinger cultivated some of the monads in ,cohn's fluid1 and found that they lived and multiplied in it4 ,their spores were killed at a temperature of #bej ,f4 ,there is a big field of research open in this direction4 ,the consideration of the chemical aspect of putrefaction is a vast subject1 and would demand a special treatise4 ,i shall only call your attention to one or two points of interest4 ,taking the simpler bodies first1 sulphuretted hydrogen is formed in putrefying liquids in two ways3 7#a7 by reduction of the sulphates in the liquid by an anrobic organism ,spirillum desulfuricans2 7#b7 by bacteria capable of growing in the presence of oxygen such as ,b4 coli commune and ,b4 lactis rogenes1 which ferment glucoses with formation of lvorotatory lactic acid and evolution of ,,co#b and hydrogen1 and if at the same time the material contains albumin or sulphur1 ,h#b,s is given off2 these organisms are incapable of reducing sulphates4 ,beijerinck 7#fd7 has investigated this process1 and found a variety of different forms intermediate between the two above-mentioned1 but all possessing the same characteristics so far as their chemical action is concerned1 so that they may be classed as one order1 which he calls ,aerobacter4 ,stich 7#fe7 found phosphorus pentoxide in the residue from the putrefaction of casein1 nuclein1 lecithin1 and protagon2 and in the putrefaction of certain organs of animals and plants1 gases containing phosphorus are evolved4 ,the nucleic acid of yeast yielded phosphoric acid along with hypoxanthin and xanthin4 ,vitali 7#ff7 found in the putrefaction of muscle1 which had been freed from sugars and fat1 that some alcohol was produced4 ,he considers that a hexose is split off from the albumin in a similar manner to the splitting off of a fermentable sugar from the glucoproteids 7compounds of simple proteins with carbohydrates74 ,the formation of alcohol in the putrefaction of muscle occurs in the alkaline stage4 ,thus alcoholic fermentation is caused not alone by saccharomyces1 but also by certain putrefactive bacteria4 ,lermer 7#gg7 finds that the putrefaction of barley resembles butyric fermentation4 ,an analysis of the gases given off during the later stages of the process gave the following result3 nitrogen1 #ehhh2 hydrogen1 #cgdc2 methane1 #cae4 ,in the residue from the putrefaction he found acetic1 butyric and valerianic acids1 but not caproic or caprilic acid4 ,in the normal steeping process employed for barley the gases given off consisted almost entirely of carbon dioxide and nitrogen4 ,this observation is interesting to compare with the evolution of nitrogen in the fermentation of bran shown by ,wood and ,willcox4#ic #ic ,j4,s4,c4,i41 #ahic1 #ddb4 ,the action of putrefactive bacteria has been found capable of transforming hexoses into pentoses4 ,salkowski and ,neuberg 7#gh7 inoculated a solution of d-glukuronic acid with putrefying meat1 and showed that it was changed into l-xylose with evolution of ,,co#b according to the following formula3-- ,,coh7,,choh7#d;,,cooh ,,co#b ,,coh,,choh#c;,,ch#b,,oh4 ,this is an interesting fact1 especially as1 according to ,neuberg1 the pentose contained in animal nucleo-proteids is l-xylose4 ,i wish to express my indebtedness to ,dr4 ,alfred ,koch's 8,jahresbericht ber ,grungs-organismen0 for some of the abstracts4 ,the following is a list of putrefactive bacteria which have been studied in pure cultures3-- #a4 ,proteus ,vulgaris 7,hauser74 #b4 ,proteus mirabilis4 #c4 ,proteus ,zenckeri4 #d4 ,bacillus ,oedematis maligni 7,kerry1 ,nencki1 ,bovet74 #e4 ,bacillus ,chauvi ,b4 sarcophyematos bovis4 #f4 ,b4 ,liquefaciens magnus4 #g4 ,b4 spinosus4 #h4 ,b4 putrificus 7,bienstock74 #i4 ,b4 pseudo dematicus 7,liborius74 #aj4 ,b4 enteritidis sporogenes 7,klein74 #aa4 ,b4 tetani4 #ab4 ,clostridium ftidum4 #ac4 ,b4 cadaveris sporogenes 7,klein74 #ad4 ,spirillum desulfuricans 7,beijerinck74 #ae4 ,b4 coli commune4 #af4 ,b4 lactis rogenes4 #ag4 ,b4 fermentationis cellulos4 #ah4 ,micrococcus flavus liquefaciens 7,flgge74 #ai4 ,diplococcus griseus non liquefaciens 7n4 sp474 #bj4 ,streptococcus pyogenes4 #ba4 ,staphylococcus pyogenes albus4 #bb4 ,bacillus filiformis robius 7n4 sp474 #bc4 ,diplococcus magnus anrobius 7n4 sp474 #bd4 ,bacillus putidus gracilis 7n4 sp474 #be4 ,b4 perfringens 7,frankel74 #bf4 ,b4 bifermentans sporogenes 7n4 sp474 ,moulds taking part in putrefaction1 principally of fruit and vegetable matter3-- #a4 ,penicillium glaucum4 #b4 ,mucor mucedo4 #c4 ,mucor piriformis 7,fischer1 possibly identical with #b74 #d4 ,mucor stolonifer 7,ehrenberg74 #e4 ,botrytis cinerea 7,pers74 #f4 ,mucor racemosus 7,fres74 #g4 ,monilia fructigena 7,pers74 #h4 ,fusarium putrefaciens 7,osterwalder74 #i4 ,cephalothecium roseum4 ,,chapter ,v4 ,,action ,,of ,,enzymes4 8,the living organism is enabled by the use of enzymes to bring about1 under ordinary conditions of temperature and moderate concentrations of acid or alkali1 many chemical reactions which would otherwise require a high temperature or powerful reagents40--,w4 ,m4 ,,bayliss4 ,in a recent work1#id ,dr4 ,bayliss defines enzymes as the 8catalysts produced by living organisms40 ,a catalyst is a body which greatly accelerates the rate of reaction in chemical processes1 without apparently taking part in the process4 ,for instance1 peroxide of hydrogen is decomposed into oxygen and water by mere contact with finely divided platinum1 while the latter remains unaltered in the process4 ,in this case the platinum black is the catalyst4#ie #id 8,the ,nature of ,enzyme ,action10 by ,dr4 ,w4 ,m4 ,bayliss1 ,,frs4 #ie ,the important discoveries of ,,mm4 ,paul ,sabatier and ,senderens on the catalytic action of finely divided metals1 notably nickel and copper1 have recently been extended to a study of the catalytic action of various metallic oxides4 ,in the ,comptes rendus1 ,,mm4 ,paul ,sabatier and ,a4 ,mailhe give an account of a new synthetic method1 based on the catalytic effect of titanium oxide1 which would appear to possess many practical applications4 ,they show that if a column of titanium dioxide is maintained at a temperature of #bhj-cjj ,c41 and a mixture of the vapours of a primary alcohol and a fatty acid 7other than formic acid7 is led over it1 the corresponding ester is formed4 ,the same limit is here reached instantaneously as was found by ,berthelot after prolonged contact4 ,an excess of either constituent favours the limit of combination of the other4 ,following this method1 the methyl1 ethyl1 propyl1 butyl1 isobutyl1 and isoamyl esters of acetic1 propionic1 butyric1 isobutyric1 isovaleric and caproic acids have been prepared4 ,esters of benzyl alcohol have also been readily obtained by this method4 ,the inverse action--the direct hydrolysis of esters by water--is also easily effected1 and the use of titanium dioxide reduces any secondary reactions to a negligible amount4 ,see ,nature1 ,march #i1 #aiaa1 p4 #ed4 ,see also ,dr4 ,sand's paper--bibliography4 ,in natural processes the best known type of an enzyme is diastase 7amylase71 the enzyme contained in malt1 and which enables the malt to convert starch into dextrin and sugar 7maltose74 ,it is capable of transforming more than #bjjj times its own weight into sugar1 which fact is quite sufficient to show that its action differs from that of an ordinary chemical reaction4 ,another enzyme1 sucrase1 according to ,o',sullivan and ,thompson1 will hydrolyze #ajj1jjj times its weight of cane sugar to invert sugar4 ,rennet will coagulate #bej1jjj times its own weight of casein in milk4 ,the list of enzymes grows longer almost daily1 as some new one is separated having a specific action1 until one is almost led to believe that the mechanism of life itself1 as manifested in the cell1 is due to enzymes4 ,it has been found that enzymes act very much in the same way as inorganic catalysers4 ,as an example1 the velocity of the reaction of invertase 7the enzyme of yeast which hydrolyses cane sugar to grape sugar7 has been compared with the same hydrolysis brought about by heating a solution of cane sugar with a mineral acid4 ,in both cases the reaction is in accordance with the law of mass action 7,guldberg and ,waage7 that the amount of sugar transformed will decrease as less remains to be transformed4 ,in the diagram 7,fig4 #bf7 the curve ,a is for invertase 7,jas4 ,o',sullivan1 8,journ4 ,inst4 of ,brewing10 vol4 v4 p4 #afh72 curve ,b is for the hydrolysis by acid 7,wilhelmy71 from which it will be seen that the manner in which the hydrolysis proceeds is practically the same in both cases4#if #if ,there are apparent exceptions and complications of this law which we shall not here enter into1 except to say that they may be explained by the fact that the action of some enzymes is reversible 7see p4 #ada1 under lipase47 ,illustration3 ,fig4 #bf4--;,curves showing ,rate of ,hydrolysis4 ,in the case of fermentation by the living organism1 the fermentation rises rapidly1 and then gradually slows down and comes to an end before the whole of the fermentable matter is used up2 the curve1 therefore1 is of a hyperbolic character1 ,c in the diagram1 which represents1 in a general way1 the fermentation of glucose by ,b4 furfuris4 ,the ordinates represent the amount of acid produced by the bacteria4 ,the time in this case would be more nearly represented by hours instead of minutes on the abscissa4 ,the mathematical expression for the velocity of the reaction is dx_/dt k7a x7 where a original concentration of solution x the quantity transformed in time t k coefficient of velocity of the reaction ,by integrating the above equation1 it may be shown that #a_/t log7a_/7a x77 k ,for the experiment of ,j4 ,o',sullivan with invertase1 k has a mean value of #jjjac2 for ,wilhelmy's experiment with acid1 k has a mean value of #jjjacgg4 ,enzymes are produced by the living cell1 with other secretions1 and as a consequence are found in all plants and animals4 ,certain organs1 however1 produce enzymes in large quantities1 or appear to be specially set apart for their production4 ,in plants1 the seeds are the chief seat of enzyme activity2 in animals1 certain glands1 such as the salivary glands and the pancreas4 ,the mucous membrane of the stomach and intestines also secrete enormous quantities4 ,the production of enzymes by bacteria was observed by ,wortmann in #ahhb4 ,it has been found that the secretion of the enzymes depends upon the composition of the nutrient medium in which the bacteria are grown4 ,for instance1 ,pfeffer found that the secretion of diastase by ,bacillus megatherium depended upon the amount of cane sugar in the nutrient medium4 ,the cane sugar checked the secretion of the diastase1 and the same effect was observed in the case of the common mould ,penicillium glaucum4 ,in ,bacillus mesentericus vulgatus1 diastase has been found to exist side by side with four other enzymes4 ,passini1#ig in studying the putrefactive anaerobic bacteria of the normal human intestines1 succeeded in separating from ,b4 putrificus a proteolytic enzyme filtered free from bacteria1 and which caused proteolysis in media which were too acid to permit of the bacteria growing4 ,the enzyme easily dissolved1 without previous neutralization1 the coagulated casein caused in milk by old coli cultures4 ,acid gelatin media were also liquefied by the enzyme4 #ig 8,zeit4 f4 ,hygiene10 ,bd4 xlix4 p4 #ace4 ,from the evidence we have at present it seems probable that every variety of enzyme1 hydrolysing1 oxidizing1 ammoniacal1 etc41 can be produced by bacteria4 ,the following useful classification of enzymes is due to ,effront4#ih #ih ,les ,enzymes1 ,dr4 ,jean ,effront1 ,paris1 #ahii4 ---------------------------------------- ---------------------------- ,name of ,enzyme ,substance on which ,products of the the ,enzyme acts ,reaction ---------------------------------------- ---------------------------- ,a4 ,,hydrolyzing ,,enzymes #a4 ,fermenting ,carbo- hydrates3 ,sucrase or invertin ,cane sugar ,invert sugar ,diastase or amylase ,starch and dextrin ,maltose ,maltase or glucase ,dextrin and maltose,glucose ,lactase ,milk sugar ,glucose and galactose ,trehalase ,trehalose ,glucose ,inulase ,inulin ,levulose ,cytase ,cellulose ,sugars ,pectase ,pectin ,pectates and sugars ,caroubinase ,carobin ,carobinose #b4 ,fermenting ,glucosides3 ,emulsin ,amygdalin and ,glucose1 oil of other glucosides bitter almonds1 and prussic acid ,myrosin ,myronate of potash ,glucose and allyl isosulphocyanate ,betulase ,gaultherin ,oil of gaultheria1 glucose ,rhamnase ,xanthoramin ,rhamnetine1 isodulcite #c4 ,fermenting ,fats 7,lipolytic73 ,steapsin ,fats ,glycerin and ,lipase ,fats fatty acids #d4 ,fermenting ,proteids3 ,rennet ,casein ,caseuin ,plasmase ,fibrinogen ,fibrin ,casease ,casein ,pepsin ,albuminoids ,proteoses1 peptones ,trypsin ,ditto ,proteose1 peptones1 ,papain ,ditto amides #e4 ,fermenting ,urea3 ,urease ,urea ,ammonium carbonate ,b4 ,,oxidizing ,,ferments ,laccase ,uruschic acid1 ,oxyuruschic acid1 tannin1 anilin1 various oxidation etc4 products ,oxydin ,colouring matters ,ditto of cereals ,malase ,ditto1 of fruits ,ditto ,olease ,olive oil ,ditto ,tyrosinase ,tyrosin ,ditto ,oenoxydase ,colouring matter ,ditto of wine ,c4 ,,ferment ,,which ,,splits ,,up ,,the ,,molecule ,zymase ,various sugars ,alcohol and carbon-dioxide ---------------------------------------- ---------------------------- ,a more recent classification based on chemical properties is that of ,kossel and ,dakin4#ii ,they divide ferments into two classes3-- 7#a7 ,oxylytic ferments capable of breaking the ,o-link by which the radicals are held together in fats and carbohydrates4 7#b7 ,imino-lytic ferments1 including the amino-lytic ferments which act on the amino groups of urea4 ,group #b is sub-divided into-- 7a7 ,trypsin and erepsin1 which separate the imide ,,nh from the neighbouring carbonyl ,,co4 7b7 ,arginase1 which separates off urea from arginin4 #ii ,zeit4 f4 ,physiol4 ,chem4 xli4 f4 #aec 7#aijd74 ,see also the articles by ,mr4 ,a4 ,seymour ,jones1 ,b4,sc41 writing under the pseudonym of 8,heof ,joppa10 in the ,leather ,trades' ,review1 ,july #ai1 #aiaa1 p4 #edj2 and ,aug4 #af1 #aiaa1 p4 #fbe4 ,although it is somewhat doubtful whether the enzymes contained in dog dung are of glandular origin1#ajj it is quite certain that other enzymes are secreted by bacteria developing in the dung while it is kept prior to being used for puering4 ,these enzymes may be separated by the following method4 ,about #aej c4c4 of puer is well mixed with an equal quantity of glycerin1 and allowed to stand for seven days4 ,it is then filtered through paper by means of a pump1 and yields a clear filtrate of a deep golden-brown colour2 the filtrate is poured in a thin stream into a tall vessel containing about #aejj c4c4 of #ih per cent4 alcohol4 ,a copious flocculent precipitate of the albuminous matter and enzymes is thrown down1 the solution is filtered and the precipitate washed on the filter with absolute alcohol1 and then dried over sulphuric acid in vacuo4 ,the resulting powder is1 of course1 a mixture of all the albumins in solution1 and probably only a small portion of it consists of the pure enzymes4 ,we have merely succeeded by this method in concentrating them4 ,the property of albuminous bodies in the act of coagulation to carry down soluble matter is well known1 and this also renders the preparation of any pure proteid extremely difficult4 ,it may be mentioned here that recent evidence goes to show that enzymes are not of a proteid nature1 since1 by repeated purification1 the proteid matter may be almost entirely got rid of1 while the activity of the residue containing the enzyme becomes considerably greater4 #ajj ,see1 however1 the recent paper by ,eberle and ,krall1 ,ueber den ,nachweis des ,trypsins im ,hundekot1 ,collegium #aiaa1 p4 #bja1 in which the authors endeavour to show the presence of unchanged trypsin in dog dung4 ,their proof depends upon the action of an antipancreatic serum on infusions of dog dung based on the work of ,achalme1 ,ann4 de l',inst4 ,pasteur1 #aija1 p4 #gcg4 ,see also the criticism on this paper by ,dr4 ,otto ,rhm and ,dr4 ,max ,goldman1 ,collegium1 #aiaa1 p4 #bfe4 ,hammarsten 7,physiol4 ,chemistry1 #aiaa1 p4 #did7 states that 8among the secretions which undergo putrefaction in the intestine1 the pancreatic juice1 which putrefies most readily1 takes place first40 ,krawkov's method of preparing diastase from saliva 7,green1 p4 #df7 may also be mentioned1 as it is of general application4 ,it consists in salting out the enzymes1 by saturating the clear solution 7in this case saliva diluted with an equal volume of water7 with neutral ammonium sulphate4 ,the precipitate which is caused by the saturation is collected on a filter1 and washed for a short time with strong alcohol4 ,it is then allowed to stand under absolute alcohol for one or two days1 and finally dried at #cj ,c4 ,on extraction with water it yields a solution which is strongly diastatic1 and which gives no proteid reactions4 ,there are several other methods for the preparation and purification of enzymes1 but up to the present it may safely be stated that no one has succeeded in preparing an enzyme in a state of purity4 ,in considering the mechanism by which enzymes act1 it must be remembered in the first place that they are colloids1 and1 as such1 will form absorption compounds with the substrate1 or body1 upon which they are acting4 ,it is difficult to understand how an enzyme can exert an action on the substrate1 unless it enters into some kind of combination with it1 although this may be only a temporary one4 ,the action of some enzymes has been found to be due to extremely small amounts of certain metals1 e4g4 in the case of the oxidizing enzyme laccase1 the metal is manganese4 ,in the purest samples of this enzyme prepared1 #jaf per cent4 ,mn was found1 and it has been supposed by some observers that the whole of the action of the enzyme may be attributed to the physical state of the manganese which it contains4 ,according to this hypothesis1#aja the active part of the enzyme is the ion ,mn4 ,this ion may exist in the solution in two conditions1 differing by the electric charge which they carry4 ,one of them ,mn carries two positive charges1 the other ,mn carries three4 ,in the first phase1 ,mn is transformed into ,mn by absorbing the charge of one ion of hydrogen 7,h71 and two hydrogen ions thus discharged1 in the nascent state1 unite with the oxygen dissolved in the liquid to form water4 #aja ,duclaux4 ,see ,bibliography4 #b,mn #b;,h #j #b,mn ,h#b,o ,in the second phase the ion ,mn with three charges will be transformed into the ion with two charges1 by decomposing a molecule of water1 of which the nascent oxygen will attach itself to the oxidizable body ,r yielding the oxide ,,ro4 #b,mn ,h#b,o ,r #b,mn #b;,h ,,ro and the same cycle of operations will begin again1 and continue indefinitely4 ,in the above illustration the enzyme action was an oxidizing one4 ,in the case of puering it is a hydrolytic action1 in other words a molecule of water is added to the skin substance4 ,the fibre or some portion of it is converted first into proteoses1 and finally into peptones1 and simpler bodies4 ,the active metal in these cases appears to be calcium1 but by what mechanism it brings about the hydrolysis is at present unknown4 ,pozerski#ajb found that the pancreatic juice1 which is secreted after injections of certain sera 7anti-pancreatic action71 and as a consequence has no pancreatic action1 contains no calcium1 but pancreatic juice secreted under the influence of pilo-carpin is more or less rich in calcium1 and its proteolytic action increases about equally with the amount of calcium contained in it4 ,the same probably holds good for the intestinal juice4 #ajb ,koch's ,jahresbericht ber ,grhungs ,organismen1 #aijh1 #fce4 ,victor ,henri has shown that the power of metals in the colloidal state to bring about these catalytic actions varies with the metal employed1 and is in inverse ratio to the size of the particle4 ,there is a very interesting and wide field of research open here in order to determine the conditions under which the various metals act4 ,to this end the ashes from the purest enzyme preparations might be studied1 and methods devised for producing these metals in the colloidal state1 for it seems evident that it is the state of the body acting which gives it the properties observed1 and not its chemical properties in the usual sense4 ,the enzymes contained in dog dung which are effective in the puering process belong to several groups1 principally the proteolytic and lipolytic groups1 but indirectly enzymes of the first group 7see p4 #acb71 7fermenting carbohydrates7 and of the fifth group 7fermenting urea7 also play some part by decomposing various compounds 7e4g4 cellulose and urea7 contained in the puer4 ,the action of certain enzymes from the animal body upon skin has been tried by the author4#ajc ,those selected were pepsin and pancreatin1#ajd as being most likely to be present in dung4 ,pepsin only acts in presence of ,h,cl4 ,two portions of the same skin were taken1 one of them was treated with a #a per cent4 solution of pepsin1 acidified with #jb per cent4 of hydrochloric acid2 the other in a bate liquor of dogs' dung 7puer71 both at a temperature of #dj;,c4 ,at the end of one hour the skin in the pepsin solution was considerably 8fallen10 but that in the manure solution was bated nearly away1 i4e4 the greater part of it was dissolved4 ,a #a per cent4 solution of pancreatin 7,mercks7 was found to act far more rapidly than pepsin2 #ae per cent4 of chloroform was added to the solution1 to prevent the development of bacteria4 ,the skin was reduced1 but had not the peculiar touch of a puered skin4 ,as will be shown later1 this was found to be due to the absence of any chemical action upon the lime salts in the skin1 and consequently it felt 8limey40 ,this action took place in the puered skin1 but not in the skin treated with pancreatin alone4 #ajc ,j4,s4,c4,i41 vol4 xiii41 #ahid1 p4 #bah4 #ajd ,the word pancreatin is used throughout in the sense of pancreas extract4 ,as is well known1 this contains several enzymes1 trypsin1 steapsin1 maltase1 and also a rennin4 ,w4 ,j4 ,salomon 7#i7 has also attributed the activity of the bate to pepsin and pancreatin1 but he does not give any proof of the presence of these ferments in the bate4 ,since it is practically impossible up to the present1 to separate these enzymes from the dung in a state of purity1 the method described on p4 #acd was employed4 ,the enzymes prepared in this way consist of a mixture of all the enzymes present in the dung1 the amount obtained from #ajjj grm4 of dung being about #d grm4 ,the product had a slight diastatic action upon starch2 #je grm4 in #ajj c4c4 of water at #ce ,c4 was found to have a very considerable reducing action upon skin1 and when combined with the amine compounds prepared from the dung1 the action was more powerful1 and more rapid than with puer4 ,limed skin was puered in thirty minutes in this solution to a perfect condition1 in the absence of bacteria1 and with no evil smelling compounds4 ,the reaction of the solution at the beginning of the experiment was faintly alkaline2 at the end of the experiment it was considerably alkaline4 ,this experiment proves that the action of the dung is a complex one1 due to the combined action of enzymes and chemical compounds upon the skin4 ,these compounds1 which are principally amines1 and salts of amino-acids1 probably assist the enzymes1 and at the same time act upon the lime remaining in the skin from the previous liming process4 ,whether a skin1 which has never been submitted to the liming operation1 could be bated by enzymes alone1 without the addition of amines1 has not1 so far as ,i know1 been tried1 but it is highly probable that this would be the case4 ,in order to compare the action of the enzymes prepared from dung with that of the enzymes produced by bacteria1 a mixed culture of bacteria from puer in dextrose gelatin1 after seven days' growth1 was taken4 #bjj c4c4 of this was mixed with #bjj c4c4 of dilute alcohol 7#fe per cent471 and well shaken3 gelatin and albuminoid bodies are by this means precipitated4 ,the liquid was filtered and poured into eight times its volume of #ih per cent4 alcohol4 ,the precipitate which came down was washed with absolute alcohol1 and dried in vacuo4 ,the enzymes thus obtained were re-dissolved in water1 and the former experiment with the skin repeated with this solution1 with the addition of the amines4 ,the skin was brought down in exactly the same way as before1 showing conclusively that it is the enzymes produced by bacteria1 acting in conjunction with the amines1 which bate the skin4 ,it would seem that the action of the enzymes is aided by the presence of amine compounds1 in addition to the chemical action which these latter have upon the skin4 ,the action is interdependent1 i4e4 bacterial action alone is insufficient1 and chemical action alone is insufficient1 the true bating action being a combination of the two4 ,there seems little doubt that it is the enzymes which dissolve the skin substance1 or rather certain parts of the intercellular substance of the fibres1 and the compound of this substance with lime4 ,the action is a digestive one1 and may be compared1 as we have shown1 to that of the digestive ferment of the pancreas4 ,this fact has been made use of in the artificial bate 8,oropon0 7see ,chapter ,,vii471 in which extract of pancreas is combined with ammonium chloride1 and some inert material4 ,the effect of puering on the fatty matter in the skin is well known4 ,the fat and grease are partially emulsified1 and set free1 so that they can be removed by scudding4 ,this action is a most important one1 and one in which artificial bates have hitherto been wanting4 ,the emulsification of the fats is brought about by means of an enzyme either identical with1 or closely resembling1 lipase4#aje ,this enzyme is found in the pancreatic juice1 and in the seeds of many plants4 ,it brings about the emulsification of the fat by saponifying a portion of it1 i4e4 the fat is split up into glycerin#ajf and a fatty acid1 according to the equation-- ,c#c;,h#e7;,c#ah;,h#ce,o#b7c #c;,h#b,o ,stearin4 ,c#c;,h#e7,,oh7#c #c7;,c#ah;,h#ce,,oho7 ,glycerin4 ,stearic ,acid4 #aje ,also known as steapsin1 or pyolin 7,allen1 p4 #ceg1 vol4 iv41 ,comm4 ,org4 ,analysis74 #ajf ,in the digestion of fat by dogs the glycerol produced is all absorbed before the ileum is reached1 so that none exists in the excrement4 7,levites1 ,chem4 ,soc4 ,abst4 #aijg1 vol4 iv4 p4 #hia47 ,lipase was one of the first enzymes in which the reversibility of the reaction was shown1 i4e4 it is not only capable of hydrolysing a fat1 but also of causing the formation of one by the combination of the fatty acid and glycerin4#ajg ,this explains why the reaction of such an enzyme is never complete4 ,an equilibrium is reached just as with ordinary reversible chemical reactions like the precipitation of magnesium hydroxide by ammonia4 #ajg ,another instance of the reversibility of enzyme action is the secretion of a peptolytic enzyme1 by ,b4 pyocyaneus2 i4e4 it has the power of synthesizing proteins1 as well as of decomposing them4 7,zak4 ,chem4 ,soc4 ,abst4 #aijg1 p4 #iif47 ,lecithin1 and possibly other fatty compounds1 are known#ajh to be important auxiliaries in the ferment-like actions produced by toxins2 cholesterol has a similar effect1 and as this body is a constituent of dung1 it may play some part in puering4 ,here1 again1 is a further problem awaiting investigation4 #ajh ,chem4 ,soc4 ,annual ,reports ,,iv41 #aijg1 p4 #beb4 ,loevenhart has shown that the bile salts1 sodium cholate1 and sodium glycocholate1 greatly increase the activity of lipase1 and ,magnus found that synthetic bile salts have the same effect2 such bodies are known as co-enzymes4 ,i have shown that bile itself is not favourable to the bating action1 but the bile salts1 by stimulating the action of the fat splitting enzymes1 are probably essential to the full action of the dung bate4 ,another enzyme which may be of importance in puering is erepsin1 the enzyme of the intestinal juice1 which is responsible for the completion of the digestive process4 ,the pancreatic enzymes act upon the peptones produced by the pepsin of the stomach1 splitting them up into simpler compounds1 while the erepsin acts further upon these products4 ,it dissociates albumoses and peptones into amino acids1 taking as it were the last traces of nutriment from the food passing through the intestine4 ,it acts best in alkaline solutions4 ,this ferment is very widely distributed in the animal kingdom1 and occurs in other organs and tissues besides the intestines4 ,the quantity of erepsin in the fresh fces must be considerable1 since a dog secretes from #djj to #ejj c4c4 of intestinal juice per day4 ,it remains to be shown whether this retains its properties after excretion1 and for how long4 ,a most important point in connexion with the activity of enzymes is the reaction of the medium1 i4e4 its acidity or alkalinity1 or1 more strictly speaking1 its hydrogen ion concentration4 ,a very slight increase or decrease of the acidity or alkalinity of the liquor will diminish the rate of action of the enzyme by a large amount1 and in some cases cause the action to cease4 ,in all cases enzymes have an optimum acidity or alkalinity2 in other words1 for every enzyme there is a particular hydrogen ion concentration at which its activity is at a maximum4 ,the work of ,soerensen1 to which ,i have already referred1 gives a very complete account of this aspect of enzyme action and also of the methods he employed to investigate it4 ,his work should certainly be carefully studied by anyone wishing to take up this part of the subject4 ,the same remarks as to optimum conditions apply to temperature1 although the effect of this is better known4 ,most tryptic enzymes act best at the body temperature1 viz4 #ih to #ajj ,f4 7#cg to #dj ,c471 and hence puering should be conducted at this temperature4 ,in the case of the hen or pigeon-dung bate the enzymes have not yet been studied1 so far as ,i am aware1 so that it is not possible to give an account of them4 ,at the same time it seems highly probable that1 as these bates are employed at comparatively low temperatures1 the enzyme action is kept back1 and therefore the chief action would be a chemical one4 ,enzymes are retarded in their action in the first place by their own products1 in a very similar manner to bacteria1 in the second place the retarding or inhibiting action is brought about by the so-called anti-bodies4 ,of these the longest known and best studied are those which are produced by toxins1 and which neutralize the action of the toxins upon the animal organism 7anti-toxins74#aji ,normal serum also inhibits the action of trypsin and many other enzymes4 ,another very important group of anti-bodies are the precipitins4 ,if the serum of an animal be injected repeatedly into another animal of different species1 a precipitin appears in the serum of the animal treated1 which causes a precipitate when added to the serum of the first animal4 ,the special importance of this fact is1 that it can be utilized as a method of distinguishing between human blood and that of animals1 which is often of importance in medical juris-prudence4#aaj #aji ,hammarsten1 p4 #gj4 #aaj ,gulland1 ,ency4 ,britt4 iv41 p4 #hc4 ,this fact has been made use of to distinguish dog dung from other matters1 with which it has been adulterated4#aaa ,a perfectly clear extract of dog dung filtered free from bacteria was injected into a rabbit4 ,the serum obtained from the rabbit was found to contain a precipitin1 and on addition of the serum to the dog dung extract a precipitate was produced4 ,when the serum was added to the extract from the dung of another animal no precipitate was formed4 ,when added to the extract of the adulterated dung a very much smaller precipitate was produced than with the extract from dog dung alone4 #aaa ,appelius1 ,technische ,briefe1 ,no4 #bc1 ,april #aiji4 ,the coli bacteria in the puer also produce an anti-body--agglutinin4#aab ,if a culture of ,b4 coli be examined under the microscope1 the bacteria are seen moving here and there in the liquid1 evenly distributed4 ,on the addition of a trace of the serum of an animal which has been previously injected with coli bacteria the bacteria on the slide cease their movements and collect together in clumps4 ,they are said to be agglutinated4 ,this property is used to diagnose bacteria in suspected cases of cholera and some other diseases4 #aab ,harden1 see ,bibliography4 ,the wonderful discoveries that have been made in this direction constitute one of the most marvellous chapters in the history of science4 ,serum diagnosis and serum therapeutics are now firmly established as invaluable aids to the physician in his fight against disease and death4 ,the extent of our present knowledge of the action of enzymes in puering may be summed up as follows4 ,active enzymes are produced by bacteria growing in the infusion of dung1 in addition to digestive enzymes which may be originally present in the dung2 the bacterial enzymes are produced more rapidly in a dilute infusion1 as employed in the puer wheel1 than in the dung itself4 ,the enzymes are of various kinds1 proteolytic1 peptolytic1 lipolytic1 etc41 but the proteolytic and lipolytic are the most important4 ,these have a solvent action on the fibres of the skin1 but little or no action on the hyaline layer1 at the concentration usually found in the puer liquor4 ,the fatty matters and soaps in the skin are acted upon by the lipolytic enzymes1 and the fats to some extent emulsified1 so that they may be easily removed from the skin by scudding or pressing4 ,it must be clearly understood that enzyme action alone is not sufficient1 as has been previously explained1 but that the dung enzymes1 acting in conjunction with the chemical compounds present1 produce the specific puering effect4 ,there is still much work to be done before the action of the enzymes in dung is fully understood1 but from the above short account it will be seen that the part they play in the bate is of great importance4 ,,chapter ,,vi4 ,,original ,,papers ,,on ,,bating4 ,the reprints of these papers being no longer available1 ,i have thought it best to print them in the present volume exactly as published1 with the exception of the paper entitled 8,fermentation in the ,leather ,industry0 from which only so much is reproduced as relates to puering and bating4 ,i4 ,,part ,,of ,,paper ,,entitled 8,,fermentation ,,in ,,the ,,leather ,,industry40 ,read before the ,nottingham ,section of the ,society of ,chemical ,industry1 ,february #ad1 #ahid4 ,in the next process1 that of 8bating10 the bacteria play a more important part1 and may be put in our second category1 viz4 helpful to the tanner1 though1 from the very nature of the material used1 it forms a nidus for various putrefactive ferments1 and is therefore dangerous4 ,the materials usually employed are bird dung and dog dung2 the former of these is sharp and piercing in its action1 while the latter has a more softening action on the skin4 ,in both bates1 however1 a rapid solution of the gelatinous and albuminous hide substance 7coriin7 takes place4 ,the hide fibres1 however1 are not attacked until all the nutrient material in the liquid has been consumed by the bacteria4 ,eitner 7,der ,gerber1 xv41 #aeh7 states that a sterile bate is without action on the skins1 and appears in that article to attribute the entire working of the bate to the action of micro-organisms4 ,he seems to have based his conclusions on experiments with an old bate sterilised with creolin1 which he found had no action on the skins4 ,if1 however1 a fresh bate be made and boiled for half an hour1 then allowed to cool to #ij-ie ,f41 it will be found to have a considerable action on the skins1 though not so rapid a one as the unboiled bate4 ,the boiling kills all organisms1 and fresh ones have not time to develop from spores still remaining before the experiment is at an end4 ,lately1 the action of unorganised digestive ferments in the dung has been found to be considerable4 ,thus bating is an exceedingly complex process4 ,the action appears to be threefold3-- 7i7 ,a purely chemical action of the soluble salts present in the bate on the lime in the skin4#aac 7ii7 ,an action due to organised ferments4 7iii7 ,an action due to unorganised ferments4 #aac ,references to bating3 ,procter4 ,text-book of ,tanning1 #ahhe1 #ahd4 ,der ,gerber1 x4 7#ahhd71 #aig1 ,mistbeizen4 ,der ,gerber1 xv4 7#ahhi71 #bfg4 ,j4 ,anal1 and ,appl4 ,chem41 #ahic1 vii4 #hg1 #ie4 ,j4,s4,c4,i41 xii4 #ecj1 ,palmer and ,sandford4 ,salomon1 ,w4 ,j41 ,tech4 ,quarter1 #ahib1 v4 #ha1 etc4 ,j4,s4,c4,i41 xii4 #ggd1 ix4 #bg4 ,the precise amount of influence each of these actions has on the skin is difficult to assign4 ,the chemical action of the ammonia compounds dissolves the lime remaining in the skin1 but the simple removal of the lime is not sufficient1 as may be shown by removing it completely with dilute hydrochloric acid or other similar means1 and washing perfectly free from acid in distilled water4 ,when tanned1 such a skin is hard and brittle4 ,the organised ferments or bacteria1 of which there are many species in the bate1 probably act on the skin by secreting soluble ferments1 which have the power of dissolving hide fibre4 ,i have isolated in plate cultivations several species which liquefy the gelatin4 ,if skins are allowed to lie in the bate1 zooglo of these bacteria collect in the folds and attack the fine 8grain10 so that the leather is covered with lines and markings1 or 8flaked40 ,thus the operation is a very critical one1 requiring careful watching2 under certain atmospheric conditions and at a temperature of #ce-dj ,c4 the skin1 if only left a short time too long1 will completely melt away4 ,the more skin substance is dissolved in the liquid1 the more rapid and pronounced the bacterial action becomes4 ,so far as is at present known the unorganised ferments in the dung1 besides those which are secreted by the bacteria1 are mostly digestive ferments#aad --pepsin1 pancreatin1 and trypsin--certain quantities of which pass out of the animal's body in an unchanged condition4 ,of these1 pepsin only acts in an acid solution1 and1 although fresh bate liquor is faintly acid to litmus1 it quickly becomes neutralised by the lime in the skins1 so that the action of this ferment can only be limited in extent4 ,pancreatin will act in a neutral solution1 and has1 therefore1 a considerable effect on the skin4 #aad ,harris and ,gow1 ,jour4 of ,physiol41 xiii4 #dfi4 ,g4 ,tammian1 ,zeitschr4 f4 ,physiol4 ,chem41 xv4 #bga4 ,o4 ,loew41 ,j4 ,prak4 ,chem41 #cg1 #aja4 ,j4,s4,c4,i41 #ahhh1 #bbd4 ,,some ,,dung ,,analyses4 ---------------------------------------- -------------------------------- ,hen ,dung ,dog ,dung ,guano ---------------------------------------- -------------------------------- ,per ,cent4 ,per ,cent4 ,per ,cent4 ,moisture #fjhh ,ca #dcjdi ,urea #ejj ,organic matter #aibb ,mg #jjhg ,k#b,,so#d #gij ,phosphates #ddg ,k #jcjb ,na,cl #ejj ,ca,c,o#c and ,na #jdch 7,,nh#d7c,,po#d #eej ,ca,s,o#d #ghe ,si #jjjd 7,,nh#d7b,o #jfj ,alkaline salts #aji ,,po#d #cddf ,si,o#b #bbe ,silica and sand #ffi ,,co#b #gdfd ,ca#c7,,po#d7b #ijj ------ ,cl #jjcg ,mg,n,h#d,,po#d #aebe #ajj4jj ,fe and loss #jjjh ,ammon4 urate #aebe ,organic ,organic matter matter #adaeb 7#ag per cent4 ,n7 #dagc ,containing ,h#b,o #cajac ,moisture #feb ,n ammonia #jgd ------- ------ #ajj4jjj #ajj4jj ---------------------------------------- -------------------------------- ,w4 ,i4 ,macadam1 ,j4,s4,c4,i41 #ahhh1 #hj4 ,viollet1 ,diction d',analyses ,chim4 ,the dog dung actually used in a tannery is from animals fed on a more vegetable diet1 the one given having an extremely high percentage of lime1 no doubt owing to the animal having eaten bones4 ,a dung as brought from the kennels was found to contain3-- ,per ,cent4 ,mineral matter #dfgi ,organic #igca ,water #heeij ------ #ajjjjj ,i find by experiments with the purified ferments that their action is very slow compared with the bate itself4 ,two portions of the same skin were taken3 one of them was treated with a #a per cent4 solution of pepsin acidified with #jb per cent4 of hydrochloric acid1 the other in a bate liquor of dog's dung2 both at a temperature of #dj ,c4 7#ajd ,f474 ,at the end of one hour1 the skin in the pepsin solution was considerably 8fallen10 but that in the manure solution was bated nearly away1 i4e4 the greater part of it was dissolved4 ,a #a per cent4 solution of pancreatin 7,merck's7 was found to act far more rapidly than pepsin4 ,at #dj ,c4 in a neutral solution the skin fell rapidly1 and the action continued even in the cold4 ,in this experiment it was found that in #ae hours the liquid was swarming with minute bacteria4 ,in order to guard against the influence of bacteria a similar experiment1 at the suggestion of ,mr4 ,h4 ,r4 ,procter1 of the ,yorkshire ,college1 ,leeds1 was tried with the addition to the pancreatic solution of #ae per cent4 of chloroform2 this prevents the development of bacteria1 while it does not interfere with the action of the pancreatin4 ,the skin was reduced as before1 but in neither case had it the peculiar touch of a 8puered0 skin1 nor were the characteristics of the leather the same4 ,,ii4 ,,notes ,,on ,,the ,,constitution ,,and ,,mode ,,of ,,action ,,of ,,the ,,dung ,,bate ,,in ,,leather ,,manufacture4 ,read before the ,nottingham section of the ,society of ,chemical ,industry1 ,oct4 #bf1 #ahih4 ,in a paper read before the ,society of ,chemical ,industry 7,j4,s4,c4,i41 #ahid1 #bai71 the author gave an outline of the bating process as far as he had then investigated it4 ,further researches have shown that1 although the views then put forward must be somewhat modified1 in the main they are correct4 ,in #ahie-if a series of experiments was undertaken with a view of ascertaining how much of the reducing action of the bate was due to3 7#a7 the chemical constituents2 7#b7 the bacteria2 7#c7 the digestive ferments and enzymes4 ,the puer used was dog dung obtained freshly every week from hunting kennels4 ,it contained on an average3 water1 #he per cent42 organic matter1 #aj per cent42 mineral matter1 #e per cent42 about #c per cent4 of the organic is soluble and about #a per cent4 of the mineral matter4 ,according to ,gamgee 7,phys4 ,chem4 #b71 a dog fed on flesh diet excretes from #bg to #dj grm4 of fces in #bd hours1 of which #abi grm4 are solids4 ,on a bread diet the amount of fces is much more4 ,an ultimate analysis gave the following results3-- ------------------------------------- ,bread ,diet ,meat ,diet ------------------------------------- ,c #dgci #dcdd ,h #fei #fdg ,n #bib #fej ,o #cfjh #aceh ,mineral matter #gjb #cjja ------------------------------------- ,these figures alone are sufficient to show what variable quantity is the puer employed in a tannery4 ,the mineral matter is composed as follows3-- ---------------------------------------- --------------- ,soluble in water ,na,cl and ,na#b,,so#d #acg #djj ,sodium phosphate #bfe ,earthy phosphates #hjcg ,insoluble in water ,ferric phosphate #bji #idic ,ca,s,o#d #deb ,silicic acid #gid ---------------------------------------- --------------- ,the ammonia compounds combine with the lime remaining in the skin1 but the constitution of these compounds was unknown4 ,the puer was examined for ammonia by ,schlsing's method1 #ej c4c4 being mixed with #ej c4c4 milk of lime placed under an air-tight bell-glass1 together with an open vessel containing a measured quantity of standard acid1 for #cf hours4 ,no ,,nh#c was given off4#aae #aae ,this is not invariably the case3 other samples of puer examined have given off ,,nh#c when similarly treated1 but only in small quantity4 ,a similar instance has been observed by ,rideal and ,orchard in the liquefaction and decomposition of gelatin by ,b4 fluorescens liquefaciens 7,the ,analyst1 ,october #ahig71 where the quantity of ammonia produced was insignificant1 amounting even after #af days' incubation to only #jafh grm4 of ,n per #ajj c4c41 corresponding to #jbjd grm4 of ammonia4 ,the mixture of dung and ,ca7,,oh7#b was filtered and a perfectly clear filtrate of a golden-yellow colour obtained4 ,this contained free amines1 calcium salts of volatile and non-volatile acids4 ,it was distilled until the distillate was no longer alkaline1 and made up to #ejj c4c4 #ej c4c4 required for neutralisation #eg c4c4 of 7,n_/#ajj7 ,h#b,,so#d1 equivalent to #jaich grm4 of ,,nh#c per litre of original puer1 being the amines set free by ,ca7,,oh7#b in cold solution4 ,a further #ej c4c4 was distilled with ,na,o,h1 the amines given off neutralised #h c4c4 of 7,n_/#a7 ,h,cl1 equivalent to #bgb grm4 of ,,nh#c per litre4 ,the neutralised liquid was evaporated to dryness2 the residue1 consisting of amine hydrochlorates1 amounted #jbg grm4 ,a qualitative test showed both primary and secondary amines to be present4 ,the action of these amine hydrochlorides was tried upon skin1 pieces of limed sheep grain previously washed in water being used4 ,the solution was maintained at #ce;,c4 ,in the first experiment #jbg grm4 was dissolved in #ajj c4c4 of water4 ,in two hours the skin was considerably reduced1 but had not the touch of a 8puered0 skin4 ,it tanned well and was a good colour1 showing that the lime had been removed1 but the leather was not sufficiently soft4 ,with a strength of #a grm4 per #ajj c4c4 the action was hastened1 the same result being obtained in #a-a_/d hours1 but the coriin of the skin was not dissolved4 ,a comparison piece of the same skin in dung was bated too much4 ,with a view of comparing the action of analogous bodies1 skin was treated in a solution of anilin hydrochloride1 #a grm4 per #ajj c4c4 for #a-a_/d hours at #ce ,c4 ,the solution was acid1 lime was removed1 and the skin felt very similar to that in the previous experiment4 ,coriin was not dissolved1 and the skin did not 8come down40 ,of the mineral constituents mentioned above1 only the chlorides#aaf have a reducing action on skin1 the other compounds being inert1 e4g4 silicates1 or merely supply food for the bacteria4 #aaf ,procter1 ,text ,book of ,tanning1 p4 #he4 ,for a general outline of the decompositions taking place in dung1 see ,dr4 ,herfeld's paper 7,j4,s4,c4,i41 ,may #ahie74 ,we need only consider the action of the chief organic compounds1 as the amount of chlorine is too small 7in one case #jjec per cent4 on the dry dung7 to be of importance4 ,the principal compounds are3-- ,organic ,acids4--,formic1 acetic1 butyric1 valerianic1 lactic1 malic1 tartaric1 citric1 and glyceric4 ,amido ,compounds4--,leucin1 tyrosin1 glutamic acid1 glutamine1 asparagin1 glycocol4 ,bases1 consisting of amines1 skatol1 and indol1 and varying amounts of ammonia1 according to the age of the dung4 ,the organic acids exist partly as salts of the alkaline earths1 partly combined with amines4 ,a distillation of 8puer10 after acidifying with ,h#b,,so#d1 gave #bb grm4 per litre of volatile acids reckoned as acetic4 ,no ,h,cl came over4 ,on decomposing the sodium salts of the acids with ,h#b,,so#d1 the smell of butyric acid predominated4 ,i have also shown the presence of lactic acid in the dung1 but have been unable to determine the amount4 ,action of ,amido ,compounds4--,a mixture of glycocol and leucin#aag was prepared by boiling #h grm4 of gelatin in #djj c4c4 of water1 acidified with #a c4c4 of ,h,cl for two hours with inverted condenser4 ,the acid was then neutralised with ammonia4 ,the solution had a very considerable reducing action on skin at #ce ,c4 in #ij minutes1 but not sufficient for practical purposes4 ,it appears to dissolve a little coriin in a similar way to dilute acids4 ,it was found on further investigation that the action was largely due to the ,,nh#d;,cl present4 #aag ,according to the text books2 but for later researches see ,paal and ,schilling1 ,chem4 ,zeit4 #ahie1 #adhg2 also ,j4,s4,c4,i41 #ahih1 #ehi4 ,action of ,dilute ,acids4--,although the bate in practice is almost always alkaline1 yet a fresh bate is acid1 and it may be as well1 before proceeding1 to consider briefly the action of weak and dilute acids on skin4 ,the fibres of the skin have only a limited capacity for holding acids1 and soon begin to swell abnormally and partially dissolve4 ,reimer#aah has found that the material may be reprecipitated by lime water4 ,it forms a fibrous mass1 which has not the sticky feel of gelatin1 but is at once converted into that body by boiling4 #aah ,h4 ,k4 ,procter1 8,text ,book of ,tanning10 #ahhe1 p4 #ah4 ,the author has examined the action of dilute ,h#b,,so#d on sheep skins1 and this may be considered typical of the action of acids on skin generally4 ,when puered and drenched sheep skin is treated for #bj minutes with a very dilute solution of ,h#b,,so#d 7#a_/bhj71 it swells up considerably and becomes soft and semi-transparent1 ,the fibres of the skin1 which under normal conditions have a diameter of #d-f become #bj or more2 on staining with picro-carmin there are seen to be certain fibres which are unaffected or only slightly affected by the acid4 ,these are the elastic fibres#aai and the capillary blood vessels4 #aai ,see ,procter1 8,text ,book of ,tanning10 pp4 #h and #ba4 ,on filtering a solution of the above strength in which skin in excess has been treated for #bj minutes1 and evaporating #ajj c4c4 to dryness in a platinum dish1 a residue of #jdiib grm4 was obtained4 ,a second experiment gave #jdif grm4 of which #fa per cent4 was organic matter4 ,by ,kjeldahling another portion of the residue1 the ,n in #jab grm4 amounted to #jjabb grm4 equivalent to #jjgc grm4 of skin substance2 i4e4 #fj per cent4 of the soluble matter is skin4 ,it is evident that the matter in solution is a compound of skin substance and ,h#b,,so#d together with a little soluble mineral matter contained in the skin4 ,the amount of substance dissolved depends upon the condition and previous treatment of the skin4 ,in the presence of ,na,cl1 which prevents the swelling of the fibres1 puered sheep grains take up #gj c4c4 of 7,n_/#a7 ,h#b,,so#d from a solution containing #ag c4c4 of 7,n_/#a7 ,h#b,,so#d 7#jhcc grm4 ,h#b,,so#d7 and #gh grm4 of ,na,cl per #ajj c4c4 ,about #cjj grm4 wet skin per litre were used4 ,the skin substance dissolved by the acid in the time named does not appear to be more than that dissolved by the weak acids of a drench1 although an equivalent weight of ,h#b,,so#d has a much more powerful swelling action on skin than these acids4 ,a piece of puered and drenched sheep skin was carefully washed in distilled water and then dried in vacuo until it ceased to lose weight2 the absolute dry weight was #dbfgj grm4 ,the skin was soaked down in distilled water and again drenched for #cj hours in a clean bran drench1 developing approximately #jh grm4 lactic acid1 and #je grm4 acetic acid per litre 7see this ,journal1 ,may #ahic74 ,it was again washed and dried in vacuo4 ,it weighed #dab grm41 a loss of #jad grm4 #cdd per cent4 ,the action1 therefore1 of the acids is a reducing one1 inasmuch as skin is dissolved1 but as the fibres hold a certain amount of acid1 the skin appears to be plumped4 ,where the acid is a mineral one the skin tans plump1 but with a brittle and inelastic fibre1 weak organic acids make a plump1 soft leather with a moderately elastic fibre1 giving to the skin a somewhat india-rubber feel4 ,we thus see that weak acids alone do not produce a similar result to a dung bate1 which causes the skin to fall and produces a flat soft leather with a stretch in it1 which will not spring back4 ,i have also tried the action of the following ,na and ,,nh#c salts upon skin3-- ,sodium lactate1 ,c#c;,h#e,o#c,na1 prepared by neutralising #b grm4 lactic acid with sodium carbonate in #ajjj c4c4 water4 ,the solution was used under the same conditions as the other bating experiments1 viz4 at #cg ,c4 the reducing action was nil1 but on prolonging the digestion1 the medium was found to be very suitable for the development of putrefactive organisms1 and1 as a consequence1 the skin was attacked and partly peptonised4 ,ammonium lactate1 prepared in a similar way1 had an almost identical action on the skin1 but was more effective in removing the last traces of lime4 ,ammonium butyrate1 prepared as above1 removed lime1 but instead of a reducing action it appeared to plump the skin slightly4 ,action of ,bile4 ,amongst other compounds in the dung which might have some action on skin were the bile salts and bile colouring matters4 7,for a full description of these1 see ,gamgee1 ,phys4 ,chem4 ii47 ,experiments were made with ox bile1 #be c4c4 being diluted with #bej c4c4 of water4 ,pieces of sheep grain previously washed in water were digested in this solution at #cg ,c4 for #a-d hours4 ,the bile had no reducing action on the skin and in fact hardened it1 at the same time staining it a dirty yellowish brown1 the colour differing from that of the colouring matter of dung 7hydrobilirubin74 ,even after continued standing there was little or no development of bacteria1 the bile appearing to have an antiseptic action4 ,action of ,bacteria4 ,having ascertained the action of the chief chemical constituents of the dung1 that of the bacteria was next examined4 ,in the first experiment1 eliminating all but bacterial action1 a tube of nutrient gelatin was inoculated from an active bate4 ,in two days the gelatin had liquefied along the needle track4 ,the culture was now transferred to the following solution3-- ,gelatin #d grm4 ,dextrose #d ,k#b;,,hpo#d #aj ,mg,s,o#d #jb ,na,cl #jd ,water #bjjj c4c4 ,the growth in this was fairly rapid and the smell very slight at the end of a week4 ,a piece of washed sheep grain worked in this culture at #cg ,c4 for four hours was considerably reduced1 the grain was not attacked1 the action differing in this respect from a prolonged puering4 ,this mixed culture was grown in various other nutrient media1 gelatin1 gelatin and mineral salts1 broth made from sheep and calf fleshings1 etc41 with practically the same results4 ,in no case did the bating action equal that of dung1 and was insufficient for practical purposes4 ,a cursory bacteriological examination of dung will show that the number of species of bacteria it contains is very large1 but on making a plate cultivation from a sufficiently dilute infusion of fresh dog dung1 most of the colonies developing appear to belong to four or five species4 ,the following is a list of all the organisms which1 so far as my knowledge goes1 have been isolated from different kinds of dung3-- ,,list ,,of ,,known ,,bacteria ,,in ,,dung4 ,these organisms have #a4 ,bacillus fluorescens putridus been formerly de- #b4 liquefaciens scribed as ,bacterium #c4 ,proteus vulgaris4 termo by various #d4 mirabilis4 authors4 #e4 ,bacillus subtilis4 ,j4 ,t4 ,wood1 ,j4,s4,c4,i41 #f4 ,micrococcus fulvus4 #ahij1 #bh4 #g4 ,bacterium ure4 7,cohn47 #h4 ,bacillus saprogenes1 ,i41 ,,ii41 ,,iii4 ,vide ,herfeld1 ,j4,s4,c4,i41 ,may #ahie4 #i4 ,bacillus butyricus4 #aj4 ,b4 putrificus coli4 #aa4 ,b4 pyocyaneus4 #ab4 ,b4 janthinus4 #ac4 ,b4 coprogenes ftidus4 #ad4 ,b4 pyogenes ftidus4 #ae4 ,b4 prodigiosus4 #af4 ,b4 zenkeri4 #ag4 ,b4 magnus4 #ah4 ,b4 spinosus4 #ai4 ,b4 liquefaciens4 #bj4 ,b4 coli4 #ba4 ,b4 duclauxii ,b4 ure4 #bb4 ,micrococcus ure4 #bc4 liquefaciens4 #bd4 ,proteus sulphureus4 #be4 ,bacterium sulphureum4 #bf4 ,bacillus amylobacter4 #bg4 ,clostridium butyricum4 #bh4 ,b4 acidi paralactici4 #bi4 ,bacillus ,i4 ,isolated from horse manure by #cj4 ,,ii4 ,s4 ,a4 ,severin1 ,centr4-,bl4 f4 ,bakt4 ii4 #ca4 ,,iii4 #a1 #ig4 #cb4 ,spirillum serpens4 #cc4 tenue4 #cd4 undula4 ,isolated by ,kutscher1 ,zeit4 f4 #ce4 volutans4 ,hyg4 xx4 #de4 #cf4 ,vibrio ,i4 #cg4 ,,ii4 #ch4 ,,iii4 #ci4 ,spirillum from pig dung4 ,smith4 ,centr4-,bl4 f4 ,bakt4 xvi4 #a1 #abd4 #dj4 ,streptococcus liquefaciens coli4 ,gamgee4 ,phys4 ,chem4 ii4 #da4 ,bacillus mycoides4#abj #abj ,since the above was written1 ,severin 7,centr4-,bl4 iii4 #b1 #fbh7 has described seven other species of bacteria1 isolated from horse dung2 for the description and property of these the original memoir must be consulted4 ,popp and ,becker1 ,german ,patent #hf1cce1 #bh1 describe fourteen species which they isolated from dog and pigeon dung1 of which three have considerable bating action on skins1 and which form the subject of the patent4 ,some of these are probably identical with organisms in the above list4 ,there are besides many unnamed species of bacteria in dung1 among which are the two following isolated by me from puer-- 7a7 ,plate ,cultures4--,small yellowish colonies1 slightly fluorescent1 liquefy the gelatin slowly4 ,rods resembling ,b4 subtilis when at rest1 but moving with a rapid undulatory motion4 ,cultures in nutrient gelatin have a considerable reducing action on skin4 7b7 ,plate ,cultures4--,bluish colonies liquefying gelatin rapidly1 micro-bacteria in pairs4 ,not so marked an action on skin as 7a74 ,the organism resembles ,proteus vulgaris1 but swarming islets not observed4 ,of the species mentioned above1 a pure culture of ,b4 subtilis in meat broth1 maintained for one week at #ce ,c41 had no reducing action on skin4 ,b4 fluorescens liquefaciens had a moderate reducing action4 ,the species developing on the plates vary according to the age of the dung4 ,in horse manure1 according to ,severin1#aba bacilli predominate in the early stages4 ,at the end of two to three weeks micro-bacteria1 cocci and diplococci make their appearance1 while the bacillar form becomes scarce4 ,in three months cocci predominate1 forming zooglo2 strepto- and staphylo-cocci and spirilli were seldom found4 ,yeasts and sarcina were never observed4 ,from observations extending over several years it is evident that a similar cycle occurs in dog dung4 ,when quite fresh it contains comparatively few bacteria2 then certain groups of species take possession1 causing decompositions in the dung2 these in their turn give place to other species1 which decompose the products formed by the first1 so that no one species produces or can produce the complex chemical and physiological changes which take place1 or the bodies necessary for the bating of skin1 as has been supposed by some observers4 #aba ,centr4-,bl4 ii4 #a1 #ig4 ,none of the experiments1 either with mixed or pure cultures of bacteria1 had a perfect reducing action on skin1 although the action was considerably greater than that of the chemical solutions4 ,it was found1 however1 that by adding a small quantity of the amines above mentioned to the bacterial cultures1 the reducing action became nearly as rapid and effective as with dung itself2 and it was1 therefore1 clear that the principal bating effect was due to a combination of two things1 viz4 an active growth of bacteria in the presence of amine compounds4 ,it was now necessary to ascertain the mode of action of the bacteria on the skins4 ,i have previously shown#abb the action of digestive ferments or enzymes to be notable in the case of pancreatin4 ,a careful study of the behaviour of the digestive enzymes in the animal body shows1 however1 pretty conclusively1 that they are all destroyed before the fcal matter is discharged1#abc and1 therefore1 the enzymes in the dung are not from this source4 #abb ,j4,s4,c4,i41 #ahid1 ,march #ca1 #bah-bba4 #abc ,see ,gamgee1 ,phys4 ,chem4 #b4 ,an attempt was made to filter the dung diluted with water through a ,berkefeld filter1 and thus obtain a clear filtrate containing all the enzymes and free from bacteria2 it was found impossible to filter the liquid in this way4 ,the method of ,claudio ,fermi#abd was also tried1 but a clear filtrate could not be obtained4 #abd ,ann4 de ,micrograph1 ii4 #f1 ,march #bj1 #ahif4 ,the author has succeeded in obtaining the enzymes best in the following manner3--,about #aej c4c4 of the above-mentioned 8puer0 was well mixed with an equal quantity of glycerin and allowed to stand for seven days2 it was then capable of being filtered on a filter pump1 although very slowly1 and yielded a clear filtrate of a deep golden brown colour2 the filtrate was poured in a thin stream into a tall vessel containing about #aejj c4c4 of #ih per cent4 alcohol4 ,a copious flocculent precipitate of the albuminous matters and enzymes was thrown down1 the alcohol was filtered off and the precipitate washed on the filter with absolute alcohol1 and dried over sulphuric acid4 ,the resulting amorphous body was of light brown colour1 and became darker when exposed to the air4 ,the amount obtained from #aej c4c4 of dung was #jee grm4 7#cff grm4 per litre74 ,the body consists of a mixture#abe of all the enzymes existing in the dung along with other albuminous bodies4 ,it has a very slight diastatic action on starch4 #je grm4 in #ajj c4c4 of water at #ce ,c4 had a very considerable reducing action on skin4 ,a further experiment with #je grm4 of amine hydrochlorides1 #je grm4 of enzymes and #ajj c4c4 of water1 at #ce ,c4 brought down a piece of limed sheep grain in #cj minutes exactly like puer2 the reaction of the solution at the commencement of the experiment was faintly alkaline2 at the end of the experiment it was considerably alkaline4 #abe ,i did not consider it necessary to purify the enzymes1 the object being to examine the action of the bacterial products apart from the living organisms4 ,it was noted that the fcal odour of the glycerin solution disappeared on standing for two or three weeks1 and the solution smelt strongly of ethyl butyrate1 the enzymes being still present4 ,these enzymes were prepared from dung1 and it now remained to prepare them in the laboratory by the action of bacteria alone4 ,for this purpose #bjj c4c4 of a mixed culture of dung bacteria in the solution above described1 seven days old1 was mixed with #bjj c4c4 of dilute alcohol 7alcohol #fe1 water #ajj7 and well shaken4 ,gelatin and albuminoid bodies are by this means precipitated4 ,the liquid was filtered and poured into eight times its volume of #ih per cent4 alcohol4 ,the precipitate which came down was washed with absolute alcohol and dried in the usual way4 ,the enzymes thus obtained were redissolved in water and the former experiment with skin repeated with this solution4 ,the same effect was produced1 showing conclusively that it is the enzymes produced by the bacteria1 acting in conjunction with the amines1 which bate the skin4 ,it would seem that the special action of the enzymes is aided by the presence of amine compounds1 in addition to the chemical action which these latter have upon the skin4 ,the action is shown to be interdependent1 i4e41 bacterial action alone is insufficient1 and chemical action alone is insufficient1 the true bating action being a combination of the two4 ,in conclusion the author has pleasure in acknowledging the valuable assistance of ,mr4 ,h4 ,s4 ,shrewsbury in carrying out some of the experiments4 ,,iii4 ,,further ,,notes ,,on ,,the ,,action ,,of ,,the ,,dung ,,bate4#abf #abf ,reprinted from the ,journal of the ,society of ,chemical ,industry1 ,november #cj1 #ahii1 ,no4 #aa1 vol4 xviii4 ,the present notes are a continuation of those published in #ahih4 ,it has been impossible for me to follow up the subject except in a desultory manner1 but ,i think it desirable to put further results1 however meagre1 before you with the object of throwing more light on the complex process of bating hides and skins4 ,since the previous notes were written1 ,dr4 ,th4 ,krner#abg has called attention to the physics of the process1 a matter which ,i had not previously mentioned4 ,he explains part of the action by differences of osmotic pressure4 ,the ammonium salts and salts of organic bases contained in the dung1 possess a smaller osmotic pressure than the solution of calcium hydrate contained in the skins4 ,the ammonium ion endeavours to unite with the hydroxyl ion of the calcium hydrate to form undissociated ammonium hydroxide4 ,in consequence of the osmotic pressure and the electrostatic attraction of the oppositely charged ions1 the calcium hydrate solution is withdrawn from the skin and the latter falls4 #abg #aj ,jahresber4 d4 ,deutsch4 ,gerberschule zu ,freiberg1 #ahih-ii3 ,beitrge zur ,kentniss der wissenschaftlichen ,grundlagen der ,gerberei1 p4 #cb4 ,experiments with ,bacteria on a ,large ,scale4 ,i have shown#abh that simple cultures of bacteria in certain nutrient media1 in the absence of amines and other bodies1 have an imperfect bating action on skin4 ,this was the case1 whether the cultures were pure or mixed1 but the mixed cultures have a better action than the pure cultures of any of the organisms ,i have hitherto used4 ,bacteriological processes in nature are usually carried on by a mixture of species of bacteria2 still there are fermentations like the spontaneous souring of milk1 the formation of nitrites from nitrates1 and the ammoniacal fermentation of urea1 which may be considered as natural pure cultures4 ,these are examples of what ,i may call the selective influence of the nutrient medium4 ,the nutrient medium used in my former experiments was a solution of gelatin and mineral salts1 such as is used in general bacteriological work1 modified in various ways4 ,on careful consideration1 this did not appear to be a medium at all corresponding to the natural bate4 ,the albuminoids in the process of digestion are peptonised1 and dung contains only those bodies which the animal is incapable of assimilating4 ,it is from these bodies that the necessary enzymes are produced by bacteria4 ,of the numerous trials with pure cultures of different organisms from dung1 ,i found that most of those having the property of secreting bating enzymes1 were non-liquefying bacteria4 ,popp and ,becker have also pointed out that peptonising bacteria do not exert a favourable reducing action on skin4 ,it is impracticable to grow these non-peptonising organisms on a large scale in a solid medium1 and it occurred to me that gelatin1 previously peptonised by chemical means1 would be a favourable medium4 ,experiments with hydrochloric and sulphuric acids gave hopeful results4 ,the acid was neutralised with ammonia after the chemical action was complete1 and the bacteria cultivated in this solution4 #abh ,j4,s4,c4,i41 #ahih1 p4 #ajaa1 see previous paper1 p4 #aeb4 ,a better result was obtained by digesting #aj grm4 gelatin1 #e grm4 lactic acid 7anhydrous by calculation71 #ajj c4c4 of water1 in a closed vessel on the water bath for three hours4 ,a slight black precipitate of melanoidic acid 7humic acid7 is formed4 ,the liquid is of a clear brown colour1 and contains a large number of nitrogenous bodies resulting from the breaking down of the gelatin molecule4 ,it has been impossible for me to ascertain its exact composition1 but ,i have partially examined it with the following results3-- #a4 ,a small quantity of the liquid poured into absolute alcohol1 gives a white precipitate which re-dissolves on the addition of about #cj per cent4 water4 ,this shows absence of gelatin4 #b4 ,on saturating with ammonium sulphate1 a brownish precipitate is thrown down which is perfectly soluble in cold water4 ,it consists of gelatose lactates which are evidently formed in an analogous manner1 to the gelatose hydrochlorides prepared by ,c4 ,paal4#abi ,the gelatoses correspond to the protoses formed during the digestion of albumin4 ,in one sample #ac grm4 gelatose lactates per #ajj c4c4 was found4 #abi ,ber4 #be1 #abjb2 also ,allen1 8,comm4 ,org4 ,analysis10 iv41 #dff4 ,f4 ,marpmann1 ,centralblatt f4 ,bakt4 #b1 #e1 #fg4 #c4 ,the filtrate from 7#b7 was dialysed against running water for #ae hours to get rid of the ammonium sulphate4 ,the resulting gelatin-peptones1 or gelatones1 amounted to #ia grm4 per #ajj c4c4 ,in other words1 the heating under pressure had transformed #hg per cent4 of the original gelatin into true peptones4 ,it may be presumed that the other and simpler nitrogenous bodies formed1 are the same as those produced by the treatment of gelatin solutions by dilute mineral acids1 and that the bases combine with the free lactic acid4 ,an excellent list of these and a very interesting account of the protamines and hexones which go to form the complex albumin molecule is given in a paper by ,dr4 ,a4 ,kossel4#acj #acj ,rev4 ,gen4 des ,sciences1 #ahii1 p4 #chj4 ,the solution of gelatone lactates and free lactic acid prepared as above1 was neutralised with sodium carbonate and diluted to #ajjj c4c42 it was found to be a very good medium for the growth of the bating organisms after the addition of a small quantity of potassium phosphate4 ,in looking round for suitable means of testing the action of both pure and mixed cultures of bacteria on a practical scale1 it occurred to me that the ,carlsberg vessels1 as used by ,hansen for the pure cultivation of yeast1#aca would answer for the cultivation of bacteria also4 ,i was unable to obtain any information on the subject1 and was surprised to find that the apparatus is very little used in ,england4 ,i procured two of these vessels from ,jensen of ,copenhagen1 and found they answered very well4 ,the bacteria were transferred from the test tube in which the original inoculation had been made to a ,pasteur flask of #bej c4c4 capacity containing the nutrient solution2 when the growth in this flask was sufficiently vigorous the ,carlsberg vessel was inoculated from it in the manner described by ,hansen1 and with all the usual precautions4 #aca ,jorgensen1 the 8,micro-organisms of ,fermentation10 p4 #bj4 ,after three days at a temperature of #cg ,c4 the whole of the #aj litres was used for inoculating #ajj litres of the nutrient medium above mentioned contained in a clean barrel standing in a room1 the temperature of which was maintained at #cg ,c4 ,by using this comparatively large volume of pure culture for pitching1 if ,i may be allowed to use a familiar brewing term1 the large culture was kept practically pure1 although it could not be supplied with germ-free air1 as in the case of the ,carlsberg vessel4 ,using a nutrient medium containing #a per cent4 original gelatin1 the maximum bating effect was obtained with the majority of organisms in three days4 ,in my previous notes ,i showed#acb that a mixture of digestive enzymes and amine hydrochlorates was effective in bating skin4 ,the liquid in this case was free from bacteria4 ,it was found1 however1 that the action of the bate was hastened when an active growth of bacteria was going on at the same time in the liquid1 even though the quantity of enzyme present was smaller4 ,this is what one might infer from a careful study of the process4 ,it appears better for small quantities of enzymes to be produced in the liquid as required1 than to use larger quantities of stale enzymes4 #acb ,j4,s4,c4,i41 #ahih1 p4 #ajab4 ,mr4 ,loxley ,meggitt was kind enough to concentrate for me about #agj litres of a culture of bating organisms4 ,the concentration was conducted in vacuo at a temperature below #ej ,c41 at which the enzymes were certainly not injured1 and it was found that when this concentrated culture was diluted to the same strength as the original1 the action was considerably diminished4 ,this diminution of activity was due in part to a loss of volatile products in the evaporation1 but more especially to the absence of an active fermentation going on in the liquid4 ,the nutrient medium above described1 besides acting in a selective manner on a mixture of bacteria1 and providing them with food stuff1 contains amido compounds and other bodies1 which are eminently favourable to the proteolytic action of the enzymes1 and therefore act in the same way as the amine hydrochlorates which ,i used in former experiments4 ,the action of the following bacteria grown in this medium has been tried on skin4 ,the pure cultures are lettered in continuation of previous descriptions 7see previous paper1 p4 #afb74 #a4 ,bacillus c1 isolated from pigeon dung bate4 ,small1 round1 bluish-white colonies1 standing up slightly above the surface of the gelatin1 but not spreading out on the surface1 non-liquefying pairs of micro-bacteria4 ,this was the principal organism found in a pigeon dung bate as used for the bating of ,e4,i4 kips4 ,grown in nutrient broth or in the special medium it had no reducing effect on skin4 #b4 ,bacillus pyocyaneus from blue skin1 i4e4 skin in an early stage of putrefaction4 ,no action4 #c4 ,mixed culture from fresh pigeon dung1 collected in a sterile vessel4 ,this contained very few bacteria capable of developing in the special medium4 ,the action on skin was no more than that due to the chemical compounds present4 #d4 ,mixed culture from fresh dog dung4 ,this contained remarkably few species of bacteria which came to a good development in the special medium4 ,the principal organisms were a jointed bacillus with extremely rapid vibrionic movement1 and a small bacterium in pairs2 the action on skin was perceptible but slight4 #e4 ,mixed culture from dog dung one month old1 as used in the bate4 ,the action of this in a certain medium has already been described 7see p4 #afj74 ,in the special medium it was distinctly better and almost equal to that of the dung bate4 #f4 ,mixed culture from fresh fces gave a similar result to 7#c74 ,a microscopic examination showed pairs of small bacteria and micrococci1 but no bacillar forms4 #g4 ,mixed culture from fresh horse dung had a moderate but distinct action on skin1 about equal to 7#d74 #h4 ,bacillus d1 isolated from wool infusion4 ,very slight action4 #i4 ,bacillus e1 isolated from wool infusion4 ,similar result to 7#h74 #aj4 ,mixed culture of bacilli d and e only4 ,very powerful bating action1 skin bated more rapidly than with dung4 ,these experiments tend to confirm the conclusion ,i previously arrived at1 viz4 that no single species of bacteria produces the complex chemical and physiological changes which take place in the dung1 and which result in the production of the bodies necessary for the proper bating of skin4 ,it is a well-known fact that dog dung requires keeping for at least a month before it gives the best result4 ,during this time it undergoes a kind of fermentation and continues to improve up to two months1 after which it deteriorates4 ,the rate of fermentation depends upon the season4 ,it is evident from these facts that the bacteria present in the dung when it leaves the animal's body do not produce the required enzymes and chemical compounds1 and that these are produced by bacteria which obtain access from the air4 ,it is also evident that the production of these enzymes depends upon the composition of the nutrient medium1 since this exerts a selective influence on the species of bacteria obtaining access to it4 ,in the spontaneous souring of milk numerous bacteria in the air have free access to the milk1 yet the lactic ferment is generally so pure that it may be and is used as a pure culture on a large scale in the manufacture of lactic acid4 ,dog dung is a favourable medium for the bacteria secreting the bating enzymes2 but if dextrose or other carbohydrate be added to fresh dung an acid fermentation is set up which effectually prevents the development of the bating organisms4 ,reasoning along these lines ,i was led to try some cultures of air bacteria in my special medium1 and ,i found that a good source of such organisms likely to have a useful effect was a sweating stove as used for the depilation of skins4 ,the hair roots are loosened by bacterial action2 the wool1 when it slips1 brings away with it the epidermis4 ,the root portions of the wool were cut off and digested in water at #ce ,c41 the liquid strained off and used for making plate cultures in the usual way4 ,in making the attenuations for the plate cultures1 the fourth was found to be practically a pure culture of the organism ,i have called bacillus d1 or the sweating bacillus4 ,it forms large whitish colonies1 spreading on the surface1 with irregular contour4 ,the bacilli are very small1 mostly in pairs1 but sometimes joining together in thread-like forms4 7,fig4 #ba47 ,grown in the special medium it had little or no action on skin4 ,at the same time ,i found that a culture made from the original liquid1 i4e41 a mixed culture of the sweating organisms1 had an exceedingly powerful bating action2 indeed1 the skin was bated more rapidly than with dung4 ,all the experiments carried out so far tend to prove that mixed cultures of suitable bacteria possessed the required action1 whereas pure cultures do not4 ,a further examination of the infusion of wool roots showed that the bacteria contained in it1 consisted practically of two species only4 ,the first of these ,i have already described1 the second one1 bacillus e 7,fig4 #bb71 forms small brownish-yellow boat-shaped colonies on gelatin plates1 very similar to one of the dung bacteria4 ,they consist of plump cells1 two or three times the size of bacillus d1 united in pairs and short chains and surrounded by a capsule2 the cells appear to vary considerably in size4 ,cultivated in the same way as the others it has very little action on skin4 ,it is evident from these facts that the growth of the bacteria is a symbiotic one2 separately they exert little or no action1 whereas used together the action is most remarkable4 ,the author wishes to express his indebtedness to ,mr4 ,j4 ,golding1 ,f4,i4,c41 of ,university ,college1 ,nottingham1 who made the first pure cultures of these 8wool0 bacteria4 ,the ,influence of ,solid ,matter in the ,bate4 ,in making comparative tests of my artificial bates and dog dung1 ,i usually took the latter from the paddles in which it was diluted ready for use1 and maintained both solutions at exactly the same temperature4 ,parts of the same skin were then digested in each solution1 and the results noted after #a-a_/b hours4 ,in order to make them more strictly comparable ,i filtered the dung bate1 so as to employ the matter actually in solution when the bate was made up4 ,it was found that the filtered bate had far less action than when it was used in an unfiltered condition4 ,that this is not wholly due to the passing into solution of some of the solid matter during the bating was shown by adding an inert solid1 viz41 kaolin1 to the filtered bate1 when the action was greatly hastened4 ,on adding kaolin to the artificial bate and keeping the liquid agitated1 the same result was obtained4 ,it seems that the finely-divided solid matter acts as a carrier for the enzymes1 perhaps by a kind of mass action1 each particle offering a surface vastly greater than the molecules of dissolved solids4 ,in the case of 8puer10 the organic insoluble matter is gradually brought into solution by bacterial action as the bating proceeds1 though ,i do not believe this occurs to any great extent4 ,the following quantities of soluble and insoluble matter were found in puer wheels in actual practice per #ajj c4c43-- -------------------------------------- ---- #a #b #c #d -------------------------------------- ,total solids #ajbj #hfc #hfd #cbf ,soluble #fjj #deg #fai #bad ,insoluble #dbj #djf #bde #aab -------------------------------------- #a4 ,wheel in constant use for a week4 #b4 ,wheel freshly made up4 #c4 ,the same wheel after one lot of skins4 #d4 ,from pigeon dung bate pit4 ,on comparing #b and #c it will be seen that apparently #afa grm4 of the insoluble matter has passed into solution4 ,this is not entirely the case1 for part of the additional soluble matter is lime and hide substance from the skins1 while part of the insoluble at the same time adheres to the skins and is not estimated4 ,in conclusion1 it will be seen that it is now quite possible to produce an artificial dung bate1 or rather a bate having the essential properties of a dung bate1 by producing the required enzymes by fermentation and then adding to them the amine compounds4 ,such a bate ,i am able to show you here4 ,the chief difficulty in its practical application in the tannery is the question of cost4 ,if this can be overcome1 and efforts are being made to overcome it1 there is no doubt that the tanners of the next generation will be supplied with a bate which will do the same work as the dung bate1 and which will have a definite and uniform composition and properties1 and a regular and certain action4 ,the tannery will become cleaner and healthier1 and what is perhaps of equal importance1 the sewage effluents will be comparatively harmless4 ,,chapter ,,vii4 ,,artificial ,,bates4 ,as may be supposed1 inventors have from very early times turned their attention to the substitution of some other material in place of the unappetizing one so long in use4 ,but as ,i pointed out in a short article entitled 8,rationale of ,bating0#acc many of them looked upon bating and puering as a process for removing lime from the skins1 and nothing more2 whereas we have seen that it is a very complicated process in which1 not only is lime removed more or less effectively1 but the skin fibres are acted upon1 and portions of them rendered soluble1 and the skin thus got into the necessary condition4 #acc ,leather ,industries1 ,sept4 #ahih4 ,this misconception of the object of bating or puering prevented the success of most inventions of artificial bates up to quite recent times4 ,procter states that the use of ammonium chloride as a bate was patented by ,zollikoffer in #ahch4 ,such agents as this1 and various acids1 which have been proposed are merely chemical deliming agents1 and1 as such1 we do not propose to discuss their use as artificial bates4 ,procter#acd gives an excellent account of these processes1 including one of his own1 in which ammonium chloride is used in conjunction with metabisulphite of soda1 and for successive packs sufficient sulphuric acid is added to neutralize the ammonia formed4 #acd ,principles of ,leather ,manufacture1 p4 #afj4 ,the same author#ace also mentions an ,american invention for bating by the use of old lime liquors neutralized with sulphuric acid4 ,this method is much more scientific than would at first sight appear1 and more nearly approximates to the conditions of the dung bate than any of the early inventions4 ,old lime liquors contain much ammonia and weak organic acids1 such as caproic1 amido-caproic 7leucin7 and tyrosin4 ,on adding sulphuric acid1 the lime forms an inert sulphate1 and the sulphate of ammonia and the weak organic acids which remain dissolved are just what are required in a chemical bate4 ,the author has used this bate with success on certain classes of goods4 #ace ,text ,book of ,tanning1 #ahhe1 p4 #ahe4 99,tiffany's bate991 which is used in ,america1 is composed of glucose and glue1 and bates of this composition are also in use in ,england4 ,as an example1 #aj lb4 glucose and #a_/b lb4 of glue dissolved in #ajjj gallons water1 at a temperature of #ge ,f41 and allowed to ferment for a few hours1 may be used for the bating of bellies1 and if used in a paddle or latticed drum will bring them 8down0 very rapidly4 ,davis#acf gives a list of twenty-nine patents for bating issued by the ,u4,s4,a4 ,government from #agij to #ahhc inclusive4 ,i do not know whether any of these are in use at the present day4 #acf ,the ,manufacture of ,leather1 ,philadelphia1 #ahhe4 99,erodin499--,since the publication of the authors researches on the constitution and mode of action of the dung bate1 renewed attention has been given to the construction of bates1 or puers1 having an identical action4 ,one of these has been worked out by ,professor ,dr4 ,h4 ,becker1 of ,frankfort o_/,m1 in conjunction with the author under the name of ,erodin 7,latin1 erodere1 the equivalent of the ,german beizen--to bate74 ,as this was the first artificial bate in which a pure culture of bacteria has been applied to the treatment of skins1 ,i propose to describe it in some detail4 ,erodin#acg consists essentially of a nutrient material in the form of powder and of a pure culture of ,b4 erodiens which is added to the powder mixed in a definite quantity of warm water 7#dj ,c474 ,on the average about #aj grm4 of this material is sufficient to bate one kilo of wet prepared skin4 #acg ,at the third ,conference of the ,i4,a4,l4,t4,c41 held in ,copenhagen ,aug41 #ahii1 ,f4 ,kathreiner 7,worms7 brought forward communications from ,wood 7,nottingham7 and ,dr4 ,becker 7,frankfort-on-,main7 on artificial bates1 from which it is shown by experiments and trials on a large scale at the works of ,messrs4 ,doerr and ,reinhart that both these gentlemen had worked out similar processes quite independently4 ,wiss4 ,techn4 ,beilage des ,ledermarkt1 #ahii-aijj1 p4 #h4 ,bemerkungen ber die ,wirkung der ,kothbeizen1 ,j4 ,t4 ,wood4 ,idem1 p4 #dc4 ,popp and ,becker's und ,wood's ,ersatzmittel fr ,kthbeizen4 ,franz ,kathreiner4 ,idem1 p4 #ej4 ,einiges ber die ,anwendung von ,erodin einem ,ersatzmittel fr ,hundekoth u4 dergl4 in der ,leder industrie4 ,bericht von ,dr4 ,h4 ,becker1 ,frankfort-on-,main4 ,wiss4 ,techn4 ,beilage des ,ledermarkt4 ,bd4 i41 p4 #ci4 ,further particulars about the bate and its construction will be found in ,chapter ,,viii4 ,in practice it is found that this material acts far more energetically on the skins when living bacteria are present in the liquid2 we suppose that they penetrate the skin and form their products in the intercellular spaces4 ,it was found that1 in the evaporation of the cultures to dryness1 the bacteria were mostly killed or so far reduced in activity1 that on preparing the bate after a certain lapse of time it was liable to become infected by foreign organisms4 ,in order to ensure uniform results a pure culture of the special bating bacteria is supplied with every #e kilos of the erodin powder4 ,the weighed amount of erodin is placed in a perfectly clean mashing-tub1 with #ej times the weight of water at a temperature of #dj ,c4 a pure culture of ,bacillus erodiens is added to the mixture1 and the whole covered with a clean cover and allowed to stand for two or three days4 ,a little steam is admitted morning and evening so as to maintain the temperature at about #dj ,c41 or some other suitable device for heating is applied4 ,several tubs may be kept in a small stove heated to the right temperature by steam pipes4 ,in this way the bating bacteria develop rapidly1 and if the proper precautions as to cleanliness and temperature have been observed1 there is no fear of any adventitious germs getting the upper hand4 ,as soon as a vigorous growth is attained1 usually on the third day1 the bate is ready for use4 ,erodin is in use on a fairly large scale1 and1 as is usually the case1 difficulties have arisen on a manufacturing scale which do not occur in the laboratory4 ,in the practical application of the material the mashing-tub may be #c ft4 #i in4 in diameter and #c ft4 #c in4 in height and of a capacity of #bjj galls4 ,steam is admitted directly by means of a copper pipe fitted with a boiling jet4 ,the goods are bated in the ordinary bating paddle or puer wheel 7,fig4 #c1 p4 #ac74 ,during the year #aija about #ijjj dozens of sheep 8grains0 were puered with ,erodin at ,trent ,bridge ,works 7,messrs4 ,turney ,brothers1 ,ltd47 ,nottingham1 and considerable experience gained in its use4 ,the mode of operation was as follows3--,on ,fridays #cj kilos of ,erodin powder was mashed in a wooden vessel in #afjj litres water at #dj ,c4 and inoculated with a sufficient quantity of a pure culture of ,b4 erodiens4 ,the temperature was kept at #ce-dj ,c4 by admission of a little steam first thing in the morning1 again at noon1 and in the evening1 and the liquid so prepared was ready for use on ,monday4 ,one wheel or paddle was kept going for the work4 ,to start the operation1 #bjj litres of stock liquor was put into the wheel1 and sufficient water added for the goods to turn freely4 ,the skins previously washed1 as described in ,chapter ,i41 were paddled until sufficiently 8fallen0 or 8down40 ,for the following lots1 the liquor was strengthened by the addition of #ajj to #adj litres of the stock liquor1 the wheel being run off and cleaned out once a week4 ,the general result showed that 8high-limed0 skins and previously salted skins were more refractory to this bate than to dung4 ,as in the ,english system of collecting pelts there are all stages of liming1 skins containing from #a4e to #i per cent4 ,ca,o on the dry skin1 it is not surprising that considerable difficulty was experienced in keeping the puering uniform4 ,skins containing over #c per cent4 ,ca,o on the dry skin1 seem to require a real putrefactive action in order to 8bring them down0 sufficiently1 or it may be that their alkalinity is too great to allow the bating enzymes to act properly4 ,it may here be said that if the fibres of skin are actually damaged by excessive action of lime or any other chemical1 no subsequent treatment is of avail to remedy the defects4 ,shearling pelts were excellent when puered with erodin1 a further proof that the alkalinity is of importance1 since these pelts do not require so much lime as 8old fells0 to bring them into proper condition for splitting4 ,for sheep and calf skins treated from the market condition and consequently containing a uniform amount of lime--#b-c per cent4--the process is quite reliable1 and is in practical use on a large scale4 ,goat skins have been successfully bated with erodin by treating them in a concentrated liquor in a drum1#ach instead of a paddle1 the mechanical effect of the drumming enabling the bate to penetrate the hard and compact skin1 while the more concentrated solution of the enzymes attacks the so-called 8beard10 and renders the skins as supple as sheep skins bated in a paddle4 #ach ,one litre of erodin stock liquor 7#a part erodin1 #dj parts water7 were used per kilo drained washed pelt1 in the drum for #a-a_/b hours4 ,in some cases less than #a litre sufficed4 ,it may be of interest to give here some of the results of the early trials of erodin in a tabular form1 due to the late ,franz ,kathreiner4 ,they are a further proof of the thoroughness with which he carried out all his work4 ,,leather1 ,n4,f4 ,,and ,,kalochrom4 ,date of ,trial1 ,nov4 #bb1 #ahih4 ---------------------------------------- ------------------------- ,no4 ,test ,e #dg ,b #c ,b #d ,b #e ---------------------------------------- ------------------------- #a ,erodin1 mark and date,erodin ,m ,wood ,wood ,wood #ba_/i_/ih #a_/aa_/ih #a_/aa_/ih #a_/aa_/ih #b reaction ,slightly acid ,acid ,acid ,acid #c total quantity #ejj gr4 #bf ,l4 #ac ,l4 #gjj gr4 #ac ,l4 kaolin #d quant4 per kilo scudded weight #e quant4 per kilo slated #f quant4 per kilo tumbled #c gr4 #afj c4c4 ,as for ,b#c #bfj c4c4 not neutralized neutralized #g #h #i #aj ,water used #bfj l4 #baj l4 #adj l4 #abe l4 #aa ,temperature of bate at #aj4be #cd ,r4 #cd ,r4 #cc ,r4 #cb ,r4 #ab of bate at #aj4cj #bh #bg #bh #bf #ac of bate at #b4cj #bf #be #be #bd-a_/b #ad ,time run #d hrs4 #c-a_/d hrs4 #c-a_/d hrs4#c-a_/d hrs4 #ae standing -- #a_/b hr4 #a_/b hr4 #a_/b hr4 #af ,mode of motion ,paddle #a ,paddle #b ,paddle #c ,paddle #d #ag ,acidity of #ej c4c4 #jb ,n_/#aj #ah ,n_/#aj #aae ,n_/#aj #bg ,n_/#aj before neutralizing soda soda soda soda #ah #ej c4c4 after kaolin -- -- #aae ,n_/#aj -- soda #ai #ej c4c4 after kaolin #bj ,alkalinity of #ej c4c4#ab ,n_/#aj #bb ,n_/#aj #ad ,n_/#aj #ac ,n_/#aj after #b hrs acid acid acid acid #ba #ej c4c4 #bb #ej c4c4 #bc ,no4 of skins and size #de ,x #df ,x #c #bc ,x #bc ,x goat skins #bd ,weight after #be #bf tumbling #ajj kilo #ajj kilo #ej kilo #ej kilo #b-a_/b goat #bg #bh striking out #gg #gg #cf #cf #bi ,invoice #cj ,date of soaks -- #e_/aa_/ih -- -- #ca ,mark -- ,t4 #ga -- -- #cb #cc #cd ---------------------------------------- ------------------------ ,remarks4--#bb skins of ,e #dg after #c hours running had #bej c4c4 #gj per cent4 lactic acid2 they were marked with a hole in the tail2 were more fallen than the others4 ,judgment after ,scudding4--,all lots well down2 ,e #dg whitest colour2 all smooth grain1 ,e #dg and ,b #c smoothest4 ,the #c goat were not low enough4 ,it was observed both in laboratory experiments#aci and in practical work that the presence of solid matter in the puering liquor had a considerable influence on the speed at which the goods fell4 ,the clearer the liquor the slower the action4 ,the explanation of this fact is not quite clear4 ,possibly the finely divided solid matter acts as a carrier for the enzymes1 each particle offering a very extended surface1 or it may be that the action of the solid matter is mechanical1 like that observed in bran drenching4 #aci ,j4,s4,c4,i41 #ahii1 p4 #iaj4 ,see also p4 #gc4 ,the goods puered with erodin1 whether split or unsplit skins1 should be scudded on the grain4 ,sheep splits are scudded with a machine of ,sir ,john ,turney's type4 7,fig4 #f1 p4 #ag47 ,roans and goat may be scudded with any of the spiral knife machines 7,turner1 ,mnus1 etc47 in general use4 ,the following figures1 p4 #ahg1 giving the reactions of an erodin bate in c4c4 ,n_/#e alkali or acid required to neutralize #ej c4c4 filtered bate1 are of interest as being taken from actual work4 ,they were kindly communicated to me by ,herr ,karl ,schorlemmer1 chemist to ,messrs4 ,doerr and ,reinhart1 of ,worms4 ,erodin1 tested by the electrometric method1 was found to have the following hydrogen ion concentrations3--,paddle before goods1 #jfgb volt1 equivalent to a hydrogen ion concentration p,h #ff4 ,the same liquor after goods1 #jgaj1 equivalent to p,h #gc4 ,compare puer liquors1 p4 #gi4 ---------------------------------------- -- ,bate ,before ,goods ,after ,goods ---------------------------------------- -- #a4 ,old #jje alkali #jd acid #b4 ,fresh #jae neutral #c4 ,old #jje #jee acid #d4 ,fresh #jb #jje #e4 ,old #ja #ja #f4 ,fresh #jde #jae alk4 #g4 ,old #jae #jc acid #h4 ,fresh #je #ja alk4 #i4 ,old #ja #jc acid #aj4 ,fresh #jc neutral #aa4 ,old #ja #jg acid #ab4 ,fresh #jb #jje alk4 #ac4 ,old4 #ja #jbe acid #ad4 ,fresh #jd #jae alk4 #ae4 ,old4 #jje #jc acid #af4 ,fresh #jde #ja alk4 ,mean of old #jjhg #jca acid ,mean of fresh #jcc #jjea alk4 ---------------------------------------- -- 99,oropon499--,an interesting application of the theory of the bating process which was put forward by me#adj is that of ,dr4 ,otto ,rhm#ada in #aijh1 in which1 instead of a bacterial culture1 he employs an infusion of pancreas in conjunction with ammonium salts4 ,this bate has been put upon the market in the form of a powder under the name of ,oropon4 #adj ,j4,s4,c4,i41 #ahih1 p4 #ajac4 #ada ,see ,chapter ,,viii4 ,the approximate composition is3-- ,per cent4 ,ammonium chloride #fe ,wood fibre #ca ,dry pancreas about #ce ,the nitrogen unaccounted for by ammonium chloride is #jcb per cent4 ,its chief advantage is the simplicity of application1 no previous fermentation being required4 ,about #e oz4 to #i oz4 are required per #ajj lb4 wet pelt1 and it is recommended to soften the water by adding a certain quantity of clear lime water to it previous to making up the puer4 ,its disadvantages are1 that unless a previous bath is used1 the quantity of ammonia given off is detrimental to a proper bating action1 so that for good working a preliminary bating is required4 ,another disadvantage is that the whole of the enzymes being in the bate their action is more superficial and the grain may be puered too much while the interior of the skin is not penetrated by the enzymes4 ,the author has made some experiments with an enzyme bate using ammonium butyrate instead of ammonium chloride1 and castor oil seed meal in place of the wood fibre4 ,it was found that the amount of ammonium salts in solution in the most effective bate was approximately one gram per litre4 ,the bating liquid was therefore made up as follows3-- ,ammonium butyrate #a grm4 ,castor oil seed meal #b ,dry pancreas #jja ,water #ajjj c4c4 ,this liquid at #dj ,c4 bated a skin well in one hour4 ,on increasing the quantity of castor oil seed meal to #d grm4 per litre1 the bating effect was not so good4 ,substituting #je c4c4 liquor pancreaticus 7,benger7 for the solid pancreas1 the bating effect was too powerful1 the thinner skins were attacked by the bate1 and the grain destroyed in patches in a very similar manner to over-puered skins4 ,further experiments showed that a little more than one-tenth of this amount of pancreatic solution per litre would be sufficient 7#gj_/ajj c4c4 liquor pancreaticus per #ajjj litres74 ,castor oil seed contains a lipatic enzyme1 and when shaken up with olive oil will emulsify the oil4 #ge grm4 castor oil seed meal1 and #aj c4c4 of olive oil were shaken up with #dij c4c4 of water and formed a perfect emulsion1 no fat being visible on the surface of the liquid4 ,the mixture was diluted to #g litres1 and a grain treated in it at #dj ,c4 for half an hour2 it was fairly well bated in this time1 and had a smooth slippery feel1 such as skins have in the puer1 but was perceptibly 8higher0 than the skins bated in the new bate containing pancreatin4 ,this experiment appears to confirm the fact that a mixture of enzymes is necessary1 or1 at any rate1 that a lipatic enzyme alone is insufficient for complete puering4 99,dermiforma499#adb--,this is an ,american preparation1 put on the market by the ,nowak ,manufacturing ,co4 of ,chicago1 and is described as a natural bacterial liquor of organic acidity4 ,for #abjj lb4 scudded calf skins1 #i gallons of the liquid ,dermiforma are used at #ajj ,f41 one-third being put in to start with and the remainder added gradually2 time required1 about #c hours4 ,for sheep skin a less quantity is required4 ,this bate was found to be a preparation of whey1 and contains a certain quantity 7#ah-bj per cent47 of lactic and other organic acids1 produced by fermentation2 it is therefore to be classed as a drench1 and is not a true bate or puer1 since tryptic ferments or bacteria are not present4 #adb ,see ,chapter ,,viii42 also ,j4,s4,c4,i4 #aijf1 p4 #fdg4 99,puerine499--,another bate1 manufactured in ,america is advertised under the name of ,puerine1 8the long-looked-for bacterial bate40 ,the manufacturers give the following directions for use4 ,to start a bating liquor1 #aj lb4 of the dry powdered puerine is put into a half barrel of warm water 7#ajj ,f471 and allowed to stand for #c or #d days1 maintaining the temperature by occasionally warming the infusion with a steam pipe4 ,this amount is sufficient for each #ajj galls4 water in the bating vat or paddle wheel1 and will bate as many skins as can be turned in #ajj galls4 ,when the warm infusion of puerine has stood the required length of time1 in order to generate the necessary bacterial ferments1 the bating vat is run up with warm water say1 #ajj degrees in warm weather and #aaj in cold weather1 and the infusion of puerine1 including the undissolved portion1 is added to the bating vat1 and the skins entered into the bating liquor4 ,as the action of the puerine on the skins is exactly the same as a dung bate1 the judgment of the operator must determine when the skins are 8low enough40 ,it is not necessary to make a fresh bating liquor for each pack of skins1 because the bating liquor improves with age4 ,with each succeeding pack of skins1 enough warm water is added to the bating vat to make up for the loss of liquor which is occasioned by the removal of the previous pack1 and from #c to #e lb4 of puerine for each #ajj galls4 added directly to the bating liquor2 it is then in condition immediately to use again4 ,the bate was found to consist of ,sugar4 ,gelatin4 ,sodium ,ammonium ,chlorides and sulphates4 ,bisulphite of lime4 ,meal4 ,as it is allowed to ferment without the addition of bacteria1 it will be seen that it acts in quite a different manner to erodin1 being more of a modified drench than a true bate1 and is not in any way a perfect substitute for the dung bate4 99,sucanine499--,this is a ,french bate1 put on the market by ,messrs4 ,muller and ,co41 ,rouen2 it is described as 8concentrated dog puer1 chemically clean1 i4e41 all foreign matters have been eliminated and it contains only that which is really necessary40 ,the directions state that the quantity to be used is the same as of dog puer prepared ready for use4 ,the paddle is kept at a temperature of #cj ,c4 ,this material was found to be a liquid containing ammonium sulphide1 phosphates and chlorides of sodium in solution1 a considerable quantity of solid matter in suspension consisted of calcium phosphate and calcium sulphide4 ,there was sufficient organic matter to permit of bacteria growing in the diluted liquid4 ,it had no harmful effect on skins and 8brought down0 most sheep skins in an effective manner2 some resistant skins appeared to require further puering4 99,purgatol99 is a patent bate put on the market by ,dr4 ,g4 ,eberle and ,co41 of ,stuttgart4 #a-c_/d lb4 is said to be sufficient to bate #ajj lb4 wet pelt in #a-b hours at #ch-dj ,c4 ,it is a dark brown liquid with an unpleasant smell4 ,when boiled with potash it gives volatile alkaline products4 ,distilled with sulphuric acid it gives an acid distillate consisting of organic acids mostly of the fatty series4 ,it contains amines and volatile nitrogenous bases1 but no enzymes or bacteria4 ,it must therefore be classed as a deliming agent and not as a true bate or puer4 998,esco4099--,this recent artificial bate is of an acid character1 and is said to have an action intermediate between the bran drench and pigeon dung2 it contains no animal enzymes1 but appears to contain some vegetable enzymes of a lipatic character2 it also contains #ah per cent4 of ammonium chloride in which respect it resembles 8,oropon40 ,it is manufactured by ,e4 ,stickelberger and ,co41 ,haltigen1 near ,basle4 ,other artificial bates are treated of in the next chapter under the respective patents4 ,there is also an interesting article on new bates by ,eitner in ,der ,gerber1 ,nos4 #hgh and #hgi1 #aiaa4 ,see also ,collegium1 #aiaa1 p4 #djb4 ,,chapter ,,viii4 ,,patents4 ,in ,chapter ,,vii4 we have described a few of the many artificial bates which have been proposed1 and for which in many cases patents have been taken out4 ,it would be impossible within the limits of a single chapter to give an adequate account of all these patents1 and therefore it is not proposed to deal with those which are merely deliming processes1 but solely those in which the use of bacteria and enzymes is directly applied4 ,we mention1 however1 one or two of the more interesting deliming patents4#adc #adc ,a most useful source of information is ,section ,,xv4 7,journal and ,patent ,literature7 in the ,journal of the ,society of ,chemical ,industry1 published fortnightly at ,palace ,chambers1 ,westminster4 ,abstracts of all patents relating to bates will be found under the above heading4 99,amend1 ,otto ,paul991 ,new ,york 7,u4,s4 ,pat4 #gfc1cdg1 #aijd2 ,eng4 ,pat4 #ah1ead and #ah1ead;,a1 #aijd74--;,improved ,process for ,bating and ,puering ,skins1 and ,improvements relating to the ,bating1 ,de-acidifying and ,oxidizing of ,hides and ,skins4 ,the skins are treated with a solution of an ammoniacal salt1 small quantities of an acid such as hydrochloric acid being added at intervals1 so as to reform the salts4 ,pickled skins are de-acidified and oxidized by treatment in a neutral or slightly alkaline solution of a nitrite of an alkali or alkaline earth such as sodium nitrite4 99,nowak1 ,o4 ,h4991 ,chicago 7,french ,pat4 #cfj1hed1 #aije2 ,eng4 ,pat4 #bf1gga1 #aije74--,substance for ,treating ,hides and ,process for ,making same4 ,this is the 8dermiforma0 described in ,chapter ,,vii4 ,although bacterial action is used to prepare the bate1 the essential action is an acid one1 and1 as we have said1 resembles the drench4 99,norris1 ,w4 ,m4991 ,new ,jersey 7,u4,s4 ,pat4 #hdj1gid1 #aijg2 ,eng4 ,pat4 #bi1ffa1 #aijf74--;,improved ,process of ,treating ,hides and ,skins4 ,in this process the skins are subjected to treatment with a dilute solution of hyposulphite of soda1 which is said to 8set0 the gelatinous fibres of the skin4 ,the deliming is completed with hydrochloric acid in the presence of salt4 99,boehringer ,sohn1 ,c4 ,h499 7,eng4 ,pat4 #c1adj1 #aiaa7 ,proposes to use in place of the free organic acid1 in this case lactic1 the sodium salt1 and then to add slowly the amount of hydrochloric or sulphuric acid requisite for deliming4 ,the mineral acid combines with the sodium salt1 liberating an equivalent amount of the weaker organic acid1 which then acts upon the lime in the skins4 ,for deliming #ajj kilos4 of pelt1 #jbe kilo4 of sodium lactate 7#ej per cent47 and #jef kilo4 hydrochloric acid 7#bj ,b47 are used4 ,the advantage of the method is that a considerable saving is effected in comparison to the quantity of the free organic acid which would be required4 ,in the above example #a kilo4 of lactic acid 7#dc per cent47 would be required to neutralize a corresponding amount of lime4 ,in addition to these deliming processes1 there are a number of bates in which various nutritive media are allowed to ferment naturally1 without the addition of any specific bacteria4 ,among these may be mentioned3-- 99,dr4 ,nrdlinger's ,bate991 in which a paste of potatoes is allowed to ferment at #cj-cg ,c4 for several days2 it is then dried at #dj-ej ,c41 and used in the same way as dog dung4 99,h4 ,e4 ,simons'1 ,phosphorbutyralin991 consists of the beetroot residues in sugar manufacture which have undergone an acid fermentation1 and contain butyrates and phosphates of ammonia4 99,oakes99 7,,us4 ,pat4 #gih1jgj1 #aije2 ,eng4 ,pat4 #bd1dhh1 #aije74--;,in this patent an albuminous body1 such as casein is allowed to putrefy1 at a temperature of #ajj ,f41 for several days2 an equal weight of flowers of sulphur is then added1 and the mixture used as a bate or puer4 ,the sulphur is said to play an essential part in the bate4 ,a similar process1 by the same author 7,u4,s4 ,pat4 #gih1bic71 is described by ,dr4 ,allen ,rogers#add in which #e per cent4 of glucose syrup and #aj per cent4 of sulphur1 computed on the weight of the skins1 is fermented with yeast for twenty-four hours1 after which it is used as a bate4 ,from a chemical point of view1 it is difficult to express the reactions taking place4 #add ,j4,s4,c4,i4 #aijf1 p4 #ajc4 ,when the bath is first prepared1 it is neutral in reaction1 but1 after standing1 gradually assumes a slight acid reaction4 ,on introducing the skins1 it becomes alkaline1 owing to diffusion of the lime4 ,after a short time1 it becomes neutral again1 and remains thus until the skins are in a perfect condition1 when a slight acid reaction is observed4 ,these changes are caused by the fermentation of the glucose1 carbon dioxide and alcohol being generated4 ,owing to the presence of sulphur1 a quantity of hydrogen sulphide is produced1 which1 in its nascent condition1 combines with the alcohol to form mercaptans1 which in their turn are slowly oxidized to thioacids4 ,these mercaptans and thioacids1 being of weak acid character1 act in conjunction with any excess of hydrogen sulphide upon the lime1 converting it into soluble compounds1 which are readily removed by diffusion4 99,lederer1 ,l499 7,french ,pat4 ,no4 #djd1ibf of #aiji74--,method of ,preparing a ,substitute for ,animal ,excrement 7dog dung7 in ,puering ,skins for ,glac ,leather4 ,in this process a mixture of #aj parts finely powdered bone meal1 and #a part of crushed lupin seeds or beans is formed into a paste with water and allowed to undergo spontaneous fermentation from #c-d weeks4 ,the mixture is said to form a perfect culture medium for the micro-organisms indispensable in bating4 ,the removal of the lime is facilitated by the addition of #b per cent4 of fat1 #jge per cent4 sodium polysulphide and #a-a_/b per cent4 common salt reckoned on the weight of the bone meal4 ,in this patent the researches of ,wood1 ,andreasch and ,eitner are referred to1 and also ,benker's process of bating with ,peruvian guano to which soda has been added4 99,turney1 ,sir ,j4 and ,wood1 ,j4 ,t499--,coming now to bacterial and enzymatic bates1 the author in conjunction with ,sir ,john ,turney applied for a patent for a new and improved method of bating skins 7,no4 #be1hid1 #ahif71 in which cultures of suitable bacteria were to be used in place of infusions of dog or pigeon dung4 ,it was found however that this patent had been anticipated by the patent #ba1gbj of #ahie1 of ,dr4 ,popp and ,dr4 ,becker of ,frankfort o_/,m1 and the application was therefore not proceeded with4 ,as has been related in ,chapter ,,vii4 the late ,franz ,kathreiner1 who knew of the work which was being done both by ,dr4 ,h4 ,becker and the author1 made us personally acquainted1 and most of our later work was done in conjunction4 ,like many other new ideas1 it was arrived at quite independently by ,dr4 ,h4 ,becker and the author4 7,see ,report of ,third ,conference of ,i4,a4,l4,t4,c41 ,copenhagen1 #ahii1 ,wiss4 ,techn4 ,beilage des ,ledermarkt1 #ahii-aijj1 p4 #h47 ,we shall therefore give the original patents in full1 and afterwards the translation of ,dr4 ,otto ,rhms' patent1 and the recent patent of ,dr4 ,eberle1 as these cover the whole ground of the bacterial and enzymatic bates up to the present time4 99,dr4 ,popp and ,dr4 ,becker's ,english ,patent99 7,no4 #ba1gbj1 #ahie74 ,improvements in ,lyes or ,liquors for ,preparing ,hides for ,tanning4 ,an important role in the process of manufacture of many kinds of leather is played by the dung liquor or lye1 which in particular for calf skins and skivers constitutes one of the necessary preparatory operations for the subsequent actual tanning process1 and which has for its purpose to bring the skins or hides1 which have been previously swelled by the liming process1 into a condition which allows the easy and thorough removal of the lime and lime soap as well as the remaining hairs by the subsequent mechanical treatment1 and to obtain a uniform shrinking of the swelled hides4 ,the process hitherto employed consists in treating the hides or skins for some time 7such as for #d or #e hours7 in a vat provided with a reel1 and containing a lye or brine formed of solutions of dog or pigeon or poultry dung4 ,generally speaking1 the dog dung acts best in some cases1 and pigeon or poultry dung in other cases1 but no satisfactory and sound explanation has as yet been given as to the nature of the action4 ,my correspondents have in the first place ascertained that the action of these lyes or brines is the result of bacteriological processes1 especially of the products created by the action of certain bacteria1 and is certainly not1 as it has hitherto been generally assumed1 the result of the action of phosphoric acid or other acids4 ,the examination of the dog1 pigeon and poultry dung in bacteriological respect1 and of the industrial applicability of all the different results obtained1 shows in the first instance that1 even after removal of all other ingredients1 which1 according to the hitherto ruling views1 enter into reaction1 the result of the treatment remains the same as it had been before the removal4 ,the continued research led to the second result that a great number of micro-organisms play a role in the lye1 partially an advantageous1 and partially a detrimental one4 ,generally speaking1 the non-peptonizing bacteria act advantageously1 while the peptonizing ones generally have a detrimental effect4 ,in connexion herewith two methods of utilizing these discoveries have been found4 ,one can either1 according to the methods of bacteriology 7plate process71 remove all the detrimental or even the less useful bacteria1 and effect the treatment of the hide or skins by applying a pure culture of one or at least a mixture of the different most effective bacteria2 or one can1 without employing such a refined process1 but still utilizing the said discoveries1 apply the dog dung1 and in particular the white descriptions which are most effective1 or1 for certain kinds of leather1 the pigeon or poultry dung1 subjecting the said dungs to a certain treatment1 which1 by the use of a suitable cultivating bed1 will develop the useful bacteria1 while on the other hand1 the increase of detrimental bacteria may be prevented or retarded by the addition of materials hindering the development of the latter4 ,in every case the employment of the process secures greater rapidity of execution1 and more reliable and better results than the process heretofore applied4 ,the leathers obtained are tough and yet softer1 and in any case any discolouring1 such as is often unavoidable with dog dung1 is avoided4 ,an advantage not to be underrated with the use of germ cultures1 is that liquors or cakes having a definite percentage of really effective substance can be prepared1 whereas it was heretofore necessary to proceed by way of trials1 the result being subject to great uncertainty4 ,in addition1 the dung liquors are subject to changes overnight under the influence of atmospheric changes 7thunder-storms7 in a most unaccountable manner1 owing1 as has now been discovered by my correspondents1 to the growth of detrimental bacteria which are mixed with the effective ones1 and which gain the upper hand over the latter under the change of atmospheric conditions4 ,the features of the newly discovered useful bacteria are fully described in the following1 and experiments have shown that the particular kinds designed with #c1 #g and #ab in the table of bacteria1 set forth in the ,specification to ,german ,patent ,no4 #hf1cce and hereinafter fully described1 are those which are of value for the purpose in question2 in particular ,no4 #ab is the most effective1 and #c the least effective of these three descriptions4 ,all three are bacteria to be found in the dog dung1 and bacteria ,no4 #c consists of very small rods rounded at the ends and are exceedingly mobile1 while bacteria ,no4 #g1 which are similar to the hay bacillus1 are slowly-moving rods1 and bacteria ,no4 #ab are medium-sized rods having rapid motion4 ,the prick-culture gives with bacteria ,no4 #c a very good growth in the depth2 from the inoculating prick extend laterally many arms into the gelatin4 ,at the ends of the arms are formed small knots4 ,on the surface is formed a thin white covering4 ,the gelatin is not liquefied4 ,on gelatin plates1 the deep-seated colonies consist of pale yellow round disks1 which gradually penetrate to the surface1 and there they form circular disks which show at the centre larger spots4 ,on inclined agar-agar there is formed a white superstratum4 ,with bacteria ,no4 #g1 the gelatin is strongly liquefied in the prick-culture4 ,on the surface of the zone of liquefaction there is formed a white skin4 ,along the liquefied prick are formed radiations into the solid gelatin4 ,on gelatin plates there are formed rapidly liquefying colonies forming at top a white skin1 agar-agar gives a white unequal thin superstratum with branchings4 ,bacteria ,no4 #ab grow with prick-culture equally well along the prick2 the gelatin is not liquefied4 ,on the surface there is formed a thin shining covering4 ,on gelatin plates1 the deep lying colonies consist of pale yellow circular disks4 ,many colonies have tails similar to the surface colonies of the ,proteus4 ,during the growth of this bacterium on gelatin plates a strong putrid smell is developed4 ,on agar-agar this bacterium forms a strong white shining superstratum4 ,these bacteria grow easily in any decoction of meat1 and the flesh particles from the flesh sides of the hides1 which otherwise form a waste product of little or no value1 may be advantageously employed for this purpose2 bran1 and other materials known to offer good culture-beds1 may be employed instead4 ,for this purpose a vessel provided with a cover is charged with equal parts of waste flesh1 such as is obtained in the tannery1 and water1 and this is boiled for about half an hour by the direct introduction of steam1 after which concentrated carbonate of soda solution is introduced until the reaction is slightly alkaline1 after which the decoction is cooled down4 ,as soon as the temperature has sunk to about #ce ,c4 there is added the pure culture obtained by the gelatin plate process 7with dilution71 described in the works on bacteriology of ,koch1 ,fraenkel1 ,hueppe and others1 and also by the further treatment corresponding to the characteristic peculiarities of the bacteria1 and the whole is allowed to stand covered up for a period of from twelve hours to five days1 depending on the time of year and the temperature4 ,the hides or skins are then dipped into the concentrated decoction for a short time1 according to the state of development of the bacteria2 or the decoction can be diluted and the hides be then immersed therein for a greater length of time4 ,the further treatment is then carried out in exactly the same way as though the hides or skins had been treated in dog-dung lye1 with the exception that the duration is shorter4 ,in case the pure culture of the bacteria is to be dispensed with1 and it is only desired to obtain an advantage over the existing methods in so far as to obtain1 on the one hand an artificial increase of the ooze medium viz4 the number of useful bacteria and their products existing in the dog dung1 by providing a suitable culture bed1 and on the other hand to be in a position to limit oneself to the best initial material1 the process can be carried out by starting with a practically proved dog dung1 therefore in particular the white kinds1 and the bacteria are caused to propagate in a decoction such as above described4 ,afterwards it is advantageous to effect the killing of the detrimental bacteria by a small addition of acid1 such as #je per cent4 of dilute sulphuric acid or equivalent materials1 as in this case the useful bacteria are also the most enduring4 ,the more useful bacteria show1 in particular in the presence of alkalis1 the same behaviour4 ,for example1 the more useful bacteria arrive at development equally with the detrimental ones1 if to the described culture bed be added #je per cent4 of carbonate of soda1 while the useful bacteria preponderate to a considerable extent1 and the detrimental ones are practically unimportant1 if the additions of carbonate of soda be raised to about one per cent4 ,the pure cultures of the bacteria may be preserved in a suitable liquid or solid material1 and brought on the market in a suitable packing4 ,in order to obtain a product which shall both be durable1 and capable of being delivered in definite doses1 sterilized bran1 flour1 etc41 can be inoculated with definite quantities of the pure cultures1 and the percentage of water be reduced1 by drying1 pressing1 etc41 to under a certain percentage 7#aj to #ab per cent47 which will not allow of1 or will retard the evolution of germs4 ,the bacteria may also1 after having been properly developed1 especially after having created a sufficient quantity of their products1 be killed1 for instance by heating1 and the resulting stuff be brought on the market in liquid or solid form1 as an effectual lye or brine1 it having been found that the liquids containing the said bacteria do not lose their effect if they are sterilized and the bacteria thereby killed1 provided that a sufficient number of bacteria has been produced4 ,claim4--#a4 ,the process for the production of a lye for treating hides or skins preparatory to tanning1 consisting in the propagation of the bacteria of dung1 in particular dog and bird dung1 by means of suitable culture beds substantially as described4 #b4 ,as a new article of manufacture a lye containing a pure culture of one or more of the described bacteria4 #c4 ,in the process of producing a lye referred to in the first claim1 the elimination of the detrimental agents substantially as described4 #d4 ,in the process referred to in the first claim1 the addition of acids or alkalis for the purpose set forth and substantially as described4 #e4 ,the process for the production of a lye for treating hides1 consisting in the separation from the dung of the bacteria herein designated as #c1 #g and #ab1 producing pure cultures thereof1 and introducing the same into a decoction preferably freed by boiling from other bacteria and containing a suitable culture bed1 substantially as described4 #f4 ,a process for the production of cakes1 for the treatment of hides1 consisting in the inoculation of sterilized bran1 flour1 etc41 with cultures having a definite percentage of bacteria and the removal of the proportion of water that is necessary for the development of the bacteria1 substantially as described4 #g4 ,as a new article of manufacture sterilized cakes1 containing a certain quantity of the described bacteria1 substantially as described4 #h4 ,as a new article of manufacture the solid or liquid material containing the products of the decomposition1 as generated by the pure cultures of the said bacteria1 whether such material does or does not also contain the said bacteria1 either in the active condition or killed by sterilization1 substantially as described4 99,wood's ,english ,patent99 7#ab1edi1 #ahih74--;,improvements in and relating to the means used for the ,bating of ,hides and ,skins4 ,this invention has reference to improvements in and relating to the means1 liquid or bate1 used for the bating or puering of hides and skins previous to the process of tanning the same4 ,at the present time skins are usually bated by means of a liquid or bate prepared from dog or pigeon dung1 and although the bating action or actions have not hitherto been thoroughly understood1 it is a well known fact that fermentations going on in the dung play an essential part4 ,it was also pointed out in #ahhe by ,h4 ,r4 ,procter1 in his 8,text ,book on ,tanning10 that the action of the bate was in a great measure due to bacteria4 ,it is also a known fact to practical tanners that a dung bate1 properly applied1 produces the best quality of leather4 ,owing1 however1 to the varying composition of the dung used1 the bate made therefrom possesses varying properties1 its bating action is uncertain1 its properties are readily affected by atmospheric influences1 and the skins treated are liable to putrefaction4 ,as a substitute for dung bate1 it has been proposed1 as set forth in the ,specification of ,patent ,no4 #ba1gbj1 ,a4,d4 #ahie1 to use a bate made from a pure culture of bacteria4 ,such bate1 however1 does not possess all the essential properties of a dung bate2 and although bacterial action is necessary1 such action alone is not sufficient1 as was pointed out by the present inventor in #ahid in the 8,journal of the ,society of ,chemical ,industry40 ,the present inventor has now discovered that the bating action of a dung bate is due to the combined action of enzymes or unorganized ferments1 and to certain amine compounds in the dung4 ,these compounds consist of amines 7i4e4 ammonia in which one or more atoms of hydrogen has or have been replaced by alcohol radicles71 in combination with lactic1 acetic and other organic acids contained in the dung1 the acids named being the principal ones4 ,the present inventor has also discovered that the bating action of the enzymes alone1 or the action of the chemical compounds alone1 are inefficient1 and that the enzymes exert their bating action in the presence of the chemical compounds1 while these latter in addition have an independent action4 ,the object of this invention is the production1 according to scientific methods1 of a bate having similar properties to those of a dung bate1 such properties in the improved bate being defined and definite1 but capable of being modified according to the requirements of the skins to be bated and the leather to be produced4 ,according to this invention1 the liquid or bate is made by producing by fermentation an enzyme or enzymes of the same character as the enzymes contained in dog dung or produced from bacteria obtained from dung1 and to the liquid thus obtained there is added an organic acid and an alkali4 ,the inventor has discovered that for an efficient bate a pure culture of bacteria is insufficient1 and that no single organism hitherto isolated will give results equal to dung4 ,he has also discovered that the production of these enzymes depends more upon the composition of the nutrient medium in which the bacteria are cultivated than upon the kind of bacteria1 although these latter must be capable of producing the required enzymes1 the production of which appears to be due to a symbiotic growth of bacteria1 at present little understood4 ,it is desirable that the nutrient medium should be without sugars or starchy matters1 and1 although the composition of the nutrient medium may be varied1 good results can be obtained according to ordinary bacteriological methods by using a medium composed of-- ,gelatin #ej parts ,potassium or sodium phosphate #a do4 ,water #bejj do4 ,this medium is maintained at a temperature of about #cg ,c4 7the most favourable temperature for the fermentation7 until the required bacterial action is completed1 the time necessary being about seven days1 and to each litre of the liquid thus obtained there are added from #b to #f grs4 of lactic acid4 ,acetic or other similar organic acid may be used instead of the lactic acid1 but sulphuric or mineral acids must not be used4 ,the acid liquid is afterwards neutralized by ammonia1 which is added when the bate is to be used1 and there are then formed certain chemical compounds similar to those found in a dung bate4 ,the addition of the acid to the nutrient medium will immediately stop the growth of bacteria1 but the acid is not added for that particular reason1 but for the particular purpose set forth4 ,instead of the enzymes obtained from the bacteria of dung1 other enzymes of a similar character may be used1 such as the enzymes obtained from the bacteria found on skins during the sweating process4 ,for bating skins in a practical manner with the improved bate herein set forth1 the method of using the same is preferably varied according to the skins to be treated and the kind of leather it is required to produce4 ,thus for kid skins1 skivers and other skins for which dog dung has hitherto been used1 the skins1 after the liming process1 are first well washed in water in the usual way to remove the bulk of the lime4 ,the skins are then placed in a wheel or paddle with the bate prepared as before described1 with the acid exactly neutralized by the ammonia or so nearly neutralized that the alkaline action of the skins will complete the neutralization1 all skins being alkaline when introduced into the bate4 ,the bate is diluted according to the amount of liming the skins have undergone1 and when in the paddle or wheel the skins and bate are maintained at a temperature of about #cg ,c41 and the skins paddled until they have 8fallen0 considerably4 ,the skins are then removed from the wheel or paddle and scudded preferably on the 8grain0 side1 after which they are returned to the wheel or paddle and the paddling continued until the bating action is completed1 this being judged in the usual way by a practical tanner according to the feel of the skins4 ,the strength of the bate after the scudding process may be varied if found desirable4 ,after the bating process is completed the skins are treated in the usual manner4 ,when the improved bate is to be used for light hides and similar skins which have hitherto been treated with pigeon dung1 the skins1 after the liming process1 are washed in the usual manner1 heated to a temperature of about #cg ,c41 and placed in a wheel or paddle containing by preference the improved bate in an acid condition1 that is before the ammonia has been added1 the bate being previously diluted according to the amounts of liming the skins have undergone4 ,the skins are then paddled until the tanner1 by the feel1 judges that the whole of the lime has been removed4 ,the acid bate is then neutralized by ammonia1 with or without removing the skins1 and the paddling is continued until the bating process is completed1 this being judged of by the feel of the skins4 ,the bated skins are then scudded1 washed1 and treated in the usual manner4 ,the strength of the bate1 into which the skins are placed for both methods1 is varied according to the amount of liming the skins have undergone2 that is to say1 for 8high0 limed skins1 a stronger bate is required than for skins which have been subjected to a moderate liming4 ,claim4--#a4 ,a bate having the essential properties of a natural dung bate1 but prepared according to scientific methods from the means and in the manner substantially as set forth in the accompanying specification4 #b4 ,the bate described and set forth in the accompanying specification4 99,wood's ,american ,patent99 7#fch1hbh1 ,dec4 #ab1 #ahii7 99,bate499--,this invention has reference to improvements in and relating to the means1 liquid1 or bate1 used for the bating or puering of skins previous to the process of tanning the same4 ,at the present time1 skins are usually bated by means of a liquid or bate prepared from dog or pigeon dung2 and1 although the bating action or actions have not hitherto been thoroughly understood1 it is a well-known fact that fermentations which the dung undergoes play an essential part4 ,it was also pointed out1 by ,h4 ,e4 ,procter in #ahhe1 in his 8,text ,book of ,tanning10 that the action of the bate was in a great measure due to bacteria4 ,it is also a known fact to practical tanners that a dung bate properly applied produces the finest and most supple leather4 ,owing1 however1 to the varying compositions of the dung used1 the bate made therefrom possesses varying properties3 its bating action is uncertain1 its properties are readily affected by atmospheric influences1 and the skins treated are liable to putrefaction4 ,as a substitute for a dung bate1 it has been proposed1 as set forth in the specification of the ,british ,patent ,no4 #ba1gbj1 ,a4,d4 #ahie1 and the specification of the ,german ,patent ,no4 #hf1cce1 ,class #bh1 to use a bate made from a pure culture of bacteria4 ,such bate1 however1 does not possess all the essential properties of a dung bate1 and1 although bacterial action is necessary1 such action alone is not sufficient1 as was pointed out by me in #ahid in the 8,journal of the ,society of ,chemical ,industry40 ,i have now discovered that the bating action of a dung bate is due to the combined action of enzymes1 or unorganized ferments1 and certain chemical compounds1 which compounds consist principally of amines--i4e4 ammonia in which one or more atoms of hydrogen has or have been replaced by alcohol radicles--in combination with organic acids usually found in dung1 and of the compounds so formed the lactates and acetates are the most important4 ,i have also discovered that the bating action of the enzymes alone1 or the action of the above-referred-to chemical compounds alone1 is inefficient1 and that the enzymes exert their bating action in the presence of the chemical compounds1 while these latter1 in addition1 have an independent action on the limes in the skins1 and on the skin fibre4 ,the object of this invention is the production1 according to scientific methods1 of a bate having similar properties to those of a dung bate1 such properties in the improved bate being modified according to the requirements of the skins to be bated and the leather to be produced4 ,according to this invention1 the liquid or bate is made by producing by fermentation1 an enzyme or enzymes of the same character as the enzymes contained in dog dung1 or produced from bacteria contained in the dung1 and to the liquid thus obtained there is added an organic acid and an alkali4 ,i have discovered that for an efficient bate a pure culture or single species of bacteria is insufficient1 and that no single organism hitherto isolated will give results equal to dung4 ,i have also discovered that the production of enzymes of the character above referred to1 depends more upon the composition of the nutrient medium in which the bacteria are cultivated1 than upon the kind of bacteria1 although these latter must be capable of producing the required enzymes1 the production of which appears to be due to a symbiotic growth of bacteria at present little understood4 ,the bacteria used for the purpose of this invention may be the bacteria found in dog dung1 or the bacteria obtained from the roots of the hairs of skins during the sweating process1 these latter being used1 by preference1 on account of the ease with which they are obtained1 compared with the difficulty of isolating from the dog dung the particular mixture of species most desirable1 there being so many undesirable species present4 ,of the bacteria found on the roots of the hair during the sweating process1 and hereinafter referred to as 8sweating0 bacteria1 ,i have found that two species predominate1 and1 so far as ,i am aware1 these have not been previously isolated4 ,the principal organism1 which ,i call 8bacillus d10 in continuation of a series of previous investigations described in the 8,journal of the ,society of ,chemical ,industry10 ,a4,d4 #ahih1 forms large whitish colonies1 with irregular contour spreading on the surface of the gelatin1 the bacilli being very small1 mostly occurring in pairs1 but sometimes joined together in thread-like forms4 ,the second organism1 called by me 8bacillus e10 forms small brownish-yellow boat-shaped colonies on gelatin plates4 ,the bacteria consist of plump cells two or three times the size of bacillus d1 united in pairs and chains1 but the cells vary considerably in size1 and are surrounded by a capsule4 ,i have discovered that the above bacteria1 when used separately as pure cultures1 exert little or no action on the skin1 but when used together the action is very remarkable4 ,the gelatin and gelatin plates referred to in the above description are the gelatin and gelatin plates used for the cultivation of bacteria1 according to the ordinary bacteriological methods as described in ,gnther's 8,bakteriologie10 published by ,george ,thieme1 ,leipzig1 in #ahih1 and in other text-books4 ,in the accompanying drawings1 made from photographs which are of record in this case1 the bacillus d is shown in ,fig4 #ba1 and the bacillus e in ,fig4 #bb1 both photographs showing the bacilli magnified #ajjj diameters4 ,a culture may be prepared from the sweating bacteria by taking the hair from the skin when it 8slips0--that is1 when it can be removed by simply pulling it4 ,the root portion of the hairs are then cut off1 and about #aj grm4 carefully digested in #ajj c4c4 of water at a temperature of #cb to #ce centigrade for several hours4 ,the liquid portion is then poured off1 and used for inoculating #aj1jjj c4c4 of a nutrient medium of the character hereinafter described4 ,the inoculated nutrient medium is then maintained for three days at a temperature of #cg centigrade1 and may then be used for the inoculation of a larger quantity of nutrient medium4 ,theoretically1 a single cell of a bacterium is sufficient to inoculate any quantity of any suitable fluid2 but in practice it is found necessary or expedient to employ #e or #aj per cent4 of inoculating matter to the volume of the liquid to be inoculated4 ,the inoculation of the #aj1jjj c4c4 of nutrient medium may be done in a ,carlsberg vessel1 as described by ,hansen in his 8,untersuchungen aus der ,praxis der ,grungsindustrie40 ,it is desirable that the nutrient medium should be without sugars or carbohydrates2 and1 although its composition may be varied1 good results can be obtained by ordinary bacteriological methods1 by using a medium composed of gelatin1 #ej parts or #bj grm42 potassium or sodium phosphate1 #a part or #jd grm42 sodium chloride1 #a part or #jd grm42 water1 #bejj parts or #ajjj c4c4 ,this medium1 after inoculation1 is maintained at a temperature of #cg centigrade1 until the required bacterial action is completed1 i4e41 until the whole of the nutriment for the bacteria is exhausted1 at which time the maximum quantity of the required enzymes has been produced4 ,the time required for this action is not less than three days1 nor more than seven days4 ,the exhaustion of the nutriment may be ascertained scientifically by a microscopic examination of the liquid1 the bacilli at this period commencing to form spores4 ,to each litre of this liquid there is then added from #b to #f grm4 of lactic acid1 and the acid liquid is afterward neutralized by ammonia1 which is added when the liquid is to be used as a bate1 the addition of the ammonia forming certain chemical compounds similar to those found in the dung4 ,instead of lactic acid1 acetic or other similar organic acid may be used1 but sulphuric or mineral acids must not be used4 ,the addition of the acid to the liquid will immediately stop the growth of the bacteria2 but the acid is not added for that particular purpose1 but for the formation of the chemical compounds above referred to4 ,the above-described method is most suitable1 when the bate has to be kept for a time before being used1 or when it is desired to concentrate it for transit or export2 but if the bate is to be used immediately1 it may be prepared as follows3 #ajj parts of gelatin are dissolved in #ajjj parts of water1 and there is then added #ej parts of commercial lactic acid4 ,the mixture is then heated1 in a closed vessel1 to #ajj centigrade1 by which operation the gelatin is partially peptonized1 and the subsequent bacterial action is hastened4 ,the acid liquid is afterward neutralized with ammonia1 or other alkali1 and the whole diluted with water to #bj1jjj parts4 ,the dilution may conveniently take place in the wheel or paddle in which the bating is to be done1 and to the liquid thus obtained there is added from #e to #aj per cent4 of the active culture from the ,carlsberg vessel1 as above described4 ,the liquid is then allowed to stand for #ae to #bj hours at a temperature of #cg centigrade1 and is then ready for use4 ,for bating skins in a practical manner with the improved bate herein set forth1 the method of using the same is varied1 according to the skins to be treated and the kind of leather it is required to produce1 and the strength of the bate is varied in exactly the same manner as the strength of a dung bate1 and such variation is made according to the judgment of the tanner1 the improved bate acting in the same manner as a dung bate4 ,for kid-skins1 calf-skins1 skivers1 and other skins for which dog dung has hitherto been used1 the skins1 after the liming process1 are first well washed in water in the usual way1 to remove the bulk of the lime4 ,the skins are then placed in a wheel or paddle1 with the bate prepared1 as above described1 with the acid exactly neutralized1 or so nearly neutralized1 that the alkaline action of the skins will complete the neutralization1 all skins being alkaline when introduced into the bate4 ,the bate is maintained at a temperature of #cg centigrade1 and the skins are kept in motion until they have 8fallen0 considerably1 i4e41 until the swollen condition of the fibres due to the liming has disappeared4 ,the skins are then removed from the wheel or paddle and scudded by hand or machine1 preferably on the grain side1 and the skins not sufficiently reduced are returned to the paddle1 and the bating continued until the action is completed1 this being judged in the usual way by the tanner by the feel of the skins4 ,the strength of the bate1 when skins are returned thereto1 may be varied from the original strength1 if desired1 and after the bating is completed the skins are treated in the usual manner4 ,the strength of the bate into which the skins are placed1 is varied according to the amount of liming the skins have undergone--that is to say1 for a high-limed skin a strong bate is required4 ,for moderately-limed skins the bate may be of such a strength that each litre as prepared for use contains five grm4 of the original gelatin contained in the nutrient medium1 which is equal to one part of liquid in which the culture has taken place to three parts of water4 ,when the bate is prepared for immediate use1 its strength is varied in the paddle as required4 ,for very hard skins1 such as goat-skins1 the culture may be used as a bate undiluted or it may be diluted with an equal quantity of water4 ,for light-dressing hides and similar skins1 which have hitherto been treated with pigeon dung1 the skins are washed in the usual manner after the liming process1 heated to #cg ,c41 and placed in a wheel or paddle containing the improved bate1 preferably in an acid condition--that is1 before the ammonia or alkali has been added--the strength of the bate being equivalent to five grm4 of original gelatin contained in the nutrient medium to each litre of the bate used4 ,when the lime has been removed from the skins by the bate1 which will be in about one hour1 a quantity of the original culture previously neutralized with ammonia or other alkali and equal to about one-half of the quantity of the original culture first added is placed in the wheel and the bating continued until the process is completed1 this being judged by the feel of the skins4 ,if in the above method the chemical reaction of the bate be examined before the second portion of culture be added1 it will be found neutral1 and the action of the enzymes takes place in a neutral or alkaline solution1 as in the first-described method4 ,the character of the principal enzyme in dung and in the improved bate is a proteolytic one2 i4e4 it resembles the trypsin contained in pancreatic juice4 ,instead of adding an organic acid and neutralizing it by an alkali1 as described with reference to both processes1 there may be added an organic salt of the same character as that formed by the combination of the acid and the alkali4 ,claim4--#a4 ,a bating liquor or bate containing enzymes of the same character as the enzymes contained in dog dung1 an organic acid1 and an alkali1 or their chemical equivalent1 i4e4 an organic salt substantially as herein set forth4 #b4 ,a bating liquor or bate containing enzymes of the same character as the enzymes contained in dog dung and produced by fermentation an organic acid and an alkali1 or their chemical equivalent substantially as herein set forth4 #c4 ,a bating liquor or bate containing one or more enzymes of the character of the enzymes contained in dog dung1 an organic acid and an alkali1 or their chemical equivalent substantially as herein set forth4 #d4 ,a bating liquor or bate containing one or more enzymes of the character of the enzymes contained in dog dung1 or produced from bacteria obtained from dog dung1 an organic acid1 and an alkali or their chemical equivalent substantially as herein set forth4 #e4 ,a bating liquor or bate containing enzymes of the same character as the enzymes contained in dog dung1 two to six grm4 of an organic acid to each litre of the liquid and neutralized by an alkali substantially as herein described4 #f4 ,a bating liquor or bate containing enzymes of the same character as the enzymes contained in dog dung1 from two to six grm4 of lactic acid to each litre of liquor and neutralized by ammonia substantially as herein described4 #g4 ,a bating liquor or bate containing enzymes of the same character as the enzymes contained in dog dung and obtained from bacteria found on the roots of hairs during the sweating process1 from two to six grm4 of lactic acid1 and neutralized by ammonia substantially as herein set forth4 #h4 ,a bating liquor or bate containing enzymes produced from bacteria obtained from dog dung and cultivated in a medium composed of fifty parts of gelatin1 one part of potassium or sodium phosphate1 one part of sodium chloride and two thousand five hundred parts of water1 two to six grm4 of lactic acid to each litre of liquor and neutralized by the addition of ammonia substantially as herein described4 99,oropon99 7,german ,patent #bjj1eai1 ,july #ba1 #aijh74--,process for ,bating ,hides4 ,dr4 ,otto ,rhm1 ,esslingen a_/,neckar4 ,in the present process1 a watery extract of the pancreas in combination with ammonia or alkaline salts or mixtures of these salts is used as a bate liquor4 ,the object of the process is to replace the dung bate4 ,from the researches of ,wood#ade also ,jettmar#adf it appears that the peculiar behaviour of the dog dung bate is to be attributed to the action of enzymes in combination with organic amine compounds and ammonia salts4 ,starting from the assumption that other enzymes1 known to have an action on hide substance1 might have an analogous action to the dog dung bate1 the author discovered that the trypsin of the pancreas had exactly the same bating action as the enzymes of dog dung4 ,the action is aided by the fat-splitting enzyme of the pancreas1 steapsin1 which saponifies the fat in the hides4 #ade ,j4,s4,c4,i4 #ahih1 pp4 #ajaj to #ajac1 and #ahii1 pp4 #iij to #iic4 #adf ,an abstract of ,wood's work4 #aija1 p4 #adh1 section #d1 p4 #adi4 ,a good bating action is obtained by a watery extract of pancreas1 by the addition of an ammonium salt1 which changes the caustic lime 7from the limed pelt7 into a soluble lime salt1 and gradually reduces the alkalinity of the bate liquor caused by the lime in the skins1 since the ammonia liberated by the lime escapes to a great extent from the liquor4 ,the favourable action of the ammonium salt on the skins causes them to fall and become thinner1 nor do they become rough when placed in clean water after bating1 as a strongly alkaline skin will if placed in water containing calcium carbonate4 ,for example1 the process may be conducted by extracting a pancreas weighing about #bej grm4 with #a litre of water1 and adding #aj c4c4 of such extract to #iij c4c4 of a solution containing #jae per cent4 ammonium hydrosulphide and #jc per cent4 sodium chloride4 ,such a solution forms a very active bate4 ,in place of the ammonium hydrosulphide1 any other ammonium salt yielding a soluble lime salt may be used1 e4g41 ammonium chloride4 ,the pancreas extract used in the above process must be used in a fresh condition or preserved from putrefaction by the addition of some suitable preservative2 if putrefied1 and consequently acid1 it will not work4 ,the preservation of the pancreas may also be brought about by drying1 and the bate liquor made from the dry material by putting it in water4 ,no putrefaction occurs during the bating process4 ,the action of the enzymes is favoured by the alkaline reaction of the hide4 ,claim4--,process for bating hides1 characterized by the use of a watery extract of the pancreas1 with the addition of an ammonium or alkali salt which forms soluble lime salts1 or mixtures of such salts to the liquid4 ,in an addition to the above patent1 ,dr4 ,rhm proposes to soften the water used by adding the proper amount of clear lime water to it4 ,starch paste can also be used for the same purpose1 or a mixture of lime water and starch paste4 ,in a further addition1 a weak acid mixture1 consisting of #jje to #ja per cent4 lactic acid and #jje to #ja per cent4 ammonium chloride1 is proposed in place of the ammonium salt alone1 since the evolution of free ammonia had been found to be detrimental to the skins4 99,eberle's ,english ,patent99 7#ba1bjb1 #aiji74--;,improved ,process for ,bating ,hides4 ,efforts have been made for years to replace dogs' excrement used in many cases in tanning as a bate1 by other simpler products and methods which in particular shall have the advantage of greater uniformity and thereby act with greater certainty4 ,now it has been ascertained that substances which are only solvents of lime1 such as acids of inorganic or organic nature and their salts1 form an incomplete substitute4 ,it has been shown by ,eitner1 ,wood and others that there are enzymes and bacteria to which dogs' dung owes its specific or bating properties4 ,the action of dogs' dung is explained as one which liquefies or dissolves the skin substance1 such as is otherwise only done by enzymes and bacteria4 ,experiments in the laboratory and in practice have shown that it is not the dissolving action on the skin substance in the narrow sense which is desired in bating the derm with dogs' dung1 but in order to prepare the hide for the manufacture of a soft and elastic leather1 the albuminous intercellular substances and more particularly the layers of fat lying at the roots of the hair1 in the corium and in many cases also on the epidermis1 must be dissolved and thereby the fibrils of the skin loosened4 ,the highly solvent action of the dung bate on the skin substance means in very many cases a direct disadvantage by reason of the loss of leather substance4 ,extensive experiments with the separate constituents of dogs' dung have shown that with none of them employed alone can a satisfactory action be obtained4 ,for the experiments1 the organic and inorganic salts contained in dog's dung were employed4 ,pure cultures of intestinal bacteria were also examined and also the intestinal juices1 secretions of the gall bladder1 of the pancreatic gland and secretions of the intestinal mucous membrane4 ,the relatively best bating action was obtained with the secretion of the gall bladder2 only a moderate bating action could be obtained with the juices of the pancreatic gland and the secretions of the intestinal mucous membrane4 ,it was therefore very surprising to find and could not be foreseen that mixtures of these three secretions of the digestive apparatus alone exerted an excellent bating action1 and that such mixtures not only formed a perfect substitute for the bate of dogs' dung1 but that they acted far better than the latter1 without it being necessary1 as was recommended elsewhere1#adg to add lime-dissolving salts to the bate1 or to take measures in any other manner for the removal of the lime from the water4#adh #adg #a4 ,see ,german ,patent ,no4 #bjj1eai or ,british ,patent ,no4 #ecggjh ,roehm1 ,esslingen4 #adh #a4 ,see ,german ,patent of ,addition ,no4 #bjc1hhi ,roehm1 ,esslingen4 ,the explanation of the effective action of such mixtures is evident from the following statements3-- ,pancreatic juice contains three ferments1 of which for our purpose trypsin1 which decomposes albumen1 and steapsin which decomposes fat1 are the most important4 ,both ferments are contained as zymogens1 that is to say in an inactive form1 in the pancreatic juice4 ,the latter therefore only gives an incomplete bating action4 ,gall contains ferments which have properties which are mainly fat decomposing1 but are also albumen dissolving4 ,gall also contains the salts of gallic acids which have the power in a high degree of dissolving and emulsioning greases or fats1 and among others have a great solvent action on the chloresterin contained in the skin1 more particularly in the roots of the hair4 ,as regards the fat-decomposing and dissolving action1 gall is far superior to pancreatic juice4 ,the ferments of gall are1 however1 also capable of energising the action of the steapsin in the pancreatic juice as a fat-decomposing ferment1 that is to say of imparting to the pancreatic juice1 which in a pure condition has a very slight action on fat1 a high capacity for decomposing fat4#adi #adi #b4 ,see ,abderhalden1 8,text-book of ,physiological ,chemistry10 #aijf1 page #eee and following4 ,finally gall in bating the derms may be of great importance inasmuch as its acids form easily soluble lime salts4 ,extensive experiments have shown that gall1 as such1 is adapted to dissolve a comparatively large quantity of lime4 ,in hard water an addition of gall prevents the precipitation of calcium carbonate1 and the roughening of the derm1 which1 for instance1 has been noticed when pure bacteria cultures are employed1 is prevented by the addition of gall4 ,the intestinal juice contains in addition to carbonates and alkalis1 enzymes which again exert a slighter bating action on the hide than those of gall4 ,the intestinal juice alone has a similar action to pancreatic juice1 but if intestinal juice be added to pancreatic juice1 the most powerful enzyme of pancreatic juice1 namely the albumen-decomposing trypsin is energised1 and only in this way does the pancreatic juice fully acquire the property of dissolving albuminous substances4#aej #aej #a4 ,see ,abderhalden1 8,text-book of ,physiological ,chemistry10 #aijf1 page #eef4 ,the proportions in which such mixtures best develop their actions1 are those which obtain in animal organisms2 the temperature also especially plays a great part4 ,the maximum temperature lies about #dj ,c4 ,from the above statements it is evident that it is possible to produce various actions with the juices of the pancreas1 gall and the intestines1 quite dependent on which are considered the most important in the bating4 ,similarly1 as the proteolytic action of the mixture of the three juices may be increased or diminished by using larger or smaller quantities of intestinal juice and pancreas1 the fat-decomposing and fat-dissolving action of the mixture may also be increased or diminished by using larger or smaller quantities of gall1 and of gall and pancreas respectively4 ,finally the quantity of the gall to be added is decided according to the amount of lime contained in the water employed in the bating4 ,experience has shown that a relatively small addition of gall will act very advantageously4 ,it must be especially remarked that artificial bates made in this way are extremely cheap as compared with the natural dogs' dung1 as gall and intestinal juice may be procured at very low prices and a considerably smaller quantity of the energised1 more expensive1 pancreatic juice is necessary than1 for instance1 would be necessary if this juice were employed in a pure condition4 ,the advantage of this invention also consists in its being possible to make better bates than that which is made1 for instance1 from dogs' dung because1 as hereinbefore stated1 it is a disadvantage of this latter bate that it in many cases dissolves too large a quantity of the albuminous substance4 ,otherwise1 the composition of the improved bate quite coincides qualitatively with the composition of dogs' dung1 as the latter actually consists in addition to the unabsorbed portions of food1 of secretions of gall1 the pancreatic gland and the mucous membrane of the intestines4 ,the trypsin and steapsin respectively as well as being derived from the pancreatic juice1 may also be derived from the vegetable kingdom1 for instance1 there are considerable quantities of trypsin in the sap of the fig4 ,steapsin1 in not inconsiderable quantity1 is found in the saps of flax1 hemp1 maize1 etc4 ,it must also be remarked that the colouring matters in gall are of quite subordinate importance1 and may be disregarded4 ,the view formerly adopted that the colouring matters in gall stain the leather is incorrect4 ,example3--#bjj c4cm4 of gall juice in #a litre of water are mixed with the watery extract of #bjj grm4 of chopped small intestine in #a litre of water on the one hand1 and #ajj grm4 of the pancreatic gland in #a litre of water1 on the other hand4 ,this watery solution is added to the bating bath1 according to the bating action desired4 ,it can also1 in order to allow of being more easily handled1 be obtained in solid form by absorption in sawdust or kieselguhr and drying at #cj to #dj ,c4 ,claim4--,a process for bating hides1 characterised by the use of mixtures of gall1 the secretion of the pancreatic gland and intestinal juice1 and by the use of mixtures of the active enzymes in these1 or active enzymes derived from the vegetable kingdom1 substantially as described4 99,prof4 ,dr4 ,h4 ,becker's ,english ,patent99 7#bd1ihb1 #aiaj74--;,improvements in ,puering and ,bating ,hides and ,skins4--,it has been shown by ,wood1 of ,nottingham1 and by ,dr4 ,popp and ,dr4 ,becker1 of ,frankfort-on-the-,main1 that the action of a good puer or bate on hides1 is connected with the development of certain species of bacteria4 ,the preparation of pure cultures of these bacteria 7which are derived from dog dung7 has enabled what may be properly termed a safe puer to be obtained1 inasmuch as by its use overpuering the hides is entirely prevented4 ,furthermore1 the leathers are fuller and do not lose any excess of hide substance1 so that a dozen sheepskins that have been suitably puered by the bacteriological method1 will weigh about #i ounces more than a dozen skins of the same kind and origin1 that have been treated in exactly the same way in other respects1 but puered with dog dung4 ,the method of action of the bacterial puer has been elucidated as follows4 ,the bacteria present in the puer are microscopically small and pass easily into the skin through the pores of the latter1 while on the surface and in the substance of the skin they produce their metabolic products and enzymes4 ,these substances are partly proteolytic1 partly fat decomposing1 and also diastatic in character1 so that the highly proteid intermediate substance of the skin is degraded4 ,by means of the ultimately formed ammonia1 amine bases and ammonium bases assisted by the action of organic acids produced by the bacteria1 the lime soaps are decomposed4 ,lime and fat are partially dissolved1 and partially further decomposed or converted into a form which enables them to be worked out by mechanical means4 ,at the same time the roots of the hairs are also loosened so that the hairs also can be readily removed by mechanical treatment4 ,another essential factor is the liberation of gases formed within the skin by the action of the micro-organisms and exerting a very gentle pressure on their environment4 ,the structure of the fibres is loosened1 the fibrils are straightened individually without sustaining any important loss of corporeal matter1 and in this way a firm1 tough and yet soft handling leather is obtained4 ,attempts have been made to improve this puer by adding1 for instance1 organic acids and salts to the bacterial cultures4 ,other methods of puering1 based on the direct weakening of the skin fibres from the outside1 may also effect the pulling down of the hides1 and moreover1 in consequence of that attack on the skin fibres without straightening the fibrils1 an immoderate amount of substance is lost1 and therefore a hard1 stiff1 thin and light leather is obtained4 ,to this class belong also the purely digestive puers such as pancreatic juice1 intestinal juice and the like1 or purified enzymes4 ,these enzymes are colloidal and therefore incapable of diffusion1 and consequently they digest the hide mainly from the surface1 that is to say1 the grain side and inner side of the hide4 ,the fibres1 in-so-far as they are accessible at all to the action of the colloidal enzymes1 are removed from outside without the fibrils being loosened and straightened4 ,hence they are weakened by the digestive puer to such an extent that the hides seem to be gradually pulled down2 but the skin will by that time have lost too much substance1 so that1 inter alia1 even the grain appears to have been corroded4 ,in this way the leather is rendered thinner and lighter than that from the dung or bacterial puer--a defect manifest to every expert4 ,this danger is particularly great when1 by the artificial admixture of corporeal juices1 complications are set up1 that intensify the destructive action of the digestive enzymes on the material1 and when their supplementary action is not suitably controlled4 ,these animal or digestive enzymes and fat decomposing substances originate1 in-so-far as they are not of vegetable origin1 for the most part in the upper portions of the digestive tract4 ,the use of these substances effects an imitation of the purely enzymatic and fat decomposing processes that go on in the upper part of the intestines1 but omits the processes--not less important for digestion and the formation of excrement--occurring in the large intestine and the adjoining portions of the digestive tract4 ,here the bacteria and the vegetable enzymes secreted thereby1 play the chief part4 ,they decompose not only the food constituents--partly by putrefaction--but also the albuminoid digestive secretions and the gall1 so that only small quantities thereof are left4 ,hence when applied to the puering process1 the use of bacteria1 together with their specific enzymes and metabolic products1 is equivalent to a restriction of the immoderate digestive action of the pancreatic and digestive juices1 i4e4 of the animal enzymes4 ,digestion therefore1 with the resulting formation of excrement1 is carried on with the accompaniment of a mutual control1 excitation and restriction on the part of the digestive secretions and the bacterial phenomena4 ,these latter form the real basis of the puering of hides in dung preparations4 ,this is also evident from the purely practical experience that dog dung puer1 e4g4 for glove leather1 is essentially improved by leaving the dung to ferment for several weeks or rather months4 ,during this process an increase occurs in the micro-organisms present1 and also in their metabolic products and enzymes1 but not in the digestive juices originating in the organs of the animal body--the term 8digestive juices0 being restricted to indicate only such juices as are produced in the course of the digestive tract by the organs and cells of the animal body1 in contradistinction to the juices produced by bacteria4 ,according to the present invention1 the bacterial cultures1 together with their metabolic products or products of digestion and enzymes1 are used in combination with one or more of the substances that are excreted in the digestive tract by the animal body itself in order that not only each of these substances may exert its special action on the skin1 but also that the aforesaid mutual influencing1 and more particularly regulating of the action may take place4 ,on this principle1 in preparing an artificial puer for hides1 and in accordance with the nature and preliminary treatment of the raw material1 and the requirements put forward in respect of the finished product1 the bacterial puer1 nutrient medium or culture is mixed with the corresponding digestive juices1 or with purified animal or vegetable enzymes1 as well as with fat decomposing media1 if necessary1 such as ground castor-oil seeds1 hemp seed or the like1 or with extracts of same1 or with gall4 ,where it seems necessary1 substances capable of dissolving lime may also be added1 for example1 sugar1 molasses1 salts of ammonia1 organic acids1 or the corresponding salts or the like4 ,finally1 also1 the several operations may be carried out independently of one another1 it being in such case again advisable to adhere to the processes going on in the intestines4 ,if1 for instance1 specially hard goat skins are to be pulled down strongly by puering1 it is advisable to add to the nutrient medium of the bacteria a little papayotin or papain1 either--according as rendered necessary by the local conditions--in the preparation of the bacterial puering liquor1 or during the propagation of the bacteria4 ,if the fells are less hard so that less pulling down is required1 the hides are first treated with a weak solution of the digestive ferments1 and then with the bacterial liquor4 ,in this way excessive digestive action is counteracted in good time4 ,sheep and goat skins that are particularly rich in fat are immersed in a bacterial puering liquor1 containing ground castor-oil seed or castor-oil cake in suspension4 ,the fat-decomposing ferment contained in this meal then comes into immediate action1 and the liberated fatty acids form readily soluble soaps with the ammonia1 originating from the degradation of the proteid substances1 and with the allied bases4 ,extensive practical experiments have also shown that1 in the case of very fat skins1 the action of the bacterial puer is increased by mixing a suitable salt of sulpho-ricinoleic acid with the puering liquor1 or by washing the skins with solutions of similar soaps either before they are immersed in the puering liquor1 or subsequently4 ,local conditions1 and the requirements laid on the finished leather1 must decide which of these methods is specially advisable4 ,in any event1 however1 the combinations of the bacterial puer afford a means of obtaining an increased puering effect in many cases where puering with the separate auxiliaries mentioned does not produce a sufficient result4 ,claim4--,in the method of puering hides wherein bacterial cultures1 their metabolic products and enzymes are employed1 the combined use with these agents of digestive juices1 mixtures of digestive enzymes or pure digestive enzymes 7and1 if desired1 of fat-decomposing substances71 either simultaneously with said agents or subsequently thereto4 ,,chapter ,,ix4 ,,drenching4 ,in the manufacture of many kinds of light leathers1 skins1 after bating1 are drenched4 ,the process usually consists in placing the skins in a mixture of bran and water1 half to one per cent4 of bran being used 7#e to #aj grm4 per litre1 or #a_/b to #a lb4 per #aj gall47 at a temperature of #bi to #ce ,c4 ,this ferments vigorously for #ah to #bd hours1 with evolution of a considerable quantity of gas1 and the formation of weak organic acids4 ,the acids neutralize any lime which has not been neutralized in the bate1 and they do this in a very gradual and mild way1 being produced by bacterial fermentation exactly as required1 in a similar manner to fermentations taking place in presence of calcium carbonate4 ,the gases evolved bring the skins to the surface of the drench1 and distend the fibres2 the workman attending to the drenches puts the skins down under the liquor with a pole1 but a better way is to have the drench vat fitted with a wooden paddle1 which may be pulled round by hand when necessary2 in this way the skins are put under the liquor without danger of tearing or trapping them2 in the case of grain splits the paddle is a great advantage over the pole4 ,the skins are allowed to rise two or three times1 according to the condition required4 ,for many kinds of alum leather the bate is omitted and the drench only is used4 ,in ,english practice the bran is mashed in the vat1 in which the drenching is to take place1 at a temperature of about #ie ,f4 7#ce ,c472 the skins are then put in and the drench well stirred or paddled until the whole is uniform1 the temperature is then usually down to #he to #hc ,f4 7#bie to #bhb ,c471 at which temperature the fermentation begins4 ,the temperature allowed varies with the state of the goods and the prevailing exterior temperature2 in winter it may be higher than in summer1 but never usually higher than #ij ,f4 7#cbb ,c474 ,in some continental works the bran is mashed in boiling water1 allowed to stand for some hours to cool1 and only the bran-water is used2 in this case the fermentation is different to that in which the bran is mashed at a lower temperature4 ,in the first process the starch of the bran undergoes changes to dextrin and glucoses1 which are then fermented by bacteria with the production of acids and gases 7see ,chapter ,x471 in the latter case the starch1 which has been gelatinized is fermented by other organisms1 which probably secrete diastatic enzymes4 ,less gas is given off in this fermentation than where the bran is mashed at #ie to #ajj ,f4 ,the temperature of fermentation is kept low1 usually #be ,c4 7#gg ,f474 ,bran contains a sufficient amount of nitrogenous matter1#aea to furnish the bacteria with nutriment1 and until this is exhausted there is no fear of the skins being attacked4 #aea ,bran examined by ,kjeldahl's process contained #bb per cent4 ,n1 equivalent to about #ac-ad per cent4 proteids4 ,there is also a 8sweet0 bran drench used on the continent1 in which fermentation is not allowed to take place1 the skins being paddled in an infusion of bran in water for a short time only1 two to three hours at the most4 ,in addition to the mechanical cleaning action1 which the fresh bran has upon the skins1 there is also a softening effect due to some constituent of the bran1 which is at present not understood4 ,one reason for this1 is that the usual drench employed being an acid one1 research has practically been confined to the latter4 ,another method of preparing the bran drench1 consists in allowing the required quantity of bran to soak in cold water for several hours2 a sufficient quantity of hot water is then added to bring the temperature up to #ej ,c42 at this temperature the diastatic enzymes in the bran act rapidly on the starch and transform it into easily fermentable sugars4 ,the temperature is allowed to fall to #cd to #ce ,c41 and then a quantity of an old drench is added to start the fermentation4 ,the liquor becomes acid1 and in two days usually reaches its maximum acidity1 when it is ready for use4 ,the bran is strained off and only the milky liquor used4 ,such a drench is largely employed in the manufacture of chamois leather1 the goods 7sheep fleshes7 being paddled in it for some hours previous to pressing4 ,the ,french also use a similar process in the preparation of suede leather4 ,the bran is strained off and only the sour partly fermented and fermenting liquor used4 ,the straining off of the bran also saves working over the beam which would otherwise be required to get rid of the bran adhering to the skins4 ,it has recently been proposed to employ the bacillus bulgaricus1 the organism which causes the fermentation of milk in the preparation of ,bulgarian and ,turkish 8,yoghurt0 7,bibliography #abd7 for drenching4 ,bacillus bulgaricus is capable of producing up to #be per cent4 of lactic acid1 or about three times the quantity of that produced by ordinary lactic bacteria4 ,dr4 ,hugo ,khl 7loc4 cit47 proposes to cultivate the bacillus in the mother liquors1 which are a by-product in the manufacture of milk sugar1 and to use such liquor as a drench4 ,where skim milk or butter milk is to be had1 this may also be used4 ,a similar process is already in use in ,america1 where the evaporated product is put upon the market under the name of ,dermiforma 7see pp4 #ahi and #aid74 ,as a substitute for the drench1 and in order to further remove lime after erodin1 the late ,franz ,kathreiner employed a solution of anticalcium1 #a in #ejj water1 in which the skins remained overnight4 ,anticalcium is a mixture of sulphonic acids derived from cresols1 and has antiseptic properties1 so that its action is quite distinct from that of the bran drench4 ,it is put on the market by ,j4 ,hauff1 ,feuerbach1 near ,stuttgart4 99,drench ,damage499--,drenching is a very important and useful process in leather manufacture1 but1 like other fermentive processes1 requires great care and experience in its application4 ,although not so risky as puering1 a good deal of serious damage may occur in the drench4 ,the writer knows of no fuller discussion of all the various forms of drench damage than the articles of ,eitner and others which appeared in 8,der ,gerber0 during a long series of years 7#ahhb-aijj74 ,in these articles perhaps every known form of drench damage is described4 ,procter#aeb also gives a concise account of drenching4 ,it will suffice to mention briefly the chief accidents to which the drench is liable2 these are generally known as the 8turning0 of the drench4 #aeb ,principles1 pp4 #aff-agj4 #a4 ,acid 8turning40--,this usually occurs when the atmosphere is charged with electricity--during thunderstorms4 ,it appears to be an extremely rapid form of butyric fermentation1 which has not been fully investigated4 ,the skins become swollen1 transparent and tender1 and1 unless the fermentation is stopped1 soon dissolve to a jelly4 ,the only way to save the skins from destruction is to add salt to the drench2 this reduces the swelling and1 in fact1 pickles the skin4 ,i have pointed out elsewhere that this is really the origin of the modern pickling process1 which is still known by the name of 8rising40 ,a very acid drench will swell the skins almost the same as dilute sulphuric acid1 and if they are then placed in a salt solution1 or salt is added to the sour liquor1 it is absorbed by the skins1 and they are preserved almost as effectually as by the use of mineral acids4 #b4 ,putrid 8turning40--,this occurs under very similar atmospheric conditions to #a1 and may be almost as rapid4 ,instead of becoming acid1 the liquor turns slightly alkaline1 frequently becoming bluish black1 due to the presence of certain chromogenic bacteria4 ,the goods fall as in a puer4 ,both the chromogenic and other bacteria present are peptonizing organisms1 which obtain the upper hand owing to favourable conditions1 and rapidly digest the skin unless the action is stopped4 ,the best remedy is to remove the skins from the drench and pickle them without delay by the usual acid and salt process4 #c4 8,pinholey0 drench4--,this is the same as the ,germans call 8pikiren10 and is generally due to a too rapid evolution of gas both in the drench and in the capillary spaces of the skin itself4 ,the gases form under the hyaline layer1 and finally burst through in small holes4 ,a damage very similar in appearance is also caused by colonies of gelatin liquefying bacteria developing on the grain4 ,each colony forms a small hole4 ,the trouble is usually due to the setting of the drench at too high a temperature4 #d4 ,spongy leather may be produced by leaving the goods too long in a sound drench1 if they are allowed to rise too often4 ,in this case experience alone can determine the proper duration of the drenching process4 ,a special case in which the hyaline layer is slightly attacked and its brilliance destroyed has been described by ,eitner4#aec ,a slimy film was formed on the surface of the drench and also on the grain of the skins4 ,this film was found to consist of ,bacillus megaterium 7the potato bacillus71 and where it was growing on the hyaline layer the latter was etched as it were1 by the peptonizing enzyme secreted by the bacillus1 so that when tanned the grain was covered with dull patches very much resembling 8blast40 #aec ,der ,gerber1 #ahih1 p4 #bjd4 99,fermentations in the ,drench499--,compared with the dung bate1 or puer1 the fermentation taking place in the bran drench is a simple one2 as will be shown in detail in the next chapter1 about half the weight of the bran consists of starch2 this becomes hydrolysed by the enzymes in the bran 7and in some cases secreted by the bacteria7 into glucoses4 ,according to the following equation3-- 7,c#f;,h#aj,o#e7n ,h#b,o n ,c#f;,h#ab,o#f starch glucose ,this expresses the change in its simplest form2 in reality it is much more complex1 various dextrins and sugars being formed simultaneously4 ,the sugars are then fermented by a variety of bacteria with formation of various organic acids1 in accordance with the equation ,c#f;,h#ab,o#f #b ,,ch#c;,,ch7,,oh7,,cooh which represents the formation of lactic acid4 ,in addition1 formic and butyric acids are produced along with small quantities of other bodies1 as will be shown4 ,it is pretty certain that the butyric acid is formed by the further fermentation of the lactic acid and lactic salts in the liquid2 at the same time ,,co#b and hydrogen are evolved as follows3-- #b ,c#c;,h#f,o#c ,c#d;,h#h,o#b #b ,,co#b ,h#b ,illustration3 ,fig4 #bg4--,organisms in ,bran ,drench #ajjj4 ,fig4 #bg is a drawing of the organisms seen in the drench1 under a magnification of #ajjj diameters4 ,this was taken from a drench which had been set about #c hours1 and was just beginning to ferment2 the bacteria form chains of varying length3 the short chains have a slow motion in the liquor4 ,as the fermentation proceeds1 these form longer chains 7,fig4 #bh71 some of which are very beautiful objects1 especially when viewed by dark ground illumination4 ,the other organisms present are bacteria and bacilli from the puer1 and at a later stage1 as the nutrient material for the bran ferment becomes less1 they begin to develop1 first causing butyric and finally putrefactive fermentation4 ,illustration3 ,fig4 #bh4--;,chains of ,bran ,bacteria #ajjj4 ,illustration3 ,fig4 #bi4--;,bran ,fermentation4 ,advanced ,stage4 ,a fairly pure culture may be obtained by inoculating a tube of bran infusion1 previously sterilized1 by means of a freshly made capillary pipette1 which is pushed into the tube without removing the cotton-wool plug4 ,the tube is placed in the incubator at #cj ,c41 and the organisms causing the fermentation develop rapidly2 as soon as the tube is observed to become cloudy1 indicating the development of the bacteria1 another tube is inoculated in the same manner1 using a very minute quantity of liquid2 this second 8attenuation0 is then carried on to five or six more tubes4 ,in the fifth tube will usually be found a pure culture of the bran fermenting organisms1 which ,i have called ,bacterium furfuris4 ,the bacteria 7see ,fig4 #cj7 are mostly in the form of dumb-bells or pairs1 each cell #jge #abe 3 they vary slightly in size1 some forming chains2 those on the surface become surrounded by a kind of jelly1 and form an iridescent pellicle on the surface of the liquid1 the zoogloae form4 ,when the nutriment of the liquid is exhausted or the acidity becomes too great1#aed this film sinks to the bottom and the liquid above becomes comparatively clear4 ,there is no spore formation1 and1 consequently1 the culture soon dies unless inoculated into a fresh nutrient medium4 ,the liquor1 after the fermentation both in the drenches and tubes of pure cultivations1 is always slightly ropy4 #aed ,claflin 7#ib7 gives the limits of acidity for lactic bacteria from #jjb to #je per cent4 ,reynolds ,green 7#ig1 p4 #cdf7 gives the upper limit for ,b4 acidi lactici as #h per cent4 lactic acid4 ,b4 furfuris probably belongs to the group of coli bacteria1 some of which ferment milk and other sugars with production of lactic acid and gases4 ,this explains the ease with which the fermentation takes place1 since the skins bring in immense numbers of bacteria from the bate1 among which are the organisms described4 ,eitner#aee states that the action of the bran drench cannot be considered a chemical one1 and that the chief action is a dynamical one1 resulting from the gases generated in the liquid and in the skin4 ,while ,i do not deny that the gas has such action--indeed ,i pointed out in #ahicaef that the gas acted by floating and distending the skins1 and so enabling them better to take up the acids--,i maintain1 however1 that the chief action is a chemical one and due to the weak organic acids produced2 this was confirmed experimentally4 ,the researches on bran drenching commenced in #ahhg by myself1 and later in conjunction with ,dr4 ,w4 ,h4 ,willcox1 prove conclusively that the amount of acid produced1 and especially the lactic acid1 is sufficient to produce a very decided action on skin4 ,in actual working we found from #ajg to #bcd grm4 total acids per #ajjj c4c41 while in artificial cultures1 with addition of calcium carbonate1 inoculated with pure cultures of bacteria1 obtained from drenches1 we obtained from #dec to #aadd grm4 total acids per #ajjj c4c4 ,now traces of lime in the skins act in just the same way as the calcium carbonate2 they neutralize a portion of the acid produced by the bacteria1 and so allow a greater amount of acid to be produced than if it accumulated in the liquid4 ,by preparing solutions of the above acids of suitable strength and agitating skins in them1 results were obtained in #a-a_/b hours equal to a drenching of #ad hours4 ,the defect of such artificially prepared liquids in practice is due to the fact that they do not contain any particles of bran or flour2 these take up dirt from the skin mechanically1 and so produce a better-coloured leather4 ,where the skin has been bated in a perfectly clean bate1 and then paddled in such an artificial drench1 the leather is in every way equal to that prepared by means of the dung bate1 followed by a bran drench4 #aee ,der ,gerber1 #bd1 #egj4 #aef ,jour4 ,soc4 ,chem4 ,ind41 #ahic1 p4 #dbf4 ,by far the most important action for the tanner is the solution of the last traces of lime not dissolved by the bate1 and this is the chief reason for its use1 where colour is a desideratum1 and where sweet liquors are used2 for some kinds of leather where it is desirable not to lose pelt1 the drench is used alone for this purpose4 ,a dung bate1 such as most light leather tanners use1 is seldom run off more than once a week1 and contains a considerable amount of dissolved lime2 the amount in a freshly made-up puer wheel is from #ja grm4 to #jc grm4 lime 7,ca,o7 per litre4 ,after the wheel has been in use for a week1 it rises to #je grm4 to #jh grm4 per litre4 ,it will be readily seen that a liquid which already contains such considerable quantities of lime is not an especially good medium to use for its complete removal from the skins1 hence drenching is necessary to get rid of the lime left in the skins4 ,eitner states that the fermentation is alcoholic at the commencement1 and then becomes an acid fermentation with generation of gas4 ,in tan liquors there is no doubt that this is the course of the acetic fermentation1 as has been shown by ,andreasch1#aeg but in the usual type of bran drench the action is certainly a different one4 ,the acetic acid1 as far as we can ascertain1 is produced directly from the dextrose1 without the previous production of alcohol1 since the presence of the latter is not shown by tests in any stage of the fermentation4#aeh ,no yeasts were observed#aei and no alcohol was found in any stage of the fermentation4#afj ,j4 ,o',sullivan remarks that although it has not been noticed it is possible that in this case the production of alcohol and its oxidation into acetic acid are simultaneous1 but that there is no preliminary fermentation by yeasts followed by acetic fermentation by bacteria such as ,eitner indicates is certain4 #aeg ,der ,gerber1 #ahie1 p4 #aic1 etc4 #aeh ,j4,s4,c4,i41 #ahig1 p4 #eac4 #aei ,ibid41 #ahij1 p4 #bh4 #afj ,ibid41 #ahic1 p4 #dbb4 ,to sum up the conclusions arrived at from the experiments above quoted4 ,the starch of the bran or flour is first transformed into glucoses and dextrin by the action of an unorganized ferment called cerealin4 ,the glucoses are then fermented by certain species of bacteria1 ,bacillus furfuris being perhaps the chief1 with the formation of lactic1 acetic1 formic and butyric acids1 and the evolution of carbon dioxide1 hydrogen1 nitrogen1 and a small quantity of sulphuretted hydrogen4 ,the principal acid produced is lactic2 the acetic acid is produced directly from the glucoses by the above-mentioned bacteria without any preliminary alcoholic fermentation by yeasts4 ,the mode of action of the drench on the skins may be summed up as follows3-- #a4 ,the solution of the last traces of lime which has not been removed by the bate1 by the organic acids produced by the fermentation1 and the subsequent swelling action of these on the skin fibres4 ,the acids also dissolve a small amount of skin substance4 #b4 ,simultaneously with 7#a7 the distension and floating of the skins by gases produced by the fermentation1 so enabling them better to take up the acids4 #c4 ,the mechanical absorption of dirt by the particles of bran or flour in the drench4 ,it is not proposed to enter into further detail1 since the next chapter1 consisting of the original papers of ,dr4 ,w4 ,h4 ,willcox and the author1 contains a pretty complete account of the analysis of the drench and theory of the drenching process4 ,,chapter ,x4 ,,original ,,papers ,,on ,,drenching4 #a4 ,,further ,,contribution ,,on ,,the ,,nature ,,of ,,bran ,,fermentation4 ,by ,j4 ,t4 ,wood ,w4 ,h4 ,willcox1 ,b4,sc47,lond474 7,reprinted from the ,journal of the ,society of ,chemical ,industry1 ,may #ca1 #ahic4 ,no4 #e1 vol4 xii4 p4 #dbb47 ,the paper which one of us had the honour of reading before this ,section on ,december #aa1 #ahij1afa dealt chiefly with methods of bacteriological research1 but especially in connection with the fermentation of bran as applied in the manufacture of light leathers4 ,the object of the present paper is to give an account of further research into the nature of the fermentation and its products1 the former communication being very incomplete4 ,in further investigating the matter1 we endeavoured-- #afa ,j4,s4,c4,i41 #ahij1 #bg4 #a4 ,to obtain a complete knowledge of the products of the actual fermentation as it takes place in practice4 #b4 ,to discover in what way the ferment acts1 both on the materials fermenting and on the skins4 #c4 ,to examine in the same way the products of a pure cultivation of the bacterium causing the fermentation4 #a4 99,the ,products of the ,actual ,fermentation499--,these may be divided into three groups3--7#a7 gases2 7#b7 volatile bodies2 7#c7 non-volatile bodies4 ,it was stated in the former paper that the ferment produced an inflammable gas along with considerable quantities of ,,co#b1 ,h#b,s1 etc4 ,the inflammable gas was thought by analogy from the researches of ,tappeiner#afb to be methane2 it has1 however1 proved to be pure hydrogen4 ,the absence of hydro-carbons was shown by the following method4 ,some of the gases were collected1 the ,,co#b and ,,sh#b removed by absorption with ,,koh1 and the remaining gases exploded in a eudiometer tube with oxygen4 ,the gases which remained after explosion did not diminish in volume after standing over ,,koh solution1 showing absence of the paraffins and olefines4 #afb ,zeits4 fr ,biologie1 xxiv4 #aje4 ,for the purpose of analysis1 about #a-a_/b litres of the gas were collected at a time in a large flask1 fitted with a caoutchouc stopper and a funnel having an area of #bh sq4 in4 ,this was inverted1 filled with the drench liquid1 over the vat4 ,the gas when collected was transferred immediately in the vat to a glass-stoppered bottle1 sealed with a small quantity of the fermenting liquid and examined at once4 ,nine analyses have been made1 most of them in duplicate4 ,the following table1 p4 #bdh1 gives the results of three of these duplicate analyses1 which have been performed by ,hempel's method1 the hydrogen being estimated by combustion in air over heated palladinised asbestos4 ,we find that the gases given off during the fermentation are practically the same1 with or without skins4 --------------------------------------- ,gases ,a ,b ,c --------------------------------------- ,,co#b and ,h#b,s #bai #beb #dbd ,o#b #aj #ba #cf ,h#b #eca #dfg #bhb ,n#b #bdj #bfj #beh --------------------------------------- ,a is from a vat containing no skins1 #a-b days4 ,b from a vat containing skins1 #b-c days4 ,c from a vat containing skins1 #c-d days4 ,the ,h#b,s is present only in small quantities from #a-b per cent4 ,its presence was shown by aspirating the gases dissolved in #a litre of drench through a dilute solution of lead acetate containing a few drops of acetic acid4 ,the gases were liberated by heating the liquid1 and at the same time aspirating air through it4 ,the ,h#b,s is present both in the gases evolved from drenches which do not contain skins1 and from those which do1 though to a slightly greater extent in the latter4 ,the amount of ,,co#b given off increases as the fermentation proceeds2 the oxygen also increases1 the nitrogen remaining practically constant4 ,we consider that some of the nitrogen given off is that dissolved in the water1 the oxygen being partly used up by the ferment in its earlier stages2 the remainder of the nitrogen is probably produced from the decomposition of the nitrogenous bodies contained in the bran4 ,it may be noted here that the bran fermentation under ordinary circumstances ceases on the fourth day1 and sometimes earlier4 ,frankland and ,frew1 in a paper on a pure fermentation of mannitol and dulcitol#afc have shown the hydrogen and carbon di-oxide given off were produced by the decomposition of formic acid1 the ferment producing formic acid and the latter immediately splitting up into an equal number of molecules of carbonic anhydride and hydrogen4 ,we have every reason to believe1 from experiments which will be included in the third section of the paper1 that the source of the ,h and ,,co#b is the same in the fermentation we are considering4 #afc ,jour4 ,chem4 ,soc41 #ahib1 ,trans4 #bed4 #b4 99,volatile ,bodies499--,these may be divided into 7#a7 acids1 and 7#b7 amines4 ,we had previously shown the absence of aldehyde by the rosaniline reaction1 and of alcohol by ,lieben's iodoform test4 ,in the first experiment to determine the acids1 #ae1fgj c4c4 of the liquid from a normally fermenting vat was taken when the fermentation was at its height2 this was submitted to distillation1 and to the last portions distilled water added and #af1bjj c4c4 distilled over2 the distillate was neutralised with sodium carbonate1 and the whole was then evaporated in a porcelain dish1 the residue dried first at #ajj ,c41 then over strong sulphuric acid1 the weight of the sodium salts of the volatile acids thus obtained being #ahjg grm4 ,these salts were treated with #bjj c4c4 absolute alcohol and #bj c4c1 strong ,h#b,,so#d2 heat was evolved1 and there was a strong smell of ethyl acetate and butyrate4#afd ,the mixture was allowed to stand for #bd hours and then distilled on the oil-bath1 the temperature for a long time remaining at #ha ,c41 finally rising to #if ,c4 #bai c4c4 of distillate was obtained1 and to this a saturated solution of common salt was added1 but the esters of the volatile acids did not separate out4 ,the whole was again redistilled with the same result4 #afd ,der ,gerber1 xvi4 7#cfh71 #d4 ,failing in this way to separate the acids in the form of their esters1 the mixture of esters and alcohol was examined qualitatively2 #ge c4c4 was taken and saponified with #hj c4c4 ,n_/#a ,na,o,h in a distilling flask1 with inverted condenser1 for half an hour1 until all the fragrant smell of the esters had disappeared4 #ga c4c4 ,n_/#a ,h,cl was then added1 and the apparatus connected with a condenser in the usual way4 ,the distillate was acid4 #hjj c4c4 was taken off1 forming fraction #a4 ,the remainder of the acid required to neutralise the sodium hydrate was added1 and another #hjj c4c4 distilled off1 forming fraction #b4 ,fraction #a smelt strongly of butyric acid1 fraction #b of acetic acid4 ,the fractions were then each boiled for half an hour with excess of barium carbonate2 this was filtered off and washed1 the filtrate evaporated to dryness1 and dried at #acj4 ,a portion of barium salt of fraction #a was heated with alcohol and sulphuric acid and gave the characteristic pineapple smell of ethyl butyrate4 ,the solution of the barium salts of fraction #b was concentrated by evaporation1 and to a portion excess of ,h#b,,so#d was added1 the ,ba,s,o#d filtered off1 and the filtrate carefully neutralised with ammonia and a portion added to a solution of neutral ferric chloride4 ,it was coloured dark red1 and a finely-divided precipitate of basic acetate of iron came down on boiling4 ,a second portion of the concentrated solution was heated with sulphuric acid and gave off a strong smell of acetic acid4 ,to a third portion silver nitrate was added1 and a slight excess of acetic acid2 a little silver was deposited in the form of a film1 showing a trace of formic acid4 ,having thus shown the presence of butyric1 acetic1 and formic acids in the drench1 we proceeded to ascertain the quantities formed in a normal fermentation of bran without skins4 ,for this purpose a drench was made in a clean vessel with #aj litres of distilled water and #bjj grm4 of bran mashed at a temperature of #ch ,c41 and1 after cooling to #cc1 inoculated with bacteria from an actual drench which was fermenting vigorously2 this was kept in the drench house so that the fermentation and general conditions might be exactly similar4 ,in #dh hours all gases had ceased to be evolved1 and the true fermentation was at an end4 ,the liquid had an acid1 not unpleasant smell1 and was acid to litmus paper4 ,the bran was strained off through muslin1 washed with a little water1 and well squeezed2 the liquid measured #aj litres4 ,three litres of this were taken for the separation and estimation of the volatile acids1 the remainder being set aside for examination and estimation of the non-volatile acids1 etc4 ,two of the three litres were placed in a distilling flask with #e grm4 of pure ,ca,c,o#c1 and distilled down to one litre4 ,the distillate was alkaline to litmus1 and had a peculiar fishy smell2 the remaining litre of drench was added1 and the liquid taken down until the distillate ceased to be alkaline and only bad a faint smell4 ,the alkaline distillate gave a yellow precipitate with ,nessler's solution1 as well as the following reactions3-- ,ag,n,o#c ,a faint brown precipitate4 ,hg,cl#b ,a yellowish-white curdy precipitate4 ,pb,a ,a brownish-white precipitate4 ,cu,s,o#d ,a dirty blue precipitate1 which changed to a brownish turbidity on boiling4 ,h,cl was added to the distillate in slight excess and the liquid evaporated to a small bulk2 to a portion chloroform and alcoholic potash were added1 and the liquid heated2 no smell of isocyanides was given off2 the body is1 therefore1 not a primary amine4 ,phosphomolybdic acid gives no precipitate1 therefore the body is not an alkaloid4 ,from the above tests and its characteristic smell1 we conclude that the body is trimethylamine4 ,the platinum salt was formed by evaporating the above concentrated solution of trimethylammonium hydrochloride with excess of platinum chloride1 a precipitate of the platinum salt insoluble in alcohol being formed4 ,there was not1 however1 a sufficient quantity from the three litres to ascertain the molecular weight4 ,proceeding with the estimation of the volatile acids1 #ajj c4c4 ,n ,h,cl being required to completely neutralise the ,ca,c,o#c used1 #ej c4c4 were first added and the distillation continued2 the distillate was only very faintly acid4 ,four fractions were now distilled off1 using respectively #aj1 #aj1 #aj1 and #bj c4c4 ,n ,h,cl4#afe #afe ,method recommended to us by ,dr4 ,frankland4 ,vide ,jour4 ,chem4 ,soc4 ,trans4 #ei1 p4 #id4 ,appendix ,,ii4 ,determ4 of ,vol4 ,acids by dist4 with ,h,cl4 ,fraction #a was boiled with excess of barium carbonate1 filtered1 the ,ba,c,o#c washed with hot water1 and the filtrate evaporated to dryness1 and the ,ba salts dried at #acj ,c4 till the weight was constant2 the salts were then decomposed with strong sulphuric acid1 ignited1 and the barium sulphate weighed4 ,fractions #b1 #c1 and #d were treated in an exactly similar way1 the barium salts obtained and the weight and percentage of barium sulphate being shown in the following table3-- ---------------------------------------- --- ,fraction ,weight of ,weight of ,per ,cent ,salts ,ba,s,o#d ,ba,s,o#d ---------------------------------------- --- ,i4 #jeehe #jdiia #hicfe ,,ii4 #jejfj #jdfah #iabfe ,,iii4 #jcafge #jbidae #ibhf ,,iv4 #jddge #jdbeb #iejb ---------------------------------------- --- ,calculating the fractions #a and #b as mixtures of barium butyrate and acetate1 and fractions #c and #d as mixtures of barium acetate and formate1 we may summarise the results thus3-- ---------------------------------------- --------- ,fraction ,weight of ,ba ,ba ,ba ,salt ,acetate ,butyrate ,formate ---------------------------------------- --------- ,i4 #jeehe #jdijd #jjfha 44 ,,ii4 #jejfj #jejcj #jjjcj 44 ,,iii4 #jcafge #jbgdi 44 #jjdahe ,,iv4 #jddge #jbfbi 44 #jahdfj ,total #ahbhge #aecab #jjgaa #jbbfde ---------------------------------------- --------- or as free acids3-- ----------------------------------- ,fraction ,acetic ,butyric ,formic ----------------------------------- ,i4 #jbcjh #jjche 44 ,,ii4 #jbcfg #jjjag 44 ,,iii4 #jabic 44 #jjagj ,,iv4 #jabcg 44 #jjgdh ,total #jgbje #jjdjb #jjiah ----------------------------------- ,proceeding now to 7#c7 non-volatile bodies1 we find these to consist of 7#a7 acids1 and 7#b7 soluble carbohydrates4 ,for examination1 the remaining #d litres of experimental drench were evaporated down to #a litre and filtered2 the residue 7consisting of starchy matter7 was well washed and the washings added to the filtrate1 the whole placed in a large distilling-flask and distilled with continued addition of distilled water until the distillate was no longer acid 7this required the addition and distillation of #d litres of distilled water74 ,a further deposit of solid matter rendering boiling dangerous1 the liquid was again filtered and the residue washed free from acid4 ,this residue was found to consist of nitrogenous organic matter and calcium phosphate1 together with a trace of calcium oxalate1 both being derived from the bran4 ,the clear liquid containing the non-volatile acids and other bodies was further concentrated and made up to #ejj c4c42 it was dark brown in colour and was very acid to litmus2 owing to a trace of flocculent matter1 it was again filtered4 ,the presence of lactic acid was shown in the following manner3 #aj c4c4 of the liquid were placed in a small distilling-flask along with #b c4c4 strong ,h#b,,so#d and about #je grm4 potassium chromate in a little water4 ,this was distilled and the vapours received in a test-tube surrounded by cold water2 on adding magenta solution1 decolorised by ,,so#b1 to the liquid in the test-tube1 a red colour was produced by the aldehyde formed from the lactic acid2 aldehyde was also recognised by its smell4 ,we find this an exceedingly delicate test for lactic acid1 and as far as we know it is quite new in this form4 ,for #aj c4c4 of liquid to be examined1 we find #b c4c4 strong ,h#b,,so#d and #a grm4 of potassium chromate to be the best proportions4 ,formic1 acetic1 propionic1 butyric1 valerianic1 succinic1 malic1 tartaric1 and citric acids do not give the reaction4 ,the liquid was now tested for succinic and malic acids4 #be c4c4 was taken and decolorised by treatment with pure animal charcoal for half an hour2 the liquid was then filtered1 the charcoal washed free from acid1 and the filtrate concentrated2 ammonia was added in slight excess1 the precipitate of calcium phosphate filtered off4 ,to the filtrate ,ca,cl#b was added in slight excess to remove the remainder of phosphates1 the liquid filtered1 and the filtrate cautiously neutralised with ,h,cl2 the addition of neutral ferric chloride to a portion gave no precipitate1 showing the absence of succinic acid4 ,to the remainder an equal volume of absolute alcohol was added and the liquid boiled2 there was no precipitate4 ,twice the volume of absolute alcohol was then added and gave no precipitate4 ,on the addition of four times the volume of absolute alcohol1 a slight white precipitate came down1 which evidently consisted of dextrin1 from the manner in which it settled round the sides of the tube1 and from its insolubility on adding ,h,cl4 ,we therefore conclude that there is no malic acid present1 and that the only non-volatile acid produced is lactic acid4 ,the acidity was first determined by titrating #aj c4c4 of the solution with ,n_/#aj sodium hydrate1 using glazed litmus paper to determine the point of neutralisation4 ,the #aj c4c4 required #fff c4c4 ,n_/#aj ,na,o,h1 equivalent to #jfff of ,n lactic acid #jgdha grm4 per litre of original drench4 ,in order to separate the lactic acid from the colouring matter and other bodies 7dextrin and soluble starch7 present1 #ajj c4c4 of the concentrated liquid was decolorised with #aj grm4 of animal charcoal1 the mixture filtered and the charcoal well washed1 the filtrate evaporated to dryness1 and #ae drops of ,n_/#aj ,h#b,,so#d added to decompose any salts of lactic acid present2 this was now extracted with ether1 the ethereal extract of lactic acid placed in a distilling-flask1 the ether distilled off1 and the residue boiled with distilled water and pure calcium carbonate4 ,the small amount of calcium sulphate present was removed by boiling the filtrate from the ,ca,c,o#c with barium carbonate1 and filtering4 ,the filtered liquid now consisted of a solution of calcium lactate2 it was evaporated to dryness in a platinum dish1 and the residue dried at #aaj ,c42 it was then washed first with ether1 then absolute alcohol4#aff #aff ,julius ,wladika4 ,vide ,der ,gerber1 xvi4 #bh4 ,zur ,kenntniss der ,organ4 ,suren in ,fichtenbrhen4 ,the insoluble residue was dried at #aaj ,c4 till the weight was constant4 ,the total weight of calcium salts obtained was #jgffa grm4 7from #d_/e litre of drench71 of which #jedic grm4 yielded on ignition #jacih grm4 ,ca,o #bede per cent4 ,theory requires for calcium lactate 7,c#c;,h#e,o#c7b;,ca #befi per cent4 ,ca,o4 #jgffa grm4 calcium lactate in the quantity used #jiegf grm4 per litre #jgijg grm4 lactic acid per litre4 ,the difference between this and the preceding amount of lactic acid found by titration1 viz4 #jjdbf grm41 is probably accounted for by the presence of a small quantity of salts of lactic acid in the drench4 ,the second part of the subject which we proposed to consider was 8,in what way does the ferment act on the bran and on the skins80 ,the average composition of bran is shown in the following table3-- ,per ,cent4 ,water4 #ad ,fibrin1 etc4 #ae ,starch #dd ,fat #d ,lignose and cellulose #ag ,ash #f ,it will be seen1 as stated in the former communication1#afg that the starch must be the principal body acted upon2 but the cellulose is also an important constituent1 and before going further it was necessary to ascertain if it took part in the fermentation4 ,for this purpose some pure cellulose was prepared from cotton wool in the usual way1 and small portions placed in tubes containing yeast-water#afh as a nutrient material4 ,these were sterilised by steaming2 two tubes were inoculated from a pure cultivation of the bacteria obtained in #ahhi1 two were inoculated from an actual drench1 and three left uninoculated2 all of them were placed on the incubator at a temperature of #cj-cc4 ,on the second day the inoculated tubes were cloudy1 but no gas was given off1 nor was any acid formed2 in #aj days the cellulose had not disappeared1 nor on examination with the microscope could any action be detected4 ,the experiment was repeated with peptone as a nutrient medium1 but with the same result4 ,the conclusion is that the bacterium does not attack the cellulose1 which thus takes no part in the fermentation4 ,the starch and nitrogenous bodies of the bran are therefore the only bodies acted upon by the bacteria in this fermentation4 #afg ,j4,s4,c4,i4 #ahij1 #bg4 #afh #g grm4 of yeast boiled in #ajj c4c4 ,h#b,o4 ,from the fact that bran drenches ferment in the same way when mashed at all temperatures from #bj ,c4 to #dj ,c41 and that in all cases the starch is decomposed1 it was supposed that the ferment was capable of attacking the starch in its undissolved condition4 ,to ascertain if this were so1 it was necessary to use pure cultivations in the laboratory4 ,the usual methods employed had thrown no light on this part of the subject1 as in order to sterilise the solutions they had been repeatedly boiled1 and were thus not comparable with the fermentation as it takes place in the works4 ,in order to get rid of this difficulty1 the starch was sterilised in a dry condition in the hot-air oven1 by heating for several hours on successive days to #aaj ,c4 ,this sterile starch was mixed with sterilised water in tubes plugged with sterile cotton-wool4 ,eight tubes were taken1 as follows3-- #a4 ,sterile starch and water4 #b4 ,sterile starch and water inoculated pure culture4 #c4 ,sterile starch and yeast-water inoculated pure culture4 #d4 ,sterile starch and asparagin inoculated pure culture4 #e4 ,yeast-water alone inoculated pure culture4 #f4 ,dextrin#afi and yeast-water inoculated pure culture4 #afi ,prepared by precipitation with alcohol4 #g4 ,soluble starch#agj and yeast-water inoculated pure culture4 #agj ,prepared by heating starch and water to #ej ,c4 for #ah hours and filtering4 #h4 ,starch mucilage and yeast-water inoculated pure culture4 ,these were allowed to stand on the incubator at #cc-ce;,c41 and examined for acid each day by the method described in the previous communication for starch testing4 ,they all remained neutral1 although the bacteria developed in all but ,no4 #a4 ,these experiments were repeated several times1 with the same result in every case4 ,they show that this ferment is unable to act on starch either in its insoluble or soluble condition1 alone or in the presence of nitrogenous bodies4 ,now it has been known for a considerable period that bran contains an unorganised ferment called cerealin1#aga which is capable of changing starch into dextrin and other carbohydrates2 but the information to be obtained about it was very meagre1 and as it appeared that this body might play an important part in the fermentation1 we proceeded to prepare some pure cerealin and to ascertain its action on pure starch4 ,the cerealin was prepared by taking a kilo of bran and extracting it with #b litres of distilled water at #cj ,c2 the extract was filtered clear and #b litres of strong spirits of wine containing #ij per cent4 alcohol was added1 when a flocculent precipitate separated1 which was washed on a filter with alcohol1 dehydrated with absolute alcohol1 and dried over ,h#b,,so#d4 ,the cerealin thus prepared is an amorphous substance not quite white1 difficultly soluble in water1 though we think this is due to its having been coagulated1 and that it might be prepared in some other way which would show it to be more soluble than that which you now see4 #aga ,watts' ,dict41 ,old ,ed4 ,cerealin discovered by ,mje ,mouris1 ,comptes rend4 #cg1 #cea2 #ch1 #eje2 #dc1 #aabb2 #dh1 #dca2 #ej1 #dfg4 ,to show its action on starch we took #aj grm4 of pure starch in #bjj c4c4 water at #dj ,c41 and placed equal quantities in two flasks2 to ,no4 #a about #ja grm4 of the cerealin was added2 ,no4 #b was left blank4 ,these were kept at #dj ,c4 for #aj hours1 the clear liquid filtered off1 and examined with ,fehling's solution4 ,no4 #a reduced it strongly1 showing that glucoses were present in considerable quantity4 ,no4 #b had no effect whatever4 ,addition of alcohol to ,no4 #a gave a white precipitate2 this was thrown on to a filter1 washed with alcohol1 and dried at #ajj1 again dissolved in water1 and inverted by boiling the solution with #a_/bj part of strong sulphuric acid and then neutralising with sodium hydrate4 ,the resulting solution reduced ,fehling's solution1 showing that the body was dextrin4 ,strong bran infusion 7which of course contains cerealin7 acting on a thick starch mucilage1 liquefies it1 and forms glucoses and dextrin4 ,we have thus shown that the cerealin produces glucoses as well as dextrin1 both from solid starch and from starch mucilage4 ,this is most important1 as it has been previously shown by one of us that the ferment attacks glucose very easily4 ,the drenches were now examined in order to ascertain the presence of glucose and dextrin2 in the former communication it was stated that these were absent4 ,we find1 however1 that by concentrating the liquid1 that both are present in the early stages4 ,samples were taken one hour after mashing1 and at #c1 #f1 #ab1 and #ah hours1 while the drench was working4 ,these were evaporated to #a_/e bulk1 filtered1 and divided into two portions1 one of which was examined with ,fehling's solution2 to the other alcohol was added2 the white precipitate after addition of alcohol was filtered off1 washed with alcohol1 dried at #ajj ,c41 redissolved in water1 and boiled with sulphuric acid to invert it1 then examined with ,fehling's solution4 ,the following results were obtained3-- ---------------------------------------- ------------------- ,hours #a #c #f #ab #ah ---------------------------------------- ------------------- ,glucoses or sugars ,present in ,present ,absent,absent,absent reducing ,fehling's considerablein small solution directly quantity quantity ,dextrins1 ,fehling's ,present in ,present ,traces,faint ,absent solution reduced considerable traces after inversion quantity ,soluble starch ,absent ,absent ,absent,absent,absent ---------------------------------------- ------------------- ,in a bran infusion kept from fermenting by a little ether or chloroform1 the formation of glucose and dextrin goes on continuously1 the glucose increasing in quantity2 the action is1 however1 much slower than in the case of diastase2 at the end of #ab hours1 at a temperature of #dj ,c41 about half the starch is transformed4 ,it appears from this and a number of other experiments that glucoses and dextrin are formed by the cerealin1 the former only being decomposed by the bacteria almost as fast as it is produced1 for after three hours no glucose is found in the drenches4 ,we have thus shown that the acids and gases are produced from the starch contained in the bran1 the starch being first changed into glucoses by the action of an unorganised ferment or ferments2 and that the glucoses are decomposed by a specific organism1 the nitrogenous material in the bran serving for its nutriment2 that the action is the same with or without skins although there appears to be a little more ,h#b,s gas given off from drenches containing skins1 than from those containing none4 ,the ferment has no direct action on the skins4 ,this may be shown by taking a piece of limed skin1 in which a considerable portion of the lime exists as carbonate1 and submitting it to the action of the ferment2 in this case the action goes on much longer than in the drenches1 being complete in about #ae days1 but the skin may be left in the resulting liquid for three months without undergoing further change than solution of the lime1 provided that suitable means be taken to exclude moulds1 which1 by destroying the organic salts and acids produced1 enable putrefactive fermentation to begin4 ,it has been thought that the bran itself exercised some peculiar action on the skin1 and possibly this may be so to a slight extent1#agb as the sweet bran drench is occasionally used on the continent1 but if skins are placed in a mixture of bran and water 7in the proportions for drenching7 which is prevented from working by the addition of a minute quantity of ,hg,cl#b #a_/ajjjj1 such a drench has no action on them1 and when tanned they are harsh and hard1 similar experiments have been made on a smaller scale1 using ether and chloroform to prevent fermentation1 with the same results4 #agb ,vide der ,gerber xiv4 #beg ,ssse ,kleienbeize4 ,in order to show whether the acids alone were the cause of the action on the skins1 an artificial drench was made up of the following composition-- #je grm4 per #ajjj glacial acetic acid4 #aj lactic acid sp4 gr4 #abaj4 ,in this skins were worked intermittently for #a-a_/b - #b hours1 and it was found that in this time they were in a similar condition to skins which had been in a drench from #ab-af hours4 ,they were afterwards tanned1 and found to be good leather1 and in every way equal to similar skins which had been 8drenched40 ,a number of experiments have been tried with sulphuric and hydrochloric acids in order to ascertain if these had a similar action1 but the results have not been satisfactory4 ,with regard to the third portion of the research1 viz4 the products of a pure cultivation of the bacteria1 we have obtained a good number of results2 but as the description of the experiments is of a greater length than we anticipated1 and as there is still some work to do in verifying them1 we are obliged to leave this portion for another paper1 which we hope to have ready by the next session4 ,in conclusion1 we may summarise the results obtained up to the present in the fermentation of bran by the organism we have used2 remarking that there may be other organisms capable of fermenting bran in a somewhat similar manner4 #a4 ,it has been shown that the fermentation investigated is due to a specific organism1 of which we find no account1 and which1 pending further experiments1 we have therefore provisionally named ,bacterium furfuris4 #b4 ,that the starch and nitrogenous bodies in the bran1 alone take part in the fermentation1 the starch being first transformed into glucoses and dextrin by the action of an unorganised ferment or ferments2 the glucoses and nitrogenous bodies only1 being decomposed by the bacteria1 with the formation of formic1 acetic1 butyric1 and lactic acids1 and the simultaneous evolution of hydrogen1 carbon dioxide1 nitrogen1 and a small quantity of sulphuretted hydrogen4 ,the following table shows the quantities found in an experimental drench per #ajjj c4c4 ,grm4 ,formic acid #jjcjf ,acetic acid #jbdjb ,butyric acid #jjacd ,lactic acid #jgijg ------ ,total #ajgdi ,we find in actual work that the quantity of acid produced varies from #a to #c grm4 per litre4 #c4 ,that if these acids are applied to the skins in the same proportions as they occur in the drench1 the action on them is the same1 and much quicker than an ordinary drench4 #d4 ,that the gas therefore1 has no action on the skins per se1 with the exception of floating and distending them1 and so enabling them better to take up the acids4 ,we are indebted to ,mr4 ,h4 ,r4 ,procter1 of the ,yorkshire ,college1 ,leeds1 and to ,dr4 ,percy ,f4 ,frankland for valuable suggestions in carrying out some of the work4 ,,ii4 ,,on ,a ,,pure ,,cultivation ,,of ,a ,,bacillus ,,fermenting ,,bran ,,infusions4 ,by ,j4 ,t4 ,wood and ,w4 ,h4 ,willcox1 ,b4,sc47,lond474 ,reprinted from the ,journal of the ,society of ,chemical ,industry1 #cjth ,june1 #ahig1 ,no4 #f1 vol4 xvi4 p4 #eaj4 99,isolation of ,pure ,culture499--,in our previous communication on bran fermentation as applied in the manufacture of light leathers1#agc we gave an account of the actual fermentation and its products1 together with the mode of action on the bran and on the skins for which this fermentation is used1 reserving to the present paper an account of the products of a pure cultivation of the bacteria causing the fermentation4 #agc ,j4,s4,c4,i4 #ahic1 #dbb4 ,the cultivation used in the first experiments for this purpose was one isolated in #ahhi1 and used in the cellulose and starch experiments described in the above-mentioned paper4 ,this cultivation had not been obtained from a single colony from gelatin1 and in order to make quite sure that the cultures used were pure1 it was decided to make another attempt to isolate the bacillus by plate cultivation4 ,previous attempts to do this had failed1 bate organisms and gelatin liquefying bacilli1 developing in such numbers that the plates were spoiled before the organism1 which caused the fermentation1 had time to develop2 beside which the organisms1 as obtained direct from the drenches1 grew with difficulty in the ordinary nutrient gelatin4 ,a special gelatin was therefore prepared of the following composition3-- ,gelatin #ajj grm4 ,glucose #cj #agd,salt solution #bjj c4c4 ,water #hjj #agd ,potassium phosphate1 #a grm42 magnesium sulphate1 #jb grm42 calcium chloride1 #ja2 water1 #ajjj c4c4 ,vide ,frankland and ,frew1 ,trans4 #ahib1 #bee4 ,plates of this gelatin in ,petri dishes were prepared from the previously used supposed pure cultures which had been preserved in sealed tubes4 ,these were found to be dead4 ,a modification of the method previously described by one of us#age was adopted4 #age ,j4,s4,c4,i4 #ahij1 #bh4 ,a solution of nutrient glucose was inoculated from a working drench1 and as soon as the liquid was observed to become cloudy1 a tube of the solid glucose gelatin was inoculated from it by plunging in a platinum needle4 ,in two days the bacteria developed along the needle track4 ,fig4 #cb shows the appearance of the tube four days after inoculation1 a bubble of gas being formed in the solid gelatin4 ,on the following day1 the tube was broken1 and from the portion where gas was given off most vigorously other tubes of solid and liquid media were inoculated4 ,acid was quickly formed in the nutrient glucose solutions4 ,in the gelatin tubes1 the bacteria developed well in the depth4 ,the now purified culture was passed through three more glucose gelatin tubes1 each time also a glucose tube being inoculated4 ,from the last of these tubes a very minute quantity was taken #ab hours after inoculation on the point of a platinum needle1 and a streak culture made on glucose gelatin4 ,in #bd hours a growth could be seen on the surface of the gelatin in the form of minute dots perfectly separated one from another4 ,illustration3 ,fig4 #cb4--;,cultures of in ,glucose ,gelatin1 showing ,bubbles of ,gas4 ,illustration3 ,fig4 #cj4--;,b4 ,furfuris 4 ,illustration3 ,fig4 #ca4--;,b4 ,furfuris 4 ,,organisms ,,causing ,,bran ,,fermentation4 ,,pure ,,cultures4 ,from one of these dots a tube was inoculated and from this several plate cultivations were made4 ,the colonies which developed on these plates were of two kinds1 the majority being round1 yellowish and of small size1 a smaller number spreading out on the surface of the gelatin and slightly iridescent4 ,these surface expansion colonies when examined with a low power appear like a milky drop1 with very fine granular contents1 the whole surrounded by wavy lines which follow exactly the irregular contour of the expansion4 ,the small round colonies growing in the depth occur in the proportion of about #c to #a of the surface expansion colonies4 ,the microscopic appearance of the bacteria composing the two kinds of colonies1 is almost exactly similar1 they are extremely small and regular in size1 #jge #je to #jg #a 4 ,when spread upon a slide1 they are not readily miscible with water1 and appear greasy4 ,both colonies inoculated into glucose tubes produced acid4 ,the existence of these two organisms was confirmed in the following way3--,a glucose tube was inoculated from a drench in active fermentation2 as soon as the liquid became cloudy1 a second tube was inoculated from it by means of a platinum needle2 from this tube the fermentation was carried through two more tubes2 a plate cultivation was made from the last tube #aj hours after inoculation4 ,again1 the two kinds of colonies developed exactly similar in every respect to those obtained from the streak cultures4 ,it seems probable from these results1 and also from a comparison of the fermentations made with the organisms from an actual drench1#agf and from purified cultures with those from a single organism1 which are described in the present paper1 that the action in the drenches is a symbiotic one in which two or more organisms take part4 #agf ,j4,s4,c4,i4 #ahib1 #dbb4 99,the ,fermentations499--,during the time occupied by the isolation of pure cultures of the bacteria1 two fermentations were conducted with the supposed pure cultures4 ,these fermentations 7or rather the second of them1 for the first was unfortunately lost through the breakage of a bottle7 may prove of considerable interest as throwing some light on the symbiotic action of the two organisms4 ,the first fermentation with pure cultures of the bacillus 7,b4 furfuris7 obtained from a single colony in glucose gelatin1 was inoculated on ,september #af1 #ahid1 the composition of the fermenting liquid being-- ,glucose #bg grm4 ,peptone #ad ,salt solution #adj c4c4 ,water #hfj ,pure calcium carbonate #aj grm4 ,this was contained in a narrow-necked litre flask fitted with a rubber stopper1 and narrow delivery tube dipping under mercury1 and sterilised with all the usual precautions4 ,the fermentation began on the second day1 reached its height from the #fth-#hth day1 and continued for #ci days1 when gas ceased to come off4 ,the examination of the gases will be described later on4 ,when the fermentation was over1 the liquid was brought to boiling temperature4 ,it was then examined for the volatile acids in exactly the same manner as we described in our previous paper4 #adj c4c4 normal ,h,cl was added and distillation commenced2 the distillate was acid4 ,the distillation was continued until the distillate ceased to be acid1 forming fraction ,i4 ,three more fractions were now distilled off using respectively #aj1 #bj1 and #ag c4c4 ,n#a;,h,cl4 ,the fractions were boiled with excess of ,ba,c,o#c filtered1 the ,ba,c,o#c washed with hot water1 the filtrate evaporated to dryness1 and the barium salts dried at #acj ,c4 till the weight was constant4#agg ,the salts were then decomposed with strong ,h#b,,so#d1 ignited1 and the barium sulphate weighed4 ,the following is a tabulated statement of the results3-- #agg ,vide ,note on the ,estimation of ,butyric ,acid1 ,w4 ,h4 ,willcox1 ,j4 ,chem4 ,soc41 ,nov4 #ba1 #ahie4 ---------------------------------------- - ,fraction ,weight of,weight of,per ,cent4 of ,salts ,ba,s,o#d ,ba,s,o#d ---------------------------------------- - ,i4 #abdbj #ajiae #hghh ,,ii4 #jiiae #jiagj #ibdi ,,iii4 #abaee #aaihj #ihef ,,iv4 #jfcej #jfbcj #ihaa ---------------------------------------- - ,calculating fraction ,i4 as a mixture of barium acetate and butyrate1 and fractions ,,ii41 ,,iii41 and ,,iv4 as mixtures of barium acetate and formate1#agh we get3-- #agh ,vide ,j4 ,chem4 ,soc4 7,trans471 lix41 #id1 ,app4 ,,ii4 ---------------------------------------- -- ,fraction ,weight of ,ba ,ba ,ba ,salts ,butyrate,acetate,formate ---------------------------------------- -- ,i4 #abdbj #jbfcj #jigij 44 ,,ii4 #jiiaea 44 #jhiccj #jjihb ,,iii4 #jbaee 44 #jddjjj #jggee ,,iv4 #jfcej 44 #jbeeb #jcgih ---------------------------------------- -- ,totals #djhdj #jbfcj #befge #abece ---------------------------------------- -- ,calculating the barium salts into their respective acids we get3-- ---------------------------------------- ----- ,fraction ,formic ,acid,acetic ,acid,butyric ,acid ---------------------------------------- ----- ,i4 44 #jdfjgj #jadhh ,,ii4 #jjcihj #jdbjdj 44 ,,iii4 #jcadc #jbjgaj 44 ,,iv4 #jaeci #jabja 44 ---------------------------------------- ----- ,totals #jejhj #abjhc #jadhh ---------------------------------------- ----- ,the total volatile acids produced amounting to #ahfea grm4 ,the residual liquid containing the non-volatile acids was submitted to the test for lactic acid previously used1#agi and it was found to be present4 #agi ,j4,s4,c4,i4 #ahic1 #dbd2 vide supra1 p4 #bed4 ,the method employed for estimating lactic acid in our previous communication proving somewhat difficult1 we endeavoured to improve it by extracting the concentrated solution of the non-volatile acids on prepared pumice stone with ether in a paper thimble contained in a ,soxhlet fat-extraction apparatus4 ,after repeated trials we found that this method did not give accurate results4 ,the solution was therefore titrated with #a_/aj ,n sodium hydrate1 using glazed litmus paper to determine the point of neutralisation4 ,the acidity found corresponded to #bdch grm4 of lactic acid per #ajjj c4c4 of the fermented liquid4 ,we have done several other fermentations with this organism and find the same acids produced and the same gases evolved1 the results just given being fully confirmed4 ,at the same time the amount of the acids produced and their proportions vary1 that is to say1 the quantity of acid from a given fermentation cannot be predicted with absolute accuracy1 although the conditions under which we carried out the experiments were made as like as possible4 ,we give the total acids from four fermentations to show the amount of variation4 ,i4 is a symbiotic fermentation caused by organisms and 2 the remainder are fermentations by alone4 ---------------------------------------- ----------------------- ,fermentation ,i ,,ii ,,iii#ahj ,,iv ---------------------------------------- ----------------------- ,total vol4 acids1 grm4 per #bdifh #ahfea #jigch #aefcf #ajjj c4c4 ,mean percentage ,ba,s,o#d #hiag #iagf #ied #icf from ,ba salts of vol4 acids ,lactic acid #hiejj #bdchj #adgcg #bigjj ---------------------------------------- ----------------------- ,,comparison ,,of ,,acids ,,from ,,fermentation ,,ii4 ,,and ,,iii4#ahj --------------------------------------- -- ,lactic ,formic ,acetic ,butyric --------------------------------------- ,,ii4 #bdchj #jejhj #abjhc #jadhh ,,iii4 #adgcg #jciad #jeeic #jjbca --------------------------------------- #ahj #bjjj c4c4 gave only about the same amount of acids as #ajjj c4c4 fermentations4 ,for percentages of acids1 see table1 p4 #bha4 ,,fermentation ,,iii41 #bjjj ,c4,c4 --------------------------------------- ,weight of,weight of,per ,cent4 of ,fraction ,salts ,ba,s,o#d ,ba,s,o#d --------------------------------------- ,i4 #jgbfj #jfece #ijja ,,ii4 #jhaej #jgdaj #ijib ,,iii4 #baebe #bacdb #iiae ,,iv4 #jcfie #jcfbg #ihaf ,v4 #jcecj #jcejj #iiae --------------------------------------- ,,calculation ,,of ,,barium ,,salts ,,as ,,barium ,,butyrate1 ,,acetate1 ,,and ,,formate4 ---------------------------------------- - -- ,ba ,butyrate,ba ,acetate,ba ,formate ---------------------------------------- - ,i4 #jjeig #jfffc 44 ,,ii4 #jjbbc #jgibg 44 ,,iii4 44 #jfffb #adhfc ,,iv4 44 #jadfi #jbbbf ,v4 44 #jajgj #jbddj -------------------------------- ,totals #jjhbj #bcgia #aiebi ---------------------------------------- - ,equivalent to #jjdfc grm4 butyric acid4 #aaahf acetic #jghbh formic or one-half of these quantities per litre of the fermented liquid4 ,,note4--,mr4 ,adrian ,j4 ,brown1 of ,burton-on-,trent1 has been kind enough to examine a sample of the glucose used in the above fermentations1 and found the rotary power to be equivalent to #ief per cent4 pure dextrose4 ,the zinc salt of the lactic acid produced had no rotary power4 99,the ,gases499--,in dealing with the gases evolved1 we first compare those given off in the fermentation of glucose with that of bran under exactly similar conditions4 ,the fermentation was conducted in open vessels as before described1#aha and the gases were collected and examined in the same way4 #aha ,j4,s4,c4,i4 #ahic1 #dbc4 ,,mean ,,of ,,three ,,analyses4 ---------------------------------------- -- ,bran and ,skins ,glucose and ,skins ---------------------------------------- ,,co#b #beb #bde ,o#b #ba #ae ,h#b #dfg #dih ,n#b #bfj #bdb ---------------------------------------- ,the composition of the gases is thus almost exactly similar1 and1 we think1 fully proves our previous conclusions as to the change of the starch of the bran into glucoses by means of an unorganised ferment 7cerealin74 ,in the closed fermentations we had previously collected only small quantities of gas over mercury1 owing to the difficulty of continuously collecting large quantities which came off during the night4 ,in the fermentation of ,september #af1 #ahid1 we collected the whole of the gas given off1 taking samples every day over mercury1 the gas coming off at night being collected over warm water4 ,of course this method does not give the total amount of gas evolved with absolute accuracy1 but the exact composition of the gases was known from day to day1 and the amount of ,,co#b absorbed by the water could be calculated with moderate accuracy4 ,the fermentation was conducted in a narrow-necked litre flask fitted with a narrow delivery tube dipping under mercury1 and sterilised with all the usual precautions4 ,the temperature was maintained at #be-cj1 gas was evolved for #ci days1 when it ceased to come off1 the total amount collected being #cdce c4c4 ,one-half of this quantity1 however1 came off in seven days4 ,about #cjj c4c4 of ,,co#b was absorbed by the water during the whole period4 ,the diagram 7,fig4 #cc7 shows the manner of evolution of the gases1 the ordinates representing volume of gas and the absciss lapse of time after inoculation4 ,the following table shows the composition of the gas at different stages of the fermentation4 7,the fermentation 7,,ii47 is the one of which the chemical analysis has been previously given1 page #bgc73-- ,,composition ,,of ,,gases ,,evolved ,,in ,,fermentation ,,of #ajjj ,c4,c4 ,,glucose ,,with ,,pure ,,ferment4 ,,september #af1 #ahid4 ---------------------------------------- ------------- ,day -- ------------------------------------ ,mean #e #i #ab #ai #bf-ca #ce-ci ---------------------------------------- -------- ,,co#b #ecg #efd #ddc #ebf #eef #dcb #dii ,o#b #ah #je #ag #ai #jh #bh #ah ,h#b #ceh #cdf #dab #cjc #cdg #cah #cdh ,n#b #hg #he #abh #aeb #hi #bbb #ace ---------------------------------------- -------- ,the total quantity of ,,co#b actually collected #aefc c4c4 #cjij grm42 the amount of ,,co#b due to decomposition of the ,ca,c,o#c by the acids produced was found to be #ffg c4c4 7#acahi grm74 ,the vol4 of hydrogen collected was #ajhf c4c4 #jigc grm4 ,illustration3 ,fig4 #cc4--;,evolution of ,gases from ,pure ,cultivation of ,b4 ,furfuris4 ,in a second fermentation 7,,iii47 we endeavoured to ascertain the exact amount of ,,co#b evolved1 as in the previous fermentation this had not been done4 ,it was therefore decided to absorb the ,,co#b by means of potash4 ,the fermentation in this case was conducted in a narrow-necked flask of #bjjj c4c4 capacity1 connected by means of a narrow glass tube with two potash bulbs containing strong caustic potash1 and furnished with a delivery tube dipping under water2 the whole apparatus stood upon an iron plate1 and was maintained at a temperature of #be-cj in the same manner as the previous fermentation4 ,the gases were evolved for #ba days--a considerably shorter period than the #ajjj c4c4 fermentation2 but resembling it in that one-half the gas was evolved in eight days4 ,the diagram shows the curve as in the previous fermentation1 which it resembles for the first #ad days1 afterwards however stopping suddenly4 ,when the fermentation was at an end the flask and contents were heated to boiling point1 at the same time a current of air free from ,,co#b was drawn through it1 and the ,,co#b given off being collected in potash bulbs as in the fermentation4 ,unfortunately the estimation of the ,,co#b was rendered valueless owing to an accident4 ,the table shows the composition of the gases other than ,,co#b evolved in this second fermentation4 ,,gases ,,from ,,fermentation ,,of #bjjj ,c4,c4 7,,excluding ,,co#b7 ,,fermentation ,,iii4 ---------------------------------------- ---------------- ,days -- -------------------------------------- ,mean #b-d #d-e #e-f #aa #ad-ae #af-ag ---------------------------------------- ----------- ,o#b #cd #bb #ae #jdb #ji #bd #adh ,h#b #hac #hcc #hbd #gij #gag #gbb #gggb ,n#b #aec #ade #afa #bje #bgd #bed #bjgh ---------------------------------------- ----------- ,the gas from days #ah-ba was unfortunately mixed with air4 ,on comparing the mean composition of gases other than ,,co#b collected from both fermentations1 we get the following result3-- -------------------------------- -- ,fermentation1,fermentation1 #ajjj c4c4 #bjjj c4c4 -------------------------------- ,o#b #ceg #adh ,h#b #fid #gggb ,n#b #bgj #bjgh -------------------------------- ,if now the ,o and part of the ,n in the proportion to form air be taken away1 the composition of the gases from the two fermentations is found to be almost exactly similar3-- -------------------------------- -- ,fermentation1,fermentation1 #ajjj c4c4 #bjjj c4c4 -------------------------------- ,h#b #hdd #hci ,n#b #aef #afa -------------------------- #ajj4j #ajj4j -------------------------------- ,the gases from a third fermentation were almost exactly similar in composition1 but the total volume was not measured4 ,a remarkable fact in this fermentation is the evolution of free ,n1 which seems to be rare1 except in the case of putrefactive organisms1 as in the vast number of fermentative decompositions due to bacteria1 almost the only gases found are carbonic anhydride1 hydrogen1 ,h#b,s1 and marsh gas4 ,gayon#ahb in #ahge1 in an investigation on the putrefaction of eggs1 collected the gas given off from large ostrich eggs1 and found in it #bi per cent4 of nitrogen2 he adds1 however1 that its presence may be due to the accumulation of a certain quantity of air in the air-bubble before putrefaction4 #ahb ,schutzenberger1 8,fermentation10 #ahgf1 p4 #bbg4 ,bchamp#ahc found that yeast cells under suitable conditions1 but sugar being withheld1 produced pure nitrogen along with leucin1 tyrosin1 a soluble albuminous substance coagulable by heat1 an enzyme1 a peculiar gummy substance1 phosphates and acetic acid1 alcohol and ,,co#b4 ,these are almost the only instances where observers of repute have been convinced of the evolution of free ,n by bacteria4 ,we find since the above work was carried out that ,immendorf#ahd has found certain bacteria in dung which form ammonium nitrate1 and this body1 as is known1 splits up at a comparatively low temperature into nitrogen and water4 #ahc ,woodhead1 8,bacteria and their ,products10 p4 #abe4 #ahd ,die ,stickstoffkonservirung im ,stalldnger1 ,jour4 f4 ,landwirthsh41 xlii4 p4 #fi4 ,from the bacteriological as well as the chemical results1 it is now evident that the fermentation as it takes place in practice is a symbiotic one in which two organisms play the most important part1 and very probably cause the entire fermentation4 ,this is shown by comparing the acids produced by the fermentation in the works with those produced by a mixture of the organisms and 1 the relative amounts being very close1 while in all the fermentations with alone a much less proportion of lactic acid is produced1 as the following table shows3-- ---------------------------------------- ------------------- -- ,fermentation,fermentation,fermentation, fermentation in ,works and 7,,ii47 7,,iii47 ---------------------------------------- ------------------- ,formic acid #bh #jh #aah #afj ,acetic #bbe #afd #bgi #bbg ,butyric #ab #de #ce #ji ,lactic #gce #ghc #efg #fjb ---------------------------------------- ------------------- ,,note4--,ruge 7,sitzungsber4 d4 ,wien4 ,akad4 d4 ,wiss1 ,vol4 xliv41 #ahfb1 #gcd7 found that the gases of the large intestine contained #egh per cent4 of ,n1 and ,gamgee remarks 8in part a diffusate from the blood1 but is certainly in part derived from the bacterial decomposition of proteids40 7,gamgee1 ,phys4 ,chem4 ,vol4 ii41 p4 #dfg47 ,the acetic acid1 as far as we can ascertain1 is produced directly from dextrose without the previous production of alcohol1 since the presence of the latter is not shown by its tests at any stage of the fermentation4 ,we have also ascertained that the organism is without action on dilute solutions of alcohol1 in yeast water1 no acid being produced4 ,we are indebted to ,mr4 ,h4 ,s4 ,shrewsbury for the analysis of some of the gases and volatile acids1 and also for the preparation of the diagrams4 ,in conclusion we may state that the investigation of this fermentation in the tannery has been the means of pointing the way to a still more complicated process1 viz41 8bating40 ,it may even be possible in the future to place these processes on somewhat the same footing as the accurately understood fermentations in the brewing industry although the difficulties in the way are much greater4 ,,chapter ,,xi4 ,,bibliography4 ,the following short bibliography of works on tanning and the bacteriology of leather manufacture1 does not profess to be complete1 but is given in the hope that it may prove useful4 ,it includes most of the works consulted or referred to in this book4 ,for particulars of some of the earlier works 7,nos4 #a1 #b1 #d1 #e1 #f1 #g1 and #h71 ,i am indebted to ,dr4 ,e4 ,stiasny1 of ,leeds ,university4 ,nos4 #a-aj are old works on ,tanning generally4 ,nos4 #aa-eg books and papers referring chiefly to bating and the bacteriology of ,leather ,manufacture4 ,nos4 #eh-gh deal with putrefaction4 ,nos4 #gi-acc are general works consulted1 in order of date4 #a4 ,la ,tannerie et la preparation des ,cuirs4 7,,ms47 ,desbillettes4 #agjh4 #b4 ,l'art du tanneur4 ,de la ,lande4 #agfd4 #c4 ,the art of tanning and currying leather1 with an account of all the different processes made use of in ,europe and ,asia for dyeing leather red and yellow1 collected and published at the expense of the ,dublin ,society4 ,to which are added ,mr4 ,philipo's method of dyeing the ,turkey leather as approved of by the ,society for the ,encouragement of ,arts1 etc41 and for which he had a reward of #ajj and their gold medal for the secret4 ,also the new method of tanning invented by the late ,david ,macbride1 ,m4,d41 ,london1 reprinted for ,j4 ,nourse in the ,strand1 ,bookseller to ,his ,majesty4 #aghj4 #d4 ,lohgerberei1 ,ignatz ,bautsch4 ,dresden1 #agic4 #e4 ,ueber die ,bearbeitung der ,tierhute zu allen ,gattungen von ,leder4 ,p4 ,j4 ,kasteleyn4 ,german translation from the ,dutch4 ,leipzig1 #agig4 #f4 ,chemisch-technologische ,grundstze der gesammten ,ledergerberei4 #b vols4 ,s4 ,f4 ,hermbstdt4 ,berlin1 #ahje and #ahjg4 #g4 ,dictionary of ,chemistry and ,mineralogy4 #b vols4 ,a4 and ,c4 ,r4 ,aikin1 #ahjg4 #h4 ,hand-,encyclopdie fr das ,gerben1 ,zurichten1 etc41 des ,leders1 ,l4 ,f4 ,kummer1 ,berlin1 #ahcj4 #i4 ,handbuch der ,gesammten ,lohgerberei4 ,vom ,dr4 ,ch4 ,h4 ,schmidt4 ,weimar1 #ahdg4 #aj4 ,lehrbuch der ,sohlledergerberei4 ,dr4 ,g4 ,w4 ,bichon1 ,berlin4 #aa4 8,das ,beizen der ,glac-,felle0 in ,handbuch der ,weissgerberei4 ,anton ,brggemann4 ,quedlinburg and ,leipzig1 #aheg4 p4 #ba4 #ab4 ,erfahrungen auf dem ,gebiete der ,gerberei4 ,j4 ,c4 ,h4 ,lietzmann1 ,berlin1 #ahfb4 #ac4 8,das ,behandeln in der ,kleienbeize0 in ,handbuch der ,weissgerberei4 ,dr4 ,w4 ,f4 ,gintl4 ,weimar1 #ahgc4 p4 #ea4 #ad4 ,mistbeizen4 ,der ,gerber1 #ahhd4 p4 #aig4 #ae4 ,the ,manufacture of ,leather4 ,davis1 ,philadelphia1 #ahhe4 p4 #cce1 etc4 #af4 ,trait pratique de la ,fabrication des cuirs et du ,travail des peaux4 ,villon1 #ahhi4 p4 #djg4 #ag4 ,die ,englische ,methode fr die ,chevrettengerbung4 ,beizverfahren1 ,der ,gerber1 ,bd4 ,,xv4 #ahhi4 p4 #bfg4 #ah4 ,methods of ,bacteriological ,research1 with some account of ,bran ,fermentation1 by ,j4 ,t4 ,wood4 ,jour4 ,soc4 ,chem4 ,ind4 ,,ix4 #ahij4 p4 #bg4 #ai4 ,the ,theory and ,practice of ,tanning4 ,w4 ,j4 ,salomon4 ,tech4 ,quarterly1 #ahib4 #e 7#a and #b71 #ha-hh4 #bj4 ,further contribution on the ,nature of ,bran ,fermentation1 by ,j4 ,t4 ,wood1 and ,w4 ,h4 ,willcox1 ,b4,sc41 ,london4 ,jour4 ,soc4 ,chem4 ,ind4 ,,xii4 #ahic4 p4 #dbb4 #ba4 ,the ,chemistry of the ,grainer ,pit1 by ,t4 ,palmer and ,p4 ,g4 ,sandford4 ,j4 ,anal4 and ,appl4 ,chem41 #ahic1 #g1 #hg-ie4 #bb4 ,fermentation in the ,leather ,industry1 by ,j4 ,t4 ,wood4 ,jour4 ,soc4 ,chem4 ,ind4 ,,xiii4 #ahid4 p4 #bah4 #bc4 ,the ,bacteria of ,stable ,manure and their ,action4 ,dr4 ,e4 ,herfeldt1 ,bonn4 ,jour4 ,soc4 ,chem4 ,ind4 ,,xiv4 #ahie1 pp4 #ddi-deb4 ,translated with foreword by ,j4 ,t4 ,wood4 7,this paper contains a ,bibliography of #ba items47 #bd4 ,uber die ,beziehung der ,bakteriologie zur ,gerberei4 ,dr4 ,f4 ,h4 ,haenlein4 ,cent4 ,bl4 f4 ,bakt4 ,,ii4 #ahie4 p4 #bf4 #be4 ,die im ,miste vorkommenden ,bacterien und deren physiologische ,rolle bei der ,zerzetzung desselben4 ,s4 ,a4 ,severin4 ,central ,bl4 f4 ,bakt4 7,,ii71 ,vol4 ,i41 #ahie1 pp4 #ig1 #afj1 #gii4 ,vol4 ,,iii4 pp4 #fbh1 #gjf4 #bf4 ,ghrungserscheinungen in ,gerbbrhen4 ,fr4 ,andreasch4 ,der ,gerber1 #ahie-g4 #bg4 ,w4 ,schmitz ,dumont4 ,the ,sweating ,process in the ,tannery4 ,ding4 ,polyt4 ,jour4 #ahif1 #cjj1 #aci-add4 ,j4,s4,c4,i4 #ahif1 p4 #dfa4 #bh4 ,on a pure cultivation of a ,bacillus fermenting ,bran ,infusions1 by ,j4 ,t4 ,wood and ,w4 ,h4 ,willcox1 ,b4,sc41 ,london4 ,jour4 ,soc4 ,chem4 ,ind4 ,,xvi4 #ahig4 p4 #eaj4 #bi4 ,the ,rationale of ,bating1 by ,j4 ,t4 ,wood4 ,leather ,industries4 ,september1 #ahih4 #cj4 ,notes on the constitution and mode of action of the ,dung ,bate in leather manufacture4 ,j4 ,t4 ,wood1 ,jour4 ,soc4 ,chem4 ,ind4 ,,xvii4 #ahih4 p4 #ajaj4 #ca4 8,schwitzen0 in ,gerberei ,chemie1 ,sammlung von ,aufstzen ,professors ,dr4 ,julius von ,schroder1 #ahhf-ahie1 published #ahih4 #cb4 ,beizen und neue ,beizmittel1 ,w4 ,eitner1 ,der ,gerber4 ,bd4 ,,xxiv4 ,no4 #efc-efg1 #ahih4 #cc4 ,the ,rationale of ,drenching1 by ,j4 ,t4 ,wood4 ,leather ,trades ,review1 ,nov4 #ae1 #ahih4 #cd4 ,cantor ,lectures on ,leather ,manufacture1 by ,prof4 ,h4 ,r4 ,procter1 ,f4,i4,c41 ,society of ,arts4 ,lecture ,,ii41 ,april #bd1 #ahii4 #ce4 ,further notes on the ,action of the ,dung ,bate1 by ,joseph ,t4 ,wood4 ,jour4 ,soc4 ,chem4 ,ind4 ,,xviii4 #ahii4 p4 #iij4 #cf4 ,das ,beizen der ,blssen in ,handbuch der ,chromgerbung4 ,jos4 ,jettmar4 ,schulze and ,co41 ,leipzig1 #aijj4 #cg4 ,j4 ,borgmann4 ,die ,feinleder ,fabrikation1 ,berlin1 #aija4 ,das ,beizverfahren1 p4 #fe4 #ch4 ,das ,beizen der ,blssen in ,praxis und ,theorie der ,leder ,erzeugung1 von ,josef ,jettmar1 ,julius ,springer1 #aija4 #ci4 ,micro-organisms and ,antiseptics in ,tanning4 ,f4 ,jean1 ,rev4 ,chim4 ,ind41 #aija4 #dj4 ,the ,principles of ,leather ,manufacture1 by ,professor ,h4 ,r4 ,procter4 ,e4 and ,f4 ,n4 ,spon1 ,london1 #aijc4 ,chap4 ,,xiii4 #da4 ,la ,tannerie1 par ,louis ,meunier and ,clment ,vaney1 ,gauthier-,villars4 ,paris1 #aijc4 p4 #abe1 etc4 #db4 ,bakteriologische ,vorgnge in der ,lederindustrie4 #aijd1 ,h4 ,becker4 ,zeitschrift f4 ,offentliche ,chemie1 ,heft4 ,,xxiii4 ,jahrgang4 ,x4 #dc4 ,untersuchungen ber die ,bakterien im ,verdauungskanal des ,rindes4 ,p4 ,ankersmit4 ,centralbl4 f4 ,bacter4 ,i1 ,o1 ,bd4 #ci1 #aije4 p4 #cei4 #dd4 ber anaerobe ,bakterien im ,rinderdarm1 ,neubauer4 ,archiv f4 wissensch4 u4 prakt4 ,tierheilk4 ,bd4 #ca1 p4 #aec1 #aije4 #de4 ,studien ber fulnisserregende anaerobe ,bakterien des normalen menschlichen ,darmes1 und ihre ,bedeutung4 ,f4 ,passini4 ,zeitsch4 f4 ,hygiene4 ,bd4 #di1 p4 #ace4 #aije4 #df4 ,a new process of puering or bating hides and skins4 ,allen ,roger4 ,j4,s4,c4,i41 p4 #ajc1 #aijf4 #dg4 ,recent advances in the ,bacteriology of ,putrefaction1 by ,j4 ,t4 ,wood4 ,j4,s4,c4,i4 ,,xxv4 #aijf1 p4 #aai4 7,contains a bibliography of #ba items47 #dh4 ber den ,bakteriengehalt menschlicher und thierischer ,fces4 ,m4 ,lissauer4 7,archiv f4 ,hyg4 ,bd4 #eh1 p4 #acf47 ,see also ,koch's ,jahresbericht1 #aijf1 p4 #aie4 #di4 ,character of the ,bacterial ,flora of ,carnivorous and ,herbivorous animals4 ,a4 ,herter4 7,science ,n4,s4 ,vol4 #bd1 p4 #hei4 #aijf47 #ej4 ,leather ,trades ,chemistry4 ,s4 ,r4 ,trotman1 ,griffin1 #aijh4 p4 #gi4 #ea4 ,le ,rle des ,microbes dans la putrefaction des peaux en poils et en tripe et dans les confits1 par ,dr4 ,gr4 ,abt4 ,bull4 ,mens4 du ,synd4 ,gen4 de cuirs et peaux de ,france4 ,nov4-,dec41 #aijh4 p4 #daf4 #eb4 ,bakterien in der ,lederindustrie4 ,h4 ,becker1 ,collegium1 #aiji4 p4 #afi4 #ec4 ,a new ,chromogenic ,organism4 ,s4 ,r4 ,trotman1 ,j4,s4,c4,i41 #aiji4 p4 #abch4 #ed4 ,problems of the ,leather ,industry4 ,prof4 ,h4 ,r4 ,procter1 ,j4,s4,c4,i41 #aiaj4 p4 #cbi4 #ee4 ,les ,anaerobies1 par ,m4 ,jungano et ,a4 ,distaso4 ,paris1 ,masson and ,cie41 #aiaj4 #ef4 ,the ,bacteriology of the ,leather ,industry4 ,j4 ,t4 ,wood1 ,j4,s4,c4,i41 ,june #aeth1 #aiaj4 p4 #fff4 #eg4 ,the ,seymour-,jones ,anthrax ,sterilization ,method1 by ,alfred ,seymour-,jones4 ,bradbury1 ,agnew and ,co41 ,ltd41 ,december1 #aiaj4 #eh4 ,hauser1 ,g4 ,ueber ,fulnissbacterien und deren ,beziehungen zur ,septicmie4 ,ein ,beitrag zur ,morphologie der ,spaltpilze1 #ahhe4 #ei4 ,woodhead1 ,g4 ,s4 ,bacteria and their products4 7,w4 ,scott1 #ahia47 #fj4 ,carbone1 ,tito4 ,ueber die von ,proteus ,vulgaris erzeugten ,gifte 7,cent4 ,blat4 f4 ,bakt41 ,dec4 #d1 #ahij74 #fa4 ,mac1 ,trait pratique de ,bacteriologie4 ,paris4 ,baillire4 #fb4 ,bienstock1 ,recherches sur la putrfaction4 7,ann4 de l',inst4 ,pasteur1 #ac1 #hed47 #fc4 ,klein4 ,ein ,beitrag zur ,kentniss der ,leichenverwesung4 7,cent4 ,blatt4 l4 #be1 #bgh47 #fd4 ,beijerinck1 ,w4 ,schwefelwasserstoffbildung in den ,stadt4 grben und ,aufstellung der ,gattung ,aerobacter4 7,central ,bl4 f4 ,bakt4 ,,ii41 ,bd4 #f1 p4 #aic47 #fe4 ,stich1 ,c4 ,ueber die ,bildung gasfrmiger ,phosphorverbindungen bei der ,fulniss4 7,mitth4 a4 d4 analyt4 ,laborat1 der ,krankenhausapotheke ,leipzig1 p4 #bb47 #ff4 ,vitali1 ,d4 ,bildung von ,alcohol bei der ,fulniss von ,proteinsubstanzen1 die von ,kohlehydraten befreit sind4 7,bul4 chimico farmaceutico1 vol4 #ch1 #ahhi1 p4 #gbi47 #fg4 ,behrens1 ,j4 ,fadenziehendes ,brot4 7,wochenbl4 d4 landw4 ,vereins im ,grossherzogthum ,baden1 p4 #efi47 #fh4 ,bienstock4 ,untersuchungen ber die ,aetiologie der ,eiweissfulniss1 ,milchfulniss1 ,verhinderung der ,fulniss durch ,milch1 ,darmfulniss4 7,archiv f4 ,hygiene1 ,bd4 #ci1 #cij47 #fi4 ,taylor1 ,a4 ,e4 ,ueber ,eiweissspaltung durch ,bacterien1 ,zeitschr4 f4 ,phys4 ,chemie1 ,bd4 #cf1 p4 #dhg4 #gj4 ,tissier1 ,h41 et ,martelly4 ,recherches sur la putrefaction de la viande de boucherie4 ,ann4 de l',inst4 ,pasteur1 t4 #ah1 p4 #hfe4 #ga4 ,wohltmann1 ,f41 ,fischer1 ,h41 and ,schneider1 ,ph4 ,bodenbakteriologische und ,bodenchemische ,studien aus dem ,popplesdorfer ,versuchsfelde4 7,jour4 f4 ,landwirthschaft1 #aijd1 #ig47 #gb4 ,osterwalder1 ,a4 ,ueber eine bisher unbekannte ,art der ,kernobstfule1 verursacht durch ,fusarium putrefaciens nov4 spec4 7,centralbl4 f4 ,bakt4 #b ,ab4 ,bd4 #ac1 p4 #bjg47 #gc4 ,schreiber1 ,karl4 ,fettzersetzung durch ,microorganismen4 7,archiv f4 ,hygiene1 ,bd4 ,,xli4 #cbh1 ,cent4 ,bl4 ,,ix4 #hdi47 #gd4 ,rahn1 ,otto4 ,die ,zersetzung der ,fette4 7,cent4 ,bl4 f4 ,bakt4 ,zweite ,abth4 ,,xv4 #ec47 #ge4 ,omelianski1 ,w4 ,sur la fermentation formnique de la cellulose4 7,arch4 de sciences biol4 ,st4 ,petersburg1 t4 #aa1 #bea4 ,centr4 ,bl4 f4 ,bakt4 ,,ii41 ,bd4 #h1 #aic47 #gf4 ,dallinger and ,drysdale4 ,monthly ,microscopical ,journal1 vol4 ,x41 #ec1 #bde2 ,,xi41 #g1 #fi2 ,,xii41 #bfa2 ,,xiii41 #ahe2 ,,xiv41 #ajf4 #gg4 ,lermer1 ,k4 ,ueber die ,produkte der ,fulniss der ,gerste1 ,zeitschr4 f4 d4 ges4 ,brauwesen1 p4 #afe4 #gh4 ,salkowski and ,neuberg4 ,die ,verwandlung von d4 ,glukuronsaure in #a-,xylose ,zeitschr4 f4 physiol4 ,chemie ,bd4 #cf1 p4 #bfa4 #gi4 tudes chimiques sur la ,vgtation4 ,j4 ,raulin1 ,paris1 #ahgj4 #hj4 ,die ,spaltpilze4 ,w4 ,zopf4 ,breslau1 #ahhe4 #ha4 ,a ,text ,book of ,tanning4 ,h4 ,r4 ,procter4 ,spon1 #ahhe4 #hb4 ,micro-organisms and ,disease4 ,e4 ,klein4 ,macmillan1 #ahhf4 #hc4 ,manual of ,bacteriology4 ,e4 ,m4 ,crookshank4 ,lewis1 #ahhg4 #hd4 ,manures1 ,natural and ,artificial4 ,w4 ,iveson ,macadam4 ,j4,s4,c4,i41 #ahhh1 p4 #gi4 #he4 ,methods and ,formul used in the ,preparation of ,animal and ,vegetable ,tissues4 ,p4 ,w4 ,squire4 ,churchill1 #ahib4 #hf4 ,micro-organisms and ,fermentation4 ,a4 ,jrgensen4 ,macmillan 7,london71 #aijj4 #hg4 ,micro-organisms in ,water4 ,percy ,frankland and ,mrs4 ,frankland4 ,longmans1 #ahid4 #hh4 ,disinfection and ,disinfectants4 ,s4 ,rideal4 ,griffin1 #ahie4 #hi4 ,guide to the ,british ,mycetozoa1 ,dept4 of ,botany1 ,british ,museum4 ,arthur ,lister1 ,f4,l4,s41 #ahie4 #ij4 ,elementary ,practical ,bacteriology4 ,kanthack and ,drysdale4 ,macmillan1 #ahie4 #ia4 ,les ,ferments ,solubles4 ,e4 ,bourquelot4 ,paris1 #ahif4 #ib4 ,the ,manufacture and ,applications of ,lactic ,acid4 ,a4 ,claflin4 ,j4,s4,c4,i41 #ahig1 p4 #eaf4 #ic4 ,bakteriologie4 ,c4 ,gnther4 ,leipzig1 #ahih4 #id4 ,bates and ,new ,bating ,materials4 ,der ,gerber #bd #efc1 #efd and #efe4 ,j4,s4,c4,i41 #ahih1 p4 #cfa4 #ie4 ,les ,enzymes4 ,j4 ,effront4 ,paris1 #ahii4 #if4 ,fixerung1 ,frbung und ,bau des ,protoplasmas4 ,a4 ,fischer4 ,jena1 #ahii4 #ig4 ,soluble ,ferments and ,fermentation4 ,j4 ,reynolds ,green4 ,cambridge ,university ,press1 #ahii4 #ih4 ,ueber die ,zusammensetzungund ,wirkungsweise der ,mistbeizen4 ,der ,gerber1 #ahii1 p4 #ca4 #ii4 ,the ,mycetozoa4 ,sir ,edward ,fry and ,agnes ,fry1 ,london1 8,knowledge0 ,office1 #ahii4 #ajj4 ,le ,proteus ,vulgaris4 ,l4 ,felz4 ,baillire1 ,paris1 #aijj4 #aja4 ,bating ,process1 ,improvements in4 ,leather ,trades ,review1 #cd #ggc1 #ba4 ,abstr4 in ,jour4 ,soc4 ,chem4 ,ind41 #aija1 p4 #bfc4 #ajb4 ,oppenheimer1 ,c4 ,ferments and their ,actions4 ,trs4 ,c4 ,a4 ,mitchell4 ,griffin and ,co41 #aija4 #ajc4 ,harden4 ,the ,chemical ,action of ,bacillus ,coli communis on ,carbohydrates and allied ,compounds4 ,j4 ,chem4 ,soc41 ,trans4 #gi1 #aija1 #faj4 #ajd4 ,trait de ,technique ,microbiologique4 ,nicolle et ,remlinger4 ,doin41 ,paris1 #aijb4 #aje4 ,carini4 ,sull' ,applicazione della ,bilancia idrostatica per il controllo della concia delle ,pelli4 ,milan1 #aijc4 #ajf4 ,trait d',electrochimie4 ,max ,le ,blanc4 ,paris1 #aijd4 #ajg4 ,the ,role of ,diffusion during ,catalysis by ,colloidal ,metals and similar ,substances4 ,henry ,j4 ,s4 ,sand1 ,ph4,d4 ,m4,sc4 ,proc4 ,chem4 ,soc4 #gd1 #cef4 #aijd4 #ajh4 ,chemistry of the ,proteids4 ,g4 ,mann4 ,macmillan1 #aijf4 #aji4 ,canning and ,preserving ,food ,products1 with ,bacteriological ,technique4 ,e4 ,w4 ,duckwall1 ,m4,s41 ,bacteriologist to the ,national ,canners ,laboratory1 etc4 ,new ,york1 #aije4 #aaj4 ,prcis de ,coprologie ,clinique4 ,r4 ,gaultier4 ,baillire1 ,paris1 #aijg4 #aaa4 ,allgemeine ,chemie der ,kolloide4 ,a4 ,mller4 ,leipzig1 #aijg4 #aab4 ,zur ,erkenntniss der ,kolloide4 ,r4 ,zsigmondy4 ,jena1 #aije4 #aac4 ,the ,nature of ,enzyme ,action4 ,w4 ,m4 ,bayliss4 ,longmans1 #aijh4 #aad4 ,ueber die ,interfibrillre ,substanz der ,lederhaut bei ,sugethieren4 ,g4 ,h4 ,b4 ,van ,lier4 ,coll41 #aiji1 #cba4 #aae4 ,practical ,causerie on ,deliming4 ,alex4 ,t4 ,hough4 ,tanner's ,year ,book1 #aiji1 p4 #hc4 #aaf4 ,grundriss der ,kolloid ,chemie4 ,m4 ,ostwald4 ,dresden1 #aiji4 #aag4 ,beizen4 ,w4 ,appelius4 ,technische ,briefe ,monatshefte von 8,hute und ,leder10 ,no4 #bc4 ,april #aiji4 #aah4 ,kolloid ,chemische ,beihefte4 ,ed4 ,wo4 ,ostwald4 ,dresden1 #aiji-aiaa4 #aai4 ,verfahren zum ,beizen von ,huten4 ,otto ,rhm4 ,coll41 #aiji1 p4 #eh4 #abj4 ,a ,brief ,review of ,bacteriological ,research in ,phytopathology1 with ,bibliography4 ,m4 ,c4 ,potter1 ,sc4,d41 ,m4,a4 ,science ,progress1 ,oct4 #aiaj1 p4 #aia4 #aba4 ,la ,chimie de la ,matire ,vivante4 ,j4 ,duclaux4 ,felix ,alcan1 ,paris1 #aiaj4 #abb4 ,sensibilit de la peau verte1 et de la peau aprs l'chauffe1 les pelains1 et les confits1 l'gard de la chaux1 du sel1 et de l'acide actique4 ,georges ,abt et ,edmund ,stiasny4 ,coll41 #aiaj1 p4 #ahi4 #abc4 ,bennett1 ,h4 ,g4 ,the ,analytical ,examination of ,bating4 ,leather ,trades ,review1 #aiaa1 pp4 #fig1 #igb4 #abd4 ,der ,bacillus bulgaricus des ,yoghurt in der ,gerberei4 ,leder-technische ,rundschau1 ,no4 #be1 #aiaa4 ,collegium1 #aiaa1 p4 #dei4 #abe4 ,physiological ,chemistry4 ,olaf4 ,hammarsten4 ,trans4 ,j4 ,a4 ,mandel1 ,wiley1 #aiaa4 #abf4 ,prcis de ,biochemie4 ,e4 ,lambling4 ,paris1 #aiaa4 #abg4 ,bacteriological and ,enzyme ,chemistry1 an ,introduction to4 ,gilbert ,j4 ,fowler4 ,edward ,arnold1 #aiaa4 #abh4 ,microbes et ,toxines4 ,e4 ,burnet4 ,bibliothque de ,philosophie ,scientifique4 ,flammarion4 ,paris1 #aiaa4 #abi4 ,the ,physical ,chemistry of the ,proteins4 ,t4 ,b4 ,robertson1 ,professor at the ,berkeley ,university1 ,california1 #aiaa4 #acj4 ,contributions to the ,history of the ,enzyme ,bate4 ,collegium1 #aiaa4 ,otto ,rhm1 ,h4 ,becker1 ,g4 ,eberle1 ,j4 ,t4 ,wood1 pp4 #bga1 #bgf1 #bgh1 #bha1 #cab1 #cbd4 #aca4 ,the ,fungi of ,excreta4 ,jas4 ,scott4 ,the ,leather ,world1 ,jan4 #aa1 #aiab1 p4 #ba4 #acb4 ,microbiology1 by various ,contributors4 ,edited by ,charles ,e4 ,marshall1 ,east ,lancing1 ,michigan1 ,professor of ,bacteriology and ,hygiene1 ,michigan ,agricultural ,college4 ,j4 and ,a4 ,churchill4 #acc4 ,technical ,mycology4 ,lafar4 ,c4 ,griffin and ,co41 #aiaa4 #acd4 ,manual of ,bacteriology4 ,r4 ,t4 ,hewlett 7,churchill71 #aiab4 #ace4 ,taschenbuch fr den bakteriologischen ,praktikanten4 ,dr4 ,rudolf ,abel4 ,wrzburg4 ,a4 ,stuber's ,verlag4 ,,list ,,of ,,authors4 ,the numbers refer to the ,bibliography4 ,abel1 ,r41 #ace ,abt1 ,g41 #ea1 #abb ,aikin1 ,a4 and ,c4 ,r41 #g ,andreasch1 ,f41 #bf ,ankersmit1 ,p41 #dc ,appelius1 ,w41 #aag ,bayliss1 ,w4 ,m41 #aac ,bautsch1 ,i41 #d ,becker1 ,h41 #db1 #eb1 #acj ,behrens1 ,j41 #fg ,bennett1 ,h4 ,g41 #abc ,beijerinck1 ,w41 #fd ,bichon1 ,g4 ,w41 #aj ,bienstock1 #fb1 #fh ,borgmann1 ,j41 #cg ,bourquelot1 ,e41 #ia ,brggemann1 ,a41 #aa ,burnet1 ,e41 #abh ,carbone ,tito1 #fj ,carini1 #aje ,claflin1 ,a41 #ib ,crookshank1 ,e4 ,m41 #hc ,davis1 #ae ,dallinger1 #gf ,de la ,lande1 #ba ,desbillettes1 #a ,distaso1 ,a41 #ee ,drysdale1 #gf1 #ij ,duckwall1 ,e4 ,w41 #aji ,duclaux1 ,j41 #aba ,eberle1 ,g41 #acj ,eitner1 ,w41 #ad1 #ag1 #cb1 #id1 #ih ,effront1 ,j41 #ie ,felz1 ,l41 #ajj ,fischer1 ,a41 #if ,fischer1 ,h41 #ga ,fowler1 ,gilbert ,j41 #abg ,frankland1 ,p4 and ,mrs41 #hg ,fry1 ,sir ,edward and ,agnes1 #ii ,gaultier1 ,r41 #aaj ,gintl1 ,w4 ,f41 #ac ,green1 ,j4 ,reynolds1 #ig ,gnther1 ,c41 #ic ,haenlein1 ,f4 ,h41 #bd ,hammarsten1 ,o41 #abe ,harden1 ,a41 #ajc ,hauser1 ,g41 #eh ,herter1 ,a41 #di ,herfeldt1 ,e41 #bc ,hermbstdt1 #f ,hewlett1 ,r4 ,t41 #acd ,hough1 ,a4 ,t41 #aae ,jean1 ,f41 #ci ,jettmar1 ,j41 #cf1 #ch ,jrgensen1 ,a41 #hf ,jungano1 ,m41 #ee ,kanthack1 #ij ,kasteleyn1 ,k4 ,t41 #e ,klein1 ,e41 #fc1 #hb ,kummer1 ,l4 ,f41 #h ,lafar1 #acc ,lambling1 ,e41 #abf ,le ,blanc1 ,max1 #ajf ,lermer1 ,k41 #gg ,lietzmann1 ,j4 ,c4 ,h41 #ab ,lissauer1 ,m41 #dh ,lister1 ,arthur1 #hi ,mac,bride1 #c ,mac1 ,e41 #fa ,macadam1 ,w4 ,iveson1 #hd ,mann1 ,g41 #ajh ,marshall1 ,c4 ,e41 #acb ,martelly1 #gj ,meunier1 ,l41 #da ,mller1 ,a41 #aaa ,neubauer1 #dd ,neuberg1 #gh ,nicolle1 ,m41 #ajd ,omelianski1 ,w41 #ge ,oppenheimer1 ,c41 #ajb ,osterwalder1 ,a41 #gb ,ostwald1 ,wo41 #aaf1 #aah ,palmer1 ,t41 #ba ,passini1 ,f41 #de ,potter1 ,m4 ,c41 #abj ,procter1 ,h4 ,r41 #cd1 #dj1 #ed1 #ha ,rahn1 ,o41 #gd ,raulin1 ,j41 #gi ,remlinger1 ,p41 #ajd ,rideal1 ,s41 #hh ,rhm1 ,o41 #aai1 #acj ,robertson1 ,t4 ,b41 #abi ,roger1 ,a41 #df ,salomon1 ,w4 ,j41 #ai ,salkowski1 #gh ,sandford1 ,p4 ,g41 #ba ,sand1 ,h4 ,j4 ,s41 #ajg ,schneider1 ,ph41 #ga ,schreiber1 ,k41 #gc ,schmidt1 ,dr4 ,ch4 ,h41 #i ,schmitz-,dumont1 #bg ,schrder1 ,j4 von1 #ca ,scott1 ,j41 #aca ,severin1 ,s4 ,a41 #be ,seymour-,jones1 #eg ,squire1 ,p4 ,w41 #he ,stich1 ,c41 #fe ,stiasny1 #abb ,taylor1 ,a4 ,e41 #fi ,tissier1 ,h41 #gj ,trotman1 ,s4 ,r41 #ej1 #ec ,vaney1 ,c41 #da ,van ,lier1 ,g4 ,h4 ,b41 #aad ,villon1 #af ,vitali1 ,d41 #ff ,willcox1 ,w4 ,h41 #bj1 #bh ,wood1 ,j4 ,t41 #ah1 #bj1 #bb1 #bh1 #bi1 #cj1 #cc1 #ce1 #dg1 #ef1 #acj ,woodhead1 ,g4 ,sims1 #ei ,wohltmann1 ,f41 #ga ,zopf1 ,w41 #hj ,zsigmondy1 ,r41 #aab ,,conclusion4 8,what is a man1 ,if his chief good and market of his time1 ,be but to sleep and feed8 ,a beast--no more4 ,sure1 ,he that made us with such large discourse1 ,looking before1 and after1 gave us not ,that capability and godlike reason ,to fust in us unused40 ,professor ,procter1 in his paper1 entitled 8,problems of the ,leather ,industry10#ahe says3 8,there is1 however1 no reason that all the necessary effects both of puering and bating should not ultimately be attained by purely chemical treatment without the risk and uncertainty which must always attach to bacterial and ferment action40 #ahe ,j4,s4,c4,i4 #aiaj1 p4 #cca4 ,while ,i agree with him in this1 still it is well to remember that in the case of one of the very oldest of the fermentation industries1 that of the production of alcohol1 a comparatively simple body1 the natural process has not yet been replaced by a chemical one1 and ,i believe this applies also to the manufacture of vinegar4 ,chemical methods of bating may be used for leathers like chrome and alum leather1 but even here natural processes like drenching1 in which acids are produced gradually during the working of the skins1 give more beautiful results4 ,with vegetable tanning materials1 the advantage is still on the side of the natural processes when these are conducted in a proper manner4 ,finally1 the author regrets that the subject of the work is not an inspiring and lofty one1 such as is astronomy for example4#ahf ,limited in extent1 imperfect in execution1 and in parts only suggestive in character1 this little book may perhaps serve as a foundation1 on which students of the science of tanning may raise the superstructure of their own experience and eventually perfect the processes touched upon1 so that the use of such filthy materials may be entirely avoided4 ,in that case the author's intention will be fulfilled4 #ahf ,celestial ,objects1 ,webb1 #ahha4 ,,finis ,,index4 ,absorption phenomena1 #gj ,abt1 ,dr4 ,g41 #ea1 #gb ,acid 8turning0 of drench1 #bcg ,acids1 action of1 #aef ---- fractionating1 #bgj ---- deliming with1 #i ---- in drench1 #bfe ---- to remove lime1 cost of1 #aa ,adulteration in dog-dung1 detecting1 #add ,agglutinin1 #add ,alum1 a term for puer1 #c 8,alumed0 calf skins1 #c ,amend's bate1 #aic ,amido compounds1 #aef ,amines1 #afc1 #bjf ---- in dung1 #aed ,ammonia in puer liquors1 #da ,ammonium phosphate1 #de ,analyses1 bird excreta1 #ec ---- dog dung1 #bf1 #aej1 #aeb ---- drench1 #bdi ---- gas1 #bdg ---- grains1 #g ---- guano1 #aej ---- hen dung1 #aej ---- puer1 #bf ---- ultimate1 of dung1 #aec ,andreasch1 ,f41 #bdd ,anti-bodies1 #adc ,anti-calcium1 #bcf ,arginase1 #acc ,artificial drench1 #bfc ,ash of skin1 #ci ,authors1 list of1 #bij ,bacillus butyricus1 #aab ---- c1 #agb ---- ,coli commune1 #id ---- d1 #ajf1 #agc1 #agd ---- e1 #ajg1 #agc ---- erodiens1 #ig ---- from pigeon dung bate1 #agb ,bacteria1 action of1 #afj ---- bate1 examination of1 #hg ---- bran1 pure culture of1 #bfi ---- dung1 #hi1 #ih1 #ajb1 #afa ---- growth in various media1 #aje ---- pigeon dung1 #ajc ---- putrefactive1 #abe ---- 8,sweating10 #aje1 #bac ,bacterial diastase1 #aca ,bacterium furfuris1 #bda1 #bfd1 #bfi ---- termo1 #aah ,barium salts from pure cultures of ,b4 furfuris1 #bga ---- ---- of volatile acids1 #bec ,bate1 ,amend's1 #aic ---- ,becker's patent1 #bbg ---- bird dung1 #eb ---- ,boehringer's patent1 #aig ---- concentration of salts in1 #dg ---- ,dermiforma1 #ahi ---- ,eberle's patent1 #bba ---- ,erodin1 #agi ---- ,esco1 #aib ---- examination of bacteria in1 #hg ---- glucose1 #agi ---- ,lederer's1 #aif ---- ,nordlinger's1 #aie ---- ,norris's1 #aid ,bate1 ,nowak's patent1 #aid ---- ,oake's1 #aie ---- ,oropon1 #adj1 #ahf1 #bai ---- phosphates in1 #dc ---- pigeon dung1 #ajc ---- ,phosphorbutyralin1 #aie ---- ,popp and ,becker's patent1 #aig ---- ,puerine1 #aij ---- ,purgatol1 #aib ---- reducing action of1 #aeb ---- ,rhm's patent1 #bai ---- ,simon's1 #aie ---- solid matter1 influence of1 #agf ---- soluble matter of1 #agf ---- ,sucanine1 #aia ---- ,tiffany's1 #agi ---- ,wood's ,american patent1 #baj ---- ---- ,english patent1 #bje ---- ,zollikoffer's1 #agh ,bayliss1 ,dr4 ,w4 ,m41 #abg ,bchamp1 #bhj ,betulase1 #acb ,becker's patent1 #bbg ,bibliography1 #bhb ,bile1 #ca ---- action of1 #aei ---- colouring matters1 #cj ---- salts1 effect on puer1 #df ---- ---- ---- ---- lipase1 #adb ,bird dung bate1 #eb ---- excreta1 composition of1 #ec ,boehringer's patent1 #aid ,bone meal1 #aif ,books of reference1 #hi1 #bhb ,bran bacteria1 #bdj ---- ---- pure cultures of1 #bfi ---- composition of1 #beg ---- drench1 #bcc ---- ---- non-volatile bodies in1 #bed ---- ---- products of fermentation1 #bdg ---- ---- sweet1 #bfc ---- ---- volatile bodies in1 #bdi ---- ferments1 action on starch1 #beh ,brown1 ,adrian ,j4 ,prof41 #bgd ,butyric acid1 #aa ---- ---- fermentation1 #aaa ,calcium in enzymes1 #acf ---- phosphate1 #de ,carlsberg vessel1 #agj1 #bad ,caroubinase1 #acb ,casease1 #acb ,castor-oil seed1 #ahh1 #bcb ,catalysts1 #abg ,cellulose fermentation1 #aaj ,cerealin1 #bde1 #bfj ,chemical composition of puer1 #bd ---- deliming1 #e ,chloroform1 use of1 in pancreatin solution1 #aea ,cholesterol1 #cj ,collagen1 #ef ,colloidal state1 #eg1 #acg ,concentration of salts in bate1 #dg ,condenser1 ,abbe's1 #hg1 #hh ---- dark ground1 #hg ,conductivity of puer liquors1 #hj1 #ha ,copenhagen conference1 #ahj ,cultivation of bating bacteria1 #aii ,culture medium1 #aje1 #bjg ,cytase1 #acb ,deliming1 chemical1 #e ,density of skin1 #fj ,dermiforma1 #ahi ,dextrin1 #bei1 #bfa ,diastase1 #abh1 #aca1 #acb ---- ,krawkov's method of preparing1 #ace ,diastatic enzymes1 #bce ,digestive ferments1 #adh ---- juices1 #bcj ,dog dung1 analyses of1 #bf1 #aej1 #aeb ---- bacteria in1 #hi1 #ih ---- detecting adulteration of1 #add ---- fresh1 bacteria in1 #ajb ---- influence of food on1 #bh1 #ie1 #aec ---- method of analysis1 #be ,dog dung1 separating enzymes from1 #acd ---- trypsin in1 #acd ,doerr and ,reinhardt's laboratory1 #cb ,drench1 acid 8turning0 of1 #bcg ---- acids in1 #aef ---- action of1 #bcc1 #bdb1 #bde ---- artificial1 #bfc ---- bacteria in1 #bci ---- damage1 #bcf ---- fermentations of1 #bch ---- gases from1 #bdb1 #bdh ---- glucoses in1 #bfa ---- 8pinholey10 #bch ---- putrid 8turning0 of1 #bcg ---- sweet bran1 #bce ,dressing hides1 #ai ,drop culture1 #hg ,dung analyses1 #bf1 #aej1 #aeb1 #aec ---- mineral matter of1 #aec ,eberle1 ,g41 #ac ,eberle's patent1 #bba ,effront1 ,dr41 #aa ,eitner1 #bdb1 #bdd ,electrometric apparatus1 #gf ---- method1 #cc1 #di ,emulsin1 #acb ,enzymatic bates1 #aig ,enzymes1 action of1 #ade ---- ---- of serum on1 #add ---- ---- on skin1 #adj ---- calcium in1 #acf ---- defined1 #abg ---- diastatic1 #bce ---- from bacteria1 #aca ---- hydrolysing1 #acb ---- in dog's dung1 #acg ---- lipolytic1 #ade ---- manganese in1 #acf ---- preparation of1 #acd1 #afd ---- proteolytic1 #ade ,erepsin1 #acc1 #adb ,erodin1 #agi ,erodin1 stock liquor1 #ahb ,esco1 #aib ,esters1 synthesis of1 #abg ,ethyl butyrate1 #afe ,ethylamine butyrate1 #db ---- lactate1 #db ---- propionate1 #db ,fahrion1 ,dr41 #eb ,falling1 #fg ---- apparatus for measuring degree of1 #hb ,fat in puer1 #be1 #cj ---- in skins1 #af ,feeding of dogs1 #bh1 #ie ,fermentation in the leather industry1 #adg ---- nitrogen from1 #bgi ,ferments1 digestive1 #adh ---- gall1 #bbd ---- hydrolysing1 #acb ---- imino-lytic1 #acc ---- oxidizing1 #acc ---- oxylytic1 #acc ,flagell1 staining of1 #id 8,flaked0 grain1 #adi ,formic ,acid1 #i ,fractionating acids1 #bej ,frankland and ,frew1 #bdi ,gall ferments1 #bbd ,gamgee1 #bha ,gas analysis1 #bdg ,gases from drench1 #bdb1 #bdh ---- from pure cultures1 #bge ---- intestinal1 #bha ,gayon1 #bhj ,gelatin1 #ef ---- density of1 #fc ---- glucose1 #bfg ---- molecular weight of1 #ef ---- peptonized1 #afh ,glucose bate1 #agi ---- gelatin1 #bfg ,glucoses in drench1 #bfa ,glycerin1 #ada ,goat skins1 #ahc ---- ---- bating of1 #bca ,guano1 analysis of1 #aej ,golding1 ,j41 #age 8,grains10 analysis of1 #g ,harness backs1 #ag ,hauff1 ,j41 #bcf ,hen dung1 analysis of1 #aej ,hexoses1 #abe ,hide-powder1 density of1 #ff ,hides1 bating of1 #ag ,houston1 ,dr41 #ic1 #id1 #ig ,hydrogen from drench1 #bci ,hydrogen-ion concentration1 #gd1 #gi ,hydrochloric acid1 use in deliming1 #aa ,hydrolysis1 #abh ---- velocity of1 #acj ,hydrolysing enzymes1 #acb ,immendorf1 #bhj ,imino-lactic ferments1 #acc ,indol1 #ie1 #ajf ,infusoria1 #abc ,intestinal gases1 #bha ---- juice1 #bbe1 #bbh ,inulase1 #acb ,jean1 ,f41 #da ,jones1 ,arnold ,seymour1 #ge1 #acc ,kaolin1 #agf ,kathreiner1 ,f41 #df1 #bcf ---- bate trials by1 #ahc1 #ahd ,koch's ,jahresbericht1 #abe ,krner1 ,dr4 ,th41 #fg1 #afg ,kossel1 ,dr4 ,a41 #agj ---- and ,dakin1 #acc ,kral1 ,prof41 xv ,khl1 ,dr4 ,h41 #bcf ,laccase1 #acc1 #ace ---- manganese in1 #ace ,lactase1 #acb ,lactic acid1 #aj ---- ---- from ,b4 furfuris1 #bgb ,lamb1 ,m4 ,c41 #i ,law's volumenometer1 #fa ,lecithin1 #ada ,lederer's bate1 #aif ,lime in sheep grains1 #bc1 #cg ---- in puer liquors1 #cf1 #dj1 #dd ---- soaps1 #af ,limed skin1 #e1 #g ,lion's dung1 #bi ,lipase1 #acb1 #ada ---- effect of bile salts on1 #adb ,lipolytic enzymes1 #ade ,liquor pancreaticus1 #ahi ,malase1 #acc ,maltase1 #acb ,manganese in enzymes1 #acf ,mastering1 a term for puer1 #c ,mercaptans1 #df ,measuring truck1 #h ,meggitt1 ,loxley1 #aga ,metchnikoff1 #ic ,mineral matter of dung1 #aec ,minot1 ,prof41 #ha ,mixed cultures1 #agc ,molecular weight of gelatin1 #ef ,monads1 #abc ,morocco leather1 #c ,moulds1 #aad1 #abf ,mller1 #gb ,muscle1 contraction of1 #gc ,myrosin1 #acb ,myxomycetes1 #aaf ,nencki1 #ajg ,nitrogen from fermentation1 #bgi ---- in bran1 #bcd ---- in puer liquors1 #dh ,nitrites1 use of1 in bating1 #aic ,non-electrolytes1 influence of1 #gb ,nrdlinger's bate1 #aid ,nowak's patent1 #aid ,nuclein1 #aad ,oake's bate1 #aie ,oenoxydase1 #acc ,olease1 #acc ,organic acids1 use in deliming1 #ac ---- ---- in puer1 #aee ,oropon1 #adj1 #ahf1 #bai ,osmosis1 #eh ,osmotic pressure1 #ei1 #afg ,o',sullivan1 ,j41 #bdd ---- and ,thompson1 #abh ,oxalic acid fermentation1 #aaa 8,oxidizing0 skins1 #aic ,oxydin1 #acc ,oxylytic ferments1 #acc ,paddle1 #ad ,pancreas1 #bbj ,pancreatin1 action on skin1 #ach1 #aea ,papain1 #acb ,parker1 ,dr4 ,gordon1 xv1 #aa ,pectase1 #acb ,pentoses1 #abe ,pepsin1 #acb ---- action on skin1 #ach ,peptolytic ferments1 #aai ,peptonized gelatin1 #afh ,phosphates in the bate1 #dc ,phosphorbutyralin1 #aie ,pigeon dung1 #ajc 8,pinholey0 drench1 #bch ,plasmase1 #acb ,plate cultures1 #ajc ,popp and ,becker's patent1 #aig ,precipitin1 #add ,pribram1 ,dr41 #gc ,procter1 ,prof4 ,h4 ,r41 #aj1 #ee1 #bje1 #baj ,proteolytic enzymes1 #ade ---- ferments1 #aai ,proteus bacteria1 #aah ,puer1 amido compounds in1 #aef ---- chemical composition of1 #bd ---- fat in1 #be1 #cj ---- organic acids in1 #aee ---- quantity used1 #ae ---- reactions of1 #ca ---- wheel1 #ac ,puerine1 #aij ,puering1 solution of skin substance in1 #dg ,pure cultures of bran bacteria1 #bfi ,purgatol1 #aib ,purin bases1 #cj ,putrefaction1 #aaf ---- ,see ,nos4 #eh to #gh of ,bibliography1 #bhb ---- mechanism of1 #ajg ---- of meat1 #abj ,putrefactive bacteria1 #ajg ,putrid 8turning0 of drench1 #bcg ,reaction of puer1 #ca ,rennet1 #abh1 #acb ,rhamnase1 #acb ,rogers1 ,dr4 ,allen1 #aie ,rhm's patent1 #bai ,ruge1 #bha ,sabatier and ,senderens1 #abg ,salt solution1 physiological1 #hg ,salts solution1 #bfg ,sand1 ,dr41 xv1 #cc1 #ha ,schorlemmer1 ,k41 #ahf ,scud1 #ea ,scudding1 #af ---- machine1 #ag ,serum1 action of1 on enzymes1 #add ,shearling pelts1 #ahc ,shrewsbury1 ,h4 ,s41 #aff1 #bha ,simon's bate1 #aie ,skatol1 #df ,skin substance1 ash of1 #ci ,skin substance1 density of1 #fj ---- ---- fat in1 #af ---- ---- solution of1 #dg1 #ea ,soerensen1 ,prof41 #dc1 #hj ,solid matter in bate1 #gc ---- ---- influence of1 #age ,soluble matter of bate1 #agf ,soyka's dilution method1 #ajc ,spirillum volutans1 #aab ---- delsulfuricans1 #abd ,spongy leather1 #bch ,staining and mounting1 books on1 #hi ---- of flagell1 #id ,starch1 action of bran ferments on1 #bei ,steapsin1 #acb ,stiasny1 ,prof4 ,e41 #bhb ,sucanine1 #aia ,sucrase1 #abh1 #acb ,sulphuric acid1 use in deliming1 #aa ,sulphuretted hydrogen1 #df 8,sweating0 bacteria1 #aje1 #bac ,sweet bran drench1 #bce ,swelling1 #fg ---- alkaline1 #gb ,symbiosis1 #bfi ,synthesis of esters1 #abg ,syntonin1 #cb ,thio-acids1 #aif ,tiffany's bate1 #agi ,toxins1 #adc ,trehalase1 #acb ,trent bridge laboratory1 #ajg1 #beb ,trimethyl-amine1 #ajg1 #beb ---- butyrate1 #db ,trypsin1 #acb1 #acc ,trypsin1 in dog dung1 #acd ,turney1 ,sir ,john1 scudding machine1 #ag 8,turning0 of drench1 #bhg ,tyrosinase1 #acc ,urea1 #bi ,urease1 #acb ,uric ,acid1 #bi ,velocity of hydrolysis1 #acj ,volumenometer1 #fa ---- air1 #fg ---- ,law's1 #fa ,wladika1 ,j41 #bef ,willcox1 ,dr4 ,w4 ,h41 #bdc1 #bde ,wood's ,american patent1 #baj ---- ,english patent1 #bje ,wool bacteria1 #agd ,xylose1 #abe ,yeast water1 #bei ,yoghurt1 #bcf ,zinc1 effect on growth of moulds1 #aac ,zollikoffer's bate1 #agh ,zooglo1 #bdb ,zymase1 #acc ,,london3 ,,printed ,,by ,,william ,,clowes ,,and ,,sons1 ,,limited ,,great ,,windmill ,,street1 ,w41 ,,and ,,duke ,,street1 ,,stamford ,,street1 ,s4,e4