,,handbook ,,of ,,an,,sthetics ,,by ,j4 ,,stuart ,,ross1 ,m4,b41 ,,ch4,b41 ,f4,r4,c4,s4,e4 ,,lecturer ,,in ,,practical ,,an,,sthetics1 ,,university ,,of ,,edinburgh2 ,,honorary ,,an,,sthetist ,,edinburgh ,,dental ,,school2 ,,an,,sthetist1 ,,deaconess ,,hospital2 ,,instructor ,,in ,,an,,sthetics1 ,,edin4 ,,royal ,,infirmary ,with an ,introduction ,,by ,,hy4 ,,alexis ,,thomson1 ,c4,m4,g41 ,m4,d41 ,f4,r4,c4,s4,e4 ,,professor ,,of ,,surgery1 ,,university ,,of ,,edinburgh ,,and ,,chapters ,,upon ,local and ,spinal ,ansthesia ,,by ,,wm4 ,,quarry ,,wood1 ,m4,d41 ,f4,r4,c4,s4,e4 ,,lately ,,temporary ,,assistant ,,surgeon1 ,,edinburgh ,,royal ,,infirmary ,,and ,,upon ,intratracheal ,ansthesia ,,by ,h4 ,,torrance ,,thomson1 ,m4,d41 ,f4,r4,c4,s4,e4 ,,an,,sthetist ,,to ,,the ,,leith ,,hospital ,,edinburgh ,e4 ,s4 ,,livingstone1 #ag ,,teviot ,,place #aiai ,,contents ,,chap4 ,,page ,,introduction ,,by ,,professor ,,alexis ,,thomson ix ,,preface xi ,i4 ,,physiological ,,action ,,of ,,an,,sthetic ,,drugs #a ,,ii4 ,,shock ,,and ,,an,,sthesia #e ,,iii4 ,,asphyxia ,,or ,,anox,,mia #ae ,,iv4 ,,methods ,,of ,,an,,sthetising #bh ,v4 ,,the ,,clinical ,,observation ,,of ,,the ,,patient #ca ,,vi4 ,,the ,,preparation ,,of ,,the ,,patient #db ,,vii4 ,,nitrous ,,oxide #df ,,viii4 ,,nitrous ,,oxide ,,and ,,oxygen #fj ,,ix4 ,,ether #gd ,x4 ,,intratracheal ,,ether #if ,,xi4 ,,chloroform #aji ,,xii4 ,,ethyl ,,chloride #abb ,,xiii4 ,,mixtures ,,of ,,nitrous ,,oxide ,,and ,,ethyl ,,chloride #abh ,,xiv4 ,,mixtures ,,of ,,chloroform ,,and ,,ether #acd ,,xv4 ,,sequences #acg ,,xvi4 ,,the ,,accidents ,,of ,,an,,sthesia #adj ,,xvii4 ,,the ,,sequel ,,of ,,an,,sthesia #aea ,,xviii4 ,,posture ,,of ,,the ,,patient #aeg ,,xix4 ,,the ,,choice ,,of ,,the ,,an,,sthetic #afb ,,xx4 ,,local ,,an,,sthesia #aga ,,xxi4 ,,spinal ,,an,,sthesia #aic ,,appendix #bja ,,index #bji ,,list ,,of ,,illustrations4 ,,fig4 ,,page4 #a4 ,shock 7,grey and ,parsons7 #f #b4 ,shock 7after ,crile7 #h #c4 ,diagram to ,illustrate ,anoci-,association 7after ,crile7 #aa #d4 ,apparatus for ,lane's ,saline ,infusion #ac #e4 ,diagram of the ,vicious ,circle of ,asphyxia #bj #f4 ,hewitt's ,mouth ,props #bb #g4 ,bellamy ,gardner's ,mouth ,props #bc #h4 ,phillips' ,modification of ,hewitt's ,artificial ,air-way #bc #i4 ,silk's ,nasal ,tubes #bc #aj4 ,tongue ,forceps and ,glossotilt #bd #aa4 ,apparatus for ,opening ,clenched ,jaws #be #ab4 ,frame for ,adapting ,vertical ,cylinders to ,foot ,use #dg #ac4 ,nitrous ,oxide ,cylinders 7upright and angle7 #dh #ad4 ,complete ,nitrous ,oxide ,apparatus #di #ae4 ,barth #c-way ,nitrous ,oxide ,tap #ej #af4 ,hewitt's ,wide-bore ,nitrous ,oxide ,valves #ej #ag4 ,ash's ,modification of ,paterson's ,nasal ,gas #eh #ah4 ,hewitt's ,apparatus for ,nitrous ,oxide and ,oxygen #fc #ai4 ,diagram to ,illustrate ,action of ,hewitt's and ,teter's ,gas-,oxygen ,methods #fg #bj4 ,details of ,clark's ,expiratory ,valve #fh #ba4 ,the ,clarke ,gas-oxygen ,apparatus #fi #bb4 ,marshall's ,sight-feed ,gas-oxygen ,apparatus #gj #bc4 ,clover's ,ether ,inhaler1 with ,nitrous ,oxide ,attachment #gg #bd4 ,clover's ,inhaler1 ,diagram of a ,vertical ,section #gh #be4 ,hewitt's ,wide-bore ,ether ,inhaler #hj #bf4 ,ormsby's ,ether ,inhaler #ha #bg4 ,bellamy ,gardner's ,mask and ,ether ,dropper #hc #bh4 ,four ,photographs to ,illustrate the ,administration of ,open ,ether #hd-e #bi4 ,shipway's ,warmed ,ether ,apparatus #ia #cj4 ,diagram of ,intratracheal ,apparatus #ih #ca4 ,electric ,blower for ,intratracheal ,method #ii #cb4 ,kelly's ,intratracheal ,apparatus #ajj #cc4 ,shipway's ,intratracheal ,apparatus #ajb #cd4 ,hill's ,direct ,laryngoscope #ajd #ce4 ,diagram of ,blood-pressure ,curves ,obtainable with ,chloroform #aaj #cf4 ,vernon ,harcourt's ,percentage ,chloroform ,inhaler #aae #cg4 ,chloroform ,mask #aaf #ch4 ,chloroform ,drop ,bottles #aag #ci4 ,junker's ,chloroform ,apparatus #aai #dj4 ,tube of ,ethyl-,chloride #abb #da4 ,ethyl-,chloride ,inhaler #abd #db4 ,guy's ,gas and ,ethyl-,chloride ,inhaler #abh #dc4 ,details of ,guy's ,inhaler #abi #dd4 ,diagram of ,gas-,oxygen ,method ,introduced by ,dr ,guy and the ,author #acj #de4 ,the ,guy ,ross ,gas-,oxygen ,instrument #aca #df4 ,rendle's ,cone #ace #dg4 ,clover ,inhaler adapted for the ,ethyl ,chloride-,ether ,sequence #aci #dh4 ,two ,photographs illustrating ,sylvester's ,artificial ,respiration #adf-g #di4 ,sitting-up ,posture for ,operations upon the ,head and ,neck #aei #ej4 ,o',malley's ,posture for ,intra-nasal ,surgery #afj #ea4 ,all-metal ,syringe for ,infiltration ,ansthesia #agf #eb4 ,infiltration of the ,brachial ,plexus #ahc #ec4 ,needle and ,syringe for ,spinal ,analgesia #aid #ed4 ,position of the ,patient for ,spinal ,analgesia #aif ,,introduction4 ,the securing of a safe ansthesia during operations is more important than ever before1 partly because of the mere number of operations1 and partly because of the greater extent to which other operative risks--hmorrhage1 shock and infection--have been overcome4 ,the risk from the ansthetic is now so very small that the joint aim of the surgeon and ansthetist to abolish it altogether is not far from being accomplished4 ,the author of this volume has done a good deal to accomplish this end1 and it is a matter of congratulation that he has now published an account of his methods1 so that a larger circle may benefit from his teaching and his experience4 ,the author very properly goes further and maintains that ansthesia must not only be safe but must also be good2 good ansthesia is absolutely vital to good surgery4 ,only a generation back many surgeons professed to see no difference as to who gave the ansthetic2 at the present day no one willingly embarks upon a difficult operation without the aid of a skilled ansthetist4 ,in various parts of the book the author has very rightly laid great emphasis upon the influence which the work of the surgeon has upon that of the ansthetist4 ,the latter may learn much from an occasional glance at the field of operation4 ,he should not interest himself in the details of operative procedure to the distraction of his mind from his own responsibilities2 but he can1 in abdominal surgery1 see for himself whether the muscles are properly relaxed1 and observe the state of operation1 so that he can when necessary deepen the ansthesia in good time1 while not maintaining deep ansthesia when a light one would suffice4 ,finally1 he can check his other sources of information as to the condition of the circulation by noticing the force with which cut arteries spout1 the colour of the blood and the size of uncut veins4 ,like other branches of medicine1 adequate study as well as practical experience is required in order to master the art of administering ansthetics1 and that a reliable manual of instruction is essential1 goes without saying2 ,i feel on perfectly safe ground in recommending this book as such both to the student and the practitioner4 ,,alexis ,,thomson4 ,,preface4 ,this little book is an attempt to present to the student and practitioner a condensed account of modern ansthetic views and practice4 ,in choosing a general scheme ,i have tried to lay emphasis upon the relation of ansthesia to general medical science rather than upon elaborate descriptions of ansthetic apparatus and methods which a few years hence may be superseded4 ,i have therefore devoted the first four chapters to an account of the various forces which modify the physiology of the patient during an operation under a general ansthetic1 in so far as we at present understand them4 ,i trust that they will prove not only a sound basis for the information given in the rest of the book but also a help towards forming a judgment upon new methods and appliances as and when they meet the attention of the reader4 ,in making a selection of drugs and appliances for description1 ,i have eliminated those which do not appear to me to have any real sphere of usefulness4 ,the account of nitrous oxide and oxygen has been given in some detail4 ,both the profession and the lay public have arrived1 through the experiences of the war1 at a more just appreciation of the possibilities of this combination than was at all general before the year #aiad4 ,at the present day1 no one who proposes to engage in ansthetic work can afford to remain unpractised in its administration4 ,i have an apology to make to my women readers4 ,throughout the book1 when speaking of the ansthetist1 ,i have presumed the male sex4 ,such phrases as 8his or her0 and 8he or she0 are tedious and inelegant1 and their omission must not be taken as forgetfulness on the author's part that women frequently make very good ansthetists4 ,professor ,alexis ,thomson has added to the many kindnesses ,i have received at his hands by writing the ,introduction which immediately precedes this ,preface1 and ,i wish to express my sincere thanks to him for such a valuable addition to the book4 ,from ,mr ,david ,wallace1 ,f4,r4,c4,s4,e41 ,i have received much valuable help and guidance in ansthetic matters4 ,it was largely due to his kindly assistance and moral support that ,i was encouraged to persevere with my early attempts to use nitrous oxide and oxygen in major surgery4 ,the hints which are given in connection with ,genito-,urinary ,surgery are also derived from him4 ,the chapters upon ,local and ,spinal ,ansthesia are entirely the work of ,mr ,wood1 to whom ,i must express my gratitude for the admirable way in which he has done the work4 ,i must also thank ,dr ,torrance ,thomson most sincerely for his useful contribution in chapter ,x1 which constitutes a complete monograph upon ,intratracheal ,ansthesia4 ,to ,dr ,wm4 ,guy ,i am indebted for the photographs which appear in the book1 and ,i must express my sincere gratitude to him for the trouble he has taken in the matter4 ,much thanks are also due to the following firms who have been kind enough to lend illustrative blocks3--,messrs ,claudius ,ash ,co4 ,ltd41 ,g4 ,barth ,co41 ,de ,trey ,co41 ,j4 ,gardner ,son1 ,allen ,hanbury's ,ltd41 ,meyer ,phelps1 ,coxeter ,son1 ,down ,bros41 ,ltd41 ,krohne ,sesemann1 and ,mr ,j4 ,h4 ,montague4 ,lastly1 ,i must express my high appreciation of the courtesy which the publishers have shown to me1 and of their generosity in the matter of illustrations4 ,j4 ,,stuart ,,ross4 ,october #aiai4 ,handbook of ,ansthetics4 ,,chapter ,i4 ,,physiological ,,action ,,of ,,an,,sthetic ,,drugs4 ,every ansthetic drug has certain pharmacological peculiarities of its own1 but all have much in common1 and it is to these common features we shall first direct our attention4 ,reaching the blood stream by absorption from the lung alveoli1 the drug enters into loose combination with the red blood corpuscles2 a small proportion only is carried in the plasma4 ,within the corpuscles it must of necessity displace a certain proportion of the oxygen normally carried3 this factor is of great importance only in the case of nitrous oxide gas1 which readily displaces the larger part of the normal oxygen content4 ,in the case of other ansthetics1 the same process occurs2 but to a less extent4 ,detailed figures of the extent to which the blood gases are altered in various stages of chloroform ansthesia will be found in ,appendix ,,iii4 ,the actions of individual drugs upon the circulatory1 respiratory1 and excretory systems differ so considerably that a small section has been devoted to this subject in each of the chapters devoted to nitrous oxide1 ether1 and chloroform respectively4 ,one feature is1 however1 dependent upon the state of ansthesia rather than the action of the particular drug1 and that is a certain slight fall of blood pressure4 ,this phenomenon is seen even in natural sleep1 and is presumably due simply to lack of normal stimuli such as tactile1 visual1 and auditory impressions which in the ordinary circumstances of life1 help to maintain the tone of the vasomotor system4 ,that such a fall is due to the state of ansthesia admits of little doubt1 but the fact is not always easy to demonstrate since each of the drugs themselves have a marked influence upon the ,b4,p41 which masks the pure effect of the ansthetic sleep4 ,action upon the ,nervous ,system4 ,it is in this system1 of course1 that we look for the characteristic action of ansthetics1 since if we had a choice1 it is the brain only which we should desire to influence by our drug4 ,it used to be said that ansthetics paralyse the brain from above downwards1 but that is only approximately true4 ,more correctly we may say that the more highly developed parts of the brain are earliest affected1 and that those portions1 such as the vital medullary centres1 which man shares in common with his humbler zoological relatives1 maintain their activity until the last4 ,moreover1 it must be remembered that before any brain centre succumbs1 it passes through a preliminary stage of excitement1 varying in intensity with varying drugs and also with different types of patients4 ,those who are accustomed to administer to their nervous centres repeated large doses of such nerve poisons as alcohol and tobacco1 may show very evident signs of this preliminary cerebral irritation during the process of induction of ansthesia2 so do also the unhappy possessors of nervous systems deranged from other causes such as epilepsy4 ,the first centres to be attacked are those of thought and perception4 ,the patient is incapable of coherent reasoning1 and loses touch to some extent with impressions from the outside world4 ,muscular sense and co-ordination next become affected4 ,although still able to move the limbs or the head1 movements are incoherent1 and if at this stage the patient were put upon his feet1 he would stagger as he does in alcoholic intoxication4 ,by this time sensation1 both tactile and special1 begins to be affected4 ,the patient is no longer cognisant of pain1--if cut he would at any rate not have a remembrance of pain4 ,the special senses are at this stage also lost1 one of the last to go being the auditory sense1 a point which is sometimes forgotten by those inclined to talk while ansthesia is being induced4 ,muscle tone is the next function to be lost1 and at this stage all movements on the part of the patient should cease except those of respiration4 ,the reflexes disappear at varying stages3 the spinal reflexes1 e4g4 the knee-jerks1 disappear fairly early1 probably before muscle tone is entirely abolished1 but certain other reflexes persist to a later stage4 ,those which are of most interest to the ansthetist are the conjunctival1 corneal1 and pupillary reflexes of which he will find full details in ,chapter ,v4 ,lastly the vital medullary centres1 respiratory1 vasomotor1 and cardiac are overcome1 and at this stage we have passed beyond the stage of a proper ansthesia into that of over-dosage4 ,in passing it may be observed that the level at which one endeavours to work is that indicated by the loss of muscle tone and of some of the reflexes and the full activity of the medullary centres1 and that an ansthetic is good or bad according as it gives a wide or narrow margin between these two events4 ,upon the peripheral nerves1 ansthetics have much less effect than on the central nervous system4 ,faradisation of a motor nerve will in the deepest ansthesia still cause immediate contraction of the muscles supplied by it1 showing that the conductivity of the nerve is unaffected4 ,of far more importance1 however1 is the fact that the sensory nerves are not paralysed4 ,that pain is not felt by the patient is due simply to the loss of function of the cerebral sensory centres2 injury to the nerve still causes an impulse to be transmitted to the brain4 ,since no operative procedure can be carried out without more or less trauma 7injury7 to sensory nerves1 we may picture the brain of the patient undergoing a surgical operation while under a general ansthetic1 as being constantly bombarded by sensory stimuli1 which though not consciously appreciated by the sleeping patient1 are yet capable of producing reflex effects of a definite character1 the importance of which to the work of the surgeon and ansthetist it is difficult to exaggerate1 and of which a condensed account will be found in the succeeding chapter4 ,,chapter ,,ii4 ,,shock ,,and ,,an,,sthesia4 ,under this short and convenient title1 the author proposes to discuss all the changes observable in the patient's condition1 the causation of which can be traced to the procedure of the surgeon4 ,the use of the term shock was at one time1 and by some teachers still is1 restricted to a definite clinical condition4 ,the patient was described as lying pallid and almost pulseless1 with dilated pupils1 cold sweating skin1 and gasping1 irregular respirations4 ,in the view more generally taken to-day1 that is but the extreme and final manifestation of a syndrome1 which any patient who suffers trauma 7whether inflicted accidentally or by the surgeon7 exhibits in a greater or less degree1 and from which general ansthesia protects a patient to a very limited extent only4 ,professor ,crile1 to whose work we owe so much of our knowledge on this subject1 has said1 8,in general ansthesia1 part of the brain only is asleep40 ,though consciousness is abolished1 many parts of the brain are quite capable of responding to centripetal impulses passed to the brain through sensory nerves injured by the knife4 ,a full account of the changes demonstrated by ,crile in some of the cells of the grey matter of the brain as a result of such stimuli1 and of the interpretation put upon these by their discoverer1 is not suitable for a text-book of ansthesia4 ,it is sufficient to say that such changes have been discovered1 and that their occurrence as a result of trauma is not prevented by inhalational ansthesia4 ,such changes1 though of the utmost interest scientifically1 cannot be demonstrated clinically1 and it is to alterations of blood pressure and of respiration that we must look for clinical evidence of the effects of shock stimuli4 ,illustration3 ,,fig4 #a4--,shock--,blood pressure of a dog undergoing laminectomy under general ansthesia 7,grey and ,parsons47 7,reproduced by kind permission of the ,authors47 ,with every incision by the surgeon1 sensory nerve twigs are of necessity injured4 ,the fibres found in sensory nerves are1 it will be remembered1 either pressor1 or depressor--that is1 stimulation of them1 causes either an increase or decrease of the blood pressure1 the depth and frequency of respiration being usually affected in the same direction as the ,b4,p4 ,that such changes do commonly occur is easily recognised by clinical observation4 ,the veriest beginner in ansthesia soon learns to expect a deeper1 quicker respiration and a stronger pulse as soon as the operation has begun4 ,these changes have been studied experimentally upon animals and upon the human subject by the use of the sphygmomanometer3 ,fig4 #a1 drawn from ,grey ,parson's ,arris and ,gale ,lectures of #aiab1 shows a tracing from a dog undergoing laminectomy under general ansthesia1 and gives a good idea of the early evidences of shock4 99 99 99 99 99 ,we may condense the results of much work on this subject under the following headings3-- 7a7 ,most stimuli from the field of operation cause a sharp rise of blood pressure1 followed by a sharp fall4 7b7 ,successive stimuli delivered quickly one after another add their effects together1 the total result being considerably greater than from one severe trauma4 7c7 ,after a time1 the pressor effect of stimuli begins to lessen3 the animal or patient 8wears out10 and finally no pressor result can be obtained by the most massive stimulation3 the curve of ,b4,p4 steadily falls3 the condition of full surgical shock is produced4 7d7 ,the tearing or pulling of tissues produces more powerful stimuli than the use of a sharp knife1 and1 therefore1 brings on the full condition of shock more rapidly4 7e7 ,stimuli from some tissues cause much more reflex effect upon the organism than from other less sensitive structures4 ,this is well exemplified when an abdominal section is in progress4 ,incision of skin causes immediate response in deepened respiration and higher ,b4,p43 division of the fascia very little effect4 ,if the muscle is divided by the knife1 again little reflex effect is noticeable1 but if it be stretched and split by the fingers1 the response is powerful4 ,the parietal peritoneum1 however delicately handled1 is one of the most sensitive structures in the body1 and1 unless the patient is fully under at the stage either of opening or closing this layer1 actual breath-holding or straining will occur4 ,on the other hand1 incision or suture of the hollow viscera will cause practically no response however light the ansthesia1 provided these structures1 and their connections with the parietes1 are not pulled upon4 7f7 ,stimulation of certain selected areas1 of which the spermatic cord is a well-known but by no means the only example1 results in an almost immediate fall of blood pressure with little or no preliminary rise4 ,in the operating theatre1 we sometimes see faintness or syncope arising quite suddenly during operations in such regions4 ,this subject is explained more fully in ,chapter ,,xvi4 under the term 8,reflex ,syncope40 ,illustration3 ,,fig4 #b4--;,combined blood pressure chart showing the average of a number of experiments4--,a--,under nitrous oxide and oxygen4 ,b--,under ether4 ,at each spot marked x1 a trauma 7burning of the paw7 was inflicted4 7,after ,,crile47 7g7 ,while no general ansthetic protects absolutely from shock stimuli1 some ansthetics give more protection than others4 ,nitrous oxide is the most effective in this respect1 its powers being two and a half times greater than that of ether3 chloroform is even less effective than ether 7see ,fig4 #b74 7h7 ,the claim made by the older generation of surgeons that shock could be prevented by the use of a deep ansthesia1 and that the occurrence of any 8,reflex syncope0 was always a sign of too light an ansthesia cannot be made good4 ,at the same time1 it must be admitted that too light an ansthesia does increase the likelihood of shock4 ,prolonged deep ansthesia1 on the other hand1 produces by itself a condition indistinguishable from shock1 with the single exception of nitrous oxide gas4 7i7 ,operative shock is predisposed to by several factors of which the following are the most important3-- #a4 ,hmorrhage before or during operation4 #b4 ,sepsis4 #c4 ,fear4 #d4 ,prolonged starvation4 #e4 ,certain diseases1 especially hyperthyroidism 7exopthalmic gotre74 ,theories of ,shock4 ,so far as we have touched in the above upon theory1 it has been theory which receives general acceptance and which accords with known clinical facts4 ,when we come to discuss the reason why blood-pressure falls in shock1 we are in more debatable country4 ,crile's original view was that the upstroke seen in such charts as shown in ,fig4 #a are caused by reflex vaso-constriction1 and that the final fall of ,b4,p4 was due to exhaustion of the vaso-motor centre4 ,this view he does not seem to have modified as a result of his later discovery of degenerative changes in certain cells of the grey matter of the brain4 ,other workers1 ,j4 ,d4 ,malcolm in this country1 and ,yandell ,henderson1 of ,yale1 ,u4,s4,a41 maintain an opinion diametrically opposite4 ,in their view1 in fully developed shock1 the vessels are in vaso-constriction1 and the circulation is arrested from undue internal resistance to blood flow4 ,a third explanation of lowered ,b4,p4 has been offered1 and while its significance is not understood1 there is fairly general agreement as to its validity4 ,this factor is a reduction in the total blood volume--an oligmia4 ,no one has as yet demonstrated to what region or organ the missing blood volume has retreated4 ,,yandell ,,henderson',s ,,acapnic ,,theory ,,of ,,shock4 ,acapnia is a condition in which the ,,co#b content of the blood and tissues has been brought to too low a level4 ,those who climb mountains suffer from it1 and so do those who breathe rapidly and heavily for a prolonged period4 ,carbon dioxide is necessary for the vigour of the respiratory centre1 of which it may be termed the natural regulator4 ,moreover1 the heart and the great veins which empty into it require a certain proportion of ,,co#b in the blood4 ,admittedly1 patients inhaling ansthetics do on occasion breathe too deeply4 ,sometimes they do so voluntarily before losing consciousness1 sometimes reflexly as a result of such a manuvre as stretching the sphincter ani4 ,do they thereby bring their ,,co#b down to a level which does serious harm and which can be considered a cause of collapse under ansthesia8 ,henderson says they can and do3 most other workers deny the possibility4 ,illustration3 ,,fig #c4--;,diagram 7after ,,crile7 to illustrate anoci-association4 ,in 8,a0 the trauma is inflicted on the leg1 and the brain being wholly unprotected1 considerable shock is suffered4 ,in 8,b0 the brain is protected by inhalational ansthesia from the effects of fear1 etc4 ,in 8,c0 the sensory nerves from the seat of trauma are blocked by novocaine1 and the brain also protected by inhalational ansthesia4 ,theoretically no shock is suffered4 ,prevention and ,treatment of ,shock4 ,there are many theories of shock but only one anti-shock technique which will bear examination4 ,founding upon his own theory1 ,crile about #aiac elaborated his ,,anoci-,,association method of which the following are the leading features 7see ,fig4 #c73-- 7a7 ,prevention of fear4--,every member of this team is taught the all-important art of so dealing with the patient that no unnecessary fear is allowed to remain in his mind4 ,that art does not consist in endless repetition of the phrase1 8,do not be frightened10 but rather in each so bearing himself or herself before the patient that he may gradually acquire the conviction that he is surrounded by careful1 kindly1 and skilful persons who are doing for him what they do for hundreds of others1 and doing it with an expectation of his early and complete recovery so certain that they do not need to put it into words unless definitely questioned4 ,such an art is not acquired in a day1 and some unhappy few are so constituted that they can never acquire it4 ,as a further preventative of fear1 and also for other reasons explained in ,chapter vi41 the patient receives a dose of morphia 7th grain1 with th grain atropine1 hypodermically7 three quarters of an hour before operation4 ,some surgeons go further1 and give a sedative the night before operation4 ,veronal gr4 viii4 is the favourite prescription of ,prof4 ,alexis ,thomson of ,edinburgh4 7b7 ,the sensory nerves are 8blocked0 by infiltration with novocain4 ,by the systematic use of local in conjunction with general ansthesia1 the harmful stimuli from the area of operation are prevented from reaching the brain4 ,for the details of this measure1 the reader is referred to ,chapter xx4 7c7 ,the ansthetic of choice in ,crile's practice is nitrous oxide and oxygen 7see ,chapter vii474 ,the whole of this technique has not been generally adopted as a routine1 but nevertheless the teachings of ,crile have greatly influenced the mind and practice of most surgeons and ansthetists4 ,traces of that teaching are to be found everywhere in the organisation built up during the ,great ,war to save as many as possible of the lives of badly smashed men4 ,at no previous time in the history of surgery was the problem of shock so pressing1 and a brief resum of the methods adopted is here set down1 as an example of how shock should be dealt with4 ,illustration3 ,,fig4 #d4--,lane's apparatus for subcutaneous infusion of saline solution4 ,treatment of ,shock among the ,casualties of the ,war4 ,the first essentials demanded were the most careful organisation1 the provision of equipment far in advance of most home civilian hospitals1 and of surgical teams specially trained to a high level of excellence4 ,upon recovery from the field1 the injured man received at the ,,advanced ,,dressing ,,station1 such first aid dressing as was necessary1 and a substantial dose of morphia4 ,when the latter had had time to take effect1 the case was passed back to the ,field ,ambulance 7where he received his first dose of antitetanic serum71 and from there to the ,,casualty ,,clearing ,,station4 ,during every stage of the journey1 he received as much warm fluid nourishment as possible4 ,arrived at the ,c4,c4,s41 the severe case was passed first into the ,,resuscitation ,,ward4 ,this department1 under the charge of a specially trained ,m4,o41 concentrated largely upon two measures--the thorough warming of the patient1 and the replacing as far as possible of the fluids lost to him by hmorrhage and shock4 ,the warming in many ,c4,c4,s4's was effected by electric radiant heat baths4 ,the fluids were replaced either by way of infusing blood from another patient1 or by the use of gum saline solution4 ,introduced into a vein1 the action of this solution persists for a much longer period than that of ordinary saline1 being less easily lost by osmosis through the capillaries into the tissues4 ,from the resuscitation ward1 the patient passed to the ,,operating ,,theatre4 ,though the full technique of anoci-association was not always possible1 the maxims which ,crile had sought to inculcate into the practice of surgery influenced the work of surgeons and ansthetists very profoundly4 ,nitrous oxide and oxygen was used for all the severely shocked cases1 and infiltration with local ansthetics where feasible and necessary4 ,subcutaneous ,infusion of ,saline4 ,for those who do not feel bound to adopt the ,crile technique this is a simple measure which does much to minimise shock in prolonged abdominal operations4 ,saline infusion into a vein is so rapidly excreted that its influence is very fugacious1 but if the fluid be introduced under the skin during the period of operation it is slowly absorbed as required by the blood4 ,sir ,arbuthnot ,lane is a strong advocate of this measure4 ,fig4 #d shows a suitable apparatus4 ,the needles are thrust into the loose areolar tissue under the breast1 one on each side1 and a pint or more of fluid is slowly run in from the reservoir4 ,,chapter ,,iii4 ,,asphyxia ,,or ,,anox,,mia4 ,some degree of asphyxia is a common complication of inhalational ansthesia3 indeed some small degree of it is almost unavoidable4 ,it is hardly too much to say that the difference between a good and a bad ansthetist is that the one recognises and deals with asphyxia in its early stages1 while the other allows it to assume serious proportions before he becomes aware of its existence4 ,the man who only realises that asphyxia is present when the patient is deeply cyanosed and has ceased to be able to draw any air at all into his chest may know much of the physiology of ansthetic drugs1 and be well up in complicated ansthetic apparatus1 but knows nothing of the proper practice of ansthesia4 ,asphyxia arises during ansthesia from several causes4 ,in the first place1 the drug which the patient is inhaling and absorbing into the blood1 turns out from his red corpuscles a corresponding quantity of oxygen4 ,while this is only seen in its extreme form in the case of nitrous oxide gas1 it is a factor acting even in the case of other ansthetics4 ,secondly1 during deep ansthesia1 the respiratory centre may be somewhat depressed1 and the force and frequency of the respiratory act diminished4 ,thirdly1 the respiratory passages may be partially or wholly occluded from mechanical causes4 ,this is far the most important type of asphyxia1 being the most common1 the most fatal1 and the most easily prevented4 ,common ,causes of ,mechanical ,asphyxia4 7#a7 ,,clenching ,,of ,,the ,,jaws arises not uncommonly during ansthesia1 being specially frequent towards the end of the induction period4 ,since a very large proportion of individuals have nasal passages insufficient in bore to carry the full volume of respired air1 respiration must be obstructed if the jaws are clenched4 7#b7 ,,falling ,,back ,,of ,,the ,,lower ,,jaw ,,and ,,base ,,of ,,the ,,tongue ,,over ,,the ,,epiglottis4--,this is always liable to happen after the muscles are deeply relaxed4 7#c7 ,,mucous ,,or ,,blood ,,or ,a ,,foreign ,,body ,,is ,,drawn ,,by ,,inspiration ,,into ,,the ,,air ,,passages4--,changes of position of the head may release mucous which has been gathering in some parts of the mouth or pharynx4 ,for instance1 if the head has been lying on the side for some time1 a pool of mucous or saliva commonly gathers in the most dependent cheek1 and unless this is mopped out before the head is brought into the mesial position1 this pool will be suddenly tipped backwards1 and very probably drawn into the larynx4 ,again1 in operations upon the nasal or oral cavities1 blood is always liable to be inspired1 and not a few teeth have found their way into the air passages in the practices of dental surgeons who do not take precautions against this accident4 7#d7 ,,spasm ,,of ,,the ,,adductors ,,of ,,the ,,vocal ,,cords is one of the most common and most baffling incidents in ansthesia4 ,it announces its presence by the commencement of laryngeal stridor1 a high-pitched crowing noise1 which is as annoying for the surgeon and ansthetist to hear as it is detrimental to the progress of a smooth ansthesia4 ,inspired mucous or blood almost invariably sets it up1 and the two conditions of fluid in the larynx and narrowing of the glottis from approximation of the cords1 add their effects together1 with resulting obstruction of a high degree4 ,laryngeal stridor1 however1 frequently occurs even when no fluid has been inspirated4 ,it may be set up as a reflex from the area of operation4 ,dilatation of the sphincter ani1 and removal of the prepuce in circumcision1 are two common examples of this4 ,it is also undoubtedly sometimes caused by giving too strong a vapour during the latter part of the induction stage4 ,stridor unfortunately sometimes occurs from no obvious cause at all1 or to speak more correctly1 from causes which are at present not known to us4 ,it is the author's belief that one of these causes may prove to be morphia given as a preliminary to inhalational ansthesia4 ,in his experience1 stridor has been more frequent with morphia than without1 particularly if chloroform be the ansthetic chosen4 ,beyond that he cannot at present go4 7#e7 ,,pressure ,,upon ,,the ,,air ,,passages ,,of ,,neoplastic ,,or ,,inflammatory ,,swellings ,,in ,,the ,,neck4--,in such cases any obstruction which may exist before induction will probably become intensified during the process1 and a complete arrest of respiration is not uncommon4 ,large gotres are the most common type of neoplasm to give trouble1 and all acute inflammatory conditions in the neck which extend towards the trachea are notorious for their tendency to give cause for anxiety during ansthesia4 ,the ,physiology of ,asphyxia4 ,an animal1 subjected to asphyxia1 either mechanically or otherwise1 shows the following signs3-- 7a7 ,increase of the force and frequency of the respiratory movements of chest and abdomen4 ,even though there be a complete mechanical obstruction1 increased efforts to breathe will still be made for some moments1 although air no longer passes in and out of the chest4 7b7 ,there is a considerable rise of blood pressure owing to a high degree of vaso-construction4 7c7 ,the pupils dilate4 7d7 ,generalised convulsions4 7e7 ,the animal succumbs finally from cardiac failure4 ,no heart muscle can continue to function properly if supplied by the coronary arteries with venous blood4 ,moreover1 the heart pump has to act against the greatly increased peripheral resistance induced by vaso-constriction4 ,it must therefore be a matter of time only when the strongest and healthiest heart will cease to contract under the abnormal conditions of asphyxia4 ,there are in asphyxia1 two alterations in the blood-gasses1 i4e4 lack of oxygen and increase of ,,co#b4 ,the action of these two conditions have been differentiated by experimental work 7,starling1 ,kayala1 ,jerusalem71 and one can say definitely that the excess of ,,co#b is the cause of the increased activity of the respiratory efforts1 and that the remaining phenomena are due to oxygen starvation4 ,this point is of some importance in considering ansthetic methods in which re-breathing 7breathing in and out of a bag7 is practised4 ,the use of such methods has often been thoughtlessly condemned as 8poisoning the patient with his own ,,co#b40 ,within the limits usually practised1 a re-breathing method does not involve any such risk1 provided oxygen starvation does not occur4 ,this point is referred to again in ,chapter iv4 ,clinical ,signs of ,mechanical ,asphyxia in the ,ansthetised ,subject4 ,the classical signs of asphyxia above described are hardly to be expected in the operating theatre1 but essentially the condition of the patient who develops respiratory obstruction while under an ansthetic is similar to that produced experimentally in animals in the laboratory4 ,the changes most easily observed are as follows3-- 7#a7 ,alteration of the colour4--,cyanosis shows itself earliest in the lips1 and the lobules of the ears1--later the whole face becomes dusky4 7#b7 ,dilatation of the pupil1 which ceases to respond to the stimulus of light4 7#c7 ,the respiratory movements increase in depth and frequency4--,the chest and abdominal walls heave forcibly2 but 7#d7 ,the volume of air passing in and out of the glottis is diminished4--,in complete obstruction1 of course1 none passes at all4 ,in passing we may draw the moral that persistence of chest movements is no proof of the passage of air in and out of the chest3 that can only be proved by hearing the movement of air through glottis and mouth or nose1 or feeling it on the delicate skin of the back of the observer's hand4 7#e7 ,true convulsions are not seen1 unless we may consider the jactitation of deep ,n#b,o ansthesia as such 7see ,chapter ,,vii474 ,nevertheless1 there are obvious and most valuable signs of asphyxia to be found in the muscular system often quite early4 ,these consist in the incidence of muscular rigidity1 which is frequently observed first in the muscles of the abdominal wall4 ,a surgeon performing laparatomy will notice at once the occurrence of this phenomenon1 than which hardly anything can complicate and delay his task more effectively4 ,the ansthetist who knows his work will1 upon hearing from the surgeon a complaint as to the rigidity of the abdominal wall1 devote his attention first to securing a perfectly free air-way before deciding that a deeper ansthesia is required4 ,illustration3 ,,fig4 #e4--,vicious circle of asphyxia4 ,prevention and ,treatment of ,asphyxia4 ,once asphyxia1 especially mechanical asphyxia1 has begun1 it almost invariably tends to get worse4 ,the engorgement affects among other venules1 those which run under the mucous membrane of the respiratory tract1 still further obstructing the passage of air4 ,the muscular rigidity1 moreover1 soon manifests itself in the adductors of the vocal cords and the muscles which close the jaws3 the patient has thus entered into a 8vicious circle10 ,fig4 #e4 ,it is evident that the prevention of the earliest signs of asphyxia is to the ansthetist a matter of vital interest4 ,the cardinal points to watch are as follows3-- 7#a7 ,keep the neck of the patient as far as possible in a natural position1 i4e4 do not either flex or extend the head unduly upon the body unless the nature of the operation demands such an unusual position4 7#b7 ,maintain a free passage for air either through the nose or the mouth4 7#c7 ,keep the lower jaw in good position throughout the administration4 7#d7 ,avoid turning the face from the lateral to the dorsal 7face up7 position unless essential4 ,if it has to be done1 be careful first to mop out any 8pool0 from the dependent cheek4 7#e7 ,deal as effectively as possible with the earliest appearance of laryngeal stridor4 ,let us see how in a normal case1 these rules can be applied4 ,with the patient lying 7or1 in exceptional circumstances1 sitting7 in a comfortable position1 the shoulders and head raised above the rest of the body and the face looking upwards 7or straight forwards1 in the case of the sitting patient71 the ansthetic is begun slowly1 and the patient encouraged to take his time and to breathe naturally4 ,at this stage the jaw needs no support1 the muscles being neither relaxed by deep ansthesia1 nor spastic from asphyxia4 ,with the advent of muscular relaxation1 the head is turned to one side1 that which is opposite to the side on which the surgeon will be working1 being usually chosen4 ,we must now determine whether the patient can breathe best through the mouth or the nose1 and make sure that the channel chosen is as free as possible4 ,in the majority of cases it will be found that respiration is oral1 and that all that is necessary is to support the lower jaw by a finger hooked into the depression just below the symphysis mentes4 ,the hands of the ansthetist1 therefore1 take up a position from which in nine cases out of ten they will never require to be moved4 ,the hand of the side toward which the patient's face is turned supports the jaw and keeps the face-piece or mask adapted to the face4 ,the middle finger is pressed into the space below the symphysis mentis1 and exercises traction forwards and a little upwards1 thus preventing the jaw from slipping backwards2 the index finger lies along the lower part of the mask1 maintaining adaptation between it and the chin2 the thumb bears on the mask higher up1 keeping its upper part pressed against the bridge of the patient's nose1 and also serving as a point d'appui1 or fulcrum1 from which the jaw traction by the middle finger can conveniently be exercised4 ,this grip once learnt is not fatiguing to the hand1 and is in the author's opinion one of the essential points for the beginner to master 7see ,fig4 #bh;,c1 page #he74 ,the opposite hand holds the drop bottle1 if the method in use is an open one1 the wrist resting upon the uppermost side of the patient's head4 ,illustration3 ,,fig4 #f4--;,hewitt's dental props4 ,fig4 #bh;,c shows this grip in operation1 while ,fig4 #bh;,d shows the alternative frequently adopted4 ,this alternative has various disadvantages4 ,it covers up a larger part of the patient's face than the method recommended1 and it tends to tilt the mask sideways4 ,the little finger is supposed to be hooking forward the jaw by pressing behind its angle1 but such a method is very fatiguing if in use for more than a few moments4 ,in a proportion of cases1 it is found that a free air-way cannot be maintained by these simple measures4 ,upper or lower teeth 7or both7 may be missing and traction upon the lower jaw only closes the mouth the more firmly4 ,in most of these cases1 the difficulty can be met by the use of the dental prop4 ,these are made in various sizes and shapes1 of which the best known are ,hewitt's and ,bellamy ,gardner's 7see ,figs4 #f and #g74 ,the latter are made of aluminium and are of small size only4 ,they are the most convenient for cases with teeth both in the upper and lower jaw1 but who suffer from a receding lower jaw not easily kept forward unless the prop is used as a rocker1 as it were1 upon which it can be slid forward4 ,hewitt's props are of plated metal1 with lead on the cups1 to avoid injury to the teeth4 ,they are made in five sizes1 of which the middle and larger are very convenient for cases in which one or both rows of teeth are missing4 ,illustration3 ,,fig4 #g4--;,bellamy ,gardner's ,dental ,props4 ,illustration3 ,,fig4 #h4--,phillips' modification of ,hewitt's artificial airway4 ,for cases entirely without teeth1 and in which a large flabby tongue is prone to fall back over the epiglottis1 the mouth tube 7,fig4 #h7 is very convenient4 ,the rubber shank lies along the top of the tongue1 the metal end lies between the gums4 ,as originally introduced by ,hewitt1 the air-way was circular in cross section1 but the flattened model figured is a distinct improvement4 ,it was introduced by ,dr ,phillips4 ,illustration3 ,,fig4 #i4--,silk's nasal tubes4 ,occasionally one decides to facilitate nasal rather than oral breathing1 and if the natural passages are inadequate1 recourse may be had to the passage of a short piece of drainage tube of the calibre of a number #aj catheter1 and about #c inches in length4 ,with such a tube in one or both sides of the nose1 reaching from anterior to posterior nares1 nasal respiration is usually possible even in much obstructed noses 7,silk74 7,fig4 #i47 ,illustration3 ,,fig4 #aj;,a4--,bellamy ,gardner's tongue-clip4 ,illustration3 ,,fig4 #aj;,b4 ,ring tongue forceps4 ,illustration3 ,,fig4 #aj;,c4 ,glossotilt4 ,illustration3 ,,fig4 #aa;,a4--,boxwood wedge for opening jaws4 ,illustration3 ,,fig4 #aa;,b4--,wedge for opening jaws4 ,illustration3 ,,fig4 #aa;,c4--,mouth gag4 ,if proper and timely use be made of one or other of these simple devices1 the use of the tongue forceps is rarely necessary4 ,occasionally1 however1 it may be required1 and a suitable appliance should always be at hand for an emergency4 ,fig4 #aj shows two types4 ,the little clip of ,mr ,bellamy ,gardner is preferable to the ring type1 the passage of the spike through the tongue substance producing less after pain1 than the bruising following the use of the other instrument4 ,the third drawing in ,fig4 #aj is of an instrument not much known outside ,edinburgh2 it is called a glossotilt1 and is intended to lever forward the base of the tongue1 as an alternative to nipping the tip of the organ with forceps1 and has1 in the opinion of some1 various advantages4 ,before using either mouth prop or tongue forceps1 it is occasionally necessary to use some mechanical means to lever open a tightly clenched jaw4 ,the earlier one interferes in a case of mechanical asphyxia1 the less necessity will exist for the use of such means4 ,fig4 #aa shows two well-known mouth gags1 and also a box-wood wedge1 the use of which is less liable to injure teeth than a metal instrument4 ,if a gag is used1 the blades when closed should lie the one behind the other1 not side by side4 ,this ensures a minimal thickness to be inserted between the tightly clenched teeth4 ,treatment of ,laryngeal ,stridor4 ,this is of necessity difficult since the causation of the condition is in many cases obscure4 ,the error common to most beginners1 and to many who would resent such a title being applied to them1 is to regard the appearance of stridor as an indication to deepen the ansthesia4 ,whether the cause lie in local irritation of the laryngeal mucous membrane or in some stimulus from the area of operation1 the condition is presumably always essentially a reflex spasm of the adductors of the vocal cords1 but it is a reflex which may persist even in an ansthesia so deep that the vital medullary centres are in peril4 ,the preventive treatment consists chiefly in following the other rules set forth above for the prevention of asphyxia with such faithful care1 that the patient never enters into the vicious circle of asphyxia of which stridor is so prominent a feature4 ,patience in the induction stage--the avoidance of forcing the ansthetic upon the patient--is a safeguard not to be forgotten4 ,once the condition has arisen1 it saves time to withdraw the ansthetic altogether1 and to allow the patient to breathe nothing but fresh air4 ,brisk friction of the lips with a rough towel often does good1 presumably by setting up a 8cross reflex40 ,in severe cases1 a most valuable measure is the inhalation of pure oxygen1 a cylinder of which should always be at hand in the operating theatre4 ,even an obstructed air-way will convey enough undiluted oxygen to reduce the venosity of the blood1 and so cut across the 8vicious circle40 ,so much for the treatment of the early stages of asphyxia1 the more advanced stages constitute one of the 8accidents of ansthesia10 and are dealt with in ,chapter ,,xvi4 ,,chapter ,,iv4 ,,methods ,,of ,,an,,sthetising4 ,certain terms such as 8open method10 8closed method10 etc41 are used in describing different systems of ansthetising1 and it will save time later if these are now defined4 ,the ,,open ,,method is one in which the drug is dropped or poured upon a fabric stretched on a mask which does not lie in close apposition to the face4 ,if the student will experiment with such a mask as ,schimmelbusch's1 he will find that by no effort can he make its whole circumference touch his face at the same time4 ,ansthetics vapourised from such masks must of necessity be inhaled freely diluted with fresh air4 ,these masks are only suitable for use with chloroform4 ,the ,,perhalation ,,method4--,this term is not used often1 but it is the most strictly correct name to give to the process commonly called 8open ether40 ,if the student will examine ,bellamy ,gardner's open ether mask 7,fig4 #bg7 he will find that it is deliberately shaped to lie over its entire circumference in close apposition to the face of the average patient4 ,in actual use it is well however to make sure of this apposition by the use of a ring of gauze as shown in ,fig4 #bh;,a4 ,upon the mask is stretched gauze of a thickness just as great as will permit free respiration to take place through its layers4 ,the whole bulk of the respired air must pass through the fabric1 none escaping between the face and mask4 ,the term 8,,semi-,,open0 is applied to various methods now rarely seen4 ,one of the best known of these was the ansthetic cone1 still used by a few for ,c4,e4 mixture 7see ,fig4 #de74 ,the term 8,,closed ,,method0 is applied to one in which the patient breathes in and out of a closed bag4 ,the ,clover and ,ormsby inhalers are 8closed0 instruments4 ,with this method the patient rapidly uses up the oxygen of the contained air1 and accumulates considerable ,,co#b2 life could not be sustained for any long period of time under such a system4 ,oxygen must be supplied from time to time by permitting say one breath in five to be taken from the fresh air instead of from that in the bag4 ,alternatively1 oxygen from a cylinder may be supplied by an accessory pipe into the inhaler4 99 99 99 99 99 ,this method is also referred to as the ,,re-,,breathing ,,method4 99 99 99 99 99 ,the ,,valved ,,method is used only with 8gas0 or 8gas-oxygen40 ,the facepiece fitting accurately1 the patient draws all the volume of his inspiration from the inhaler3 his expirations he propels through a valve1 into the general atmosphere of the room4 ,if nitrous oxide unmixed with oxygen is being given1 the patient suffers from oxygen starvation even more rapidly and completely than in the re-breathing method4 ,during the induction period of gas ansthesia1 such oxygen starvation is practised deliberately1 and if not pushed too far is harmless4 ,it cannot1 however1 be continued for more than a brief space of time4 ,the admixture of oxygen to the vapour being breathed entirely abolishes this unfavourable feature of the valved method4 ,there is1 however1 another consequence of the use of 8valves0 which is unaffected by the addition of oxygen4 ,reference has already been made to ,yandell ,henderson's acapnic theory1 and if under any form of ansthesia the patient can be reduced to a condition of ,,co#b starvation1 it will be when the valved system of administration is in operation for a prolonged period4 ,as a matter of experience1 patients breathing 8on the valves0 do often exhibit shallow respirations and slight pallor which is rapidly and very strikingly remedied by turning to the rebreathing method4 ,one can hardly doubt that the improvement is due to a gradual re-accumulation of carbon di-oxide in the blood and tissues4 ,two other terms referring not to the type of inhaler but to the method of supplying the drug1 are in use4 ,by the 8,,drop0 ,,method1 we mean one in which the ansthetic is supplied in a steady series of drops4 ,the flow may be quick or slow1 but it always arrives on the mask in isolated drops of uniform size4 ,such a method demands more constant attention than the next to be described1 but it is capable of yielding that even uniformity of vapour strength so desirable in open methods4 ,,the ,,douche ,,method is unfortunately far more commonly used by those whose attention has never been drawn to the significance of the difference between the two4 ,supplies of the drug rendered1 say1 every twenty seconds cannot possibly give an even vapour strength4 8,,single ,,dose0 methods are of use chiefly in dental surgery4 ,the patient is charged up with the ansthetic1 and the operator has to begin his work as soon as the mask is withdrawn from the face1 ceasing as soon as the patient shows any signs of recovering consciousness of pain4 ,single dose ansthetics are in a class by themselves4 ,in order to achieve success with them1 special experience on the part of the administrator and mutual confidence between operator and ansthetist are essential4 ,the period of ansthesia available to the operator which any particular 8single dose0 ansthetic may be expected to yield is obviously a matter of the first importance1 and the table given in ,chapter ,,xix4 will be found helpful in this connection4 ,,chapter ,v4 ,,the ,,clinical ,,observation ,,of ,,the ,,patient4 ,stages of ,ansthesia4 ,ansthesia has been divided into four clinical stages corresponding to the degrees to which the nervous system has been affected4 ,the boundaries between these stages are often ill-defined1 but the terminology has some value as facilitating description4 ,,the ,,first ,,stage lasts from the commencement of inhalation up to the time when volitional self-control is lost by the patient4 ,,the ,,second ,,stage in the older text-books was said to be characterised by struggling1 shouting1 and breath-holding4 ,with a patient not addicted to alcohol and with the ansthetic skilfully administered1 this description is unduly lurid4 ,,the ,,third ,,stage is that of full surgical ansthesia4 ,,the ,,fourth ,,stage is that of over-dosage4 ,the ,ocular ,reflexes in ,ansthesia4 ,these give such valuable assistance to the ansthetist that it will be well to define and describe them as a preliminary4 ,they are three in number4 ,,the ,,conjunctival ,,reflex is best elicited by drawing the upper lid upwards from the eyeball and retaining it in that position with one finger1 while with another finger the ocular conjunctiva is lightly touched in the area of the inner canthus4 ,if the ansthesia is very light1 both lids attempt to approximate and close the palebral fissure4 ,the upper lid may slip down from under the retaining finger and come into its proper place1 while the lower lid is elevated4 ,at a deeper level of ansthesia there is not complete action of the orbicularis but merely of a certain part of it1 so that all that is observed is a twitch inwards of the lower lid4 ,even this form of the reflex disappears before the corneal reflex4 ,,the ,,corneal ,,reflex is elicited by pushing up the upper lid by one finger and with the pulp of the same finger lightly brushing the centre of the cornea as soon as it is exposed1 when we feel or see the upper lid come back into position with a sharp definite twitch4 ,the examining finger must be slipped smartly out of the way as soon as the cornea has been touched4 ,even in deep ansthesia1 a trace of this reflex can usually be elicited if the little manipulation be properly performed4 ,the conjunctival and corneal reflexes are frequently confused in the mind of the student4 ,the most common mistake made is to pin the upper lid firmly somewhere in the region of the bony roof of the orbit1 to dab the eye far too vigorously1 and to believe that no reflex is present because no movement of the upper lid takes place4 ,in the first place1 the upper lid cannot move if it is rigidly held against a bony plate3 in the second place1 it is wholly unnecessary to inflict upon the cornea more than the lightest of touches4 ,both these reflexes are to be used with great discretion1 undue frequency and excessive vigour of touch being alike capable of setting up serious inflammatory reaction4 ,,the ,,pupillary ,,light ,,reflex is elicited by shutting off light from both pupils for ten to twenty seconds and then smartly withdrawing the protecting fingers and allowing as strong a light as possible to fall on to the eye4 ,the response of the ciliary muscle should always be present2 its absence is a certain indication of something wrong3 some sluggishness may be permissible under ether1 but even that is suggestive of trouble if chloroform is the ansthetic4 ,the use of a preliminary hypodermic of morphia tends to make the pupil somewhat smaller than normal1 and to elicit the light reflex it may be necessary to cut off illumination for a somewhat longer period than if no morphia had been given4 ,nevertheless with a little care1 the light reflex should always be capable of demonstration even in the morphinised subject4 ,the ,observation of a ,normal ,case4 ,in the case of nitrous oxide and of ethyl chloride1 the patient passes through the various stages very rapidly1 and the picture of ansthesia as induced by either of these two is therefore best described separately4 ,the following may be taken1 therefore1 as an account of what is to be observed in the patient inhaling ether or chloroform1 unless a specific reference is made to one of the other ansthetics4 ,,first ,,stage4--,the first sign that some effect is being produced in the patient is usually the appearance of the movements of swallowing2 the hyoid and thyroid can be felt or seen to be moving in conjunction with the muscles of deglutition4 ,during this stage1 the patient being still to some extent under volitional control1 there should be no other movement noticed4 ,the eyes are usually closed and the colour normal2 the respiration may be hurried by excitement1 but judicious handling of the patient will do much to minimise this4 ,,the ,,second ,,stage is really entered when volitional control is lost4 ,it may be characterised by struggling and shouting by the patient1 even if the ansthetic is properly administered2 but with a healthy patient and a good ansthetist1 all that usually occurs in the way of movement by the patient is some rigidity of the limbs and a slight attempt1 perhaps1 to lift the head from the pillow or a limb from the couch4 ,the breathing tends during the first part of this stage to be light and is rarely entirely regular3 slight pauses occur1 usually after an inspiration1 less commonly after expiration4 ,serious 8holding of the breath0 7after an inspiration7 rarely occurs save in the type of patient who is also struggling2 if it does occur to a degree which causes any blueness of the patient's face 7cyanosis71 it usually calls for the removal of the ansthetic for a moment until normal breathing has been resumed4 ,the colour of the face rarely departs much from normal during the second stage1 unless cyanosis from breath-holding intervenes4 ,the eyes are usually opened1 as the second stage progresses1 and the eyeballs tend to rotate slowly in every plane4 ,the pupils are usually large1 but react sharply to light4 ,both conjunctival and corneal reflexes are brisk4 ,,the ,,onset ,,of ,,the ,,third ,,stage is marked by the appearance of muscular relaxation4 ,any limb which the patient may have been holding rigidly up sinks down on to the couch1 and it will be found that if an attempt be now made by the ansthetist 7as it should be7 to turn the head of the patient to one side or another1 the muscles of the neck no longer resist4 ,the respiration also alters in type1 losing its tendency to lightness and irregularity1 and becomes full1 deep1 and regular4 ,in open ether ansthesia particularly1 expiration commonly assumes a 8blowing0 type very characteristic1 and which to the trained ear is of itself an indication that full surgical ansthesia is present or at any rate not far distant4 ,the colour varies somewhat with the ansthetic in use4 ,with ether it is usually somewhat higher than normal1 and a trace of blueness may be present if the method is the 8closed0 one4 ,anything more than a trace1 however1 must be regarded as abnormal1 whatever the method or ansthetic may be4 ,with chloroform the colour is perhaps a little paler than that normal to the individual4 ,the eyelids are usually half open1 and the eyeballs at rest looking forward and slightly downwards4 ,an extreme rotation downward may usually be taken as a sign of very deep ansthesia4 ,the pupil is1 as already said1 always active to light1 but its actual size varies with the ansthetic used4 ,with ether1 particularly 8closed0 ether1 it may be large 7#d-e millimetres73 with open ether1 preceded by morphia1 about #c-d millimetres3 a good chloroform ansthesia usually exhibits a pupil of only #b-c millimetres1 and if morphia has also been given1 it may be pin-point in size4 ,too much emphasis must not be placed1 however1 upon the mere size of the pupil2 that may vary within wide limits without necessarily indicating serious abnormality4 ,the essential point is that the light reflex shall be brisk4 ,a pupil of #e millimetres reacting sharply to light may be of no special moment3 one of that size immobile to light would cause real anxiety4 ,the conjunctival reflex usually disappears fairly early in the third stage3 if briskly present1 the ansthesia is certainly a light one1 and probably insufficient for an abdominal section4 ,the corneal reflex if properly taken in the way already described can usually be elicited throughout the third stage4 ,in an ansthesia deep enough for abdominal section it is1 of course1 not brisk1 but we may say generally that its entire absence is presumptive evidence of a very deep ansthesia--probably undesirably deep4 ,it must not be forgotten that some local causes such as drying of the surface of the cornea may cause it to disappear1 and in case of doubt it is sometimes worth while to wash out the eye with a little saline solution4 ,if after doing so the ansthetist still finds the reflex not present he should be on his guard4 ,provided1 however1 that the light reflex is still present and colour and respiration satisfactory1 he need not consider that the patient is in any immediate danger4 ,broadly speaking1 then1 the third stage1 the stage which is called for by the requirements of major surgery1 is characterised by 7#a7 full regular respirations2 7#b7 colour not much removed from normal2 7#c7 moderate sized pupil1 larger in the case of ether than chloroform2 7#d7 conjunctival reflex faint or absent2 7#e7 corneal reflex just present1 or1 in a deep third stage1 just absent2 7#f7 light reflex present3 these may be regarded as the signs of fully developed surgical ansthesia4 ,the absolute beginner may be so completely out of his reckoning as to mistake the quietude of the later part of the first stage for the appearance of the third stage4 ,for the prevention of so gross an error as that1 the reader need only be referred to a patient study of the foregoing4 ,but even a man with considerable experience may frequently be in doubt exactly as to how far through the third stage his patient has passed4 ,he may have attained a level which will permit an incision to be made into the skin without movement on the part of the patient1 but not one which would relax the abdominal muscles sufficiently for the peritoneum to be opened without eliciting considerable resistance from the abdominal muscles4 ,in such moments of doubt1 the author is accustomed to request the surgeon to make his skin incision1 and observe the effect which this trauma has upon the depth1 frequency1 and regularity of respiration4 ,this furnishes a most valuable guide to the depth of ansthesia4 ,in a third stage of very light degree1 the respiratory rhythm will be interrupted and the breath held for a second in inspiration4 ,apart from any other sign1 that may be taken as an index that the ansthesia is very light--too light to permit of opening the peritoneal cavity4 ,in a very deep ansthesia the respiration is little affected by the skin incision1 while at a moderate and more desirable level the respiration is quickened and deepened1 but unaffected in the regularity of its rhythm4 ,,the ,,fourth ,,stage ,,is ,,stage ,,of ,,over-,,dose4--,this stage is1 of course1 never entered voluntarily4 ,its earliest signs are loss of all tone in the muscles of expression1 complete loss of corneal reflex1 a widely dilated pupil insensitive to light1 and a type of respiration which though definitely weakened may show occasional deep gasps4 ,circulatory failure and cessation of respiration from failure of the medullary centre are the closing phenomena of overdose4 ,the ,circulation in ,ansthesia4 ,it will be perhaps noticed that in the foregoing1 no reference has been made to the examination of the pulse4 ,this is not an oversight on the part of the author4 ,it is perfectly true that under any ansthetic not complicated by an asphysical element1 the blood pressure falls as the drug takes effect1 and that in the case of chloroform the fall is often quite considerable4 ,such a fall can be appreciated by the skilled finger1 but only by concentrating upon that examination a degree of attention which necessarily detracts from the administrator's available energy for the observation of other signs which are of equal value1 and can be more rapidly and certainly appreciated and appraised4 ,it is nevertheless essential to assure oneself during the whole progress of an ansthesia that the circulation is in a satisfactory condition4 ,two obvious guides to this are the colour of the patient's face and the force with which cut arteries spout4 ,as regards the colour in circulatory failure1 one would naturally expect a pallid face1 and this indeed is the rule4 ,it must not be forgotten1 however1 that cyanosis may sometimes be cardiac in origin4 ,cases do sometimes occur when a bluish tinge is seen on the lips1 ears1 and nostrils1 apart from any obvious cause of oxygen starvation4 ,in these we may reasonably suspect that the right heart is failing1 and take measures accordingly4 ,another valuable index to the state of the circulation is the 8skin reflex10 that is1 the speed with which the circulation returns to an area of the skin which has been pinched4 ,the student should train his eye by occasionally pinching the lobule of the patient's ear and observing first the white area so produced1 and later the rate at which1 in a normal case1 the healthy colour returns4 ,abnormal ,phenomena in ,ansthesia4 ,it is not intended to furnish here any account of matters more suitably treated under the 8,accidents of ,ansthesia10 which are fully described in ,chapter xvi41 but merely to draw the attention of the student to certain departures from the normal course of ansthesia which are encountered with varying frequency1 to ascribe them as far as possible to their true causation1 and indicate methods of prevention4 ,the abnormalities fall into two classes1 those connected with the nervous and muscular systems1 and those in which respiratory changes are evident4 ,,motor ,,and ,,nervous ,,system4 ,clonus or tremor sometimes appears in one or more limbs1 even the trunk being affected in severe cases4 ,ether is practically the only ansthetic under which the tremor ever appears1 and the condition is often spoken of as 8ether tremor40 ,it rarely appears in the female subject1 being almost limited to powerfully built young men4 ,coming on towards the end of the second stage1 it frequently persists in the deepest of third stages1 and in bad cases there is usually no option but to change over to chloroform--always supposing that the tremor will interfere with the work of the surgeon4 ,if it will not1 the condition calls for no active treatment1 since it is in itself not dangerous4 ,movements recalling to the observer the condition of athetosis seen in the limbs of hemiplegics are occasionally seen in the ansthetised patient4 ,the fingers of a hand may be slowly moved1 or one or other shoulder may be shrugged4 ,the exact cause of these movements is obscure4 ,they occur in all types1 both sexes1 and at all ages2 they are not necessarily asphyxia though a trace of asphyxia seems sometimes to conduce to them4 ,they persist for some time after the third stage has been entered1 and ultimately disappear without any obvious cause other than the passage of time4 ,it is rare for them to continue more than five or ten minutes after full ansthesia has been induced4 ,their practical importance lies purely in this1 that the inexperienced ansthetist observing some muscular movements still persisting1 may take them as an infallible sign that ansthesia is not complete1 and may deliberately take his patient to a deeper level4 ,if in doubt1 the ansthetist must1 of course1 consult all the other recognised guides1 such as the eye reflexes1 but once he has seen these movements in a case1 and had demonstrated to him their slow1 rhythmical character1 he is not likely to be misled on a future occasion4 ,muscular rigidity has been mentioned already in ,chapter iii4 ,when it persists in a patient in whom other signs suggest that a full ansthesia has been produced1 the ansthetist will usually find that attention to the air-way1 and perhaps a whiff of oxygen1 will remedy the trouble4 ,respiratory ,abnormalities4 ,shallow breathing or even slight temporary arrests of respiration arise frequently4 ,during the induction stage they may be due to3-- #a4 ,apna or acapnia following voluntary excessive breathing4 #b4 ,using morphia before chloroform4 ,at a later stage1 it may be due to3-- #a4 ,acapnia following excessive breathing excited reflexly from the seat of operation4 #b4 ,direct reflex inhibition of the respiratory centre4 ,an example of this is seen sometimes when the bladder is over-distended by lotion4 #c4 ,impending vomiting4 ,moist sounds not uncommonly appear4 ,the student's general knowledge of medicine will enable him to decide whether the fluid is likely to be in the pharynx1 larynx1 trachea1 or bronchi4 ,if in one of the first two named1 it will suffice to swab out the throat and encourage the patient to cough4 ,if1 however1 moisture is evidently present in the trachea or bronchi1 the condition is one calling for considerable care and judgment4 ,it arises more commonly with ether than with chloroform4 ,much will depend upon how much longer the surgeon requires to finish his operation4 ,if only a few minutes more are required1 nothing is necessary but to cut down the amount of ether being given to the minimum possible4 ,if1 however1 the surgeon has still a good deal to do1 the safest thing is to withdraw the ether and substitute chloroform or a mixture4 ,be it clearly understood1 however1 that such a change over is not devoid of risk4 ,if it is to be made1 it must be done early1 before the patient is cyanosed and almost drowned in his own secretion4 ,in a neglected case where cyanosis has already appeared1 there will be no option but to interrupt the operation1 empty the chest by encouraging coughing1 and to aid the process by compressing the patient's chest during expiration4 ,thereafter chloroform may be given1 but with the greatest care4 ,gasping and sighing are not common phenomena but when they occur1 call for close notice from the ansthetist4 ,excluding1 of course1 such occurrences in the first stage1 before volitional control has been lost1 they may be usually but not invariably ascribed to overdosage or to the appearance of definite surgical shock4 ,whenever they are noticed1 therefore1 it behoves the administrator to overhaul the patient thoroughly1 to consult the eye reflexes1 the skin reflex1 and the pulse1 and not to rest until he is assured that there are no other signals of danger to be found4 ,stertor and stridor4 ,the first of these is caused by flapping of the soft palate4 ,it is a noise low in pitch1 resembling ordinary snoring4 ,indicating as it does that the palatal and therefore probably other muscles1 are relaxed1 it may if moderate in volume usually be taken as a favourable sign4 ,if it becomes very loud1 however1 the probability is that the base of the tongue has fallen back2 cyanosis will begin to appear1 but will immediately be remedied by pulling forward the jaw or in extreme cases1 using the tongue forceps4 ,stridor is a high-pitched sound produced by approximation of the vocal cords4 ,it has already been dealt with in ,chapter iii4 ,false ,ansthesia4 ,this term has been applied to a condition often seen in children1 and occasionally in adults4 ,it is almost limited to chloroform3 the author has never seen a genuine case when ether has been in use4 ,it appears very quickly after inhalation has begun3 the muscles are relaxed1 the respirations quiet and regular1 the conjunctival reflex sluggish4 ,a very marked feature is the excessive smallness of the pupil4 ,obviously then1 the condition much resembles a true third stage1 but if the operation be begun1 the mistake will very rapidly be made evident1 for the patient will at once move and cry out4 ,in essence1 the condition is simply one of ordinary sleep4 ,it can be recognised by its appearance after a period of inhalation too brief for the induction of true ansthesia1 by the very small pupils and the lightness of the respiration4 ,it will be a waste of time to permit the condition to continue1 as the lightness of the respiration delays the taking in of a dose of the ansthetic sufficient to induce a proper third stage4 ,the remedy is simple1--rub the lips and face smartly with a towel or the hand1 when respiration will at once deepen and the pupil dilate4 ,thereafter1 the induction should proceed normally4 ,,chapter ,,vi4 ,,preparation ,,of ,,the ,,patient4 ,for all but short ansthesias conducted chiefly by nitrous oxide1 the intestinal tract of the patient must receive careful preparation4 ,in doing this1 one must avoid excessive starvation and purgation1 both of which tend to increase shock4 ,we will suppose that the operation is timed for #aj a4m4 on ,tuesday morning4 ,on ,monday morning the patient receives an aperient which may be varied a little to suit his taste and habits4 ,if he has no preference1 there is nothing better than an ounce of castor oil4 ,during the rest of ,monday1 he has a light diet3 fish and milk pudding in the middle of the day1 a little soup at night4 ,the aperient should operate before #i p4m4 ,when that is over1 the patient retires to bed4 ,during the day he may be allowed to move about his room a little1 but should not undertake any exertion4 ,if there be excessive nervousness1 or a natural tendency to insomnia1 sulphonal gr4 #ae or veronal gr4 #h may be given early in the evening1 to ensure a night's rest4 ,about #f a4m4 on ,tuesday morning1 a large soap and water enema is given1 and when this has operated1 a cup of tea or a little soup or ,bovril may be taken4 ,thereafter nothing should be given by mouth4 ,the early forenoon is the time of choice for any operation1 but if an afternoon time be of necessity chosen1 the patient should not be starved throughout the forenoon4 ,a repetition of the early morning meal may be allowed about #aa a4m4 ,in cases such as gastro-enterostomy1 where the alimentary tract will be opened1 the preparation must be a little more stringent4 ,it is usual to allow no solids at all the day before4 ,a saline enema may be given an hour or two before operation1 when the soap and water has been evacuated4 ,preliminary ,hypodermic ,medication4 ,this great improvement in ansthesia was practised many years ago by a few surgeons1 but it was only when open ether assumed its present position of pre-eminence that it was widely adopted4 ,the present routine is to give morphia gr4 1 atropine gr4 to adult patients three quarters of an hour before operation4 ,it has the following advantages3-- 7#a7 ,the nervous fears of the patient give place to a feeling of bien-tre4 7#b7 ,the secretions of saliva and of mucous from the respiratory mucous membranes are limited4 7#c7 ,a little less inhalational ansthetic is required4 7#d7 ,the after vomiting is lessened1 and probably the liability to inflammatory respiratory complications also reduced4 ,the disadvantages can be met by proper care and dosage4 ,they are as follows3-- 7#a7 ,morphia plus chloroform depresses the respiratory centre at an early stage of ansthesia4 ,respiration becomes infrequent and shallow1 and cyanosis appears before the patient is really sufficiently ansthetised for the purposes of the surgeon4 7#b7 ,the larger the dose of morphia1 the more troublesome is this premature failure of respiration4 ,the moral is obvious3 give the small doses above recommended and induced with mixtures weak in chloroform1 or better still with ether only 7see page #hf74 ,some years ago1 before these facts were appreciated1 there was a fashion for giving very large doses of preliminary narcotics4 ,the combinations most favoured were as follows3-- ,,scopolamine-,,morphine4 ,scopolamine is a form of hyoscyamine and is itself a powerful narcotic4 ,two or sometimes three doses of the mixed drugs were given at intervals of an hour1 the last half an hour before operation4 ,scopolamine gr4 1 morphia gr4 was the usual formula3 some surgeons added a dose of atropine or strychnine with the idea of stimulating the respiratory centre4 ,the patients went to the operating or ansthetising room so drowsy that they were unaware of their surroundings1 and afterwards had no recollection of the actual beginning of the inhalation4 ,so humane a method naturally attracted a good deal of attention1 but the serious depression of the respiratory centre which seems inevitable in the method has gradually caused it to disappear from the practice of most surgeons and ansthetists4 ,at the present day1 it is only to be recommended in midwifery practice2 to the drowsy semi-conscious condition produced1 the name of ,twilight ,sleep has been given4 ,,omnopon ,,and ,,omnopon-,,scopolamine4 ,omnopon is composed of a mixture of several of the alkaloids derived from opium2 the makers claim that it produces less after malaise than morphia alone4 ,it may be given before ansthesia in doses of - gr41 either alone or combine with a small dose of scopolamine4 ,it gives quite good results if not pushed to excess4 ,,heroin ,,hydrochloride ,this comparatively modern sedative is used by some surgeons in preference to morphia4 ,a dose of gr4 is quite sufficient1 three quarters of an hour before operation4 ,atropine should always be combined with it4 99 99 99 99 99 ,to young children1 morphia should not be given1 but atropine may be given freely4 ,a child of twelve months tolerates a dose of gr4 quite well3 one of six years1 will take gr4 ,in ages ranging from #ab years upwards1 greatly reduced doses of morphia may be given4 ,no child under #ae years requires more than gr4 of morphia at most4 ,,chapter ,,vii4 ,,nitrous ,,oxide4 ,special ,physiology4 ,upon the nervous system1 nitrous oxide acts like other ansthetics1 but the stages of ansthesia are passed through so rapidly that a second stage can hardly be distinguished4 ,it is rare for struggling or excitement to be manifest1 unless air or oxygen be admitted at the same time1 when the effect which led ,humphrey ,davy more than a century ago to apply to nitrous oxide the name of 8laughing gas0 is very evident indeed4 ,upon the other systems of the body1 nitrous oxide has little if any effect in itself4 ,the essential point to remember in connection with nitrous oxide administered unmixed with air or oxygen is that there is an inevitable element of asphyxia4 ,the larger part of the oxygen normally carried by the red blood corpuscles is eliminated and replaced by ,n#b,o3 oxygen starvation is therefore of necessity present4 ,in other words1 the 8vicious circle of asphyxia0 7see ,fig4 #e7 is entered1 and muscular spasm is bound ultimately to appear4 ,moreover1 the blood pressure rises very materially as a result of the lack of oxygen4 ,that no harm results to the normal healthy patient from this rise is due to the fact that the gas does not in itself poison the heart muscle1 which can therefore stand up to the extra strain of working against higher resistance1 so long as the process is not carried to extremes4 ,a heart muscle weakened by the action of chloroform would give out at once if exposed to such a test4 ,apparatus4 ,nitrous oxide is supplied by the makers as a fluid condensed in iron bottles or cylinders1 and only becomes gaseous upon being released from them4 ,in passing from the fluid to the gaseous state1 heat is of course lost1 and it will be noticed that the end of the cylinder which is in use becomes rapidly crusted over with frost4 ,ice1 moreover1 forms in the small channel at the head of a cylinder1 and is apt from time to time to block it4 ,the cylinders are of various sizes and designated after the numbers of gallons of gas which they will supply3 #be is the smallest size1 #ej or #ajj are more usual2 anything up to #ejj is occasionally met with in hospital practice4 ,moreover the cylinders are of two types1 called respectively vertical 7for use in the upright position71 and angle for use in the horizontal position 7see ,fig4 #ac74 ,illustration3 ,,fig4 #ab4--;,frame for adapting vertical cylinders to foot use4 ,illustration3 ,,fig4 #ac;,a4 ,,fig4 #ac;,b4 ,two types of ,n#b,o cylinders4 ,a4 ,vertical 7or ordinary74 ,b4 ,angle4 ,the cylinders are fixed in frames of various types of which examples are seen in ,figs4 #ac and #ad4 ,upon each cylinder1 of whatever size or type1 will be found a label stating its weight when full and empty1 the difference representing the weight of the contents when the bottle is full4 ,for instance1 in the case of the #ej-;gallon cylinder the weight of its full charge is #ae ounces4 ,weighing the cylinder is the only certain means which we have to estimate how much of the charge remains4 ,the student will readily appreciate therefore that once a cylinder has been used at all there is always a risk of the supply of gas from it running out during an administration4 ,it is for this reason that cylinders are habitually used in couples1 one of which is always supposed to be quite full4 ,to this one it is well to attach a label marked 8full10 and care must be taken to replace at once a cylinder known to be empty4 ,in this way we always have upon the frame one cylinder partly and another entirely full4 ,illustration3 ,,fig4 #ad4--;,complete ,n#b,o apparatus1 showing twin cylinders1 supply pipe1 #b-;gallon bag1 #c-way tap1 and face-piece4 ,by whatever makers the cylinder is supplied it will be found that the thread upon the outlet pipe is the same1 and the metal nipple figured in ,fig4 #ad will fit it4 ,to the distal end of the nipple1 a rubber tube is attached which leads to a rubber bag usually of #b gallons capacity4 ,the remainder of the apparatus may be of several types4 ,fig4 #ae shows the ordinary ,barth three-way tap with facepiece2 the indicator on the tap has three possible positions designated on the dial as 8,air10 8,valves10 and 8,no ,valves40 ,if the tap is pointed backwards towards the bag at the position marked 8air0 the end of the bag is closed and the patient is breathing air only4 ,with the tap in the middle position of 8valves10 the inspiration of the patient will draw gas from the bag1 but the expiration closes the valve which is now in operation at the orifice of the bag1 and will open the expiratory valve which conducts the expired air into the general atmosphere4 ,in the third position of 8no valves0 the patient breathes both in and out of the bag4 ,illustration3 ,,fig4 #ae4--;,barth #c-way ,n#b,o tap4 ,illustration3 ,,fig4 #af4--;,hewitt's wide-bore gas valves4 ,fig4 #af shows the ,hewitt type of inhaler4 ,the calibre of the orifices through which respiration takes place is greater than in the ,barth three-way tap1 and to that extent this type of valve is to be preferred4 ,although differently arranged exactly the same possibilities are present in it4 ,the facepiece is sometimes made of celluloid with an inflatable rubber edging4 ,the object of this type of facepiece is that the colour of the lips may be appreciated by the ansthetist during the administration4 ,the preferable plan is to make the whole facepiece of rubber with an inflatable border4 ,such a facepiece made by a good maker will last many years1 and is much more stable and reliable than its celluloid competitor4 ,the ,care of the ,nitrous ,oxide ,apparatus4 ,this is a matter of considerable moment1 particularly to those who do not use their apparatus every day4 ,after use1 the valves1 facepiece1 and bag should be disconnected from each other1 all moisture wiped away from the bright parts1 and the bag hung up with its open end downwards1 and preferably in a warm room4 ,if re-breathing has been extensively practiced it is well to wash the bag out with some carbolic lotion before hanging it up4 ,the rubber valves in the valvepiece are liable to lose their elasticity1 particularly if kept in a cold place after becoming damp4 ,from time to time the valve piece should be taken to pieces1 the valves carefully dried in front of a warm fire and powdered over with a little talc4 ,administration4 ,most commonly nitrous oxide is administered to a patient sitting in a chair4 ,care should be taken that the respiration of the patient shall not be obstructed by tight clothing round the throat or chest1 and that the head and neck are neither unduly flexed nor extended upon the shoulders4 ,the patient should not have any solid food for two hours before the ansthetic4 ,at the last moment he should be instructed to empty his bladder4 ,artificial dentures if present should be removed1 and1 if the ansthetic is being given for the purpose of the extraction of a tooth1 it will be necessary before applying the facepiece to insert between the teeth a dental prop4 7,see ,fig4 #f47 ,standing to the left and slightly behind the patient the ansthetist's first step is to secure good apposition between facepiece and face4 ,this is best done by working from above downwards3 that is to say1 secure first a good fit at the bridge of the nose1 and then approximate the remainder of the rim of the facepiece to the cheeks and lower jaw4 ,during this stage the indicator of the tap is kept at 8,air40 ,working with the left foot the administrator now opens the head of one of the cylinders with the foot key4 ,it is wise first to have loosened this with a hand key1 and leave it just 8on the swing10 otherwise one's boots are apt to suffer6 ,gas is allowed to flow into the bag until it is partially1 but by no means tightly distended4 ,the patient is instructed to breathe naturally and easily1 and during the whole process the ansthetist should converse with him in a quiet easy way4 ,the tap is now turned to 8valves0 and the patient begins to inspire the gas1 a supply of which is allowed to flow steadily from cylinder into bag4 ,after a few breaths of the gas1 when the sensibilities of the patient are a little dulled1 it is wise to allow the gas to flow a little more freely and to distend the bag4 ,this exercises upon the patient a slight positive pressure1 which has been proved both experimentally and practically to increase the rapidity of the absorption4#a ,the valves are left in operation for some thirty or forty seconds1 after which time the supply of gas should be cut off and the tap be pushed over to the position of 8no valves0 for further twenty seconds4 ,this should be ample to secure full gas ansthesia4 ,the phenomena seen in nitrous oxide ansthesia are so different from those of any other that a few words must be said about them4 ,within a few seconds of the inhalation beginning1 the colour of the patient shows evidence of the presence of the gas in his blood4 ,the normal complexion changes first to a dull pink1 and very rapidly to the definite blue of cyanosis4 ,the eye symptoms are of the utmost value4 ,very early the pupil begins to dilate1 and the eyeball tends during the first twenty or thirty seconds to rotate as if the patient were looking for some object in his field of vision4 ,in full ansthesia the eyeball1 however1 comes to rest1 usually pointed downwards4 ,the pupil is widely dilated1 the conjunctival reflex is almost or even entirely abolished1 but the corneal reflex is still brisk4 ,the respiration tends to become steadily deeper and more frequent1 and in the later stages stertor at least1 if not stridor usually develops4 ,the muscles under ordinary nitrous oxide ansthesia are rarely entirely relaxed1 but the limbs hang motionless1 and it is only if an attempt be made to move them into some abnormal position1 that one appreciates the persistence of muscular tone4 ,a phenomenon peculiar to nitrous oxide ansthesia is observed in its deepest stage4 ,designated as jactitation1 it consists in a tremor beginning in the limbs1 but spreading from them to the trunk if its development is allowed to proceed4 ,it is a finer movement than that described under 8ether tremor0 7page #ch71 and wholly different in type from the athetosis referred to on page #ch4 ,jactitation is almost wholly an asphyxial phenomenon1 and is therefore definitely an indication that the process of oxygen starvation has been carried as far as is permissible4 ,the signs of fully developed nitrous oxide ansthesia then are3-- #a4 ,deep regular snoring respirations4 #b4 ,dilated pupils4 #c4 ,rotation of the eyeball downwards4 #d4 ,loss of conjunctival but persistence of corneal reflex4 #e4 ,a colour of the skin definitely blue1 but not blackish blue4 #f4 ,the commencement of jactitations4 ,the signs of overdose are3-- #a4 ,an enormously dilated pupil not re-acting to light4 #b4 ,loss of corneal reflex4 #c4 ,a blackish blue colour4 #d4 ,jactitations fully developed4 #e4 ,failing respirations4 ,the final arrest of respiration in nitrous oxide ansthesia is usually painfully sudden4 ,upon the respiratory side the only warning is one or two gasps1 and even that is sometimes absent4 ,the paralysed pupil and the jactitations are the most useful signs of overdose4 ,the above1 then1 may be taken as an account of what one expects to see in a normal gas ansthesia during the induction stage4 ,for the great majority of cases1 nitrous oxide is given for the purpose of rendering painless the extraction of a tooth1 and it is1 in this large class of case1 the induction stage only which need be considered4 ,it requires only some fifty to sixty seconds to bring the patient to the stage described under the heading 8fully developed ansthesia0 and when that has been attained1 the mask may be removed and the operation begun4 ,from the moment of removal of the mask1 however1 it must be noted that the patient begins to breathe fresh air and to eliminate the ,n#b,o4 ,the period of ansthesia available to the surgeon or dentist during which he must perform the operation1 is therefore very small4 ,in thirty seconds the patient has frequently recovered sufficiently to begin to feel pain1 and it is rare to secure more than forty-five or fifty seconds by the use of a single dose of nitrous oxide4 ,nitrous ,oxide and ,air4 ,if the nature of the operation does not necessitate the removal of the mask from the face1 it is possible to maintain nitrous oxide ansthesia for some considerable time4 ,the exact length of that time varies a good deal with two factors--the type of patient and the experience of the administrator4 ,heavily built muscular patients are not easily dealt with by prolonged gas ansthesia 7unless with admixture of oxygen as explained in chapter viii47 ,of far greater importance1 however1 is the other factor4 ,the student can easily be taught to give a single dose of gas for the extraction of a tooth1 or the momentary incision of an abscess4 ,he will1 however1 be wise to secure a good deal of practice in that class of work before attempting to prolong gas ansthesia for more than a minute or two4 ,with reasonable skill and experience and the utmost care1 it is1 however1 perfectly possible to prolong nitrous oxide ansthesia for periods of five1 ten1 or even fifteen minutes in the average healthy patient4 ,as soon as the signs of full ansthesia appear1 the valve tap is pushed back to 8air0 for the space of one inspiration and one expiration1 and then at once pushed back to 8no valves40 ,by this manuvre1 one inspiration of air is permitted to the patient1 whose colour at once shows amelioration1 or at any rate no further progression of cyanosis4 ,the admission of air is repeated every third1 fourth1 or at most fifth respiration4 ,after the first minute or so of this cycle of events1 it is obvious that the contents of the bag will be composed of a mixture of nitrous oxide1 air1 and ,,co#b in proportions quite impossible to calculate4 ,it is therefore best to push the indicator to 8valves10 and allow the bag to be emptied by the suction of the patient's inspirations4 ,the cylinder head is then opened by the turning of the foot-key1 and the bag filled again with gas4 ,the cycle of 8air0 and 8no valves0 is then begun again for another minute or so4 ,it must be understood that by this process1 it is not to be expected that an ideal ansthesia can be produced4 ,some movement of the patient will not improbably take place when sensitive structures are cut or handled by the surgeon1 and at no time will the muscles be entirely relaxed4 ,such an ansthesia is therefore only suitable for a limited class of case1 but does admirably for1 say1 opening an abscess1 exploring its interior1 and removing from it a sequestrum or an easily found foreign body4 ,during his service in ,macedonia the author had not at his disposal any of the appliances later to be described under the heading of nitrous oxide and oxygen1 and found 8gas and air0 a most useful form of ansthesia for the requirements of military surgery as seen in a ,base ,hospital1 under active service conditions4 ,contra-indications to the ,use of ,pure ,nitrous ,oxide ,gas4 ,in the healthy subject1 there is no safer ansthetic than nitrous oxide when administered properly and limited to its proper province4 ,from the account given of the physiological action of the gas it will1 however1 be obvious to the student that in a limited class of case its use is not permissible4 ,such cases fall into two categories4 ,firstly1 cases in which an asphyxial element already exists will have their condition greatly aggravated by the substitution of ,n#b,o for the oxygen in their blood4--,already caught in the vicious circle of asphyxia1 nitrous oxide would but push them deeper into the vortex4 ,examples of such cases are patients suffering from tumours or inflammatory swellings in the neck which are pressing upon the air passages4 ,in passing1 one may note that it might be the desire of the surgeon to submit an individual case falling into this group to the operation of tracheotomy for the immediate relief of the condition4 ,the short space of time required for this little operation might well tempt the unwary to choose nitrous oxide as the ansthetic1 and in point of fact such an error of judgment has more than once been made with fatal results4 ,secondly1 no patient suffering from any condition which will be aggravated by a sudden rise of blood pressure1 should be submitted to nitrous oxide undiluted by oxygen4--,examples of such conditions are cases of dilated right heart with weakened cardiac musculature4 ,such hearts could not be expected to work against a peripheral resistance suddenly raised1 say1 from #abj mm4 of ,hg1 to #ahj or even #bjj mm4--figures well within the possible in deep gas ansthesia4 ,similarly1 so great an increase of pressure would be dangerous to a patient suffering from an aneurysm1 or from extensive arterio-scelorosis with high blood pressure4 ,it will be noted that the above warnings are limited to the use of pure nitrous oxide1 that is1 ,n#b,o unmixed with oxygen4 ,the extent to which the dangers referred to can be met by the admixture of oxygen in the manner to be described in the next chapter is largely a matter of the skill and experience of the administrator4 ,nasal ,methods4 ,the object of using this route is to be able to continue the administration throughout the period in which the dentist is doing his work4 ,the essentials of a suitable apparatus are3-- #a4 ,a malleable nosepiece which can be closely adapted to the nose4 #b4 ,two supply pipes from bag to nosepiece4 #c4 ,some means of admitting air to the stream of gas4 #d4 ,a two-gallon bag4 #e4 ,a supply of gas4 #f4 ,a mouth cover with an expiratory valve only4 ,the patient is instructed to breathe in through the nose1 but to expire through the mouth4 ,the gas is supplied under some pressure and the mouth cover ensures that no air is inspired by that route4 ,some patients find it easier to conduct both inspiration and expiration through the nose1 and for their benefit an expiratory valve is also provided in the nosepiece4 ,after unconsciousness has supervened1 nearly all patients begin to-and-fro nasal breathing4 ,the mouth cover may then be removed1 and if it be desired to economise gas1 the expiratory valve in the nosepiece may be thrown out of action4 ,illustration3 ,,fig4 #ag4--;,ash's ,modification of ,paterson's ,nasal ,gas ,,description3--,a--,nose-,cap ,attachment with ,stopcock for ,air and ,gas1 and with ,inspiratory and ,expiratory ,valves and ,shutter4 ,b--,nose-,cap4 ,c--,sliding ,clip on ,india-rubber ,tubings4 ,d--,bifurcated ,mount4 ,e--,bag ,mount4 ,f--,gas ,bag ,compressor4 ,g--,gas ,bag4 ,h--,india-rubber ,tubing4 ,,mc--,mouth ,cover4 ,this is fitted with an expiratory valve1 and should be used at the same time as the ,nose-,cap4 ,by using the two together patients are more quickly ansthetised than they would be if only the ,nose-,cap were used1 and the ,nitrous ,oxide is economised4 ,air must be admitted in limited quantity through the tap after the first thirty seconds or so2 by a judicious regulation of this mechanism1 ansthesia may be prolonged for five or ten minutes4 ,facility with nasal gas comes only after some considerable practice4 ,fig4 #ag shows ,ash's ,no4 #c ,patented ,nasal ,inhaler1 which admits of ,air or ,gas being administered either by the ,naso-,oral ,method1 or by to-and-fro nasal breathing4 ,air only is admitted when the ,shutter ,a is open and turned to the right as far as it will go4 ,nitrous ,oxide is admitted when the ,shutter ,a is open and turned to the left as far as it will go1 and the patient will breathe it in-and-out through the nose4 ,for the ,nasal ,oral ,method1 close ,shutter ,a and turn it to the left as far as it will go4 ,this will cause the patient to inhale through the nose and exhale through the mouth4 ,nasal attachments are provided with most of the gas-oxygen apparatuses mentioned in the next chapter4 ,with them good results can be obtained with much greater ease4 ,for a more detailed account of nasal methods1 the student is referred to works devoted entirely to ,dental ,ansthesia4 ,,chapter ,,viii4 ,,nitrous ,,oxide ,,and ,,oxygen4 ,the account given in the previous chapter of ansthesia by nitrous oxide and air will have convinced the student that it is a somewhat inelegant method with a limited sphere of usefulness4 ,the reason is obvious4 ,in atmospheric air1 oxygen exists only in the proportion of about one to four of nitrogen4 ,to sustain life it is therefore necessary to admit to the ansthetic mixture an amount of air which leaves too little room for the ansthetic factor--nitrous oxide4 ,if1 however1 pure oxygen be used1 the nitrous oxide is diluted to a much less degree1 and far better results are obtained4 ,the exact scope for gas-oxygen ansthesia cannot at present be defined with certainty4 ,the work of ,crile1 and the experience of the war have done much to enlarge it4 ,we may say that the following are definite indications for its use3-- 7#a7 ,minor operations lasting #e-ae minutes1 particularly if performed on out-patients4 7#b7 ,operations of any variety upon the subjects of severe shock4 7#c7 ,operations upon patients suffering from acute sepsis4 7#d7 ,operations repeated upon the same subject at short intervals4 ,as regards 7#c7 and 7#d71 the lack of toxic properties in nitrous oxide gas1 and the rapidity with which it is eliminated1 give it a tremendous advantage over ether or chloroform4 ,to men with shattered bones and extensive damage to soft tissues1 badly infected with sepsis1 who required repeated opening up of pockets1 changing of gauze packs1 etc41 the advantage of gas-oxygen over ether was evident1 and was easily appreciated by the patients themselves during the late war4 ,there are1 however1 certain drawbacks to the method which must be appreciated-- 7#a7 ,the necessary plant is heavy1 bulky1 and costly2 it cannot be easily transported4 7#b7 ,the running cost is high as compared with ether or chloroform4 7#c7 ,it has been said by some that gas-oxygen can only be given by an expert4 ,that is a statement too extreme1 in the author's opinion4 ,certainly1 of all ansthetics it is the most difficult to give successfully4 ,adequate study and proper teaching by an expert are required1 but given these two helps1 any one can soon learn to administer gas-oxygen for minor surgery4 ,considerably more experience is1 however1 necessary before the beginner should give it for an abdominal section4 ,apparatus4 ,a good gas-oxygen apparatus is necessarily rather complicated4 ,the machines in the market are numerous1 and of the most diverse external appearance4 ,certain broad principles1 however1 underlie all the machines1 and it is to be hoped that some one of them will before long become practically the standard4 ,once that is effected1 hospitals and nursing homes could be expected to provide them4 ,so long as every ansthetist asks for a different machine1 they certainly never will do4 ,a good machine must provide means for the following3-- 7#a7 ,an even flow of both gases under perfect control4 7#b7 ,a percentage of ,oxygen in the mixture rising at the will of the administrator from #b to #ae or #bj4b ,to meet this requirement it is not necessary that any indicator should be provided which shows with mathematical precision what percentage of oxygen is being given4 ,the colour of the patient tells us at once if too much or too little oxygen is being supplied1 and all we need in the apparatus is some mechanism whereby we can tell approximately to what extent we are increasing or decreasing the percentage4 7#c7 ,positive ,pressure4--,if the pressure at which the gases are supplied to the patient can be raised a little above that of the ordinary atmosphere1 absorption is increased and a deeper ansthesia produced4 ,in the author's view1 this is an essential point in a good instrument4 7#d7 ,re-breathing4--,to supply the whole volume of gases required for inspiration during a long operation is costly and quite unnecessary4 ,yet that is what is being done if the whole administration is conducted upon the 8valvular0 principle4 ,moreover1 a prolonged inhalation upon the valves tends to remove a great deal of ,,co#b from the patient's blood and tissues 7see ,chap4 ,,iv474 ,periods of partial or complete re-breathing do much to deepen respiration1 and reduce the cost of the ansthetic4 7#e7 ,warming the ,gases4--,while not essential1 this is certainly an advantage4 7#f7 ,addition of ,ether ,vapour to the mixture4--,gas-oxygen even well given is hardly capable of reducing to quiescence very robust people1 unless the oxygen percentage is kept to an undesirably low level4 ,the merest trace of ether vapour as an adjunct is a great assistance during the stages of the operation where very sensitive structures such as the parietal peritoneum are being handled4 ,the more experienced the ansthetist1 the less will he require such assistance4 ,hewitt's ,apparatus4 ,this1 with the exception of one designed by ,dr ,guy and the author1 and described on page #acj1 is the only machine with any pretence to portability by hand4 ,it does not satisfy all the requirements above referred to1 but the fact that it was the first practicable means introduced in this country to give gas-oxygen entitles it to full description4 7,see ,fig4 #ah47 ,illustration3 ,,fig4 #ah4--;,hewitt's gas oxygen apparatus4 ,essentially it consists of the following3-- 7#a7 ,a supply of nitrous oxide and oxygen in separate cylinders4 ,hewitt's own stand held two of nitrous oxide and one of oxygen4#c 7#b7 ,rubber pipes of supply for each of the two gases4 ,for convenience1 it is sometimes arranged that one of these shall run inside the other4 7#c7 ,two #b-;gallon bags4 ,nitrous oxide is led into the one1 oxygen into the other4 ,the mouth of each bag is guarded by an inspiratory valve4 7#d7 ,the mixing chamber4 ,upon the surface of this are marked successively3 8,air10 8,n#b,o10 8,o#b1 #a #b #c #d #e #f #g #h #i #aj40 ,as the indicator is pushed from 8air0 to 8,n#b,o10 the patient begins to inhale nitrous oxide only1 but as it travels into the numerals #a1 #b1 etc41 a proportion of oxygen is added4 ,immediately below the mixing chamber is the expiratory valve4 7#e7 ,lastly1 there is the facepiece1 identical with that used for pure nitrous oxide4 ,it would be fallacious to suppose that the numerals #b1 etc41 on the dial represent accurately the percentage of oxygen yielded by the instrument when the indicator points to one of these figures1 nor did ,hewitt ever make such a claim4 ,what the figures do represent is a number of holes in the wall of the mixing chamber1 opposite to the aperture from the oxygen bag1 which are uncovered one by one as the indicator moves over4 ,the amount of oxygen which enters into the mixing chamber is regulated by the number of these holes uncovered1 and also by the tension of the oxygen bag4 ,if the figure on the dial is to be even a rough index of the actual percentage of oxygen present in the mixture1 it is necessary to keep the tension reasonably constant1 i4e4 to regulate the flow of oxygen from the cylinder by manipulation of the foot key4 ,in a brief administration for1 say1 a dental case1 this is not necessary4 ,it is sufficient to fill the oxygen bag once1 and then turn off the supply4 ,if1 however1 a long administration is required1 a constant flow of oxygen of just the requisite amount must be secured4 ,administration4 ,put the lever at 8air10 and fill up each bag to an equal and moderate degree of distention4 ,adapt the facepiece accurately to the patient's face1 and then push the lever to 8,n#b,o04 ,after a few inhalations1 move to #b of oxygen2 regulate the flow of nitrous oxide from the cylinder so that the ,n#b,o bag remains slightly distended4 ,gradually move the indicator along the numerals until the figure #f or #h is reached at the end of about a minute or a minute and a half4 ,women and children require more oxygen than men4 ,the former are easily cyanosed2 if the latter are fed too generously with oxygen1 they are apt to become excited4 ,take as your guide to the amount of oxygen required the colour of the patient1 the type of respiration1 and the size of the pupil4 ,the colour aimed at can only be learnt by experience1 but is best described as a dull pink4 ,the ,type of ,respiration4--,too little oxygen leads to stertor and even stridor2 too much oxygen1 to a light almost noiseless respiration1 which to the experienced ear is the certain precursor of a stage of excitement4 ,such a stage is clear evidence of too much oxygen having been given4 ,the pupil should not be dilated to anything like the degree seen with undiluted nitrous oxide4 ,a moderate distention only is to be desired4 ,full ,ansthesia should be reached in #ajj-abj seconds4 ,it is marked by3-- 7#a7 ,dull pink complexion2 7#b7 full respiratory movements with a stertor not exceeding that of gentle snoring2 7#c7 eyeballs rotated downwards2 7#d7 moderately dilated pupils2 7#e7 loss of conjunctival reflex2 7#f7 corneal reflex present but not very active4 ,if the object be the removal of a tooth1 the mask may now be removed1 and the dentist may rely upon a period of ansthesia somewhat longer than that furnished by pure nitrous oxide4 ,he ought to secure approximately one minute in which to do his work4 ,ansthesia by this apparatus may however be prolonged for an indefinite time if desired4 ,in order to maintain the patient in the condition described above1 it will be necessary gradually to increase the supply of oxygen4 ,for this purpose ,hewitt added to his mixing chamber a supplementary oxygen supply giving #aj or #bj volumes of oxygen4 ,as a matter of fact1 all the necessary supply can be got through the original ten holes if the tension in the oxygen bag be increased4 ,the regulation of all this requires1 of course1 considerable practice and experience4 ,the signs upon which we rely for warning that the supply of oxygen is insufficient to keep the patient safe1 are chiefly the colour of the face1 which must not pass from dull pink to blue1 and the size of the pupil4 ,illustration3 ,,fig4 #ai4--;,diagrams to illustrate action of 7,a7 ,hewitt 7,b7 ,teter gas oxygen apparatus4 ,note that in ,a the mouths of both bags are guarded by valves of inspiration1 while in ,b the oxygen bag only possesses it4 ,deficiencies of ,hewitt's ,apparatus4 ,these are chiefly two3-- 7#a7 ,there is no means of producing positive pressure4 ,any attempt to distend the nitrous oxide bag beyond a certain point simply leads to escape of the gas through the mixing chamber and out of the expiratory valve even during inspiration4 ,to this defect especially must we attribute the fact that an ansthesia deep enough for abdominal section is difficult to secure with the ,hewitt instrument4 7#b7 ,there is no means of securing re-breathing4 ,the whole administration must of necessity be conducted 8upon the valves40 ,this latter fault is remedied by the modification introduced by ,burns1 who took away the inspiratory valve from the mouth of the ,n#b,o bag1 and fitted a cap over the expiratory valve which could be rotated so as to throw the valve out of action4 ,the author first met this modification at a ,base ,hospital in ,france1 and found it a great improvement upon the original instrument4 ,it is1 however1 only an imperfect attempt to adopt ,teter's chief principle4 ,the ,teter and ,allied ,machines4 ,the rapid spread of nitrous oxide and oxygen ansthesia in the ,u4,s4,a4 brought forward a number of machines of which ,teter's was the forerunner2 the other well-known machine of the group is the ,clarke4 ,they differ in principle from the ,hewitt apparatus in that they permit re-breathing and the use of positive pressure4 ,diagrammatically1 the two are contrasted in ,fig4 #ai4 ,illustration3 ,,fig4 #bj4--;,details of the ,clarke ,expiratory ,valve4 ,in the position of the lever marked 8open0 the valve lifts easily and widely1 and the breathing will be purely valvular3 in the position marked 8half open10 the valve lift is diminished1 and the breathing is partly valvular1 partly to-and-fro4 ,in the position 8closed0 re-breathing only is possible4 ,the key to ,teter's advance is his removal of the inspiratory valve from the mouth of the nitrous oxide bag1 and his substitution for ,hewitt's rubber expiratory valve1 of a rigid valve1 the lift of which can be diminished or entirely abolished1 at will 7see ,fig4 #bj74 ,by damming1 as it were1 the flow from the expiratory valve1 the administrator can oblige the patient to practise a certain amount of re-breathing1 and1 if he keeps up a free flow of the gases1 he can develop a pressure in the nitrous oxide bag definitely exceeding that of the atmosphere4 ,teter also introduced into his apparatus a means to warm the gases1 and to add a little ether vapour to the mixture when required4 ,illustration3 ,,fig4 #ba4--,the ,clark gas oxygen machine4 ,the ,clarke machine is similar in principle to the ,teter1 but makes a strong point of the intimate mixture of the two gases produced in the mixing chamber which occupies the centre of the apparatus 7,fig4 #ba74 ,in both these machines1 it will be observed1 the two bags for ,n#b,o and ,o#b respectively are attached to the stand1 and the mixed gases are led to the patient by a pipe of wide bore4 ,when re-breathing occurs1 it must therefore be up and down this pipe1 but the width of the bore seems to obviate any disadvantage which theoretically might be expected from this form of respiration4 ,illustration3 ,,fig4 #bb4--,marshall's sight-feed gas-oxygen apparatus4 ,of the two glass bottles the one to the left is the sight-feed1 that to the right the ether chamber4 ,in the experience of the author and of many other ansthetists1 very good results can be obtained from either of these machines4 ,sight ,feed ,machine4 ,in the author's opinion1 machines based upon this principle are likely to take a prominent place in the future of gas-oxygen4 ,fig4 #bb explains the simple mechanism4 ,each gas is led through a tube dipping into water contained in the sight feed mixing chamber4 ,the ends of the pipes are open1 and on the sides of each pipe also are a number of holes4 ,if the pressure at which either gas is delivered is small1 bubbles will be seen ascending towards the surface of the water from the upper holes only4 ,the greater the pressure1 the further down the pipe does the gas carry before all of it escapes through a hole1 and one can therefore get an accurate estimate of the pressure from the number of holes through which the bubbles are seen escaping4 ,upon the surface of the water1 the two gases meet and enter into mixture and are conveyed away by the third pipe which1 of course1 does not dip into the water4 ,once the eye of the ansthetist is trained to its use1 this is a very simple means of gauging the relative proportions of oxygen and nitrous oxide which are being delivered1 and manipulation of the cylinder heads combined with visual inspection of the sight feed enable one to strike the right proportions very easily4 ,the nitrous oxide is usually kept at a constant pressure sufficient to ensure bubbles1 not only from all the side holes1 but also a few from the open end of the tube4 ,the oxygen pressure is begun at the point where there is a little bubbling from the top hole only1 and is gradually increased until there is a full supply from two holes1 occasionally a little even from a third4 ,messrs ,coxeter have recently brought out two sight feed machines designed by ,mr ,leonard ,boyle and ,dr ,geoffrey ,marshall1 of which the latter is shown in ,fig4 #bb4 ,this apparatus may be put up in either portable form or a larger type for use in hospitals4 ,an ether chamber is provided for use when necessary in either type4 ,as originally introduced1 the remainder of the apparatus consisted simply of an ordinary two gallon bag1 ,barth #c-way tap1 and rubber facepiece4 ,with such an appliance1 it is not possible to secure 8positive pressure1 a point which the author brought to the notice of the makers4 ,messrs ,coxeter are willing to supply a facepiece and expiratory valve which obviate this defect1 being supplied with a mica expiratory valve the lift of which can be controlled4 ,there should be no inspiratory valve4 ,administration of ,gas-oxygen for the purposes of ,major ,surgery4 ,the patient is prepared with the same scrupulous care as if ether or chloroform is to be administered4 ,half an hour before operation1 morphia gr4 and atropine gr4 are given hypodermically4 ,the ansthetist before beginning administration1 must look over the apparatus most carefully and satisfy himself that every part of it is in perfect order1 and that a sufficient supply of both gases is at hand4 ,the inhalation is begun by the use of nitrous oxide alone1 given 8on the valves10 and at no great pressure4 ,after a few breaths1 oxygen is added very guardedly1 the proportion being steadily raised during the first two minutes3 after that point1 a further increase will not be necessary until several more minutes have elapsed4 ,the pressure at which the mixture is being given is also steadily increased and should reach the maximum permissible within a few minutes4 ,a useful plan is to allow the flow of gases to remain constant1 but to close the expiratory valve at frequent intervals for about forty to sixty seconds at a time4 ,during this period of complete re-breathing the tension in the supplying bag will of course rise1 falling again slightly when the expiratory valve is allowed once more to come into action4 ,as soon as the tension falls appreciably1 the valve is again closed down4 ,it is wise1 particularly in one's early days1 to give a trace of ether vapour during the latter part of the induction stage1 and to maintain it until the operation is well under way4 ,once the ansthetist is satisfied that the narcosis is proving deep enough for the purposes of the operation1 the ether may be shut off and will probably not be required again4 ,remember that depth of ansthesia can be secured in three ways--7#a7 cutting down the oxygen percentage2 7#b7 increasing the tension of the mixed gases2 7#c7 adding a little ether4 ,of these1 ,no4 #a is most undesirable1 and if carried to the least excess over a period of more than a minute or two may lead to an accident4 ,no4 #c is the means for the beginner to rely upon1 until he learns the judicious and skilful use of ,no #b4 ,the ansthetist who is learning the method of ansthesing must resolve that nothing shall tempt him to overstep the stage of dull pink colour1 and moderate pupils4 ,if with gas-oxygen alone1 he cannot get a satisfactory ansthesia without resorting to oxygen starvation1 let him not be ashamed to turn on his ether4 ,abdominal relaxation sufficiently complete to permit the surgeon to explore the abdominal cavity with ease1 is not readily secured by gas-oxygen in a patient of robust type4 ,fortunately1 it is the weakly or the severely shocked who really need this form of ansthesia1 and in them abdominal relaxation is fairly easily obtained4 ,professor ,crile1 as has already been explained1 does not rely upon the inhalational ansthetic alone4 ,he infiltrates each layer of the parietes with novocain1 thus producing a local ansthesia4 ,if this method be faithfully carried out by the surgeon1 a most complete relaxation of the muscles can be secured4 ,,chapter ,,ix4 ,,ether4 ,the drug commonly known as ether and otherwise described as ethylic ether or sulphuric ether1 has a chemical formula 7,c#b;,h#e7b,o4 ,it is a transparent colourless fluid with a specific gravity of #gbj to #gbc4 ,a brand much used in the ,states has an ,s4,g4 of #gac only1 a point which is greatly emphasised by its supporters1 who claim that it volatises quicker and therefore is more powerful in action4 ,the author has in actual practise not found much difference between this brand and any good ,british one4 ,ether is highly inflammable and volatilises readily at ordinary room temperatures4 ,its boiling point is #if to #ih ,fahr4 ,whether evaporating from a fabric such as gauze1 or from bulk in a jar1 ether cools very rapidly1 and the fall in temperature soon reduces the ease of its volatisation4 ,this point is of some practical importance in ansthetics1 and some years ago the author made a number of observations1 hitherto unpublished1 with a view of ascertaining some definite facts in this connection4 ,his results will be found in ,appendix ,i4 ,ether vapour is heavy--two and a half times heavier than air4 ,it therefore tends in a room to flow towards the floor1 and to remain for some time unmixed with the general atmosphere4 ,since it is highly explosive1 this constitutes a definite danger if any naked light or open fire is present4 ,everyone who handles ether should bear in mind these physical peculiarities of its vapour4 ,ether is affected by prolonged exposure to bright sunlight1 and also by prolonged bubbling through it of air1 nitrous oxide1 or oxygen4 ,ether which has been subjected to any of these measures should be inspected before being put back into reserve1 and if any brown discoloration is noticed1 it should either be sent to the hospital laboratory for redistillation1 or presented to the theatre sister for use as a cleaning agent4 ,such contributions are always gratefully received4 ,most of the ordinary impurities of ether are acid in reaction1 while ether itself is absolutely neutral4 ,any specimen which turns litmus paper red should be sent to the laboratory for examination4 ,sources of ,supply4 ,ethylic alcohol may be prepared either from ethyl alcohol or from methylated spirits4 ,in the former case it carries1 however1 the cost of the duty imposed upon potable spirit1 and since perfectly good ansthetic ether can be prepared from the latter source1 it is waste of money to use the more expensive article4 ,physiology4 ,ether acts upon the nervous system like other ansthetics3 as compared with chloroform1 however1 the stage of excitation of each centre before its paralysis is apt to be marked4 ,there is1 therefore1 in some subjects1 a greater tendency to struggle2 healthy subjects properly handled do not show much evidence of irritation of the cerebrum4 ,all1 however1 show some evidence of stimulation of the respiratory centre1 which is not prolonged4 ,prolonged deep and rapid respiration under ether is due to other causes than the action of the drug itself4 ,it is of course seen in 8closed ether10 but the active agent is excess of ,,co#b1 not ether4 ,the working margin of safety in ether1 i4e4 the stage between loss of spinal reflexes and the poisoning of respiratory centre is much wider than in chloroform4 ,some experiments of ,waller made many years ago showed that upon nerve tissue1 ether acts much less powerfully than chloroform3 in the proportion1 he found1 of one to seven or eight4 ,these laboratory results have received entire confirmation by later workers who have estimated the actual vapour strength required of either drug to produce or maintain ansthesia4 ,roughly1 to induce ansthesia1 we require #b per cent4 chloroform1 or #af to #ah per cent4 of ether 7see ,appendix ,,ii474 ,the ,circulation4 ,the first effect of ether is a temporary stimulation of the heart1 which beats more rapidly and more strongly1 thus raising the blood pressure4 ,this effect is not very prolonged2 like all other drug stimulation1 it is followed by depression4 ,in the healthy subject properly ansthetised1 such depression is very moderate in degree1 and in a normal administration it is probable that the heart1 after the first few minutes1 is acting very much at its normal speed and force4 ,ether is1 however1 a marked vaso-dilator1 and the net result upon blood pressure is a slight fall after the first few minutes4 ,if the method in use is 8closed10 the pressure remains slightly raised for some considerable time1 usually throughout the administration4 ,the slight anoxaemia induces a vaso-constriction2 and the ,,co#b excess1 in the view of ,henderson 7see page #aj71 maintains a good return of venous blood to the heart and a satisfactory cardiac output4 ,for a note of certain blood changes resulting from ether and other ansthetics 7see ,appendix ,,iii474 ,respiratory ,system4 ,in addition to the effect upon the medullary centre already referred to1 ether effects the respiratory tract more profoundly than other ansthetics4 ,the mucous membranes are irritated1 and in some cases there is a great outpouring of mucous4 ,though usually limited to the upper part of the tract 7nose1 pharynx1 and trachea71 the irritation sometimes extends deeply into the chest1 affecting even the small bronchioles4 ,these unpleasant effects of ether are in the great majority of cases1 quite transient3 after the first ten minutes no addition to the secretions is noticed4 ,in a minority1 however1 the effect persists1 the whole chest is filled with moist sounds1 and persistence with the drug is impossible4 ,the kidneys are always slightly irritated by ether1 and if they are or recently have been subject to inflammatory disease1 a very acute exacerbation is apt to follow the use of the drug4 ,in the healthy kidney this is not to be feared1 nor does it seem to be an appreciable danger where one kidney is sound1 even if the other is the seat of gross organic disease necessitating its drainage or removal4 ,illustration3 ,,fig4 #bc4--;,clover's ether inhaler1 with nitrous oxide attachment4 ,methods of ,administration4 ,many methods have been tried1 but those which at present hold the field are-- 7#a7 ,closed ,ether4 7#b7 ,open ,ether1 more properly called the ,perhalation ,method4 7#c7 ,the 8,vapour0 ,method4 7#d7 ,the ,rectal ,method 7,gwathmey's oil-ether74 7#e7 ,the ,intratracheal ,method1 described separately in ,chapter ,x4 ,illustration3 ,,fig4 #bd4--;,diagram of a vertical section through the middle of ,clover's ,inhaler4 ,a4 shows the ether dome2 ,b4 ,central tube removed from apparatus 7#a7 ,closed ,ether4 ,the two inhalers originally brought out for this were ,clover's in ,london1 and ,ormsby's in ,dublin4 ,at a later date ,hewitt's 8wide bore0 modification of the ,clover was introduced4 7a7 ,the ,clover instrument 7see ,fig4 #bc7d consists of a face-piece1 a dome-shaped ether chamber1 and a one-gallon bag1 usually attached to the top of the ether chamber by a ,t-shaped tube4 ,the details of the method by which the amount of ether inhaled by the patient is graduated are best appreciated by unscrewing the milled head at the top of the dome1 and withdrawing the tube which runs through it 7see ,fig4 #bd74 ,in the tube will be found two slots1 one about half an inch above the other1 and each extending for half the circumference of the tube4 ,between these two slots the tube is divided by a diaphragm4 ,in any case1 therefore1 air passing up or down the tube must pass in and out of these slots4 ,now turn to the tubular space left in the dome piece1 and examine visually and with the finger its interior4 ,on the one side of its middle will be found two slots leading into the circular ether chamber which occupies a large part of the dome4 ,on the other side will be found a small cavity1 as deep from above downwards as the two slots combined1 but not communicating with the ether chamber4 ,it is obvious that with the tube inside1 if this cavity is opposite the slots in the tube1 air will pass up the tube out of one slot and back into the other1 without coming into contact with the ether at all4 ,if on the other hand the slots in the tube are opposite the slots in the ether chamber1 the air passes over the surface of the contained ether1 and volatises some of it4 ,intermediate positions of the tube give a condition where part only of the air passes over the ether4 ,the indicator attached to the tube1 combined with the figuring 8,o1 one1 two1 three1 full10 to be found on the outside of the base of the dome1 shows at any moment what proportion of the air is passing into the ether chamber4 ,to use the instrument1 fill the metal measure provided with ether1 withdraw the stopper from the ether chamber1 and pour in the ounce and a half of ether which the measure contains4 ,replace the stopper1 and blow through the tube to expel any ether vapour which may have appeared in it4 ,leave the rubber bag at first unattached3 the patient will feel more comfortable if during the first minute the top of the tube is open4 ,with the indicator at #j adapt the face-piece to the face and allow the patient to breathe up and down the tube4 ,by rotating the dome1 ether is then gradually turned on1 until the figure two is reached in the first minute4 ,the indicator is then slipped back nearly to zero for a second1 and the rubber bag slipped on during an expiration3 it must be moderately inflated to supply the requisite volume of air for respiration4 ,illustration3 ,,fig4 #be4--;,hewitt's wide-bore ether inhaler4 ,the rotation of the dome is again begun and the indicator is made to travel away from the zero1 until at the end of about five minutes1 it reaches 8full40 ,after the first few minutes1 it will be necessary to give an occasional breath of fresh air1 otherwise an undesirable degree of cyanosis will result1 but it must be done with great discretion1 or struggling will ensue4 ,at the end of about five minutes1 ansthesia should be fully established4 ,a little extra ether is then poured into the chamber1 the indicator pushed back to about 8two0 and the administration continued4 ,one breath of fresh air is given in every three or four4 ,spells may be given with the bag off altogether1 but during such periods the indicator will require to be advanced a little1 and refills of ether provided more frequently than would be necessary if the bag were on4 ,hewitt's-wide-bore4 ,the principle of this is identical with that of the ,clover1 but the channels being wider1 there is less mechanical interference with the ingress and egress of air4 ,the actual construction differs also1 in that to turn on the ether1 instead of rotating the dome1 one moves the indicator 7see ,fig4 #be74 ,the instrument certainly gives results a little better than those obtainable by the ,clover1 but it is heavier1 and rather more bulky4 ,ormsby's ,inhaler 7,see ,fig4 #bf74 ,this consists of a facepiece1 a cage made of wire or thin steel slips and containing a sponge2 and lastly1 a one gallon bag which fits over the cage4 ,in the face-piece is an air vent1 which can be either entirely closed1 partially or entirely opened4 ,illustration3 ,,fig4 #bf4--,ormsby's ,inhaler4 ,the cage for the sponge does not show in the figure1 it projects upwards from the bag-mount1 and is therefore enclosed in the bag4 ,to use the instrument1 take out the sponge and warm it either by wringing it out of hot water1 or better by leaving it a few minutes on the top of a hot steriliser4 ,push it back into the cage1 open the air vent fully1 and holding the inhaler upside down1 pour on to the sponge a measure full 7about half an ounce7 of ether4 ,tell the patient to inhale deeply1 and then catch the resulting expiration in the bag by quickly adapting the facepiece to the face at the appropriate second4 ,after a few seconds1 begin to close the air vent1 when it will be found that the bag begins to wax and wane with each expiration and inspiration respectively4 ,after the first three minutes1 the inhaler must be removed1 more ether poured in1 the air vent opened again partially1 and the inhaler again applied to the face4 ,after full ansthesia is induced1 the air vent may constantly be left partially open4 ,n4,b4--,it must be observed that the air vent is not valved3 it is merely an opening through which part of the respired air may pass in and out without going near the ether sponge4 ,in actual practice1 the induction stage of closed ether is almost invariably assisted by using either nitrous oxide1 or a small dose of ethyl chloride as a preliminary3 these methods are described in ,chapter ,,xv4 ,the question now arises1 what scope is to be assigned in modern ansthesia1 to closed-ether methods4 ,formerly a large proportion of ansthesias1 long or short1 were conducted by the closed method1 and while the greater number of ansthetists no longer utilise them to the same extent as formerly1 they may still be regarded as of the utmost value in a limited class of cases4 ,they are speedy in action1 powerful enough to overcome the most refractory patient1 and with reasonable skill very safe4 ,on the other hand1 the ansthesia obtained is not of the most desirable type4 ,there is a great deal of salivation and mucous secretion from the respiratory mucous membranes2 the respiratory movements are deeper than in open methods1 from the excess of ,,co#b present in the blood1 and this leads to a good deal of heaving of the abdominal wall1 which may be most troublesome to the surgeon if he is opening or closing that cavity4 ,moreover1 after their use more headache1 malaise1 and vomiting occur than after open-ether1 and perhaps a little more tendency to bronchitis or pneumonia4 ,for these reasons1 many ansthetists and surgeons now object to their use in abdominal surgery1 though some still adhere to them for the induction stage1 passing to the open method when the patient is once well under4 7#b7 ,open ,ether4 ,as already explained the strictly accurate term for this is ,perhalational ,ether1 but so cumbersome a terminology stands small chance of general acceptance4 ,apparatus4 ,the essential points in a proper outfit have already been explained 7see page #bh7 and are all well met by the mask and ether dropper introduced by ,mr ,bellamy ,gardner 7see ,fig4 #bg74 ,the mask is covered with from twelve to sixteen layers of gauze1 and lies on the gauze ring1 shown in the ,fig4 #bh;,a1 which completes the fit between face and facepiece4 ,the dropper fits into the ordinary six ounce dispensary bottle3 the long arm dips into the ether1 the short one allows air to enter the bottle to replace the ether used4 ,a dropper can also be improvised by using a cork with slots cut at each side and with a gauze or wool wick inserted along one of these4 ,the author finds these uncertain in their action1 however3 with ,gardner's dropper1 a steady flow of drops of ether slow or fast as required1 can always be obtained once the student has acquired the knack of using the appliance4 ,illustration3 ,,fig4 #bg4--;,bellamy ,gardner's 7,a7 open ether mask2 7,b7 ether dropper4 ,illustration3 ,,fig4 #bh4 ,a4--,open ether4 ,ready to begin4 ,b4--,open ether4 ,condensing towel in position4 ,illustration3 ,,fig4 #bh4 ,c4--,open ether4 ,correct method of holding mouth and jaw4 ,d4--,open ether4 ,alternative method of holding mask4 ,the towel and gauze have been removed so as to show the tilting of the mask which this method is liable to cause4 ,to ,mr ,bellamy ,gardner's outfit1 the author adds a folded towel1 pinned at one corner1 so as to form a short cone4 ,the base of this cone embraces the mask and face2 through its upper apperture the ansthetic is dropped on to the mask4 ,the cone can be rotated into the position most convenient for this purpose in any given position of the patient's head 7,fig4 #bh74 ,problems of the ,induction ,period4 ,open-ether is not a powerful ansthetic1 just not powerful enough for one to be sure that one can induce full ansthesia with it alone1 in a powerful subject4 ,the reason for this is shown in ,appendix ,,ii1 and may be here condensed by explaining that some #ah per cent4 to #bj per cent4 of ether vapour is required to induce ansthesia1 while it is not easy to get more than #ad per cent4 off an open mask4 ,how is this situation to be met8 ,reference has already been made to one solution of the problem4 ,a closed ether method may be used for induction1 and this practice is widely used4 ,the author does not often adopt this course1 fearing that the undesirable features of closed ether may persist even after the change to an open method has been made4 ,another possibility even more widely favoured is to use chloroform as the inducing agent1 and only to turn to ether when full ansthesia is obtained4 ,to this plan the author is strongly opposed4 ,it exposes the patient to the risks of the induction stage of chloroform which are much greater than those of the later stages4 ,moreover1 to develop the full advantages of open-ether1 a preliminary hypodermic of morphia is essential1 and the drawbacks of chloroform plus morphia are elsewhere mentioned 7page #dc74 ,the use of a mixture of chloroform two parts1 ether three parts1 presents the same disadvantage1 but in a degree so much smaller that in powerful or alcoholic patients1 the author believes this to be the method of choice 7see ,chapter xiv474 ,dr ,silk has recently suggested another plan4 ,he has sought to make open-ether easy for the non-expert with a view of encouraging the wider use of so valuable a method4 ,for this purpose he advocates the admixture of one part of chloroform in thirty-two of ether 7a dram of chloroform in four ounces of ether74 ,this is to be given in exactly the same way as perhalational ether1 and will1 ,silk says1 give a type of ansthesia1 and a degree of safety1 identical with those of pure ether4 ,the author's experience with ,silk's mixture is too limited to enable him to offer any opinion upon its merits4 ,lastly1 there remains the plan of using ether as the main inducing agent1 but assisting its action by the intermittent and most guarded addition of small quantities of ,c#b;,e#c mixture4 ,this is the author's 8stock0 method2 but in teaching it to students1 too much emphasis cannot be laid upon the small quantities of chloroform mixture required or permissible4 ,as a consequence of the perhalational method here advocated1 every drop of chloroform which appears on the mask will when volatilised1 give a very much higher percentage of ,,chcl#c vapour in the inspired air1 than the same quantity exhibited on the ordinary open chloroform mask4 ,once the student has grasped this essential fact1 ordinary care and intelligence will enable him to guard against a danger which is only existent if unappreciated4 ,the ,administration4 ,for many of the hints given in this section the author is indebted to ,dr ,w4 ,j4 ,ferguson of ,new ,york1 and ,dr ,hornabrook of ,melbourne4 ,success in inducing with open-ether is attained only by attention to a number of small details4 ,the student who thinks that some of these are too trifling for his notice is usually the man who informs you that induction by open-ether is impossible1 the fact really being that he has not taken the trouble to learn1 or has never had proper tuition4 ,the following are the points demanding attention3-- #a4 ,always give a dose of morph-atropine or other narcotic1 half to three-quarters of an hour beforehand4 #b4 ,see that the patient is comfortable on the table4 ,prop up his head and shoulders a little with pillows4 ,in powerful subjects ,hornabrook tilts the whole table down at the foot-end1 for a few degrees4 #c4 ,adhere strictly to perhalation and to the drop method4 ,you will never induce with open-ether if the whole volume of the respired air does not pass through the gauze4 #d4 ,chat to the patient as long as consciousness can possibly persist4 ,tell him he is doing very well4 ,don't shout complicated instructions at him as to how to breathe3 it annoys and muddles him4 #e4 ,when the gauze ring and the mask are in position1 allow one or two drops of ether to fall on the mask1 then pause3 in a few seconds the mild ether vapour so formed will soothe the upper respiratory tract1 and prepare it for the stronger vapours yet to come4 ,this does not waste time--it saves it4 #f4 ,when the administration is again begun1 attend closely to the rate of dropping4 ,at first not more than one drop in three or four seconds is wanted4 ,the full rate of dropping cannot be attained for at least ninety seconds4 #g4 ,give no mixture for the first ninety seconds2 thereafter some five to ten drops every half minute or every twenty seconds according to type of patient4 ,have the mixture bottle handy so that no time is wasted in changing bottles4 ,stop the addition of mixture as soon as full ansthesia is attained4 #h4 ,slip the folded towel over the mask and tuck its base well round the chin and face4 ,do this only after the first two minutes have elapsed4 #i4 ,as soon as the neck muscles are relaxed1 turn the patient's head over to one side1 and let the hands assume the position described in ,chapter iii4 and illustrated in ,fig4 #bh;,c4 #aj4 ,the student is warned to discourage the too early attentions of the nurse or house-surgeon4 ,these officials are naturally anxious to 8get the patient ready for the ,chief0 and are apt to start 8cleaning up0 before the patient has lost all consciousness4 ,a man who is doing his level best to go to sleep1 derives neither pleasure nor profit from a wholly unexpected dab of ice-cold methylated spirit upon his umbilicus4 ,by the use of the method here advocated1 induction is singularly easy and successful in good subjects4 ,the struggling stage is either not represented at all1 or appears only in the form of the lifting of a limb and a slight occasional pause or catch in respiration4 ,full ansthesia is often announced audibly1 by the commencement of a gentle 8blowing40 ,once it is heard1 the ansthetist may rest assured that a workable level of ansthesia is either present or not far off4 ,amounts of ,ether required4 ,if the above instructions are followed1 the amount of ether required is not excessive4 ,ansthesia is attained after the use of about #a to #b ounces of ether and one or two drams of mixture4 ,the next forty to fifty minutes demand about another four or five ounces of ether2 no mixture at all4 ,some practice1 is required before these small figures are attained4 ,the more practice1 the less ether is required4 ,,iii4--,,vapour ,,an,,sthesia4 ,in a sense1 all forms of ether ansthesia are vapour methods1 but in all the forms so far described1 the patient has to vapourise the drug for himself3 in a true vapour ansthesia this is done for him1 and the mixture of air and ether vapour propelled towards him4 ,one of the keenest advocates of this method is ,dr ,gwathmey1 of ,new ,york4 ,he lays great stress also upon the necessity of warming the vapour1 claiming that this measure will prevent the loss of heat to the patient incidental to the warming up in the air passages of the cold vapour usually supplied by other methods2 but the results of the laboratory experiments upon which ,gwathmey founded his case are inapplicable to the human subject1 in that they were performed upon dogs and cats1 which lose heat largely from the mouth and air stream4 ,man is not a hairy animal1 and transacts most of his thermolysis through the medium of his skin4 ,none the less1 warming the vapour of ether has value since the process removes some of the irritant effects so marked in the case of cold ether vapour4 ,apparatus for the ,vapour ,method4 ,in #aiac1 ,karl ,connell described such an apparatus1 which was then in use at the ,roosevelt ,hospital1 ,new ,york4 ,the ether was vapourised by dropping it into a warm chamber4 ,air was pumped into the chamber1 and carried the ether vapour in known percentage1 and at known pressure as shown by gauges4 ,such mechanism is ideal1 but would certainly be rather costly4 ,its great value was that it informed us with certainty what proportions of ether in the atmosphere were necessary to induce and maintain ansthesia 7see ,appendix ,,ii474 ,a simple mechanism was brought out shortly afterwards by ,dr ,shipway1 of ,guy's1 and is known as ,shipway's warmed ,ether4 ,it consists essentially of the following parts 7see ,fig4 #bi73-- 7#a7 ,a small hand bellows 7,b74 7#b7 ,an ether bottle1 with tube for delivery of air stream dipping deeply into the fluid3 the exit tube of course does not dip in4 ,the bottle stands in a metal pan in which water at about #ge ,fahr4 is to be placed 7,e74 7#c7 ,a thermos flask 7,w7 in which is a metal tube 7,u74 ,the etherised air passes along this tube1 and picks up heat from its walls4 ,the thermos is filled with water at about #ahj ,fahr4 ,illustration3 ,,fig4 #bi4--,shipway's warmed ether vapour apparatus4 7#d7 ,a mask upon which a towel or gauze is to be stretched3 the rubber tube bringing the air and ether is brought through the covering material and delivers the ansthetic vapour in the region of the mouth4 7#e7 ,additional to the above1 there may be added a small chloroform bottle 7,c74 ,in specimens of the instrument containing this convenience1 there has1 of course1 to be a regulating tap 7,t7 at the head of the ether bottle1 which will divert more or less of the air stream towards the chloroform4 ,this little machine1 somewhat resembling a cruet stand in its appearance was widely used in ,france4 ,owing to the kindness of the ,edinburgh ,red ,cross ,committee1 one was provided for the ,base ,hospital with which the author proceeded to ,salonika1 where he used it extensively4 ,the impression of it formed by himself and others was that it was peculiarly easy to maintain with it a steady level of ansthesia4 ,it had1 however1 no claim to banish post-ansthetic bronchitis and pneumonia1 of which in spite of much anxious care and thought1 a fair number of cases were seen during the winter time 7see page #aea74 ,in using the machine1 it is necessary to remember that from the physical point of view1 one is providing from the machine a small part only of the total volume of air required by the patient4 ,the bellows are quite small3 one squeeze of the hand will not supply more than about the equivalent in volume of one or two fluid ounces4 ,the larger part of the volume required by the patient has to be obtained from the general atmosphere1 so that the percentage of ether which may be as high as #be in the exit tube1 will be greatly lowered by the time it reaches the patient's respiratory tract4 99 99 99 99 99 ,the actual strength of ether breathed by the patient will depend upon3-- #a4 ,the force and frequency with which the pump is compressed4 7,n4,b4 ,it is of course useless to pump during expiration74 #b4 ,the depth of ether in the bottle4 #c4 ,the temperature of the water bath in which the ether bottle stands4 ,the warm water should only be put in at the last moment before starting1 otherwise very strong ether vapour will collect on the surface of the ether1 and the first puff of the bulb will expel a highly irritant vapour towards the patient4 ,with specimens of this machine which have the addition of the chloroform bottle1 it is perfectly possible to conduct even the induction stage of ansthesia2 a mere trace of chloroform vapour will be sufficient4 ,it is unnecessary to give detailed instructions for the use of the machine4 ,a preliminary consideration of the above physical facts1 together with a little cautious practice1 will enable the student rapidly to acquire facility with the method4 ,,iv4--,,rectal ,,etherisation4 ,for such operations as the removal of jaw or tongue there are obvious advantages in being able to introduce ether vapour to the blood per rectum1 since the mouth and air passages are thereby left free for the attention of the surgeon4 ,many years ago this was attempted by vapourising ether and propelling the vapour through a tube high up into the rectum4 ,this method was abandoned1 as it led to a good deal of inflammatory trouble afterwards4 ,recently1 ,dr ,gwathmey suggested a new method of utilising the rectal route which has largely overcome this objection4 ,gwathmey's ,oil ,ether ,method4 ,this consists in passing into the rectum a mixture of olive oil and ether4 ,the bowel is first carefully washed out1 and an hour before operation1 the patient receives a hypodermic of morphia1 gr4 2 atropine1 gr4 4 ,a suppository of chloretone gr4 v is also passed into the rectum to act as a local sedative4 ,half-an-hour later1 the patient is put into the left lateral position1 a soft catheter attached to a funnel is passed some six inches up the rectum1 and the mixture of oil and ether poured into the funnel4 ,it is wise to take at least five minutes to introduce the whole dose4 ,the following table shows the dosage required3-- ---------------------------------------- --------------------------- ,strength of ,age of ,patient4 ,ether in ,quantity of ,mixture required4 ,mixture4 ---------------------------------------- --------------------------- ,under #f years #ej ,one ounce to each #bj pounds body weight 7no preliminary morphia7 #f to #ab years #ee to #fe ,do4 do4 #ab to #ae years ,do4 ,one ounce to each #bj pounds body weight 7but use gr4 morphia7 #af years and #ge ,one ounce to each #bj pounds body upwards weight with gr4 morphia as a preliminary ---------------------------------------- --------------------------- ,in practice then1 for the ordinary adult1 one uses eight ounces of the mixture1 six ounces of which are pure ether4 ,the oil and ether require to be shaken together1 but remain blended long enough for introduction4 ,in five or ten minutes1 the patient begins to feel a rather pleasing numbness and tingling in the lower1 and later the upper extremities1 and drops quietly to sleep in about twenty minutes4 ,in a large proportion of cases1 it is necessary to deepen the ansthesia by the use of the open mask for a few minutes1 but once a deep ansthesia has been thus obtained1 the absorption from the rectum will balance the loss in expiration and maintain a good ansthesia for three quarters of an hour at least4 ,on return to bed of the patient1 the nurse passes two tubes placed side by side1 as high into the rectum as she can2 the end of a ,higginson syringe is inserted into one of them1 and a considerable quantity of soap and water is pumped gently into the bowel1 escaping down the second tube4 ,the washing must be continued until all smell of ether is removed4 ,finally the soapy water itself is washed away by a little saline4 ,unless there be some pre-existing local inflammatory disease of the rectum 7in which case the method should not be used71 there are no unpleasant sequel after oil ether4 ,the chief objection to the method is the amount of labour thrown on the nursing staff1 which is so considerable as to bar it from adoption as a routine4 ,this should not1 however1 be allowed to prevent its use in the limited number of cases in which it is strongly indicated4 ,these are3-- 7#a7 ,panic-struck cases who cannot face the ordeal of ordinary methods4 7#b7 ,nose1 throat1 and tongue operations where intratracheal ether is not available4 ,,chapter ,x ,,intratracheal ,,insufflation ,,of ,,ether ,intratracheal insufflation consists in driving a current of air under pressure1 through a tube introduced by way of the mouth and larynx1 deeply into the trachea4 ,the current of air which is continuous1 returns between the tube and the wall of the trachea1 and escapes through the mouth and nose4 ,certain ,physical ,considerations4 ,the work of ,meltzer and ,auer has demonstrated that this insufflation of air into the trachea under adequate pressure ventilates the pulmonary alveoli1 and enables the normal diffusion of gases to be carried out for many hours1 independently of all respiratory movements4 ,if the air in its passage under pressure is made to pass through a chamber containing ether1 we are enabled to introduce into the pulmonary alveoli1 ether vapour of varying strength1 and1 by this means1 to maintain surgical ansthesia4 99 99 99 99 99 ,,the ,,actual ,,process ,,of ,,external ,,respiration consists in the absorption of oxygen from the alveoli into the blood of the lung capillaries1 and the elimination of carbon dioxide from the lung capillaries into the alveoli4 ,the oxygen has to be brought from the outside to the alveoli1 and the carbon dioxide has to be conducted from the alveoli to the outside4 ,between the outside and the alveoli is the long airshaft1 consisting of mouth and nose1 pharynx1 larynx1 trachea1 bronchi and bronchioles4 ,in natural respiration the conduction of oxygen inwards1 and of carbon dioxide outwards1 is carried through by a complicated pumping mechanism4 ,in ordinary inhalation ansthesia1 this mechanism is entrusted with the task of introducing ether vapour into the alveoli4 ,in intratracheal insufflation the work of this natural pumping apparatus is taken over by an artificial mechanism4 ,in considering the justification for this1 the following points are to be noted3-- 7#a7 ,the patient is unconscious--not naturally so as in sleep--but unnaturally as the result of drugs2 there is therefore a probability that the elaborate natural mechanism may not work smoothly--especially is there a danger that the free airway may be interfered with4 ,intratracheal insufflation obviates this danger4 7#b7 ,by means of the artificial mechanism1 air is brought with some force to the mouth of the bronchi1 and thus a more rapid and more powerful diffusion of gases takes place4 7#c7 ,the mechanism ensures the maintenance of a current of air blowing forcefully from the trachea and larynx through the pharynx1 mouth and nose4 ,this re-current continuous air-stream effectively prevents the entrance of blood or any infectious material into the bronchi and air cells1 and thus the danger of septic lung troubles is obviated4 7#d7 ,in certain intrathoracic operations the normal respiratory mechanism is deliberately interfered with4 ,intratracheal insufflation by the constant maintenance of sufficient positive pressure1 prevents or regulates the collapse of the lung which occurs when the thorax is opened1 and thus obviates the necessity for the somewhat elaborate positive and negative pressure cabinets and masks which had been devised for intrathoracic operations4 7#e7 ,incidentally it may be noted that intratracheal insufflation of air provides us with an excellent means for performing artificial respiration4 ,many instances have now been recorded of its utility in this respect4 ,dr ,elsberg records the case of a patient who had taken morphia with suicidal intent1 on whom artificial respiration by this method was kept up for #ab hours1 without any respiratory movements taking place1 recovery ultimately ensuing4 ,the ,apparatus4 ,this consists of 7see ,fig4 #cj73-- #a4 ,instrument for producing air current 7,a74 #b4 ,ether chamber and various regulating taps 7,b74 #c4 ,device for warming vapour 7,c74 #d4 ,safety valve 7,d74 #e4 ,manometer 7,e74 #f4 ,intratracheal catheter1 with rubber tubing linking up the various parts of the apparatus 7,h74 ,illustration3 ,,fig4 #cj4 ,diagram of intratracheal apparatus4 #a4 ,,the ,,air ,,current is obtained either by means of an ordinary glass-blower's foot bellows1 or an electric motor may actuate a rotatory blower which produces a current of air4 ,the blower may be made to rotate at a speed varying from #ej to #ajjj revolutions per minute 7see ,fig4 #ca74 ,the foot bellows is simple and inexpensive1 and there is no reason why it should not be efficient4 ,the electrically rotated blower is more efficient1 ensures a smoother air current1 and saves much labour4 #b4 ,,the ,,ether ,,chamber4--,ether vapour may be produced by either of two methods4 ,fig4 #cb shows ,kelly's instrument where air is blown over the surface of a considerable quantity of liquid ether4 ,dr ,meltzer#e maintains that the effectiveness of the etherization is proportional to the diameter of the ether bottle4 ,in this connection it may be well to recall certain points pertinent to the subject of etherization4 ,a satisfactory etherization depends on the establishment in the blood and tissues of an ether tension of definite strength4 ,boothby#f states that this tension should correspond to about #ae per cent4 of ether vapour in the alveolar cells4 8,if when this tension has been established1 less than #ae per cent4 ether vapour is administered1 outward diffusion occurs from the tissues and blood to the air and the ansthesia becomes lighter40 ,illustration3 ,,fig4 #ca4--;,electric blower to supply current of air for intratracheal ansthesia4 ,illustration3 ,,fig4 #cb4 ,kelly's intratracheal apparatus4 ,in an apparatus such as we are describing the strength of the ether vapour depends on and is influenced by a variety of factors1 among which the following may be specially noted3-- 7a7 ,the diameter of the ether chamber4--,the larger the diameter the stronger will be the ether vapour4 ,the chamber is generally kept two-thirds full3 the less the empty space in the chamber the stronger will be the vapour4 7b7 ,the rapidity of the air-current4--,the larger the amount of air passing over the ether the more rapid will be the vapouration1 with the result that the temperature of the liquid ether will rapidly fall and the strength of the ether vapour in the air will be correspondingly lowered4 7c7 ,the temperature of the liquid ether4--,the higher the temperature of the liquid ether the stronger will be the percentage of ether vapour in the air4 ,if the ether chamber is placed in a bath of water which is maintained steadily at an adequate temperature and if the rate of the air flow remains constant1 a constant strength of ether vapour will be given off4 ,it is well in this connection to remember that the boiling point of ether is low and that a very high percentage of ether vapour is readily obtained if the temperature in the water bath is allowed to rise beyond #hj;,f4 ,for further information regarding ether percentages see ,appendix ,i and ,,ii4 ,such an instrument as ,kelly's requires at its head a regulating tap1 movement of which is capable of diverting part of the air stream direct to the patient without coming in contact with the surface of the ether4 ,in this way the maximum strength of vapour may be diluted as and when required4 ,in ,fig4 #cc is shown ,shipway's instrument4 ,here the drug is dripped into a chamber1 the floor of which is kept warm4 ,the ether volatilises at once and the vapour is carried away by the air stream passing through the chamber4 ,the strength of ether vapour in this instrument is regulated solely by the rate of drip which is in complete control of the administrator4 ,whichever method of making ether vapour is utilised the instrument should be capable of producing a maximum at least of #ae per cent4 to #ah per cent41 and means must be provided to reduce this percentage at will4 #c4 ,,device ,,for ,,warming ,,vapour4--,it is doubtful if the warming of inspired or insufflated vapour has any appreciable influence on the body temperature1 but there is a fairly general consensus of opinion that if the ether vapour is warmed there is less likelihood of irritation of the respiratory mucous membrane4 ,it is to be noted1 moreover1 that in intratracheal insufflation the natural apparatus for warming the inspired air is put out of action4 ,this warming can be effected by the simple device of carrying the tube through a chamber of hot water after it emerges from the ether chamber4 #d4 ,,safety ,,valve4--,dr ,meltzer insists very strongly on the necessity of having a safety valve capable of controlling the maximum pressure under which the air may enter into the intratracheal tube4 ,by a simple device1 any excess of desired pressure will cause the air to bubble through mercury and thus never reach the lungs4 ,in this way any possibility of accident from undue intrapulmonary pressure is obviated4 ,illustration3 ,,fig4 #cc4--,shipway's intratracheal apparatus4 #e4 ,,mercury ,,manometer to indicate the pressure in the tube in m4m4 of mercury4 ,it has been experimentally established#g 8that the pressure in the trachea and in the bronchi is only a small fraction of the pressure in the manometer outside of the body1 and that the intratracheal pressure grows considerably less with the decrease of the diameter of the intratracheal tube40 #f4 ,,intratracheal ,,catheter4--,it is essential to have an instrument of adequate rigidity which can be satisfactorily sterilized4 ,the ordinary coud catheters1 or the silk web white enamelled cylindrical catheters1 are suitable4 ,the size should be selected from a range of #ah to #be ,french4 ,it is preferable to err rather on the side of a small than a large tube4 ,an ordinary adult will require a tube of about size #bb to #bd1 a plethoric alcoholic1 on the other hand1 might need a #be4 ,a tube of too large a calibre interferes with the free return of air and spontaneous respiration soon becomes too slow4 ,expiration is prolonged1 active1 and laboured1 and after a few minutes1 respiratory movements may cease entirely4 ,the only way to meet such a situation is to withdraw the tube and insert a smaller one4 ,,technique ,,of ,,administration4--,it is advisable in adults to administer about three quarters of an hour before the operation1 a hypodermic injection of morphia 7gr4 7 and atropine 7gr4 71 or of scopolamine 7gr4 7 and morphia 7gr4 74 ,the latter combination is more efficacious in alcoholic subjects4 ,in children1 atropine alone should be given4 ,it is to be remembered that intratracheal insufflation of ether is a method of maintaining not of inducing ansthesia4 ,induction is carried out in the ordinary way4 ,when this has been done1 the catheter is passed4 ,the introduction of the catheter does present some difficulty1 but this is largely overcome as skill and confidence are acquired with practice4 ,it may be carried out indirectly1 or a view of the glottis may be obtained by the aid of such an endoscope as ,hill's1 and the catheter inserted between the cords4 ,the latter method is probably the more satisfactory1 but it is well to acquire the skill to pass the catheter indirectly as in a certain small proportion of cases there are obstacles to the use of the endoscope4 ,to facilitate catherization the pharynx and epiglottic region may be cocainized with a #e per cent4 solution before induction4 ,hill's endoscope 7,fig4 #cd7 is distally illuminated by a small electric lamp1 which is connected with a small pocket battery4 ,a useful modification of this has been devised by ,mr ,dott4 ,in it1 the catheter is passed along a separate compartment1 so that the view of the glottis is undisturbed4 ,the point of the catheter comes into view at the distal extremity of the endoscope and can be guided between the cords into the trachea4 ,illustration3 ,,fig4 #cd4--;,hill's ,direct ,laryngoscope4 ,it is essential before attempting intubation1 that there should be thorough relaxation4 ,the lower jaw should be so slack that a gag is not required4 ,the head is then placed in the occipito-shoulder position1 or is allowed to hang over the end of the table4 ,the tongue is controlled by forceps1 and the endoscope passed slowly along its dorsum until the epiglottis comes into view4 ,the point of the endoscope is then passed sufficiently far below the tip of the epiglottis to ensure that it will not slip2 too deep insertion must be avoided4 ,the endoscope being held in the left hand1 the hyoid bone is lifted up by a tilting movement of the hand4 ,the glottis is thus brought into view4 ,the catheter stiffened by means of a probe is then passed through the glottis into the trachea and the endoscope withdrawn4 ,the bifurcation of the trachea in the adult is at a distance of about #bf cm4 from the incisor teeth4 ,the catheter should be marked accordingly1 and inserted to a point just short of this4 ,the probe is then withdrawn1 and connection made with the air current4 ,it occasionally happens that unexpected difficulty is met with on attempting to pass the catheter by direct vision4 ,the larynx may be so fixed that the glottis does not readily come into view2 or in the case of an intraoral neoplasm the view may be obstructed by the presence of blood4 ,in such cases the catheter can be introduced by the indirect method4 ,the middle finger of the left hand is passed along the dorsum of the tongue until the epiglottis is felt4 ,the index finger is then used to guide the point of the catheter to the glottis through which it is then passed4 ,no undue force must be used4 ,a stilette should be inserted into the catheter which should be moulded almost to a right angle at its terminal third4 ,if the stilette is withdrawn when the point of the catheter is over the mouth of the glottis1 the instrument will1 as a rule1 slip easily into the trachea4 ,occasionally the tube passes into the sophagus4 ,with care and adequate relaxation such a mistake should not occur1 but the possibility of it should be kept in mind4 ,if the operator will abstain from attempting to pass the catheter until such time as he has a satisfactory view of the glottis1 mistakes of this kind will seldom occur4 ,the essentials are a good illumination and an adequate relaxation4 ,mild glottic spasm may supervene on the passage of the catheter but this rapidly passes off4 ,at first the degree of concentration of the vapour should be low or irritation will result1 evidenced by spasm and coughing4 ,the strength of the vapour is gradually increased until the necessary concentration is attained4 ,the pressure should vary according to the requirements of the case and should range between #aj mm4 to #be mm4 ,hg4 ,the safety valve must be set so as to make any pressure above this impossible4 ,in the majority of cases the course of ansthesia is smooth and uneventful2 the colour remains a rosy pink1 the pulse is good1 and the respirations quiet and regular4 ,it is undesirable that the respiratory movements should be abolished altogether2 their presence indicates that neither the central nor the peripheral respiratory mechanism is being overdosed with ether4 ,theoretically1 the constant plus-pressure in the lungs might be thought to interfere with the circulation in the large veins1 and in the pulmonary vessels themselves4 ,it is therefore well to reduce the pressure in the catheter to zero every minute by opening the tap provided for the purpose for a second or two4 ,at the conclusion of the operation1 before withdrawing the catheter it is well to flush out the lungs with air so as to remove any ether vapour that is present4 ,in a certain number of cases1 notably in big alcoholic subjects1 difficulty may be experienced in securing a sufficiently deep ansthesia with good relaxation4 ,it is seldom1 however1 that patience and the careful introduction of a stronger vapour will not suffice to overcome this4 ,in alcoholic subjects1 as previously suggested1 preliminary medication with scopolamine and morphia will help4 ,it really becomes a question1 if one may put it so1 of coaxing the unconscious patient to tolerate an ether vapour of adequate strength4 ,advantages and ,special ,indications4 ,the general opinion of ansthetists appears strongly to favour the view that the absence of strain and the perfect ration in intratracheal ether insufflation tend to lessen the shock of operation4 ,the post-operative history of patients also suggests that there is a lessened liability to pulmonary complications as compared with cases in which ether has been administered by other methods4 ,dr ,elsberg#h of ,new ,york in this connection writes3 8,the absence of any pulmonary complications has led us to use this method of ansthesia in all patients in whom pulmonary complications were to be feared after an ansthesia or operation4 ,thus on all asthmatics1 in patients with chronic bronchitis and emphysema1 in patients who require gastric resection and the like1 we no longer1 during two years1 have seen the much dreaded post-operative pneumonia wherever intratracheal ansthesia was used40 ,in addition1 there is ample evidence#i that the introduction of a catheter into the trachea and its presence therein does not tend1 as might have been expected1 to set up any irritation at the time or predispose to subsequent trouble4 ,apart from these general considerations1 which suggest the advantage of a somewhat extended use of intratracheal ether insufflation1 the method has obvious advantages in all operations about the mouth1 such as those for excision of the upper jaw1 those undertaken for the removal of nasopharyngeal growths and various plastic operations involving the nasal and buccal cavities4 ,in such cases the danger of aspiration of blood1 mucus1 etc41 is obviated and the ansthetist is well out of the surgeon's way1 while at the same time an even interrupted delivery of ether vapour is effected4 ,in operations for removal of glands in the neck the surgeon has the field to himself1 and is not hampered nor is his asepsis endangered by the proximity of the ansthetist's mask4 ,in such operations as laminectomy and nephrectomy the postural difficulties with which the ansthetist has to contend1 and which also tend to interfere with free respiration1 are eliminated4 ,the great advantage of the method in intrathoracic operations has already been referred to4 ,the introduction of intratracheal insufflation of ether was rendered possible by the pioneer work of ,drs ,elsberg1 ,meltzer1 and ,auer4 ,the writer would like to acknowledge his indebtedness to their writings1 of which he has made free use4 ,,chapter ,,xi4 ,,chloroform4 ,physical ,characteristics4 ,chloroform is chemically trichlor-methane1 ,,chcl#c4 ,it is a colourless1 transparent fluid1 with a specific gravity of #adia at #ag;,c4 ,its vapour is even heavier than that of ether1 approximately four times heavier than air4 ,it is not inflammable1 but the action of an open fire or naked flame tends to break it up into hydrochloric acid and phosgene1 both of which are highly irritant gases to all who breathe them4 ,the patient suffers1 but since all the other occupants of the theatre are also affected1 warning is given before serious harm has been inflicted4 ,chemically pure chloroform is a somewhat unstable product1 but the addition invariably made to it by the producers1 of a trace of alcohol1 prevents any serious risk of decomposition in bulk4 ,it should be neutral in reaction and have an agreeable non-irritating odour3 departure from the normal in either respect indicates the possibility of the presence of acids or aldehydes1 and the necessity for referring a specimen to the laboratory4 ,like ether1 chloroform may be obtained from pure ethyl alcohol or from methylated spirits1 and the remarks made in the chapter upon ether apply to the case of chloroform also4 ,a third source of supply is acetone1 from which perfectly good chloroform can be produced4 ,physiology4 ,chloroform is an irritant to the skin and mucous membranes4 ,a drop left on the skin and covered over with impermeable material will produce a deep and painful blister4 ,a drop falling into the eye1 if not instantly washed away1 produces a very powerful inflammatory reaction1 and many eyes have been totally lost from carelessness in this respect4 ,such incidents are of course actionable1 and heavy damages may be given4 ,illustration3 ,,fig4 #ce4--;,diagrammatic representation of various blood pressure curves obtainable with chloroform4 ,line ,,aba represents curve desired in normal chloroform administration4 ,line ,,abcb represents gradual overdosage4 ,line ,,abcc represents recovery by inversion4 ,,dd represents syncope from vagal inhibition3 in its course1 one attempt of the heart to 8escape0 is shown4 ,the special peculiarities of the action of chloroform upon the nervous system have already been emphasised in the account given of the physiology of ether 7see page #ge74 ,its action upon the circulatory and respiratory systems has been the subject of many researches1 and of much embittered controversy4 ,the literature is therefore very extensive1 and the account of it must be severely condensed4 ,the following may be taken as a brief resum of present day opinion 7see ,fig4 #ce73-- 7#a7 ,in every case of chloroform administration1 there is a fall of blood pressure4 7#b7 ,if the drug be presented in weak concentration 7less than #b per cent4 vapour strength71 the fall is gradual and even 7line ,,ab74 7#c7 ,if the same strength 7say #b per cent47 of vapour as produced the above effect be prolonged unduly1 the respiration will cease at a time when blood pressure is still well above zero 7line ,,abcb74 7#d7 ,the fall of pressure is due to diminished force of cardiac action1 and at a later stage also to vaso-motor paresis4 7#e7 ,the cessation of respiration is due partly to fall of blood pressure in the vessels supplying the medullary centre2 partly to gradual poisoning of the centre itself by the drug4 ,that the fall of ,b4,p4 in the cerebral vessels is in itself one explanation of the cessation of respiration1 was proved many years ago by ,leonard ,hill in his inversion experiments4 ,just at the stage when respiration had ceased1 the ansthetic was withdrawn1 and the animal inverted into the head-down position4 ,the ,b4,p4 in the carotid at once began to rise1 and natural respiration was resumed 7line ,a,,bcc74 ,the above conclusions refer to chloroform given in moderate vapour strength2 other effects are produced if higher percentages are administered3-- 7#f7 ,with high concentration of chloroform vapour1 the fall of blood pressure is rapid1 and is apt to become suddenly precipitous 7line ,,dd74 7#g7 ,the cause of these sudden falls is inhibition of the heart by over-activity of the vagus3 cutting the vagi always terminates the effect unless delayed so long that the animal is dead3 in an animal fully under atropine1 these vagal actions cannot be produced4 7#h7 ,if the heart is inhibited by vagal action1 the respiration ceases at once1 usually after one deep inspiratory sigh4 7#i7 ,an inhibited heart may 8escape0 from vagal action before the animal is dead3 frequently1 however1 the inhibition persists and the animal dies4 7#aj7 ,struggling and breath-holding in the early stages of induction cause sudden falls of blood pressure4 ,many observers believe that these falls also are due to vagal activity1 others hotly deny this4 ,all are united in believing that to press chloroform upon a patient who is struggling and holding the breath1 is fraught with grave risk of causing sudden syncope4 7#aa7 ,the abnormal irritability of the vagus above referred to is a feature mainly of the induction stage1 disappearing once full ansthesia is developed4 7#ab7 ,it is an undoubted clinical fact that there is a risk of sudden arrest of heart's action if the operation is begun before the stage of full ansthesia is reached4 ,a reasonable explanation of such accidents is furnished by supposing a reflex inhibition acting through the vagal centre already rendered hyper-sensitive by partial chloroformisation4 ,views of ,goodman ,levy4 ,this worker has demonstrated in animals that the heart is sometimes thrown by chloroform into the condition of fibrillation--a delirium of the cardiac muscle1 from which recovery is rare4 ,it occurs in the early stage1 before full ansthesia has been reached1 and is predisposed to by the infliction of trauma4 ,the practical outcome of this is that the induction stage of chloroform should not be unduly prolonged1 and that the operation should not be begun until the third stage is fully developed4 ,so far as the author understands the views of ,dr ,levy1 his explanation of chloroform syncope need not be taken as introducing any new principle into the administration of the drug4 ,even those who lay most emphasis upon the danger of using vapours of too high a percentage strength would admit the force of ,levy's contentions4 ,as usual1 safety lies in steering between two extremes4 ,during his work on this subject1 ,levy further demonstrated that the introduction into the circulation of adrenalin during incomplete chloroform ansthesia was very liable to induce fatal cardiac fibrillation4 ,he thus furnished the explanation of a number of deaths which had occurred in the practice of nose and throat specialists4 ,since the publication of ,levy's work1 the rule has been absolute that if adrenalin is to be used in a case requiring chloroform ansthesia1 the adrenalin must precede1 not follow the ansthetic4 ,administration4 ,basing upon these views as to the action of chloroform1 and upon the lessons of practical experience1 we may formulate definite rules for giving the drug4 ,general ,principles for giving ,chloroform4 7#a7 ,give chloroform evenly1 not spasmodically4 7#b7 ,increase the vapour strength of chloroform gradually from zero until #b per cent4 or at most #b per cent4 is reached at the end of two or three minutes2 maintain that strength until full ansthesia is obtained2 thereafter1 drop down to #a-ae per cent4 ,this will result in a ,b4,p4 curve corresponding to the line ,,aba in the diagram 7,fig4 #ce74 7#c7 ,be guided chiefly by the patient's respiration4 ,chloroform kills by stopping the heart1 but in the immense preponderance of cases1 evidence of failure of respiration appears in ample time to give warning of approaching circulatory failure4 ,the eye reflexes give confirmatory evidence of the depth of ansthesia1 but the superlatively important thing is to maintain a free airway1 and be sure the patient is using it4 7#d7 ,if serious struggling and breath-holding occur1 withdraw the ansthetic until the patient 8resumes normal40 ,methods of ,administration4 ,the logical application of such general principles would be to use an instrument which gives a definite and known percentage of chloroform1 variable at the wish of the administrator4 ,many such machines have been brought forward1 and while none of them have obtained general acceptance1 a description of the best known instrument will be given1 as the reader may as a house-surgeon meet with it1 and with a surgeon who wishes it to be used4 ,vernon ,harcourt's ,inhaler4 ,in principle1 this is a 8draw-over0 instrument2 the patient's own inspirations are the motive power4 ,passing over the surface of the fluid drug1 the inspired air picks up from it a known percentage of vapour4 ,the other system available for the construction of percentage chloroform instruments is the 8plenum02 in this the vapour is propelled to the patient by a pump4 ,illustration3 ,,fig4 #cf4--,vernon ,harcourt's ,percentage ,chloroform ,inhaler4 ,in appearance1 the inhaler resembles the letter ,t1 with a rubber face-piece attached to the lower end of the vertical limb 7see ,fig4 #cf74 ,the ,t portion itself is made of metal tubing of a definite size in cross section4 ,one end of the horizontal limb admits pure air1 the other1 air which has passed over chloroform and picked up from it a certain proportion of vapour4 ,the proportion of the total inspired volume of air which passes through each of the ends is regulated by a lever seen at the junction of horizontal and vertical limbs1 and the exact percentage of chloroform being inhaled is indicated by a series of numerals marked on the dial over which the lever moves4 ,these figures are correct provided3-- 7#a7 ,the chloroform receptacle is not shaken 7this would greatly increase the percentage74 7#b7 ,the temperature of the chloroform is not allowed to fall below #ac centigrade4 ,to ensure that this cannot take place without the knowledge of the administrator1 two coloured beads are thrown into the chloroform4 ,at the desired temperature of the chloroform 7#ac-ae;,c7 the blue bead sinks to the bottom1 the red one nearly to the bottom4 ,below #ac;,c1 the red bead also touches bottom1 and when this is observed1 the chloroform vial is warmed up in the palm of the hand4 ,at the point #ae;,c1 both beads float1 and the warming must then stop1 or an undesirable addition to the vapour strength yielded will occur4 ,the face-piece is made of rubber1 and must be closely adapted to the face2 in its side is seen the expiratory valve4 ,inspiratory valves are present at each end of the horizontal limb4 ,the great advantage of this instrument1 to the author's mind1 is for teaching or demonstration purposes4 ,if the student sees the lever gradually being moved over from #b to #b per cent41 then slipped back to about #ae per cent4 after full ansthesia has been obtained1 he begins to appreciate what it is he is aiming at when giving chloroform by the ordinary open method4 ,illustration3 ,,fig4 #cg4--,schimmelbushch's mask4 ,open ,method4 ,the appliances requisite are3-- 7#a7 ,a mask4 ,schimmelbushch's is the best known 7,fig4 #cg73 as elsewhere explained1 it does not accurately fit the face4 7#b7 ,material to stretch on the mask4 ,the best is two layers of domette or one of flannelette3 surgical gauze is so light that heavy drops of chloroform are apt to 8spark0 through it and burn the skin of the face3 lint rapidly becomes sodden2 the drug drips away from its edge instead of vapourising properly4 7#c7 ,a good drop bottle1 of which many varieties are marketted 7,fig4 #ch73 it is essential that it should be capable of producing definite drops3 the old method of intermittent 8douching0 of chloroform is to be condemned as violating the first general principle for giving the drug4 ,illustration3 ,,fig4 #ch4--;,chloroform drop bottles4 ,it is not possible by the open method to be mathematically accurate with percentages1 but the necessary appliances are simple1 easily transported1 and practically always at hand4 ,if the student learns to use it1 and while doing so to think in percentages1 he will achieve as good results as or better than he will with percentage instruments4 ,while he may not have in front of his eyes a dial which shows the percentage graphically1 observation of the patient will inform him whether the percentage being given should be maintained1 raised1 or lowered4 ,the only remaining point for him to realise1 then1 is how in practice such regulations of percentage strength can be achieved by the open method4 ,the strength of the vapour will depend upon three factors3-- 7#a7 ,nature of the material used on the mask4 7#b7 ,closeness with which the mask is adapted to the face4 7#c7 ,amount of chloroform exhibited on the mask4 ,to ensure uniformity of result1 two of these factors should be kept constant1 and the necessary increase or decrease of vapour strength achieved by varying the third4 ,always use the same type and thickness of material on the mask1 and allow the mask to lie lightly on the face4 ,if the amount of chloroform is then regulated by a strictly 8drop0 method1 results of great uniformity may be obtained by the open method4 ,the ,junker ,inhaler4 ,this instrument was originally introduced as an attempt to achieve a percentage method4 ,air is pumped through a certain depth of chloroform contained in a bottle1 and the vapour brought to the patient in the face-piece shown in ,fig4 #ci4 ,the calculations by which it was sought to establish this as a reliable dosimetric or percentage method are of no great value4 ,from that standpoint the instrument has not achieved success4 ,it delivers to the patient a small quantity of high percentage vapour which is diluted by a much larger quantity of air inspired by the patient from the general atmosphere1 and the final percentage inhaled by the patient is therefore no more accurately known to the administrator than in the open method4 ,the instrument is1 however1 of considerable value for tongue and jaw cases1 where ansthesia has to be maintained for some considerable time after the mask with which ansthesia has been induced has had to be removed1 to give access to the surgeon4 ,illustration3 ,,fig4 #ci4--;,junker's ,chloroform ,inhaler showing hand bellows1 bottle and mask4 ,alternatively to the latter1 the nasal tube shown above1 may be used4 ,the ,figure #ci shows the instrument as usually marketed4 ,it consists of3-- 7#a7 ,a hand-bellows4 7#b7 ,chloroform bottle4 ,a mark cut on this shows the level to which it is to be filled3 if more than the proper quantity be poured in1 droplets of fluid chloroform are apt to be blown along the exit tube1 with dangerous results4 ,for convenience and neatness1 it is usual to make the exit surround the inlet tube4 ,the entering air bubbles through the chloroform1 and a stream of air and chloroform vapour passes out from the exit tube4#aj ,it is unnecessary to give a detailed account of the use of the instrument1 but the student must remember the following points3-- 7#a7 ,the amount of chloroform vapourised will depend on the vigour of the pumping1 the depth of fluid1 and the temperature of the chloroform4 ,in order to achieve uniform results1 it is therefore necessary to keep up a steady but not excessive pumping1 to warm up the bottle occasionally by holding it in the palm of a disengaged hand1 and to watch that the level of the chloroform does not fall too low4 7#b7 ,the pumping should be timed to synchronise with inspiration3 a puff of vapour delivered during an expiration will be wasted4 ,advantages and ,disadvantages of ,chloroform4 ,the light portable appliances which are alone necessary for chloroform ansthesia1 the comparative cheapness of the method1 and the apparent ease with which its administration may be conducted1 are all great temptations to its use4 ,those who feel the temptation strong upon them are advised to remember the following quotation from the writings of ,professor ,leonard ,hill3-- 8,chloroform is a drug used by the young ansthetist with the utmost hardihood1 and until he has had the misfortune in his practice to meet with a death caused by it1 he derides the danger of the drug1 and asserts that its safety merely depends on the care and skill of the administrator4 ,after losing his patient1 he falls to descanting on the unavoidable dangers of the drug1 dangers which he is now the first to maintain cannot be met by any degree of skill in administration40 ,the most distressing and probably the most common chloroform fatalities are exemplified in administration given for the most trifling conditions1 such as opening abscesses or extracting teeth4 ,in general1 we use chloroform if for any reason ether is not applicable4 ,for examples of cases of this description1 the reader is referred to the chapter upon the choice of ansthetics4 ,,chapter ,,xii4 ,,ethyl ,,chloride4 ,chemically this drug has the formula ,c#b;,h#e;,cl4 ,it is a colourless fluid so volatile that it boils at ordinary room temperature4 ,its vapour is highly explosive1 and the fluid itself very inflammable4 ,the drug is supplied by the makers in small tubes with a metal end which can be opened by pressing a little lever 7see ,fig4 #dj71 varying in type with the brands made by various makers4 ,two brands are sold by each firm2 one is chemically pure1 intended for use as a general ansthetic2 the other is not so pure1 and is only sold for local ansthesia4 ,such a product is not suitable for inhalation4 ,illustration3 ,,fig4 #dj4--,tube of ,ethyl ,chloride4 ,physiology4 ,the special points in the physiology of ethyl chloride may be briefly summarised as follows3-- #a4 ,after a trifling preliminary rise1 the effect of the drug is to lower the blood pressure appreciably4 ,in the human adult subject1 this fall becomes appreciable when more than #c c4c4 have been given2 if the dose exceed #e c4c4 a fall of #cj to #dj mm4 of ,hg4 is probable1--occurring as it does within a period of perhaps twenty or thirty seconds1 such a fall cannot be regarded as safe4 #b4 ,the cause of this fall is diminished cardiac output from weakening of heart muscle4 ,the vagus though not paralysed1 does not appear to be unduly irritable1 as it does with chloroform4 #c4 ,the respiratory centre is at first perceptibly stimulated1 and respiration is therefore deeper and quicker than normal4 ,the stimulant effect rapidly passes away and gives place to a stage of depression4 ,in the majority of cases1 death appears to take place from paralysis of the respiratory centre1 the heart still showing a little power of contraction after respiration has ceased4 ,there is therefore a fair prospect of recovery if artificial respiration be resorted to promptly4 ,methods of ,administration4 ,,open ,,method4 ,the extreme volatility of the drug has discouraged most ansthetists from giving it upon an open mask4 ,hornabrook1 of ,melbourne1 advocates this system1 however4 ,his mask fits the face accurately1 and his whole method is strictly perhalational4 ,he uses some #d-f c4c4 of the drug for a child1 #f-h c4c4 for an adult1 and achieves his ansthesia in a minute to a minute and a half4 ,he also advocates open ethyl chloride as a preliminary to open ether4 ,for some twelve months1 the author adopted the method4 ,at the end of that time he came to the conclusion that while it greatly facilitated the induction stage of open ether1 it appeared to increase the after sickness4 ,he therefore abandoned it1 though rather reluctantly4 ,,closed ,,method4 ,this is the usual means employed4 ,a variety of inhalers have been produced on the market1 one of which is shown in ,fig4 #da4 ,essentially all consist of3-- 7a7 ,a face-piece which must fit the face with reasonable accuracy4 7b7 ,a one-gallon rubber bag attached to the mask by a ,t-piece4 7c7 ,a glass vial1 with numerals from #a to #e marked on the outside to facilitate the measurement of the drug in c4c4 ,into this the drug is squirted from the makers' tube4 ,the vial is attached to the ,t-piece 7or alternatively the bottom of the bag7 by a rubber tube4 ,illustration3 ,,fig4 #da4--;,ethyl ,chloride ,inhaler4 ,administration4 ,to use such an inhaler1 the glass vial is first detached from the rubber tube1 and the chosen dose of drug squirted into it4 ,a child of five or six will require #c c4c41 an adult up to #e c4c42 this dose should never be exceeded4 ,the vial is then rapidly reconnected with the inhaler4 ,the face-piece is adapted to the face1 care being first taken to place between the teeth a mouth prop or a gag4 ,this enables one to get immediate access to the mouth when the inhaler is removed4 ,the patient is then told to breathe deeply once or twice4 ,during the inspiration the mask is lifted slightly1 and the ensuing expiration is then caught in the bag by pressing down the mask on to the face4 ,to volatilise the drug there are two alternative methods4 ,in the one1 part or the whole of the dose is tipped into the rubber bag by elevating the vial4 ,a far better is the 8,vapour0 method1 almost universally used in ,edinburgh owing to the advocacy of ,dr ,logan ,turner4 ,a tumbler is filled with hot water1 and the bottom of the glass vial is allowed first to touch1 and after a few seconds to be immersed in it4 ,some thirty to forty seconds suffice to vapourise the whole of the dose4 ,ethyl chloride given by itself should always be administered to a patient in the recumbent position4 ,a dose sufficient to produce ansthesia without the aid of nitrous oxide or ether will not be safe in the erect posture4 ,the case is quite different where a small dose only is given1 to assist the action of nitrous oxide1 or facilitate the induction stage of ether4 ,signs of ,ansthesia4 ,ethyl chloride is very rapid in its action1 some sixty seconds availing to produce quite a deep ansthesia4 ,respiration is at first deepened and quickened3 as full ansthesia is attained it remains rather deeper than normal1 and is accompanied usually by light snoring4 ,the colour should remain perfectly good3 the pupils show marked dilatation1 the corneal reflex is abolished1 and good muscular relaxation is attained4 ,with no ansthetic is it so essential as with this1 to become acquainted with the type of respiration normally to be expected1 and to watch for any departure therefrom with cat-like vigilance4 ,the other danger signal is the pupil4 ,it should be dilated1 but a rim of iris should still be perceptible4 ,once ansthesia is established1 the inhaler should be removed1 and the surgeon may begin his work4 ,he will have for its completion some #hj-ij seconds against the #dj-ej available after nitrous oxide4 ,with ethyl chloride there is a somewhat prolonged 8analgesic0 stage4 ,the patient is partly conscious and may even be phonating1 but seems unconscious of the infliction of pain unless very severe measures are being used4 ,the ,scope of ,ethyl ,chloride4 ,when first introduced1 it was expected by enthusiasts that the lightness and portability of the drug itself and of the necessary inhaler1 would enable ethyl chloride to oust nitrous oxide from its recognised place in surgery and dentistry4 ,these high expectations have for several reasons not been fulfilled4 ,in the first place1 this drug is essentially a 8single dose0 ansthetic4 ,most authorities view coldly all attempts to prolong ansthesia by repeated or continued administration4 ,secondly1 ethyl chloride has a mortality rate very much greater than nitrous oxide if doses sufficient in themselves to produce ansthesia are habitually used 7vide supra74 ,the introduction of the 8vapour0 method has done much to mitigate the risks1 but even then1 this ansthetic cannot approach the high level of safety rightly credited to ,n#b,o4 ,moreover1 it leads to after vomiting much more commonly than its rival4 ,in many schools these considerations have been held so powerful that ethyl chloride has been entirely abandoned4 ,it is1 however1 a very valuable drug for the following purposes3-- 7#a7 ,the removal of tonsils and adenoids4 ,for this operation1 the speed with which the patient 7usually a child7 loses consciousness1 the pleasant type of ansthesia and absence of all serious asphyxial phenomena1 and the rapid re-appearance of the cough reflex when once the inhaler is removed1 are all strong recommendations4 7#b7 ,as an adjuvant to gas1 or gas oxygen 7see ,chapter ,,xiii474 7#c7 ,as a help to the speedy and comfortable induction of 8closed ether0 7see ,chapter ,,xv474 ,,chapter ,,xiii4 ,,mixtures ,,of ,,nitrous ,,oxide ,,and ,,ethyl ,,chloride4 ,dr ,guy1 ,dean of the ,edinburgh ,dental ,school1 introduced some years ago a method of giving ethyl chloride in mixture with nitrous oxide4 ,guy's objective was to utilise the many excellent features of the drug without incurring the risks which are apparently inherent in it when a dose sufficient in itself to induce full narcosis is used4 ,given in mixture with gas1 a much smaller dose suffices4 ,illustration3 ,,fig4 #db4--;,guy's inhaler for ,n#b,o and ,ethyl ,chloride4 ,his original apparatus is shown in ,fig4 #db1 the details are shown in ,fig4 #dc4 ,the horizontal limb of a #c-way gas tap is prolonged half an inch4 ,in each side of the prolongation is a hole4 ,the bag mount has in its side also one hole1 which is connected by a universal ball and socket joint1 with the rubber tube to which the ethyl chloride vial is attached4 ,an indicator on the outside of the bag mount and a mark upon the outside of the horizontal limb of the #c-way tap1 serve by their apposition or the reverse to show whether the ethyl chloride vial is in direct continuity with the interior of the inhaler4 ,for purposes of description1 ,dr ,guy calls these two positions1 8in register0 and 8out of register40 ,to use the instrument1 the ethyl chloride vial is removed1 and the side pipe attached to a cylinder of nitrous oxide4 ,the indicator of the #c-way tap is put at 8air0 and the bag mount 8in register40 ,the bag is then filled with gas by opening the head of the cylinder4 ,the bag mount is now put 8out of register10 and the side tube disconnected with the cylinder4 ,the bag1 being closed1 remains full of gas4 ,illustration3 ,,fig4 #dc4--;,guy's ,instrument for ,gas and ,ethyl ,chloride4 ,details of valve piece and bag mount1 showing side tube for attachment of ,ethyl ,chloride vial4 ,a suitable dose of ethyl chloride is now squirted into the vial4 ,to an adult1 ,dr ,guy gives #c c4c43 on no account is this dose exceeded3 children take #a-b c4c4--even adults often get less than #c c4c4 ,the vial is now attached to the side tube again1 and the inhaler is ready for use4 ,after application of the mask to the face1 the #c-way tap is at once pushed over to 8no valve0 and the patient rebreathes the gas in and out of the bag for some six or eight respirations4 ,the bag mount is now turned round 8into register10 and the ethyl chloride tipped into the bag4 ,in a further twenty-five seconds the mask may be removed and the operation begun4 ,the available period of ansthesia is eighty to ninety seconds1 counting from the instant of the removal of the inhaler4 ,this method was in use for some years at the ,dental ,hospital of ,edinburgh2 no instance of danger to life was ever seen4 ,with so small a dose of ethyl chloride1 the erect position necessary for the purposes of dentistry is perfectly safe4 ,illustration3 ,,fig4 #dd4--;,diagram of the method introduced by ,dr ,guy and the author for giving ,nitrous ,oxide and ,oxygen1 with or without ,ethyl ,chloride4 ,this inhaler1 of course1 will serve admirably for giving ethyl chloride without gas1 and the author habitually uses it for giving the drug by the 8vapour0 method4 ,in #aiaa1 ,dr ,guy and the present author modified the method so as to permit the use of oxygen with the nitrous oxide4 ,the inhaler which they then introduced serves also for nitrous oxide and oxygen1 unaided by ethyl chloride1 and the author has by its means given gas-oxygen to a considerable number of major surgical cases4 ,he now1 however1 limits its use to short ansthesias1 and uses a sight-feed or a ,clarke apparatus for long cases4 ,illustration3 ,,fig4 #de4--,the ,guy-,ross ,inhaler for ,nitrous ,oxide and ,oxygen1 with or without ,ethyl ,chloride4 ,in ,fig4 #dd will be found a diagram showing the method by which the oxygen is introduced4 ,the #a-;gallon oxygen bag is either attached directly to a cylinder1 or suspended on an upright as shown in ,fig4 #de4 ,in either case1 the bag is1 before the administration1 moderately filled with oxygen3 one bagful will suffice for a short ansthesia1 and the supply of the oxygen from the cylinder is therefore turned off at once4 ,for long cases1 of course1 a small trickle of oxygen into the bag is required to replace the gas used4 ,in the outlet pipe from the oxygen bag is placed a ball syringe of #b ounces capacity4 ,a valve in the pipe obliges the flow of oxygen to take place in one direction only when the bulb is squeezed1 viz4 from oxygen bag to inhaler4 ,the remainder of the apparatus is identical with ,guy's original inhaler1 except that the bag is of #b-;gallon capacity1 and is perforated at its base by a ,y-tube1 one limb of the fork bringing in the nitrous oxide1 the other the oxygen4 ,method of ,use4 ,a few breaths of pure nitrous oxide gas are usually allowed 8on the valve40 ,rebreathing is then instituted1 and the addition of oxygen begun4 ,the amount required to each type of patient can only be learnt with experience1 but the average is one full compression of the bulb every ten seconds4 ,if ansthesia is not complete at the end of one minute1 put the indicator to 8valves0 again1 and allow the patient nearly to empty the bag4 ,then push back the indicator to 8no valves10 and refill the bag with nitrous oxide by opening the cylinder with the foot key4 ,some four to six compressions of the bulb are made while the nitrous oxide is running in4 ,the time will now have come to add the dose of ethyl chloride if it be judged necessary at all4 ,this will have been placed in the vial before the administration is begun4 ,after emptying the ethyl chloride into the bag of the inhaler1 ansthesia should be complete in twenty-five seconds4 ,the same small doses of ethyl chloride are used as is the case with ,guy's original method4 ,after a little practice under supervision1 students at the ,dental ,hospital learn to use this method safely and well4 ,no example of risk to life has arisen after eight years' daily experience4#aa ,,chapter ,,xiv4 ,,mixture ,,of ,,chloroform ,,and ,,ether4 ,the mere addition of ether does not remove all the undesirable features of chloroform ansthesia4 ,a heart poisoned by excess of ,c,h,cl#c does not respond to ether stimulation4 ,nevertheless1 ,,ce mixtures of varying proportions have great value4 ,the less lethal drug takes on part of the work of the more dangerous one2 it also keeps the respiratory centre active4 ,viewing mixtures as dilute chloroform1 it is also obvious that there will be with them a greater margin of error in dosage1 than with the pure drug4 ,some chemical change takes place when the two drugs are mixed1 for heat is evolved2 of the nature of this change we are ignorant4 ,the first mixture introduced was known as ,,ace1 and consisted of one part absolute alcohol1 two parts chloroform1 and three parts ether4 ,alcohol evaporates very slowly and if it be introduced at all it should be in much smaller proportion4 ,schfer's mixture is one part alcohol to nine parts chloroform4 ,neither of these mixtures is now much used4 ,the most useful combination is two parts chloroform and three parts ether1 and is known as ,c#b;,e#c4 ,in special cases1 one part of chloroform to two parts ether may be better4 ,methods4 ,cones of varying type were at first extensively used for mixtures4 ,the best known is ,rendle's 7,fig4 #df74 ,it is made of celluloid1 and is perforated at the top by a series of small holes through which the ansthetic is introduced4 ,a sponge is packed into the upper part of the cone1 and a flannelette cover completes the appliance4 ,the objection to the use of this and kindred cones is that since chloroform evaporates more slowly than ether1 the more dangerous drug is apt to collect in the sponge1 completely altering the strength of the vapour after a time4 ,this fault is remedied to a large extent by the open drop method now used4 ,illustration3 ,,fig4 #df4--,rendle's ,cone4 ,the ,open 7,drop7 ,method4 ,for this the mask and ether dropper of ,bellamy ,gardner are admirably suited 7,fig4 #bg74 ,a material less close than the gauze advocated for open-ether is required4 ,one layer of flannelette does very well1 or the cheap cotton towels which used to be known in ,edinburgh as 8penny towels0 in the pre-war period4 ,the mask should fit the face with reasonable accuracy3 there is no reason why a gauze ring should not be used to ensure this if the administrator is careful to adhere strictly to a 8drop0 method4 ,the bottle into which the dropper is inserted should be of different colour to those in which pure ether is habitually carried4 ,this is a greater safeguard against a dangerous forgetfulness than a mere label4 ,as already said1 the ansthetic must be given by a strict 8drop0 method4 8,douching0 at frequent intervals gives results far inferior4 ,,the ,,type ,,of ,,an,,sthesia is a compromise between that of chloroform and open-ether4 ,respirations and colour are better than with pure chloroform1 not so good as with open-ether4 ,the size of the pupil is also intermediate4 ,,scope4--,as elsewhere explained there are many patients to whom open-ether cannot well be given2 the greatest number of these can take a mixture perfectly and ,c4,e4 should certainly be chosen in preference to pure chloroform when possible4 ,for refractory cases1 it serves admirably as the inducing agent before the use of open-ether4 ,,chapter ,,xv4 ,,sequences4 ,by a sequence we mean a method in which ansthesia is partially or wholly induced by one ansthetic or one method1 and maintained by another4 ,the methods mentioned in ,chapter ,,xiii4 as devised by ,dr ,guy for dental purposes are examples which have already been sufficiently described4 ,c4,e4 ,mixture--,ether ,sequence4 ,of the method of inducing ansthesia by ,c4,e41 and turning later to open-ether1 we have also already spoken4 ,one thing remains to be said in this connection4 ,learn to judge the appearance of the type of patient who will require this alternative to open-ether induction1 and use the sequence to such patients from the beginning4 ,don't start off with open-ether1 and find out in a few minutes that the patient is too obstreperous4 ,a change from mixture to ether is harmless1 the reverse process needs much care4 ,the sequence of ,c4,e4 to closed ether was advocated by ,hewitt as a means of dealing with very alcoholic men1 and for this purpose has great merits4 ,the mixture is given until the stage of struggling is just about to commence1 a point which experience enables one to fix with considerable accuracy4 ,the remainder of the induction is conducted by a closed-ether inhaler1 either the ,hewitt wide-bore or preferably the ,ormsby4 ,the ether indicator which stands at about one when the inhaler is first applied1 may be advanced very rapidly full ether strength being attained within a minute or two4 ,as soon as rebreathing is begun with either of these instruments1 it is very striking to watch the rapid and apparently safe subsidence into ansthesia of the most troublesome patient4 ,the struggling is cut short and greatly minimised in violence1 and a stage which under ,c,h,cl#c might have presented some considerable risk of secondary syncope1 is thus eliminated4 ,nitrous ,oxide and ,ether ,sequences4 ,this is a method greatly superior to the induction by closed-ether described on p4 #gi4 ,instead of the #a-;gallon bag of the ,clover or ,hewitt instrument1 the valve piece and #b-;gallon bag of a gas apparatus are attached to the head of the ether inhaler 7,fig4 #bc1 on page #gg74 ,once the gas bag is inflated from the cylinder1 the supply of gas may be cut off4 ,a few breaths of gas 8upon the valves0 are given1 until the bag is half empty2 the valve tap is then pushed over to 8no valves0 and rebreathing begun4 ,ether may be turned on a few seconds later1 and the strength of the vapour may be increased more rapidly4 ,three-quarter strength of ether may be attained as a rule in ninety seconds4 ,there is very little likelihood of struggling in this method4 ,ethyl ,chloride and ,ether4 ,this is a valuable method for short operations1 being easily portable1 speedy and safe in action1 and fairly agreeable to the patient4 ,some ansthetists use this induction method as a prelude to open-ether4 ,the ,clover 7or ,hewitt wide-bore7 instrument is interposed between the face-piece and the ,t4 of the ethyl chloride inhaler1 as shown in ,fig4 #dg4 ,a small dose of ethyl chloride only is requisite2 for an adult1 #c c4c4 is enough4 ,this is vapourised over hot water in the usual way2 a very light ansthesia is induced in some sixty seconds1 and the ether can then be turned on at a much quicker rate than if the induction be conducted by that drug alone4 ,scope4 ,the gas-ether and ethyl chloride-ether sequences are most useful methods4 ,they are quick1 safe1 and powerful4 ,illustration3 ,,fig4 #dg4--;,clover's ,inhaler adapted for the ,ethyl ,chloride-,ether sequence4 ,either may be used as 8single dose0 ansthetic1 the ether being pushed quickly up to 8full0 and the inhaler then withdrawn4 ,if1 however1 no access to the mouth is required by the surgeon1 ether ansthesia may1 by occasional breaths of fresh air be prolonged for as long as desired4 ,,chapter ,,xvi4 ,,the ,,accidents ,,of ,,an,,sthesia4 ,the minor difficulties of ansthesia have already been dealt with1 and if the instructions already given1 particularly in ,chapter ,,iii41 are faithfully carried out1 incidents of real danger will rarely occur4 ,the soundest knowledge and the most conscientious care will1 however1 never entirely rid ansthesia of an element of danger to life4 ,the conditions now to be considered are3-- 7,a7 ,vomiting4 7,b7 ,failure of respiration4 7,c7 ,failure of circulation4 7,a7 ,vomiting4 ,this always exposes an unconscious patient to the danger of inhaling solid or fluid material into the larynx1 with resulting asphyxia4 ,if the patient be tided through that immediate difficulty1 he is liable to develop an inhalational pneumonia subsequently4 ,a healthy patient properly prepared should not vomit during the induction stage1 nor during the progress of the operation4 ,if he does1 it means that the induction has been too slow1 or that the administration has been intermittent1 and the patient has been permitted to come to too light a level of ansthesia during the operation4 ,during emergency operations where the patient's stomach may be full of food1 the case is different4 ,such patients commonly vomit early in the induction stage1 and no skill can avert the incident4 ,a patient suffering from intestinal obstruction1 or from generalised peritonitis has his stomach and intestines full of highly infective fluid4 ,reverse peristaltic may set in merely as the result of the inhalation1 or later from handling the contents of the abdomen1 and the feculent fluid gushes up the sophagus with little or no warning4 ,since vomiting in these cases may occur even in deep ansthesia1 when the cough reflex which is the normal sentry to the entrance of the larynx1 is abolished1 the dangers of insufflation are very real indeed4 ,personally1 the author prefers to wash out the stomach before beginning to induce ansthesia in these cases1 but some surgeons believe that the shock of this procedure outweighs the advantages4 ,,symptoms ,,and ,,treatment ,,of ,,vomiting4 ,in ordinary cases1 vomiting is usually heralded by a definite train of symptoms4 ,respiration becomes shallow1 the colour a little pale and the pulse rather small4 ,the pupil dilates1 but remains active to light1 indicating that the alteration of respiration and circulation is not due to overdose4 ,at the first appearance of such symptoms1 a brisk rub of the lips and thereafter an increase of the vapour strength of the ansthetic will often avert the impending vomiting by deepening the ansthesia1 but if the possibility of this complication has occurred to the ansthetist too late for its prevention1 the head must be turned well to one side1 and the other shoulder slightly elevated by a pillow1 so that vomited material will fall out of the mouth at once4 ,when the actual act of vomiting is over1 no time must be lost in mopping out the mouth and pressing on with the production of a deeper ansthesia4 7,b7 ,respiratory ,dangers4 ,these divide themselves into two groups3-- 7#a7 ,,mechanical4--,the respiratory movements continue1 but the ingress and egress of air is blocked4 ,the symptoms and preventative treatment have been referred to at some length in ,chapter ,,iii41 and no further account of these is therefore necessary4 ,the treatment of a complete blockage of the air passages which resist the measure there described1 alone remain to be mentioned4 ,of these1 the only two effective are artificial respiration and tracheotomy 7or laryngotomy if preferred by the surgeon74 ,forcible artificial respiration by the ,sylvester method1 with the mouth gagged open and the tongue held forward by the tongue forceps1 is frequently successful in getting over even a complete block1 but the last resort of opening the air passage by the knife must not be delayed until too late4 ,in deciding such a point1 considerable judgment is of course called for4 7#b7 ,,non-,,mechanical4--,respiratory arrest4 ,this is usually seen in conjunction with a serious failure of the circulation caused by over-dosage4 ,exceptionally1 some act of the surgeon sets up a reflex inhibition of the respiratory centre2 the circulation is at the same time depressed1 but to a varying degree4 ,the cardinal symptom is arrest of all respiratory effort4 ,the treatment is best dealt with under the heading of circulatory failure4 7,c7 ,circulatory ,failure1 or ,syncope4 ,by the term syncope1 we mean a more or less sudden failure of the cardiac pump1 as opposed to the form of circulatory failure seen in surgical shock1 where the condition is chiefly1 though not wholly1 one of vaso-motor paralysis 7see ,chapter ,,ii474 ,syncope occurs under varying conditions which may for descriptive purposes be divided into four classes4 ,it is not1 however1 always possible to decide with certainty into which class an individual case should be placed4 ,the symptoms common to all classes of syncope are3-- 7#a7 ,pallor1 and loss of all tone in the muscles1 noticeably those of expression4 ,the pulse is weak or imperceptible4 7#b7 ,cessation of respiration4 7#c7 ,dilatation of the pupil1 which ceases to react to light4 ,the four classes above mentioned are as follows3-- ,a4 ,,primary ,,syncope4 ,this is peculiar to chloroform4 ,with no other ansthetic is it seen1 at any rate in the healthy subject4 ,it arises during the induction period1 and is not necessarily preceded by any respiratory difficulty4 ,there is one big inspiratory gasp1 sudden and extreme pallor1 and the pupil goes out to the rim in a few seconds4 ,the only reasonable explanation of such an incident is the occurrence of vagal inhibition 7see page #aab74 ,its prevention therefore is a matter of the avoidance of a high percentage of chloroform4 ,b4 ,,secondary ,,syncope4 ,this term is applied to a collapse arising as a secondary result of embarrassed respiration4 ,though not peculiar to chloroform1 it is far more common with that drug than with any other 7ethyl chloride excepted74 ,the most common time for the accident is towards the end of the induction period4 ,the patient has probably been struggling1 has clenched the jaws1 and developed 8mechanical0 asphyxia4 ,violent inspiratory efforts are still being made1 and considerable cyanosis develops4 ,either at the very moment when the respiratory difficulty is overcome1 or while it still persists1 the colour suddenly alters from blue to white1 and the other symptoms of syncope rapidly appear4 ,the exact period required to transform a blue struggling patient with heaving chest1 into one with pallid face1 and motionless chest and limbs1 varies greatly1 for reasons furnished below4 ,the most reasonable explanation offered of such an accident is that given by ,leonard ,hill4 ,the attempts to inspire through an air way mechanically blocked cause an immense strain upon the heart muscle4 ,the flow of blood in the lung capillary is hindered1 and the right side of the heart becomes over distended with blood4 ,its musculature is further damaged by the fact that the blood in the coronary vessels is deficient in oxygen1 and that a considerable dose of ansthetic has already been absorbed4 ,there is the further fact1 not mentioned by ,hill1 that during the whole period of asphyxia the peripheral resistance is rising from vaso-constriction4 ,under circumstances such as these1 it is obvious that any heart must ultimately succumb1 no matter what ansthetic is in use4 ,it is also obvious that with chloroform and ethyl chloride1 which are themselves heart poisons1 secondary syncope will happen much more readily than with ether or nitrous oxide1 which are not2 and that a heart with diseased musculature will fail quicker than a healthy organ4 ,secondary syncope is almost certainly the commonest fatal accident of ansthesia4 ,the reason why this fact is not more widely recognised arises from the natural instinct of any one who has suffered the misery and ignominy of causing a death under an ansthetic1 to attribute it to some cause beyond human control4 ,the essential cause of secondary syncope is failure to maintain a free air way1 which cannot be styled unavoidable4 ,two consolations may1 however1 honestly be offered to the person who has acted as ansthetist in a case of secondary syncope4 ,firstly1 it is1 in certain types of cases1 very difficult indeed to maintain a free air way2 and secondly1 a heart with muscle degenerated from fatty or other changes1 may give out after very little respiratory embarrassment4 ,,syncope ,,from ,,overdose4 ,this is a more gradual affair than the two foregoing2 and has been sufficiently dealt with in the chapter devoted to the ,stages of ,ansthesia 7see p4 #cf74 ,c4 ,,reflex ,,syncope4 ,exceptionally1 a patient not overdosed with ansthetic1 and not suffering from any mechanical obstruction to respiration1 has a sudden attack of syncope during the progress of the operation4 ,we here exclude patients who are suffering from surgical shock2 the condition arises too rapidly for such an explanation to be accepted4 ,much speculation has been expended upon these cases4 ,one view is that some procedure of the surgeon has set up a reflex inhibition of the heart through the vagus2 another1 that the reflex has taken the form of sudden vasomotor paresis4 ,levy would ascribe the condition to cardiac fibrillation4 ,it may well be that all cases cannot be met by one explanation4 ,the older surgeons stoutly maintained that reflex syncope could not arise if the patient were properly under1 and that it was in the practice of those ansthetists who were afraid of pushing the ansthetic sufficiently1 that such accidents occurred4 ,the author's own belief is that a very light chloroform ansthesia does pre-dispose to this accident1 but that it may occur also at a deep1 the very deepest possible level4 ,with an ansthetic other than chloroform1 it is extremely rare--perhaps unknown4 ,treatment of ,syncope4 ,this must be speedy to be of any avail4 ,the following are the points upon which to concentrate3-- 7#a7 ,withdraw the ansthetic4 7#b7 ,make sure that the air way is free4 7#c7 ,begin artificial respiration by ,sylvester's method1 the movement of expiration being first performed 7see ,fig4 #dh74 7#d7 ,lowering of the head and shoulders is usually to be recommended4 ,it is best done by tilting the whole table as if for the ,trendelenberg position4 ,the lowering of the head attracts more blood to the carotid artery and raises the blood pressure of the main vessel and its cerebral branches 7see ,fig4 #ce74 ,it must1 however1 be remembered that it will also tend to empty the blood in the veins of the lower extremities and abdomen into the right side of the heart1 and cases in which marked cyanosis has preceded pallor1 are probably suffering already from engorgement and dilatation of the right heart4 ,the tilting of the table should in such cases be very moderate in degree1 and should not be persisted in if it seems to do no good4 ,in no case1 indeed1 should the tilting be extreme4 ,an angle of more than #ae or #bj degrees is as likely to do harm as good4 ,illustration3 ,,fig4 #dh;,a4--,artificial respiration by ,sylvester's method4 ,expiration4 7#e7 ,hot cloths may be placed over the precordial region1 care being taken not to burn the skin4 7#f7 ,the only drugs likely to be of any avail are atropine and strychnine1 the former being used with the idea of paralysing the terminations of the vagus in the heart muscle1 the latter as a cardiac tonic and a stimulant to the respiratory centre4 ,some authorities have recommended the injection of atropine by a long needle passed into the heart muscle1 but most are content to give either or both drugs hypodermically4 ,really to paralyse the vagus1 a very large dose of atropine is required--about gr4 ,strychnine should be given in a dose of - gr4 ,illustration3 ,,fig4 #dh;,b4--,artificial respiration by ,sylvester's method4 ,inspiration4 7#g7 ,in cases where the right heart has certainly been over-distended1 the expedient of venesection has been tried4 ,some six ounces may be withdrawn from the external jugular or one of the veins of the arm4 7#h7 ,as a last resort1 the heart may be massaged4 ,the only practicable route is to open the abdomen 7if not already done7 pass one hand under the left side of the vault of the diaphragm1 placing the other hand over the precordial region4 ,between the two hands1 the heart can first be thoroughly compressed to empty its presumably flaccid and over-distended cavities1 and then lightly massaged4 ,several cases of recovery from this measure are on record4 ,status ,lymphaticus4 ,before leaving the subject of accidents it may be well to allude to this condition1 which is also known as status thymicus1 and as lymphatism4 ,it is met with mostly in the young1 the commonest ages probably being five to fifteen years4 ,certain pathological conditions have been found in fatal cases1 of which the most important are an enlargement of the thymus gland1 of various lymph glands1 and of the tonsils1 including the naso-pharyngeal tonsil 7adenoids74 ,the heart muscle is frequently degenerated4 ,of the cause of these abnormalities we are as yet in doubt4 ,there is some reason to believe that the condition tends to disappear with advancing years1 if the subject survive4 ,the most outstanding clinical fact in connection with the disease is its tendency to cause sudden death on very little provocation4 ,a fright1 a sudden exertion1 and above all an ansthetic may cause sudden and fatal syncope4 ,,diagnosis4 ,suspicion that the disease is present may be aroused in several ways4 ,the presence of enlarged tonsils and adenoids1 combined with general enlargement of lymph glands from no obvious cause1 and a tendency to faint1 make a very suggestive picture4 8,night-crowing0 7a sudden attack of laryngeal spasm1 occurring at night1 and often repeated at intervals7 also raises grave doubt4 ,the diagnosis can only be established with certainty by an ,x-ray photograph1 when the great enlargement of the thymus may be seen in the upper part of the chest4 ,,an,,sthetics ,,in ,,status ,,lymphaticus4 ,too frequently the condition has never been suspected1 and a fatality occurs from sudden syncope1 usually during the induction period1 but occasionally during the progress of the operation4 ,it would1 however1 be fallacious to suppose that an ansthetic is necessarily fatal even to an undoubted case4 ,if the drug 7preferably ether7 be given with great care1 and the operation done carefully at a level of ansthesia neither too light nor too deep1 there is every reason to believe that the danger can be1 and often is1 successfully averted4 ,at the same time1 it must be understood that in a known case1 operation should always be avoided or deferred if possible4 ,,chapter ,,xvii4 ,,the ,,sequel ,,of ,,an,,sthesia4 ,respiratory ,system4 ,after operations performed under any form of ansthesia1 even spinal1 there is always a possibility of pneumonia or bronchitis4 ,the ansthetic itself is not always to blame4 ,the patient has suffered trauma and is confined to bed1 and may develop a hypostatic pneumonia just as a person who has suffered from a fractured thigh so commonly does1 even though he has had no ansthetic at all4 ,it is probable that organisms1 capable under certain circumstances of causing inflammatory disease of the respiratory tract1 are present in a large proportion of apparently healthy people4 ,pneumococci and streptococci of varying strains may be grown from nasal or pharyngeal secretions of patients who suffer from catarrh of these regions1 and may reappear upon slight provocation even when prolonged treatment had apparently banished them permanently4 ,all that is required to start an acute infection of lungs or bronchi1 is some factor that depresses vitality and lowers body resistance to the organism4 ,and if in addition use has been made of an inhalational ansthetic such as ether1 which may cause an immediate and fairly acute congestion of the respiratory mucous membranes1 it is not to be wondered at that serious sequel follow in a certain proportion of cases4 ,laboratory results go to show that ether lowers the opsonic index of the blood to pneumococci and streptococci1 but without placing undue emphasis upon a mere isolated phenomenon such as that1 it is plain that the whole conditions of the patient after operation are favourable to the occurrence of pneumonia or bronchitis1 and that of all ansthetics ether is the most likely to be the determining factor4 ,experience gained during the war has thrown a certain amount of light upon this subject4 ,post-ansthetic bronchitis and pneumonia was very prevalent among the wounded1 far more so than among civilian patients4 ,it is1 the author believes1 reasonable to attribute this fact to several causes4 ,in the first place1 the soldier's life1 alternating between stuffy billets and wet trenches1 predisposed him to naso-pharyngeal catarrh of a fairly high degree of infectivity4 ,enthusiastic press representatives might state that you could not take cold so long as your feet and legs were always buried in half frozen mud1 but experience hardly bore out their golden promises4 ,again1 the soldier did not improve his catarrh by inveterate cigarette smoking4 ,lastly1 military hospitals were large institutions1 some under canvas1 some in huts1 some in buildings constructed for other purposes1 and rapidly altered to the urgent needs of the army4 ,of whatever type1 nearly all had one feature in common--many of the surgical wards were a long 7and draughty7 way from the operating theatre4 ,for the prevention of post-ansthetic pneumonia1 the author offers the following tentative suggestions3-- 7#a7 ,see that the skin is kept covered up as much as possible during the operation and that the patient is not exposed to draughts during or after it4 ,rooms can1 and should be1 well ventilated without cold draughts4 7#b7 ,if a patient has an acute or sub-acute naso-pharyngeal catarrh1 treat it as fully as possible before operation by sprays and gargles4 7#c7 ,do not use ether to patients who suffer or recently have suffered from such conditions4 7#d7 ,give a hypodermic of morphia and atropine before operation as a routine4 7#e7 ,in so far as possible1 let the patient's shoulders and head be raised by pillows during the early hours of convalescence4 7#f7 ,lastly1 remember that while no care will absolutely banish these dangerous sequel from our practice1 the greater care and skill shown by the ansthetist1 the less bronchitis and pneumonia will appear among his patients4 ,as regards ether1 the author believes that it is the strength of vapour used1 more than the duration of the ansthesia1 which counts4 ,it is for that1 among other reasons1 that he has for the induction period1 no hesitation in recommending a method whereby a small part of the requisite ether strength is replaced by chloroform4 ,vomiting4 ,after an ansthesia lasting more than a few minutes1 it may almost be regarded as normal for the patient to vomit once or twice4 ,usually this occurs a few minutes after the administration has ceased4 ,in the case of nitrous oxide and oxygen1 even this slight disturbance may not occur4 ,the amount of vomiting which after this stage may be regarded as normal is difficult to determine4 ,the author took notes of some #cjj cases on this point4 ,the details of his results are not suitable for a text book1 but1 broadly speaking1 it would appear that after an operation of ordinary duration and severity1 the vomiting returns on the average some five or six times1 and usually ceases on the evening of the operation day4 ,a limited number continue to vomit at intervals until the early hours of the following morning4 ,with nitrous oxide and oxygen the vomiting is far less than the above1 though even with this ansthetic quite severe emesis may occur4 ,with closed-ether1 the trouble is very violent for a short time1 large quantities of mucous being ejected3 it is probable that after the first two hours1 it is no more marked than after open methods4 ,the use of morphia and atropine before operation most certainly reduces the violence and duration of this sequela4 ,prolonged more than twenty-four hours1 the condition must be regarded as definitely abnormal4 ,,prevention ,,and ,,treatment4 ,the adoption of open-ether preceded by morphia and atropine and due skill and thought on the part of the ansthetist1 combined with proper preparation of the patient1 are the only means of prevention at our command4 ,the raised position of the head and shoulders during the recovery stage undoubtedly tends to reduce the nuisance4 ,it is a vexed question whether to give or to withhold fluids after operation--and this matter is of course in the hands of the surgeon1 not the ansthetist4 ,in certain cases1 the author believes that it is worth while trying the effect of a cup of fresh tea with very little sugar or milk4 ,even if rejected in a few moments1 the astringent effect of the infusion seems to soothe the gastric mucous membrane1 and give relief4 ,post-operative ,acidosis4 7,synonym--,delayed ,chloroform ,poisoning74 ,in a limited number of cases1 post-operative emesis assumes a grave type1 and definitely threatens life4 ,such cases began to be studied in the early part of this century1 and though our knowledge of the condition is still incomplete1 the student should be acquainted with the present views held upon the subject4 ,clinically1 the earliest symptom to raise suspicion1 is the reappearance of vomiting at a time when one would expect such trouble to have abated1 usually twenty-four or thirty-six hours after operation4 ,within a few hours1 the nature of the vomit changes from the usual bilious stomach contents1 and shows obvious evidence of the presence of altered blood4 ,the pulse and temperature begin to rise1 the countenance assumes an anxious look4 ,a trace of jaundice is usually present4 ,the nervous system becomes affected as shown first in restlessness1 and later1 delirium4 ,every degree of this condition is possible1 but a very large proportion of recognisable cases pass into coma1 and death supervenes within a few days1 sometimes less4 ,investigation into such cases has shown that the essential underlying condition is an acidosis closely allied to that seen in diabetic coma4 ,the breath has the peculiar sweetish aroma of acetone1 and acetone1 diacetic acid1 and ,b4 oxybutyric acid successively appear in the urine4 ,post-mortem1 the most striking change found is a profound fatty degeneration of the liver1 the cells of which are disintegrated as in acute yellow atrophy4 ,it is obvious from the foregoing that there is present a very remarkable abnormality of metabolism4 ,mr ,rendle ,short1 in his admirable book1 ,the ,new ,physiology in ,surgical and ,general ,practice1 gives the following explanation of the condition3-- 8,the physiological process of dealing with fat is to resolve it into carbon di-oxide and water4 ,if we make a pound of fat into tallow candles and burn it1 we shall obtain carbon di-oxide and water1 and a certain amount of heat will be evolved4 ,if the pound of fat is eaten and absorbed by a man or an animal1 it will be burnt to the same end products1 and the same amount of heat will be given out4 ,but in certain circumstances1 an abnormal mode of breaking down is followed1 and there are produced1 first ,b4 oxybutyric acid1 then diacetic acid1 and finally acetone4 ,if this takes place on a large scale1 the conversion into acetone fails to keep pace with the production of acids4 ,therefore first acetone appears in the urine1 then diacetic acid1 and finally oxybutyric acid2 the last may rise rapidly to an enormous figure3 #cj1 #ej1 or even #ahj grams may be passed daily40 ,later in the same chapter1 ,short propounds the question as to what are the special circumstances in which the breaking down of fat deviates from its normal course1 and follows this dangerous route4 ,the answer is1 he says1 quite definite and decisive4 ,when the tissues are unable to obtain sugar from the blood1 fat is broken down via these dangerous acids to acetone1 instead of to carbon di-oxide and water4 ,such an inability on the part of the tissues to obtain sugar arises under several conditions3-- 7a7 ,in diabetes1 where sugar though freely present in the blood cannot1 for some reason still not clearly known1 be assimilated by the tissues4 7b7 ,in poisoning by salicylates4 7c7 ,in starvation1 for obvious reasons4 ,the supply of sugar from the liver has been used up1 and the patient1 living on his own fats1 breaks them up abnormally4 7d7 ,in post-ansthetic poisoning1 for reasons which are at present not clearly ascertained4 ,upon the theoretical side it is therefore not possible to say more than that ansthetics sometimes initiate this abnormal metabolic process4 ,to the question as to why and how they do so1 we can as yet give no answer4 ,upon the practical side1 we can1 however1 speak much more definitely4 ,acidosis follows the use of ether very rarely indeed3 after nitrous oxide it is unknown4 ,chloroform has been the drug used in almost every recorded case1 while ethyl chloride has been responsible in a few isolated instances4 ,young children are much more prone to suffer than adults1 though the author had a fatal case in a lady well over forty years of age3 he has also seen a case very nearly fatal in a soldier aged twenty4 ,this man was1 a week after recovery from acidosis1 ansthetised for half-an-hour with nitrous oxide and oxygen1 without exhibiting any signs of a return of his dangerous condition4 ,ansthesia repeated in the same subject after a short interval is more prone to start the process than a first inhalation4 ,lastly1 acute sepsis1 particularly in the young1 is notorious for its liability to be followed by acidosis4 ,,prevention ,,and ,,treatment4 ,the obvious moral of the foregoing is that chloroform should not be administered to patients suffering from acute sepsis1 particularly if they be very young4 ,indeed1 so common is a mild degree of acidosis among children1 some surgeons consider there is a definite risk in giving chloroform to them at all unless special precautions are taken4 ,chief among these are regular dosage for a day or two before operation1 with considerable doses of bicarbonate of soda and sugar1 which is a routine measure in some children's hospitals4 ,as regards curative treatment1 much can be done if the gravity of the condition is recognised early4 ,the stomach is first washed out with alkalis1 and a substantial dose 7one dram7 of bicarbonate of soda left in it4 ,the same dose is repeated hourly by the mouth1 if retained1 or per rectum4 ,a useful addition to the alkaline treatment is dextrose1 also in teaspoonful doses4 ,in grave cases1 these drugs should be given intravenously in saline solution4 ,these measures combined with warmth1 and ample fluids by mouth or rectum1 will often save life1 but to be of any value they must be begun early4 ,fulminating cases occur which succumb rapidly in spite of treatment4 ,,chapter ,,xviii4 ,,posture ,,of ,,the ,,patient4 ,the position in which the patient is lying is of as much importance to the ansthetist as to the surgeon4 ,it is for the surgeon to say what he wants and for the ansthetist to realise how his own work will be thereby affected4 ,dorsal ,decubities4 ,this is the ordinary position and calls for no extended comment4 ,the pillows must be so arranged that at no spot is the body acutely flexed or extended4 ,abdomen1 thorax1 neck1 and head must all be roughly in a straight line4 ,deep-chested subjects require a higher pillow than those with shallow chests1 otherwise the neck is bent back and respiration obstructed4 ,the arms should either be folded and retained by a bandage or other device over the chest1 or extended so that the hands can be slipped under the buttocks and retained there by the body weight4 ,an arm which is allowed to hang over the side of the table is likely to show next day and for many months afterwards1 the condition of drop-wrist from musculo-spiral paralysis4 ,face-down ,position4 ,this is an awkward position for the ansthetist2 there being a general tendency to respiratory embarrassment4 ,put a pillow under the upper part of the thorax1 leaving the lower part and the abdomen as free as possible4 ,let the head project from the pillow1 so that the face can be got at without undue rotation of the neck4 ,the intratracheal method is a great help4 ,lateral ,position4 ,this may be called for either with or without the addition of a sand-bag or inflatable air-pillow to push the loin upwards4 ,in either case1 there is a tendency for the upper shoulder to fall forwards1 the position then assimilating itself to the face-down position4 ,this is best met by a support fixed to the table1 upon which the upper arm may be rested4 ,failing such a convenience1 a sand-bag may be pushed in to keep up the shoulder1 or the assistance of a nurse may be required4 ,the ,trendelenburg ,position4 ,slight tilting of the head end of the table downwards is often useful in assisting the return of bowel into the abdomen3 in this position1 the patient usually takes the ansthetic very well4 ,it must not be assumed until the third stage of ansthesia is reached4 ,for many gyncological operations1 however1 the full ,trendelenburg position is required4 ,healthy subjects usually do quite well in it1 but stout persons not uncommonly show a good deal of cyanosis4 ,at the close of the operation it is essential to restore the table to the horizontal slowly3 the physics of the circulation are profoundly modified1 and if any serious degree of shock is present1 rapid return to normal may initiate a collapse4 ,in the full position1 the weight of the body should be taken by metal supports attached to the table against which the shoulders may rest4 ,to hang the entire weight of the body upon the legs may cause a good deal of after-suffering to the patient4 ,the ,sitting-up ,position4 7,see ,fig4 #di47 ,the object of this position is to diminish venous engorgement and bleeding in operations requiring delicate dissection in the region of the neck4 ,prof4 ,alexis ,thomson introduced the position into ,edinburgh surgery3 the author was at first rather nervous of it1 but has found that with proper precautions the patients do uncommonly well4 ,beyond all doubt1 the position is a great help to the work of the surgeon4 ,not every surgical table is capable of giving the full position without the use of many pillows and sandbags4 ,the head-piece of the table is tilted up at an angle of about #ge or even #hj1 and the patient pulled up so that the flexion of the body occurs in the lumbar1 not the dorsal spine4 ,a small sand-pillow is placed behind the neck so as to produce slight extension4 ,another heavier one is placed under the thighs to prevent the body slipping down4 ,a slight tilt downwards towards the head end may be given to the table as a whole with the same object4 ,illustration3 ,,fig4 #di4--,sitting-up posture for operations on the neck4 ,one should not in this position attempt to induce a deep chloroform ansthesia4 ,weak ,c4,e4 mixture at most1 but better simply open-ether is the method of choice4 ,the induction is begun with the shoulders raised to a modified degree1 and the full position assumed in a light third stage ansthesia4 ,intratracheal ether combined with this position is an ideal ansthesia for the removal of goitre or extensive dissections in the neck for enlarged glands4 ,o',malley's ,position for ,nasal ,surgery4 7,see ,fig4 #ej74 ,the author became acquainted with this useful position while acting as ,ansthetist at the ,royal ,herbert ,hospital1 ,woolwich1 where the ,nose and ,throat ,department was under the charge of ,major ,o',malley1 ,f4,r4,c4,s4 ,major ,o',malley was kind enough in a recent letter written by request to refresh the author's memory of the details4 ,illustration3 ,,fig4 #ej4--,o',malley's posture for intra-nasal surgery4 ,with the patient lying as shewn in the photograph1 every part of the interior of the nose can be easily inspected by the surgeon2 the elevation of the head and shoulders prevents undue bleeding1 and such hmorrhage as does occur goes down the gullet1 where it does no particular harm1 instead of into the larynx4 ,the degree of flexion of the head upon the neck is not so extreme as to interfere with respiration4 ,the details of ,o',malley's procedure are as follows3-- ,the interior of the nasal cavities are packed with gauze soaked in adrenalin and novocain a quarter of an hour before operation1 and the patient receives a very small dose of morphia and atropine immediately before ansthesis is induced2 given in this way it does not complicate the induction with chloroform to the same extent as if given earlier4 ,the patient lies with the top of the head level with the top of the table1 and the head and shoulders 7including the upper two-thirds of the shoulder blades7 supported on the usual depth of pillow4 ,induction is by chloroform or mixture2 a very light third stage only is aimed at4 ,when it is attained the mouth is opened by a gag1 and ,phillip's ,oral ,airway inserted 7see ,fig4 #h74 ,strict oral respiration is essential to success4 ,if air is passing in and out of the nose1 blood is spluttered all over the surgeon1 seriously interfering with the harmony of the proceedings4 ,junker's chloroform bottle is ready1 and the end of the supply pipe is passed into one of the side holes in the air way4 ,the head of the table is now elevated to an angle of #de1 and a small sand pillow slipped behind the occiput4 ,the gauze is removed from the nose1 and the operation can be performed with great comfort4 ,the circulation of the patient needs careful watching for the first minute or two after the table head has been elevated1 but thereafter there is usually no special cause for anxiety4 ,the area of operation is locally ansthetised by the action of the novocain and a light chloroform sleep only is required4 ,,chapter ,,xix4 ,,choice ,,of ,,an,,sthetic4 ,in considering this matter1 some repetition of points to which reference has already been made1 is inevitable4 ,indeed1 this chapter may be regarded as a revision of the whole subject4 ,before deciding upon drug and method suitable for the individual case1 we must consider the age and sex1 the physical type and temperament1 the possible presence of some definite pathological condition1 and the nature and duration of the operation4 ,in relation to this last point1 we must remember that an ansthesia must be adequate to the purpose of the surgeon1 but that it is improper to incur more risk to life than is necessary4 ,for instance1 an abdominal section case must be fully relaxed1 and if in an individual case1 chloroform is the only drug which will give that effect1 there need be no hesitation in using it4 ,on the other hand1 many other methods with a far smaller mortality rate are available if all that is required is the extraction of a tooth or the incision of an abscess1 and in that group of cases1 unfamiliarity with such ansthetics as nitrous oxide or 8ethyl chloride and ether0 will not be held as a sufficient defence if chloroform has been given with a fatal effect4 ,normal ,subjects4 ,let us take first the case of the healthy adult about to undergo a major operation4 ,for this1 we unhesitatingly choose what we may term the 8stock0 method--open-ether preceded by morphia and atropine4 ,if the operation be brief1 we have a choice of methods4 ,for the extraction of teeth1 where access to the mouth is essential1 the following table will help3-- ---------------------------------------- ------------------------------------ ,duration of ,available ,,an,,sthetic ,,drug ,,and ,ansthesia1 when ,,remarks4 ,,method4 given as 8,single ,dose40 ---------------------------------------- ------------------------------------ ,nitrous oxide #cj to #dj seconds ,nitrous oxide and #dj to #ej seconds oxygen ,ethyl chloride #gj to #ij seconds ,only to be recommended in special cases 7see page #abg74 ,gas and ethyl chloride #gj to #ij seconds ,gas-oxygen and ethyl #gj to #ij seconds chloride ,gas and ether ,anything up to #b to #e ,may cause after vomiting4 minutes according to duration of inhalation ,ethyl chloride and ether,anything up to #b to #e ,may cause after vomiting4 minutes according to ,more portable4 duration of inhalation ,nasal gas #e to #aj minutes 7not a ,requires considerable 8single dose0 ansthetic7 practice to give well4 ,nasal gas and oxygen ,no limit ,easier to give than above but apparatus rather importable4 ---------------------------------------- ------------------------------------ ,in cases where access to the mouth is not required1 and where it is therefore unnecessary to 8charge up0 the patient with ansthetic1 we have also a choice which may be expressed tabularly3-- ---------------------------------------- ------------------------------------- ,,an,,sthetic4 ,,remarks4 ---------------------------------------- ------------------------------------- ,nitrous oxide ,apparatus simple3 short administration can be mastered easily4 ,a little more practice required for cases prolonged by admitting air4 ,muscles not relaxed1 and patient may move when cut4 ,nitrous oxide and ,apparatus more complicated1 but short administrations oxygen present no great difficulty to the beginner4 ,muscles not completely relaxed unless a little ether added4 ,gas and ether ,quick and safe ansthetic4 ,deep ansthesia may be obtained if ether is 8pushed40 ,ethyl chloride and ether,the same4 ,more portable than above4 ---------------------------------------- ------------------------------------- ,in this group of short operations1 special reference must be made to the reduction of dislocations4 ,here two important features require notice4 ,the whole object of the proceeding is to relax muscles1 and therefore nitrous oxide or gas-oxygen are unsuitable4 ,secondly1 the tendency to reflex syncope just at the moment of reduction is very great4 ,for this reason1 chloroform has here a painfully high mortality rate2 closed-ether1 preceded by gas or ethyl chloride1 is undoubtedly the method of choice4 ,the ,extremes of ,age4 ,children up to the age of ten years take ether badly1 salivation and bronchial secretion being sometimes very troublesome4 ,atropine mitigates this nuisance to a limited degree only4 ,chloroform is the best drug up to five or six years2 from five to ten1 mixture2 after that1 open ether4 ,in children of any age1 suffering from acute sepsis1 the immediate annoyances and possible respiratory sequel of ether must be faced 7see page #aef71 owing to the probability of acidosis4 ,as regards short ansthetics in children1 nitrous oxide1 if given at all1 should be freely diluted with oxygen1 otherwise most undesirable cyanosis will occur4 ,to children under three or four1 even gas-oxygen is of doubtful safety4 ,short ansthesias in such cases may be induced by open ethyl chloride1 with a few drops of ether added4 ,old people are1 unless very feeble1 best ansthetised by a mixture of chloroform and ether4 ,whatever ansthetic be chosen1 the utmost care must be taken to avoid cyanosis4 ,a cylinder of oxygen should be at hand from which to enrich the atmosphere breathed1 by trickling the gas into the mouth through a rubber tube1 and is a great safeguard in dealing with the old4 ,sex4 ,on the average1 women take ansthetics much better than men1 being far less liable to jaw clenching and other forms of mechanical asphyxia1 and showing less excitement during the induction stage4 ,in the female subject induction by open-ether requires very little assistance from ,c4,e4 mixture4 ,physical ,type and ,temperament1 and ,habits of ,life4 ,heavily built muscular men are troublesome subjects4 ,induction requires a rather strong vapour of ether3 if the open method is used1 there may be to the beginner much temptation to make use during the induction stage of ,c4,e4 mixture to an extent not contemplated in the description given of that method in chapter ,,ix43 it is therefore wise to induce either with closed-ether or with ,c4,e4 mixture as described in chapter ,,xv41 and to change to the perhalation method only when full ansthesia is attained4 ,as regards alcoholics and excessive smokers1 these are well dealt with by the ,c4,e4 open-ether sequence4 ,recourse may be made to the ,ormsby inhaler as already explained on page #acg4 ,the reader is warned not to be deceived by the stout1 rosy face of the typical alcoholic4 ,he often looks a great deal stronger than he really is4 ,many such are really feeble subjects3 although they shout and struggle no great addition to the usual vapour strength of ansthetic is safe or required3 what is required1 is a little extra time4 ,once fully under1 the robust appearance of the patient disappears1 and the fact that one is dealing with a rather broken constitution and a poor circulation is obvious4 ,reference has already been made to the fact that persons with defective nervous systems1 neurotics1 and especially epileptics1 show persistence of some muscular movements for some time1 and therefore require very careful watching4 ,special ,operations and ,pathological ,conditions in the ,patient4 ,these are of the utmost importance1 but to consider each fully from the ansthetic point of view1 would lead us into great detail4 ,the ansthetist must acquaint himself with any abnormality present1 and consider it carefully in the light of the general principles already explained4 ,the following very brief hints for selected cases and operations may1 however1 be found useful4 ,,upper ,,air ,,passages4 ,artificial teeth4 ,must be removed before inducing4 ,tongue and jaw cases4--,intratracheal ether the best--failing that1 rectal oil ether1 or ,junker's inhaler4 ,nasal operations4--,if adrenalin is to be used1 it must precede1 not follow1 chloroform--many fatalities have occurred from injecting or even packing with adrenalin in light chloroform narcosis4 ,some surgeons object to ether because of the bleeding1 but this can be largely remedied by raising the head and shoulders1 and by packing with adrenalin4 ,many surgeons prefer local to general ansthesia4 ,nasal insufficiency4--,don't allow a patient to continue to make ineffectual attempts to breathe through a narrow nose4 ,establish mouth breathing1 or use ,silk's tubes 7see ,fig4 #i74 ,tonsils and adenoids4--,give ethyl chloride by the vapour method4 ,tumours and inflammatory swellings obstructing respiration4-- ,don't use closed methods4 ,have tracheotomy instruments at hand1 and a cylinder of oxygen4 ,gitres1 especially exophthalmic gitre4--,don't use chloroform3 it has caused many fatalities2 morph-atropine1 followed by open-ether is the safest4 ,in bad cases1 use rectal oil ether if intratracheal is not available4 ,the 8sitting up posture0 is a great help 7see page #afh74 ,use anoci-association if surgeon is willing4 ,,chest4 ,bronchitis and pneumonia 7see remarks in chapter ,,xvii74 ,emphysema and rigid chest wall4--,patients take ansthetics badly2 they cyanose quickly1 the abdominal wall cannot be made either lax or quiet1 since the patient's natural method of respiration is abdominal rather than thoracic4 ,lastly1 there is frequently a dilated heart with degenerate cardiac muscle1 giving an abnormal tendency to secondary syncope4 ,give a trickle of oxygen through a tube from a cylinder3 don't be tempted to overdose with ansthetic in the vain hope of securing ideal relaxation of the abdominal wall4 ,empyma4--,be careful3 a good many accidents have happened4 ,use chloroform with added oxygen3 aim at an ansthesia just deep enough to prevent straining which might rupture the empyma into the lung and drown him in his own pus4 ,withdraw the ansthetic as soon as the abscess is opened4 ,phthisis4--,don't use closed-ether3 it may start hmorrhage--open-ether rarely does any harm unless the condition is very acute4 ,,circulatory ,,system4 ,high tension1 arterio-sclerosis1 and aneurysm4--,avoid pure nitrous oxide3 in severe cases1 ,c4,e4 mixture and oxygen is the safest4 ,heart4--,well compensated cases of valvular disease take chloroform or open-ether well1 provided a free air-way is maintained4 ,closed methods should be avoided4 ,cases of myocardial disease with dilated cavities present special dangers4 ,open-ether with added oxygen meets the case better than any other ansthetic4 ,pericarditis1 both acute and chronic1 has been found as the determining factor in many ansthetic fatalities4 ,,acute ,,infectious ,,disease4 ,febrile patients absorb ansthetics very rapidly and therefore go under very quickly4 ,acute septic cases must not have chloroform or ethyl chloride 7see page #aee73 nitrous oxide and oxygen is ideal1 ether the next best4 ,patients who have suffered from acute infectious disease1 especially diphtheria and influenza1 may present some weakness of heart muscle for many months after the attack4 ,,exhausted ,,and ,,shocked ,,cases4 ,give nitrous oxide and oxygen if possible--failing that1 ether4 ,closed-ether sometimes does very well for the induction stage4 ,,diabetes4 ,chloroform is wholly inadmissible4 ,,genito-,,urinary ,,system4 ,kidneys4--,avoid ether in acute or sub-acute nephritis3 give it1 however1 for nephrectomy when the other kidney is sound4 ,bladder4--,distending the bladder with lotion often causes reflex inhibition of respiration3 if that happens1 stop the ansthetic1 give artificial respiration1 and ask the surgeon to get on with opening the bladder4 ,morphia usually arrests temporarily the secretion of urine3 it should therefore not be given if chromocystoscopy or catheterisation of the ureters is contemplated4 ,prostatectomy cases are often rather broken subjects3 give a fairly deep ansthesia until the shelling out of the prostate is begun3 then be careful--the patient is breathing deeply as a rule1 and can readily get an overdose4 ,he will inevitably suffer a fair amount of shock3 be ready to lower the table at the head end if any serious collapse occurs4 ,don't be shy of starting a little artificial respiration even though the natural function is not entirely abolished4 ,circumcision usually causes a good deal of laryngeal spasm1 especially in children4 ,don't try to abolish this by deepening the ansthesia4 ,you won't succeed unless you nearly kill the patient4 ,rub the lips1 and if very severe ask the surgeon to stop a minute until the crowing becomes less4 ,castration4--,always give ether1 or gas-oxygen4 ,castration and reduction of dislocation are the two commonest causes of reflex syncope under chloroform4 ,,menstruation1 ,,pregnancy1 ,,and ,,labour4 ,it is usual to avoid ansthetics during the menstrual period if possible1 the nervous system being unlikely to be at its best at that time4 ,pregnant patients take no harm from an ansthetic properly given1 but undue cyanosis must be avoided or abortion may occur4 ,the pains of labour may be alleviated by chloroform given to an early second stage only1 or by 8twilight sleep0 7see page #dd74 ,for the major operations of obstetrics1 however1 ether has its usual advantages1 provided no bronchitis be present4 ,the shock of such operations as a difficult version is considerable1 and quite sufficient to call for ether rather than chloroform4 ,indication for ,local and ,spinal ,ansthesia4--,the foregoing has been written in reference to inhalational ansthesia solely4 ,mr ,wood has indicated in chapters ,,xx4 and ,,xxi4 the class of case in which the methods he describes are to be preferred4 ,,chapter ,,xx4 ,,local ,,an,,sthesia4 ,by the term local ansthesia1 or more correctly local analgesia1 is meant the loss of sensibility to painful stimuli without loss of general consciousness4 ,it may be induced in a considerable number of ways1 but for practical purposes there are only four methods of value3--7#a7 by infiltration of the tissues to be operated upon by a solution of the drug1 7#b7 by injecting the solution into or around the nerve trunks supplying the part1 7#c7 by painting the solution on a mucous surface1 and 7#d7 by the application of intense cold4 ,the last method has only a limited application4 ,the method of injecting the ansthetic into the blood vessels of the part is still in the experimental stage and is not to be recommended for general use4 ,it is advisable first to consider the behaviour of the principal drugs which are employed4 ,cocaine4 ,this was the first drug to be widely used for the production of local ansthesia4 ,it is an alkaloid occurring in the leaves of ,erythroxylon ,coca4 ,it is only slightly soluble in water--about #a in #acjj1 but the hydrochloride of cocaine is freely soluble1 and it is this salt that is commonly used for aqueous solutions4 ,the solutions do not keep well1 and should be made up shortly before being used4 ,the drug is decomposed by boiling4 ,,action4--,when a solution of cocaine is injected into the tissues1 the sensory nerve endings become ansthetic over the area into which the drug penetrates1 direct paralysis of the nerve terminals being produced4 ,when it is injected into or around a nerve trunk it blocks the transmission of nerve impulses4 ,when it is applied locally to a mucous membrane1 it produces1 besides a loss of sensation1 a feeling of constriction and a distinct pallor and contraction of the vessels1 which point to a local action on the vessel walls4 ,the drug is very frequently applied to the eye4 ,there it produces not only local ansthesia1 but also contraction of the conjunctival vessels1 and this is followed by dilatation of the pupil and often by partial loss of the power of accommodation4 ,,cocaine ,,poisoning4--,certain patients show an idiosyncrasy to the action of cocaine1 and the greatest care must be exercised in its use4 ,absorption of small quantities usually causes mental excitement4 ,the patient becomes restless and garrulous1 and a feeling of happiness may be produced1 but in other cases the patient becomes anxious and confused4 ,in some patients a small dose is followed by a calm languorous state1 resembling that produced by morphia1 but with less tendency to sleep4 ,the pulse is accelerated1 the respiration is quick and deep1 and the pupils are dilated4 ,when poisonous doses have been administered1 the heart becomes extremely accelerated1 powerful tonic or clonic convulsions supervene1 the breathing becomes rapid and shallow1 and may be finally arrested during a convulsion4 ,in some cases a different set of symptoms are observed1 fainting and collapse occur1 and convulsive seizures are almost entirely absent4 ,the heart is slow and and weak1 the respirations are slow and shallow1 the skin is cyanotic and cold1 and death takes place from gradual arrest of respiration4 ,,treatment4--,the treatment consists in endeavouring to encourage the action of the heart by every possible means4 ,the patient is placed flat on his back1 if he is not already in this position1 hypodermic injections of ether and strychnine are administered1 and hot coffee given by the mouth2 warmth is of great importance4 ,artificial respiration is commenced if respiration begins to fail4 ,there is no specific antidote to cocaine4 ,,dosage4--,the maximum dose of cocaine that can be given with safety is of a grain4 ,the amount of solution that may be employed depends upon the strength4 ,to make a #a per cent solution1 #a gr4 of cocaine hydrochloride is dissolved in #aaj minims of distilled water or half strength normal saline2 from these proportions the amount of cocaine in a given solution can be calculated4 ,it will be seen that the amount of cocaine solution1 even with strengths as weak as or per cent1 that can be used with safety is small and insufficient to ansthetise an area of any great extent4 ,owing to its toxicity cocaine has largely fallen out of use for the production of infiltration or regional ansthesia1 though it is still widely used in ophthalmic surgery and in the surgery of the ear1 nose and throat4 ,novocaine4 ,this drug is immensely superior to cocaine for ordinary surgical purposes4 ,it is the hydrochloride of a synthetic base1 its chemical formula being ,c#ac;,h#bj,n#b,o#b1 ,h,cl4 ,it is soluble in water #a in #a1 and can be heated to #abj;,c without decomposition4 ,its solutions possess slight antiseptic properties1 and are capable of repeated boiling without affecting their strength4 ,they may be kept for several months without suffering any change in their action1 a quality not possessed by any other ansthetic agent4 ,the toxicity of novocaine is one-fifth or one-seventh of that of cocaine4 ,when used in conjunction with adrenalin1 its ansthetic activity is equal to that of cocaine4 ,when injected into the tissues it produces no irritant effects like certain other local ansthetics1 notably stovaine4 ,for the production of local ansthesia it is used in per cent4 solution with the addition of three or four minims of #a in #ajjj solution of adrenalin chloride to each ounce4 ,several ounces of this preparation may be used with the greatest safety4 ,allen makes the following statement regarding this drug3--8,after a rather extended experience1 including a large number of cases embracing the entire field of surgery1 in which this agent has been almost exclusively used1 we have failed to note a single case in which there has been any unpleasant local or constitutional action4 ,we1 therefore1 feel thoroughly justified in unqualifiedly recommending it as the safest1 most reliable1 and satisfactory of any local ansthetic agent yet introduced40 ,tropacocaine4 ,this drug was first isolated from the leaves of the coca plant of ,java1 but is now prepared synthetically4 ,its formula is ,c#ae;,h#ai,,no#b4 ,its action is exactly the same as that of cocaine1 except that it is one-half as toxic and the duration of ansthesia is shorter4 ,the hydrochloride is freely soluble in water1 and can be boiled without fear of decomposition4 ,it is the agent which is most suitable for spinal ansthesia1 as fewer unpleasant effects have followed its use than that of any other drug4 ,stovaine4 ,stovaine is the hydrochloride of a synthetic compound of the benzoyl group4 ,it occurs as a white crystalline powder1 soluble in water1 #a in #ad4 ,its solutions withstand boiling1 but are decomposed when heated to #abj;,c4 ,its action is the same as that of cocaine1 except that it is slightly less toxic and less powerful4 ,it has a distinct irritant effect locally4 ,when injected in dilute solution1 it produces a slight burning pain before ansthesia appears1 and very often a distinct inflammatory reaction persists for some time after the operation4 ,it is therefore unsuited for local ansthesia4 ,it has been widely used for the production of spinal ansthesia1 especially by the ,french school1 but since its injurious effects on nerve tissues have become more apparent1 it has been less used than formerly4 ,eucaine4 ,eucaine was introduced as a substitute for cocaine1 and1 before the introduction of novocaine1 was extensively used4 ,it has a similar action to cocaine1 and although it is less toxic1 it is by no means free from danger unless it is used in very dilute solutions4 ,it is a vaso-dilator1 and must therefore be used in combination with adrenalin4 ,it can be boiled without undergoing decomposition1 and is practically non-irritant4 ,it has been largely superseded by novocaine4 ,quinine and ,urea ,hydrochloride4 ,the use of this drug for purposes of local ansthesia is still in the experimental stage4 ,it is made by adding urea to a solution of quinine in hydrochloric acid4 ,the crystals are soluble in their own weight of water4 ,for the production of local ansthesia it is used in strengths of #be to #a per cent4 ,it is free from toxic effects1 and its solutions can be sterilised by boiling4 ,the striking feature about this drug is the extraordinary duration of the ansthesia1 this being from one to six days4 ,it has therefore been used by ,crile and other ,american surgeons to prevent pain during the first few days after operation4 ,the great drawback to its use1 however1 is that it causes a persistent indurated condition of the tissues which interferes with primary union1 and which is sometimes followed by actual sloughing4 ,in addition1 it is now established that its use has been followed by tetanus in several cases1 and it is recommended that a dose of antitetanic serum should be given immediately before or after the injection of quinine4 ,although the action of this drug is of great interest1 it cannot be recommended at present for ordinary purposes4 ,adrenalin4 ,adrenalin is obtained as an extract from the suprarenal glands of animals4 ,it is a greyish white powder1 slightly soluble in water1 and readily so in weak acids4 ,the usual preparation is a #a in #ajjj solution of adrenalin chloride in normal saline4 ,it contains #e per cent4 of chloroform as a preservative4 ,the drawback to the animal extract is that the solution does not keep well1 decomposition being indicated by a brownish colour4 ,of late a synthetic preparation has been introduced1 which appears to have the same action1 and which can be sterilised by boiling4 ,the action of the drug is to cause marked vaso-constriction by direct action on the vessel walls4 ,it has no analgesic action1 and is used as an addition to solutions of ansthetic drugs4 ,the advantages of its use are that the action of the ansthetic is concentrated and prolonged1 owing to the delay in absorption1 and that the field of operation is rendered practically bloodless4 ,in large doses it may produce toxic symptoms in the form of palpitations and breathlessness1 or even actual syncope1 so that care is necessary in its use4 ,for purposes of local ansthesia1 it is added to the solution of the ansthetic drug in the strength of #c drops to the ounce1 and large injections of this dilute solution may be made without risk4 ,at least twenty drops may be safely given4 ,induction of ,local ,ansthesia ,local ansthesia may be induced by the use of ansthetic drugs in three ways--7#a7 infiltration ansthesia1 7#b7 regional ansthesia1 and 7#c7 by application to a mucous surface or to the surface of the eye4 ,,infiltration ,,an,,sthesia4--,in this method ansthesia is induced by injection of the drug directly into the tissues to be operated upon4 ,this method acts by paralysing the sensory nerve-endings4 ,although the term ansthesia is constantly used1 it is1 strictly speaking1 an operative analgesia that is aimed at2 it is a paralysis of the pain-conducting fibres1 and not of those which conduct purely tactile sensations1 the patient being often able to feel the contact of the fingers and instruments during the operation4 ,true ansthesia can be secured1 but it is necessary to use considerably stronger solutions than those that are required for the production of analgesia4 ,,solution ,,of ,,the ,,drug4--,novocaine is far superior to any other drug for infiltration ansthesia4 ,the strength for most purposes is per cent41 though some operators find per cent4 quite satisfactory4 ,in specially sensitive parts1 such as the nose1 throat1 or mouth1 #a or even #b per cent4 solutions may be preferable4 ,sufficient sodium chloride should be added to prevent osmosis of the solution into the tissue cells4 ,the most satisfactory preparation is3-- ,novocaine #jbe1 #je1 #a or #b 7 to #b percent47 ,normal salt solution 7half #ajjj 7#de per cent4 ,na,cl7 strength7 ,illustration3 ,fig4 #ea4 ,all-,metal ,syringe for ,infiltration ,ansthesia4 ,adrenalin is added to the solution in the proportion of #c drops of #a in #ajjj adrenalin chloride to the ounce1 and as much as #f ounces of this preparation may be safely given4 ,the novocaine solution can be boiled before use1 but the adrenalin must not be added until after boiling4 ,for private practice it is sometimes convenient to procure the novocaine in tabloid form of definite strength combined with sodium chloride4 ,these tabloids are added to the necessary amount of water1 and the whole boiled4 ,the adrenalin can then be added4 ,,choice ,,of ,,syringe4--,the best form of syringe for infiltration ansthesia is the all-metal syringe illustrated in ,fig4 #ea4 ,it ought to have a capacity of at least #aj c4c4 ,the advantage of the all-metal syringe over glass syringes is that it can be safely sterilised by boiling1 and does not get broken4 ,between the syringe and the needle is a metal segment which is curved so that the needle is set at an obtuse angle to the syringe4 ,this renders the infiltration of the tissues at the proper depth much easier4 ,the needles employed are the ordinary hypodermic needles which are sold in small tubes4 ,the sizes which should be selected are #a inch1 and #c or #c inches4 ,the needle fits into a hole in a small metal mount1 which screws on to the intermediate metal portion4 ,this section also is attached to the syringe by a screw1 and these screw attachments have the advantage of rendering leakage impossible4 ,failing the syringe described1 a #aj c4c4 ,record syringe will be found to be quite efficient1 if suitable needles can be obtained4 ,the syringe1 needles1 and glass measure for the solution should be boiled in plain water or normal saline1 as soda interferes with the action of the drug4 ,,technique ,,of ,,injection4--,the needle is introduced into the subcutaneous tissue1 and pushed on slowly to its full length1 the fluid being injected as the needle advances4 ,the needle is then partly withdrawn1 and pushed in in a different direction so as to infiltrate a fresh area4 ,this procedure is repeated1 and as wide an area as possible infiltrated from the one puncture4 ,the needle can then be completely withdrawn and introduced at a fresh point which has already been rendered analgesic4 ,the deeper tissues can nearly always be infiltrated from the surface1 but if large blood-vessels traverse the region to be infiltrated1 it may be necessary to defer the deeper injection until these have been exposed4 ,it is wise to infiltrate wide of the intended line of the incision1 since it is not possible to anticipate with certainty the extent of an operation until it has been commenced4 ,the secret of successful ansthesia is to employ plenty of the solution1 and make the injection thorough4 ,the skin over the area becomes blanched within a few minutes of the injection owing to the action of the adrenalin4 ,ansthesia is not usually complete until ten minutes have elapsed1 and the operation should not be commenced until it has been made certain by suitable tests that the ansthesia is complete4 ,the duration of the ansthesia is usually at least an hour and a half4 ,it will be seen that the injection in the manner described above is entirely subcutaneous1 the pain-conducting nerves from the skin being caught up by the drug as they traverse the superficial fascia in the area infiltrated4 ,this method usually gives complete satisfaction1 but some surgeons advise that the infiltration should be commenced with an intra-dermal injection so as to reduce the pain of the needle punctures to a minimum4 ,a fine needle is employed1 the prick of which is practically painless4 ,if the skin at the selected point is pinched up between the finger and thumb1 and held firmly1 this lessens its sensibility4 ,the needle is advanced beneath the epidermis with a quick but light thrust4 ,the injection into the substance of the skin causes a distinct wheal1 which stands out from its surroundings like an urticarial wheal4 ,from this starting-point a long needle can be introduced into the deeper tissues without pain4 ,the intra-dermal injection may be carried along the whole length of the area to be infiltrated1 each fresh puncture being made in the margin of the wheal-like area already ansthetised4 ,,precautions4--,the most careful asepsis is essential throughout4 ,infiltration with novocaine causes no interference with the healing of the wound1 and although cases of sloughing of the tissues have been reported after its use1 these are almost certainly due to infection of the wound4 ,care must be exercised also to avoid injecting the drug into a vein4 ,when this accident takes place1 the drug is carried at once into the general circulation1 and may reach the higher nerve centres in such quantity as to produce serious toxic results4 ,the use of adrenalin calls for special care and thoroughness in securing all bleeding-points1 as1 after the effect of the adrenalin passes off1 even a slight ooze may increase and give rise to a hmatoma which may jeopardise the healing of the wound4 ,regional ,ansthesia4 ,in this method of producing ansthesia1 the sensory nerve paths are blocked by injecting the ansthetic drug into1 or around1 a nerve trunk4 ,by this procedure complete ansthesia is produced in the area of distribution of the nerve1 and the effect corresponds to a temporary physiological section of the nerve trunk4 ,a temporary motor paralysis is also produced in a mixed nerve4 ,,technique4--,the solution of the drug must be stronger than that employed for infiltration ansthesia4 ,a #b per cent4 solution of novocaine in half-strength normal saline with the addition of adrenalin is employed4 ,the injection may be paraneural or intraneural4 ,a paraneural injection is made by passing a needle through the tissues to the known position of a nerve trunk and injecting the ansthetic around it4 ,the solution gradually diffuses into the nerve tissue1 and ansthesia of the nerve is produced4 ,this method is open to the objection that unless the ansthetic is accurately placed1 no ansthesia will result1 and that in the case of certain nerves there is considerable risk of making the injection into a vein4 ,the latter risk can be avoided by using a glassbarrelled syringe and applying a little suction before the injection is made2 if a vein has been pierced1 blood will enter the syringe4 ,the intraneural method is more accurate but requires the expenditure of considerable additional time and trouble1 and is only employed where other methods of ansthesia are not feasible4 ,the tissue over the nerve having been infiltrated1 the nerve is exposed by open dissection4 ,it must not be pinched by forceps or other instruments1 as such manipulations cause severe pain referred to its peripheral distribution4 ,the injection should be made with the nerve lying in its bed by inserting a fine needle in the long axis of the nerve1 first into the sheath1 which is infiltrated1 and then into the nerve itself4 ,the infiltration of the nerve is continued until it presents a fusiform swelling and this may require from #e to #ae minims of the solution4 ,complete ansthesia of its entire distribution usually results in from five to ten minutes4 ,a third method of inducing regional ansthesia--first recommended by ,hackenbruch--which is worth mention1 is by the production of a ring of infiltration around a peripheral part1 such as a finger1 or around and underneath a tumour4 ,by this means the nerve fibres are caught up by the ansthetic and their conductivity interrupted as they enter the area to be operated upon4 ,in dealing with such conditions as a large lipoma1 or an umbilical hernia1 it may be possible to avoid the use of an excessive amount of ansthetic solution by employing this method4 ,methods of ,application of ,infiltration and ,regional ,ansthesia4 ,it is sometimes stated that local ansthesia should be limited to small and superficial operations1 but with a knowledge of anatomy and of the correct technique1 there are few operations which the surgeon cannot undertake with this form of ansthesia4 ,if we remember that the mortality from the ansthetic is practically nil1 it is obvious that it is often the duty of the operator to give the patient the choice of local ansthesia4 ,in urgent conditions in which the administration of a general ansthetic would be attended with great danger1 it is often a life-saving measure4 ,either infiltration or regional ansthesia may be used alone2 in some cases it is convenient to combine the two methods4 ,operations on the ,upper ,extremity4 ,regional ansthesia is sometimes employed in operations on the upper extremity in conditions1 such as diabetic gangrene or advanced cardiac disease1 where a general ansthetic is contra-indicated4 ,in similar conditions in the lower extremity1 spinal ansthesia is usually preferred1 though it is quite possible to ansthetise the lower limb by blocking the sciatic1 femoral1 and lateral cutaneous nerves with a local ansthetic4 ,crile lays great stress on the blocking of nerves with a local ansthetic during operations on the limbs as a means of preventing shock1 even where a general ansthetic is being employed4 ,the effect of the local ansthetic is to prevent the impulses which produce shock from passing up to the higher centres4 ,only those methods which are applied to the upper extremity need special description4 ,,an,,sthesia ,,of ,,the ,,whole ,,arm4--,the nerves of the upper extremity are all derived from the brachial plexus except the intercosto-brachial4 ,this nerve1 which is the lateral cutaneous branch of the second intercostal1 crosses the axilla and pierces the deep fascia on the medial side of the arm4 ,it supplies the skin on the dorsal part of the medial aspect of the upper arm4 ,the lateral cutaneous branch of the third intercostal nerve sometimes crosses the axilla also1 and reaches the medial side of the arm4 ,injection of the brachial plexus produces complete analgesia of the shoulder and entire arm1 and is particularly suited to high amputations and disarticulations at the shoulder4 ,if the area supplied by the intercosto-brachial is encroached upon1 this can be ansthetised by infiltration with a few drams of solution injected subcutaneously along the floor of the axilla from its lateral and posterior borders4 ,,method4--,the injection may be intraneural or paraneural4 ,the intraneural is made after exposing the plexus by an incision under infiltration ansthesia from the junction of the middle and lower thirds of the sterno-mastoid to the union of the middle and lateral thirds of the clavicle4 ,it is found lying on the scalenus medius and each of its branches is separately injected with a few drops of #e per cent4 solution of novocaine containing a few drops of adrenalin to the ounce4 ,the paraneural injection is less satisfactory1 since the nerves are too large to be readily penetrated in effective quantities by the ansthetic solution1 and since there are numerous veins in the neighbourhood into which the solution may be accidentally injected with dangerous results4 ,the injection is usually made above the clavicle4 ,in this region the plexus lies mainly above and to the lateral side of the third part of the subclavian artery1 the lowest trunk lying directly behind the vessel as it rests on the first rib4 ,the position of the artery is first localised with the finger by its pulsations1 and the skin and subcutaneous tissue infiltrated immediately above the mid-point of the clavicle4 ,from this point a long fine needle1 unattached to the syringe1 is passed downwards1 backwards1 and medially in the direction of the second or third thoracic spine4 ,the distance to which the needle penetrates varies from #b to #d c4m4 ,when the plexus is reached a slight radiating pain is felt down the distribution of the radial or median nerve4 ,at this point the needle is held stationary1 the syringe attached1 and the injection made4 ,the reason for not attaching the syringe earlier is that should the artery be entered1 blood will flow4 ,this accident is of little consequence1 the needle being withdrawn slightly and introduced a little more laterally4 ,about #aj c4c4 of a #b per cent4 solution of novocaine and adrenalin is injected2 the needle is then slightly withdrawn and a further #aj c4c4 injected in the neighbourhood4 ,ansthesia occurs in from three to fifteen minutes4 ,illustration3 ,,fig4 #eb4--,point at which the needle is introduced in paraneural injection of brachial plexus4 ,the individual nerves of the upper limb can be readily injected4 ,the median can be exposed at the bend of the elbow for an intraneural injection1 or a needle may be passed under the tendon of the palmaris longus at the wrist for a paraneural injection4 ,the ulnar can be easily reached as it lies on the posterior aspect of the medial epicondyle of the humerus for a paraneural or intraneural injection4 ,the superficial radial can be reached for a paraneural injection about two inches above the wrist to the lateral side of the tendon of the brachio-radialis 7supinator longus74 ,the injection is made into the deep fascia1 and carried across the lateral border of the forearm for about an inch1 to ensure reaching all the branches of the nerve4 ,the medial antibrachial 7internal7 cutaneous can be blocked on the front of elbow by a paraneural injection about half an inch medial to the biceps tendon1 and the lateral antibrachial cutaneous 7musculo-cutaneous7 at a corresponding point on the other side of the tendon4 ,,an,,sthesia ,,of ,,the ,,arm ,,below ,,the ,,elbow4--,in operations below the elbow1 in conditions in which a general ansthetic is not permissible1 as in diabetes1 nephritis or advanced cardiac disease1 a full ansthesia can be obtained by intraneural injection of the median1 ulnar1 and radial 7musculo-spiral7 nerves1 combined with paraneural injection of the medial and lateral antibrachial cutaneous4 ,the median and radial are each exposed by an incision under infiltration ansthesia1 the radial being exposed in the groove between the brachialis and brachio-radialis4 ,the infiltration to expose the median nerve usually blocks the anterior branch of the medial antibrachial cutaneous4 ,to make certain that the posterior branch is also ansthetised1 it is advisable to inject a little ansthetic solution over the front of the medial epicondyle4 ,the intraneural injection into the ulnar nerve can often be made without exposing it4 ,,an,,sthesia ,,of ,,finger4--,the paraneural method applied to the digital nerves at the root of the finger gives perfect results4 ,a circle of ansthetic solution is first injected round the root of the finger4 ,the needle is then passed through the infiltrated skin on each side of the finger1 and a few drops of per cent4 novocaine solution injected around the nerves4 ,complete ansthesia of the finger results in a few minutes4 ,,in ,,the ,,lower ,,limb injection of individual nerves is rarely employed1 as ansthesia is easily obtained by the method of spinal analgesia4 ,the lateral cutaneous can be injected as it lies immediately medial to the anterior superior iliac spine emerging from under cover of the inguinal ligament4 ,this procedure may be useful in obtaining skin grafts1 the grafts being taken from the antero-lateral aspect of the thigh4 ,amputations in the middle third of the thigh have been performed by injecting the sciatic1 the posterior cutaneous 7small sciatic71 the femoral 7anterior crural71 and the lateral cutaneous at the root of the limb4 ,the obturator nerve is difficult to find and ansthetise in such cases4 ,operations below the knee can be painlessly performed by this method of ansthesia4 ,operations on the ,neck4 ,,tracheotomy4--,this operation is conveniently and safely performed under infiltration ansthesia4 ,the ansthetic solution is injected in the usual way in the line of the incision down to the trachea but not into it1 as the trachea itself is insensitive to pain4 ,,goitre4--,a parenchymatous or adenomatous goitre can be readily removed under local ansthesia1 though the administration of ether by intra-tracheal insufflation is usually to be preferred4 ,the principal nerve supply to the field of operation is derived from the cervical plexus1 whose branches become superficial about the middle of the posterior border of the sterno-mastoid4 ,an intradermal injection may be made first at this point1 and a longer needle then passed down to the posterior border of the muscle1 and an area of infiltration produced4 ,from this point the needle is directed first upwards and then downwards round the margin of the goitre so as to produce a zone of infiltration4 ,the same procedure may be repeated on the opposite side1 so that the whole gland is surrounded with a zone of infiltration with a special depot of solution around the branches of the cervical plexus4 ,where only one lobe is involved1 it is sufficient to carry the injection down in the middle line after one side has been encircled4 ,when the sheath has been incised and the surface of the gland exposed1 the isthmus is infiltrated and divided4 ,the affected half of the gland is then rolled outwards1 and the attachments between the posterior aspect of the gland and the larynx and trachea are infiltrated1 special attention being paid to the upper pole4 ,the rest of the operation can then be carried out painlessly4 ,,exophthalmic ,,goitre may also be operated upon under local ansthesia after a preliminary hypodermic injection of morphia and scopolamin1 though many operators prefer a general ansthetic on account of the nervous state of the patient4 ,in bad cases a procedure which is often of great value is ligature of the superior thyroid artery on both sides under local ansthesia4 ,after ligature of the vessels a colloid degeneration takes place in the gland1 and the symptoms of hyperthyroidism subside4 ,after a delay of two or three months it may be possible to carry out the radical operation with little or no danger4 ,the incision is two and a half inches in length1 and crosses transversely the central part of the thyroid cartilage4 ,the line of the incision is infiltrated with novocain solution in the ordinary way1 and both superior thyroid arteries exposed and ligatured4 ,operations on the ,thorax4 ,the greater part of the wall of the thorax is supplied by the intercostal nerves4 ,in front the supraclavicular nerves come down as far as the second intercostal space or sometimes as far as the nipple1 and the lateral and medial anterior thoracic nerves supply the pectoral muscles1 sending a few twigs to the overlying skin4 ,the long thoracic nerve extends down the side of the chest1 supplying the serratus anterior4 ,the intercostal nerves can be blocked in the region of the angles of the ribs and the supraclavicular by carrying a line of infiltration along the clavicle4 ,the anterior thoracic can be blocked by deeper injections4 ,in this way the greater part of the chest wall and the pleura can be ansthetised4 ,,acute ,,empyema4--,this operation should always be performed under local ansthesia4 ,exhaustion from septic absorption and from the antecedent pneumonia or other disease1 with the dyspna from the pressure of the pus on the lung may render a general ansthetic highly dangerous4 ,the method of producing local ansthesia is simple and easily carried out4 ,a point is selected on the rib which is to be resected a short distance behind the line of the incision and an intra-dermal injection made with a fine needle4 ,a long needle is then substituted and passed down to the upper border of the rib until it reaches the plane between the external and internal intercostal muscle1 the injection being continued lightly as it advances4 ,when the desired point is reached one or two drams of the solution are injected4 ,the needle is then slightly withdrawn and passed to the lower border of the rib to reach the same plane and the same procedure carried out4 ,the infiltration is then carried along the line of the incision or it may be made to pass obliquely upwards to the rib above and obliquely downwards to the rib below so as to catch up the nerves coming from behind into the area of operation4 ,the ansthesia of soft parts1 bone1 and pleura is perfect after the above injection4 ,operations on the ,abdomen4 ,the anterior abdominal wall1 including the anterior parietal peritoneum1 is supplied by the lower six intercostal nerves1 the last thoracic nerve1 and the ilio-hypogastric and ilio-inguinal nerves from the first lumbar4 ,it is a very interesting and important fact that1 although the parietal peritoneum is exceedingly sensitive to touch and pain1 the visceral peritoneum and the viscera themselves are insensitive4 ,when operations are performed under local ansthesia of the abdominal wall1 the viscera can be freely handled or incised without the patient experiencing the slightest discomfort1 provided that the parietal peritoneum is not put upon the stretch by traction on the mesentery or other peritoneal attachment4 ,thus the colon can be opened twenty-four or forty-eight hours after being brought outside the abdominal wall without any ansthetic in the operation of colostomy4 ,local ansthesia is therefore well adapted to cases in which a small amount of manipulation of the viscera is required1 and where a general ansthetic would be dangerous1 as in grave cases of intestinal obstruction and in cases of carcinoma of the sophagus with weakness and loss of flesh from starvation4 ,,gastrostomy4--,this operation is commonly performed under local ansthesia and may be taken as an illustration of the procedure employed4 ,the incision is made through the middle of the left rectus and is about two and a half or three inches long1 beginning about an inch below the costal margin4 ,an intradermal wheal is established at the middle of the proposed incision4 ,a long needle is entered at this point and passed first upwards and then downwards in the line of the incision1 infiltrating the subcutaneous fat as it goes4 ,the needle is then passed in through the anterior wall of the rectus sheath1 this being easily recognised as a plane of decided resistance4 ,the needle is advanced a little inside the sheath1 the injection being continued as it advances4 ,the same procedure is repeated at various points along the line of the incision4 ,the extra-peritoneal fat may be infiltrated in the same way1 the posterior wall of the sheath being identified as a deeper plane of resistance and gently pierced4 ,this step may be deferred until the posterior wall of the sheath has been exposed4 ,the infiltration may be completed by forming a line of intradermal infiltration along the line of incision1 though this last step can often be omitted4 ,the abdomen can then be opened painlessly4 ,the only step in the operation which may cause a little discomfort is the traction which may be necessary to bring the shrunken stomach down from under cover of the ribs4 ,the incision into the stomach is quite painless4 ,,gastro-,,enterostomy can be performed under local ansthesia1 the only special step required being infiltration of the meso-colon before it is perforated4 ,,appendicectomy is not suitable1 as a rule1 for local ansthesia4 ,if the ccum is fixed or the appendix bound down by adhesions1 the traction necessary to bring the appendix to the surface causes considerable pain4 ,in ,,acute ,,obstruction1 when the procedure of enterostomy has been decided upon owing to the gravity of the patient's condition1 local ansthesia is often of great value4 ,the abdominal wall is infiltrated in the manner described1 and a distended loop of bowel brought to the surface and sutured to the parietal peritoneum4 ,a ,paul's tube can then be introduced4 ,,inguinal ,,hernia4 ,local ansthesia is specially suited to cases of strangulated hernia1 but it may be employed in the ordinary case4 ,it should be pointed out that spinal ansthesia gives equally good results and is less troublesome to carry out4 ,the injection is commenced with a fine needle a little beyond the lateral end of the proposed incision4 ,an intradermal wheal is produced at this point1 a long needle introduced into the subcutaneous tissue1 and about half-an-ounce of ansthetic solution injected in this position4 ,the needle is then passed downwards and medially1 and the subcutaneous fat infiltrated in the line of the incision4 ,the needle is then partly withdrawn and again advanced until it reaches the resistance of the aponeurosis of the external oblique4 ,this is gently pierced and about half-an-ounce of solution injected underneath so as to block the ilio-hypogastric and ilio-inguinal nerves4 ,in most cases this is all that is necessary4 ,as additional precautions the line of incision may be infiltrated intradermally1 and an injection may be made around the neck of the sac after it is exposed4 ,,femoral ,,hernia4--,a femoral hernia may be ansthetised by infiltration along the line of the incision1 or by injecting around the circumference of the hernia after the method of ,hackenbruch4 ,after the sac has been exposed and defined1 it is necessary to inject some novocaine solution around the neck1 care being taken to avoid the femoral vein which lies on the lateral side4 ,,umbilical ,,hernia4--,local ansthesia is sometimes of great value in dealing with umbilical hernia1 especially if it is strangulated1 in stout patients who are bad subjects for a general ansthetic4 ,the injection is best made around the circumference of the hernia4 ,several intradermal injections are made at points around the swelling1 and through these the long needle can be introduced and the deeper tissues infiltrated4 ,if the muscles are fairly well defined and can be felt1 they may be infiltrated at the commencement1 but it may be advisable in fat subjects to inject only the subcutaneous tissues to begin with1 and to delay the injection of the muscles and extra-peritoneal fat until the sac has been opened and a protecting finger can be introduced to guard the intestines4 ,omental adhesions can be divided without causing pain4 ,if the intestines are extensively adherent to the sac it is better to infiltrate the points of adhesion1 as extensive manipulation may cause cramp-like pains4 ,after the circumferential injection has been made in these cases1 it is best to wait for ten or fifteen minutes before making the incision in order to allow the ansthetic solution to diffuse4 ,,suprapubic ,,cystotomy4--,in operations for drainage of the bladder local ansthesia is highly successful4 ,the skin and subcutaneous tissues are infiltrated in the line of the incision4 ,the needle is then carried between or through the recti muscles and several drams injected into the layer of fat in front of the bladder4 ,it is unnecessary to inject the wall of the bladder itself4 ,h,,morrhoids4--,in patients in whom there is some contra-indication to the use of a general ansthetic the removal of hmorrhoids can be carried out quite safely and painlessly under local ansthesia4 ,a circumferential injection is first carried out round the muco-cutaneous junction4 ,it is best to start the infiltration about an inch out from the anus as the skin immediately around the anal orifice is extremely sensitive4 ,the infiltration is made subcutaneously1 and each re-insertion of the needle is made just short of where the previous injection stopped4 ,when the circumferential injection has been completed1 a finger is passed into the rectum1 and the long needle introduced through the ansthetised area1 injecting as it advances1 to a depth of about #b inches1 keeping just outside the sphincters4 ,four such injections are made1 one on each side of the bowel1 one in front and one behind1 from #e to #aj c4c4 being injected in each position4 ,ansthesia results almost immediately and the anal canal can be readily dilated4 ,,the ,,tongue4--,for the ,whitehead operation of removal of one half of the tongue1 complete ansthesia can be obtained by the infiltration method4 ,a long needle is introduced at the tip of the tongue1 and the injection carried in the middle line to a point behind the tumour4 ,the mucous membrane of the floor of the mouth and the glosso-palatine fold are infiltrated1 and a last injection made across the affected half of the tongue well behind the tumour4 ,the tongue can be ansthetised also by blocking the lingual nerve with a paraneural injection4 ,the nerve lies under the mucous membrane of the mouth opposite the last molar tooth4 ,if the tongue is drawn well over to the opposite side1 the nerve can be felt and the injection made around it4 ,the only drawback to this method is that it does not ansthetise the posterior third1 which is supplied by the glosso-pharyngeal nerve4 ,,operations ,,on ,,the ,,skull ,,and ,,brain can be readily performed by infiltration of the scalp4 ,in the later stages of the recent war1 a large proportion of operations on the skull and brain were performed under local ansthesia4 ,the brain itself is insensitive to touch and painful stimuli1 and infiltration of the scalp is all that is necessary4 ,a #a per cent4 solution of novocaine with adrenalin has been commonly employed1 and is injected into the subaponeurotic space so as to surround the field of operation with a wall of ansthetic solution--the method of ,hackenbruch4 ,the advantages are that hmorrhage is reduced to a minimum1 and the head can be conveniently and safely elevated and the intra-cranial tension thus reduced4 ,analgesia from the ,application of ,cocaine to the ,eye or to a ,mucous ,surface4 ,,for ,,operations ,,on ,,the ,,eye4--,analgesia is obtained by the instillation of a few drops of a #d per cent4 solution into the conjunctival sac4 ,this is repeated two or three times1 and analgesia is obtained in five or ten minutes4 ,it may be necessary to repeat the instillation during the course of the operation4 ,,for ,,operations ,,on ,,the ,,nose1 ,,pharynx1 ,,or ,,larynx cocaine is commonly used4 ,a #e or #aj per cent4 solution is employed and is merely painted on the surface4 ,care must be taken that such strong solutions are not swallowed4 ,,chapter ,,xxi4 ,,spinal ,,an,,sthesia4 ,spinal ,ansthesia or ,analgesia1 consists in the production of analgesia in the lower extremities and in the lower part of the trunk by the injection into the subarachnoid space of an ansthetic drug which blocks the spinal nerves as they enter and leave the spinal cord4 ,the cord ends at the lower border of the first lumbar vertebra and the subarachnoid space at the second sacral vertebra so that there is a considerable area into which the injection may be made without risk of injury to the cord4 ,it is1 in reality1 a special variety of regional analgesia1 the ansthetic being injected into that part of the subarachnoid space which is occupied by the cauda equina4 ,the subarachnoid space of the medulla spinalis contains the cerebro-spinal fluid and communicates above with the subarachnoid space inside the skull and through the foramen of ,magendie1 with the ventricular system of the brain4 ,the subdural space of the medulla spinalis is merely a capillary interval4 ,at the upper end of the cauda equina the nerve trunks of the two sides are separated by a median interval--containing only the filum terminale--which has been termed the cysterna terminalis4 ,it is into this median space that the injection is made1 in order to avoid wounding the nerve trunks and to procure equal diffusion of the ansthetic to both sides of the middle line4 ,if the injection is made among the nerve trunks on one side1 a unilateral ansthesia may result1 the drug being prevented from diffusing freely to the other side by the presence of the numerous nerves4 ,the ligamentum denticulatum forms an imperfect scalloped septum between the posterior and the anterior nerve roots1 passing from the surface of the cord to the dura mater4 ,the presence of this septum probably explains the fact that the motor nerves are not affected with the same constancy and to the same extent as the sensory roots4 ,technique4 ,the drug which is most commonly employed in the ,edinburgh school is ,tropacocaine1 and the results of its use with proper technique are eminently satisfactory4 ,the dose of the drug for most purposes is #jg gramme4 ,smaller doses are sometimes used but the larger dose gives more constant ansthesia and appears to be well within the limits of safety4 ,the dose is dissolved in #a c4cm4 of distilled water and sufficient sodium chloride added to make a solution isotonic with the cerebro-spinal fluid4 ,a convenient method of obtaining the drug is in glass ampoules1 each ampoule containing one dose1 which has been carefully sterilised4 ,illustration3 ,,fig4 #ec4--,needle and syringe for spinal analgesia4 ,note the short oblique character of the point of the needle4 ,the syringe and needle employed are illustrated in ,fig4 #ec4 ,the point of the needle must be sharp but short4 ,if a needle with a long slender point is employed1 only part of the point may enter the membranes2 a free flow of cerebro-spinal fluid may then take place1 but when the injection is made part of the ansthetic solution escapes outside the membranes4 ,the needle should he #c to #d inches long and #a m4m4 in diameter4 ,a stylet fits inside the needle and prevents it from becoming blocked during the introduction4 ,to prevent the possibility of rusting1 both needle and stylet should consist of hard nickel4 ,the barrel of the syringe must consist of glass so that the appearance of the cerebro-spinal fluid can be seen4 ,the ,record type is very satisfactory4 ,the syringe usually supplied for spinal analgesia has a capacity of #b or #c c4cm41 but one holding #aj c4cm4 is more useful4 ,syringe and needle must be carefully sterilised by boiling in plain water2 any trace of soda causes decomposition of the drug4 ,the ampoule containing the tropococaine is sterilised in a strong antiseptic solution so as to avoid the possibility of contamination of the hands when the drug is being transferred to the syringe4 ,method of ,injection4--,the patient should be given a hypodermic injection of gr4 of morphine and gr4 of scopolamine an hour before the operation4 ,there are a number of minor variations in the method of making the spinal injection1 but limitations of space forbid a discussion of theoretical questions and of the relative merits of the different procedures4 ,only one method1 which has been found safe and reliable1 will be considered here4 ,the injection is made in the space between the third and fourth lumbar spines1 the objective being the mid-line of the subarachnoid space between the two divisions of the cauda equina4 ,the position of the patient is such that the spaces between the lumbar spines are opened up as widely as possible4 ,the most convenient plan is to have the patient sitting on the table with the head and shoulders bent well forward 7see ,fig4 #ed47 ,if the patient is unable to sit up1 the injection may be made with him lying on his side1 with the knees drawn up and the shoulders bent forward4 ,illustration3 ,,fig4 #ed4 ,position for the injection4 ,the cross indicates the point at which the lumbar puncture is made--about half an inch from the median plane and in the space between the third and fourth lumbar spines4 ,the skin of the back is carefully sterilised2 painting with tincture of iodine serves admirably4 ,the ampoule containing the tropacocaine is opened1 and the drug sucked into the syringe through a spare cannula4 ,the loaded syringe is then placed on a sterile towel at the back of the patient4 ,with a little practice there is no difficulty in making the lumbar puncture4 ,the fourth lumbar spine is located by noting the level of the highest point on the iliac crest--this may be indicated by an assistant4 ,a line joining the highest points on the two iliac crests will pass through the tip of the fourth lumbar spine4 ,when this process has been carefully identified1 the needle is introduced half-an-inch to one side of the median plane and midway between the third and fourth spine4 ,some surgeons prefer to go in exactly in the middle line to make sure of entering the middle of the subarachnoid space1 but in this position the tough supra-spinous and interspinous ligaments are met with1 and to avoid the resistance of these it is best to keep a short distance out from the median plane4 ,by carefully noting the direction of the needle1 the cysterna terminalis can always be entered4 ,the needle is passed forwards1 very slightly upwards1 and slightly medially so as to hit off the centre of the subarachnoid space4 ,as the needle passes through the ligamentum flavum1 there is a sudden diminution of resistance and immediately afterwards the point of the needle lies in the subarachnoid space4 ,the passage of the needle through the membranes is sometimes accompanied by a slight pricking pain4 ,the stylet is withdrawn at this stage and the cerebro-spinal fluid usually trickles out drop by drop4 ,the syringe is picked up1 carefully emptied of air bubbles1 and fitted on to the needle4 ,the piston is withdrawn until the syringe is filled with cerebro-spinal fluid1 which mixes freely with the ansthetic solution1 and the contents then slowly injected4 ,the #aj c4cm4 syringe is to be preferred for this purpose as it is essential to mix the tropacocaine thoroughly with the cerebro-spinal fluid4 ,if the smaller syringe is used1 it should be refilled with cerebro-spinal fluid and emptied a second time so as to ensure thorough diffusion of the drug4 ,the needle is then withdrawn and the puncture sealed with collodion4 ,the injection should never be made until a free flow of cerebro-spinal fluid is obtained1 since this is the only certain indication that the needle has entered the subarachnoid space4 ,if failure is met with in the space between the third and fourth spines1 the interspinous space above or below should be tried4 ,after the injection has been completed the patient is placed flat on his back and then lowered into the ,trendelenburg position4 ,analgesia appears first in the scrotum and perineum1 extends down the medial side of the leg to the foot1 then appears on the front of the leg1 and travels up to the groin and the lower part of the abdomen4 ,the progress of the analgesia is tested from time to time by lightly pinching or pricking the skin1 the patient's eyes being screened4 ,when the analgesia reaches the level of the nipples1 the patient is raised into the horizontal position and the the operation may be commenced4 ,some surgeons object to the lowering of the head as rendering paralysis of the respiratory centre from upward diffusion of the drug more likely4 ,if tropacocaine is used in the dosage indicated and the table elevated when the ansthesia reaches the nipple line1 there seems to be little risk of this complication4 ,if analgesia is only desired in the lower extremity1 the lowering of the table may be omitted2 but if a good ansthesia is desired above the level of the groin1 it should always be carried out4 ,analgesia is complete in five or ten minutes as a rule4 ,the duration varies from three-quarters of an hour to an hour and a half4 ,if a preliminary hypodermic injection of morphine and scopolamine has been given1 the patient lies quietly and patiently until the operation is completed4 ,in some cases the patient actually drops off to sleep from the effects of the morphine4 ,it is not uncommon to observe a temporary nausea and faintness about fifteen or twenty minutes after the injection has been made1 and it is good practice to give the patient a little brandy and water at this stage4 ,complications and ,after-,effects4 ,a great deal has been written in the past with regard to unpleasant results of spinal analgesia1 but most of these would appear to have been the result of faulty technique or of the use of an impure or irritating drug4 ,when tropacocaine is used in the manner described1 the usual result is that1 except for occasional nausea and faintness at the commencement1 the patient has a comfortable1 painless operation1 and a recovery which is unmarred by the sickness and other distressing symptoms which are so common after general ansthesia4 ,deaths have been recorded1 and these have been ascribed to the drug having travelled too high and brought about paralysis of the respiratory centre in the medulla oblongata4 ,too much importance has probably been ascribed to these fatal cases4 ,they have been most common in patients greatly enfeebled by shock1 old age1 or debilitating illness1 who are liable to die during the operation whatever ansthetic is used4 ,thousands of cases have been recorded without a death1 and in the hands of surgeons of skill and judgment fatal cases are almost unknown4 ,an occasional complication is severe headache which may persist for a week or longer4 ,other complications are all exceedingly rare2 paralysis of the lateral rectus muscle of the eyeball or of other ocular muscles has been recorded1 and is probably due to toxic bye-products which are the result of impurity of the drug4 ,persistent nausea and paralysis of the bladder and rectum and even of the lower extremities have also been recorded1 but are to be regarded as the greatest rareties1 and probably due to impurity of the ansthetic4 ,indications4 ,spinal analgesia may be used for any operation at or below the level of the umbilicus4 ,excellent ansthesia is obtained for the operation for radical cure of umbilical hernia1 but ansthesia above this level is not so constant1 and is regarded by many authorities as unsafe4 ,the procedure is of special value in cases in which a general ansthetic is unsafe3--7#a7 ,in old enfeebled patients suffering from strangulated hernia1 enlarged prostate1 disease of the female pelvic organs1 and other conditions where ansthesia is necessary below the umbilicus4 7#b7 ,in patients who are already suffering1 or who are likely to suffer1 from severe shock4 ,the drug has the same effect on the nerve trunks of the cauda equina as on the peripheral nerves--it causes blocking of the centripetal sensory impulses which are such a potent factor in the causation of shock4 7#c7 ,in diabetic gangrene spinal analgesia is the safest form of ansthesia to employ4 ,contra-,indications ,children up to the age of fourteen or so are apt to be frightened1 and spinal analgesia is better avoided except in special cases4 ,it is contra-indicated also in septic conditions on account of the possibility of septic meningitis resulting from metastasis of the infection1 the drug having possibly the action of lowering the vitality of the cord and meninges4 ,in tuberculosis and syphilis it is better avoided for the same reason4 ,it should not be used where organic disease of the spinal cord or brain is already present4 ,analgesia ,produced by ,freezing4 ,a transient analgesia can be produced by freezing the skin4 ,an ether spray was formerly employed1 but was found to be troublesome and inconvenient4 ,the most convenient procedure consists in freezing the part by means of a spray of ethyl chloride4 ,this drug is supplied in a glass cylinder with a very fine outlet so that it breaks up into a fine spray as it escapes4 ,the cylinder is held about #h or #aj inches from the patient's skin1 and pressure applied with the thumb to a stopcock on the neck of the cylinder4 ,under the influence of the heat of the hand the liquid escapes in a fine jet which impinges on the patient's skin4 ,freezing takes place in a few seconds1 the frozen patch becoming hard and white4 ,the freezing can be hastened by blowing on the skin4 ,this method is only suitable for the opening of small abscesses and other procedures requiring a very short ansthesia4 ,the ansthesia is very imperfect1 and only lasts for a few seconds4 ,many patients appear to have as much pain with this form of ansthesia as without it4 ,,appendix ,i4 ,,some ,,experimental ,,observations ,,by ,,the ,,author ,,upon ,,the ,,physical ,,facts ,,of ,,ether ,,evaporation4 ,the apparatus was very simple4 ,it consisted of a pump which would propel air towards the ether bottle2 a glass bottle containing ether1 the roof of which was pierced by two tubes1 one of which carried the air from pump to bottle1 and the other from bottle to a ,waller's tube1 where it was collected4 ,the percentage of ether in the air was then estimated by ,waller's gravimetric method4 ,the ether jar stood in a water bath which could be either left otherwise empty or filled up with water of known temperature4 ,the following tables show some of the results4 ,in each case1 the air was propelled for five minutes1 by which time the cooling effect upon the ether was very marked2 the figures given are averages taken from several observations4 ,,table ,a4 ,,air ,,blowing ,,over ,,surface ,,of ,,ether4 ---------------------------------------- ------------------------------- ,temperature of ,quantity of ,rate ,temperature ,bath 7,fahr47 ether before of of ether ,percentage before experiment4 experiment4 pump4 7,fahr47 at endobtained4 of experiment4 ---------------------------------------- ------------------------------- #ge #ajj c4c4 #cj #ej ,f4 #abg #he #ajj c4c4 #cj #eb ,f4 #abh #ge #ajj c4c4 #ij #de ,f4 #hg #he #ajj c4c4 #ij #de ,f4 #hh ,no water in bath #ajj c4c4 #cj #cb ,f4 #hb ,no water in bath #ajj c4c4 #ij #bc ,f4 #ed ,no water in bath #bjj c4c4 #cj #ch ,f4 #if ,no water in bath #bjj c4c4 #ij #bi ,f4 #ff ---------------------------------------- ------------------------------- ,,table ,b4 ,showing increased percentage obtained by 8bubbling through0 instead of 8blowing over0 ether-- ,,water ,,bath ,,at #ge ,,fahr4 ,quantity of ether4 ,rate of pump4 #ajj c4c4 #cj ,air blown over surface of ether gave percentage of ether #abh ,air bubbled through ether #bch ,,table ,c4 ,showing amounts of ether vaporised at varying pump rates4 ,in each case1 the temperature of the water bath was #ge1 and the initial amount of ether was #ajj cc4-- ,pump ,amount of ,ether ,rate4 ,vaporised4 #cj #cj c4c4 #ij #ch c4c4 ,these experiments justify one in drawing the following conclusions3-- #a4 ,the effect of a water bath has a marked effect in increasing the strength of the vapour yielded1 but small variations in the temperature of the bath 7as between #ge and #he ,fahr47 have but little effect4 #b4 ,if ether is vaporising quickly1 it cannot pick up heat from the water bath as quickly as it is losing its own heat4 ,though not shown in the tables1 the actual loss of temperature on the water bath was small--about #b degrees ,fahr4 during the five minutes experiment4 #c4 ,the more forcible the blast of air blown over or through the ether1 the less the percentage of ether yielded4 ,table ,c shows that this loss of percentage is not compensated for by an increase in the total amount vaporised4 ,of course1 these results only apply to the case of a strong current of air4 ,if the current of air were very small1 the ether could pick up heat as fast as it parted with it1 and within moderate degrees a little increase of the air stream would increase the total amount of ether vaporised without reducing the percentage strength4 ,these results are of some practical importance in connection with so-called 8vapour ansthesia0 as given for instance by ,shipway's instrument 7page #ij71 and in devising and using the ether chambers of intratracheal apparatus4 ,,appendix ,,ii4 ,,the ,,percentage ,,strength ,,in ,,open ,,ether4 ,hewitt and ,syme 7,lancet1 #bgth ,jan4 #aiab7 estimated the percentage of ether obtainable from an open mask with varying materials and quantities of the drug4 ,the results are tabulated below3-- ,a4--,a ,,whole ,,mask ,,just ,,moist4 ,material stretched ,number of ,percentage on mask4 layers4 obtained4 ,gauze #d #aa #h #aad #ab #aa ,flannel #a #hj #b #hj ,lint #a #ajj ,b4--,,whole ,,mask ,,wet4 ,gauze #d #ab #h #acd #ab #adj ,flannel #a #hj #b #hj ,lint #a #hj ,by excessive douching the observers were able to obtain #ag per cent4 ,in these results1 air and ether vapour were drawn by a pump through the material to imitate the inspiration1 but no attempt seems to have been made to imitate expiration4 ,the effect upon the material used of moisture condensed from the expired air is not taken into account in these experiments4 ,this is a serious hiatus in the argument1 particularly as regards lint4 ,this material in actual use rapidly becomes quite sodden1 and ether will not vaporise from it properly4 ,in spite of this fault1 these observations may probably be taken as being reasonably accurate4 ,with them may be compared the figures of ,karl ,connell1 who1 working with quite accurate methods1 estimated the percentages of ether necessary to induce and maintain ansthesia3-- ,period of ,ansthesia4 ,percentage4 ,first #e minutes 7i4e4 induction7 #ah ,next #be #ad ,next #cj #ab ,next #fj #abh 8,bad0 subjects on the average required an extra #d per cent4 during first half hour1 feeble patients required #b per cent4 less4 7,journal of the ,american ,medical ,association1 #bbnd ,march #aiac74 ,,appendix ,,iii4 ,,the ,,action ,,of ,,an,,sthetics ,,upon ,,the ,,blood4 ,the ,blood ,gases in ,ansthesia4 ,buckmaster and ,gardner 7,journal of ,physiology1 vol4 xli41 p4 #bdf71 analysed the blood gases in various stages of chloroform ansthesia1 and some of their results are shown below in tabular form4 ,they show a very definite reduction in the oxygen content of the blood4 ,so far as one gathers from the text of the paper1 the animals were not subjected to any considerable trauma during the progress of the ansthesia1 so that the figures arrived at with regard to the ,,co#b content do not bear upon the ,acapnia question4 ,if there was no trauma1 there would be no deep breathing1 and a reduction of ,,co#b could not be expected4 ---------------------------------------- --------------------------------------- ,average volume in ,average composition c4c4 per #ajj c4c4 per cent4 ,relation of blood of gas of -----------------------------------,o#b to ,,co#b ,,co#b,o#b,nitr4,,co#b ,o#b,nitr4 ---------------------------------------- ----------------------------------- ,normal cats4 #bejgacfj #ajj #fcb #cdbh #beb #a to #ahd ,reflexes just re-appearing #bijbaadi #acc #fejf #bedd #bhg #a to #bee ,reflexes just disappearing #bieg #ggh #bae #fiad #ahag #eji #a to #ch #bnd ,stage ,ansthesia #cfjj #had #adi #gabg #afab #bie #a to #dcb ---------------------------------------- ----------------------------------- ,other ,blood changes in ,ansthesia4 ,hamburger and ,ewing 7,journal of the ,american ,medical ,assoc4 #aijh7 examined the blood changes incidental to surgical ansthesia4 ,their results may be condensed as follows3-- ,nitrous ,oxide4--,hmoglobin is not permanently decreased and no anmia follows the administration4 ,hmolysis is not increased4 ,the coagulation time of the blood is not always affected in the same direction4 ,usually it is slightly increased4 ,ether4--,the hmoglobin is slightly reduced and anmia persists for seven to ten days4 ,hmolysis is not however materially increased4 ,there is some evidence of blood inspissation4 ,the coagulation time is markedly increased4 ,chloroform4--,the hmoglobin is reduced and a distinct anmia produced4 ,hmolysis is definitely increased4 ,there is a slight increase in the coagulation time4 ,,index4 ,a ,abdominal operations1 ix1 #g local ansthesia in1 #ahg ,abdominal muscles1 rigidity of1 #ai ,abnormalities of ansthesia1 minor1 #ch major1 #adj ,acapnia1 #aj1 #bi1 #ci ,accidents of ansthesia1 #adj ,acetonuria1 #aec ,acidosis1 #aec ,adenoids1 #abg1 #aff in status lymphaticus1 #adh ,adrenalin1 #age danger of1 with chloroform1 #aac1 #aff ,aedentulous patients1 #bc ,after-effects of ansthetics1 see ,sequelae ,ages1 dosage of morphia at various1 #de selection of ansthetic at various1 #afd ,airshaft1 natural1 #if ,airway1 natural1 #ae1 #ca1 #aad1 #ade artificial1 #bc ,alcoholics1 ansthesia in1 #b1 #hg1 #ajc1 #acg1 #afe ,alkaloids1 #ab1 #dc1 #hh1 #ajc ,aneurysm1 #ef ,anoci-association1 #aa ,anoxmia1 #ae ,arm1 management of in ansthesia1 #aeg regional ansthesia of1 #aha ,arteries1 spouting of1 x1 #cg ,arterio-sclerosis1 #ef1 #afg ,artificial respiration1 #adf ,asphyxia1 #ae ,athetosis1 #ch ,atropine1 #dc1 #de1 #aab1 #adg ,auer and ,meltzer1 #if ,b ,barth #c-way tap1 #ej ,bicarbonate of soda in acidosis1 #aef ,bladder1 reflexes from1 #ci1 #afh local ansthesia in operations upon1 #aij ,blistering1 by chloroform1 #aji ,blood1 changes in1 during ansthesia1 #bjg spouting of1 from cut arteries1 x1 #cg ,blood-pressure1 in natural sleep1 #a in shock1 #f in asphyxia1 #ag in nitrous oxide1 #df in ether1 #ge in chloroform1 #aaj in ethyl chloride1 #abb clinical observation of1 #cg ,blowing respiration1 #cd1 #hi ,boothby1 on ether percentages1 #ii ,boyle1 ,mr ,leonard1 #gj ,brachial plexus1 nerve blocking in1 #aha ,brain1 see ,nervous ,system local ansthesia for operation upon1 #aia ,breath-holding1 #cd1 #aab1 #aad ,breathing1 deep 7see ,acapnia7 ,bronchitis1 #aej ,c ,carbon-dioxide1 #aj1 #ah1 #bjf ,cardiac cyanosis1 #cg ,cardiac disease1 #ajg ,cardiac failure 7see ,syncope7 ,castration1 ansthesia in1 #afi ,c4,e4 mixture1 #hd1 #acd1 #acg ,cells1 nerve1 changes in1 #e ,centripetal impulses1 #f ,children1 #de1 #id1 #abe1 #afd ,chloretone1 #ic ,chloride of ethyl 7see ,ethyl ,chloride7 ,chloroform1 administration of1 #aac decomposition of1 #aji delayed poisoning by1 #aec physiology of1 #aji ,choice of ansthetics1 #afb ,circulation1 observation of1 x1 #cg in shock1 #aj in asphyxia1 #ag in valved breathing1 #bi in nitrous oxide1 #df in ether1 #ge in chloroform1 #aaj in ethyl chloride1 #abb in ,c4,e4 mixture1 #aca failure of 7see ,syncope7 ,circumcision1 ansthesia in1 #afi ,clarke's apparatus1 #fi ,clenching of ,jaws1 #ae1 #bd ,clinical phenomena of asphyxia1 #ah of normal ansthesia1 #cc ,closed ether1 #gh ,closed method1 features of1 #bi ,clover's inhaler1 #gh1 #ach ,cocaine1 #agj ,collapse 7see ,syncope7 ,conduction of nerve impulses1 #c ,connell1 ,karl1 #ij1 #bje ,conjunctival reflex1 #ca1 #ce ,convulsions1 #ag ,corneal reflex1 #cb1 #ce ,crile1 ,prof41 #e1 #i ,crowing respiration1 #af1 #afi night crowing1 #adh ,cyanosis1 #ah1 #cg1 #ec ,cylinders for nitrous oxide1 #dc for oxygen1 #fd ,d ,dangers of chloroform1 ,prof4 ,l4 ,hill upon1 #abj ,death1 causes of1 #ag1 #aaj1 #adj1 #add1 #adh ,decomposition of chloroform1 #aji of ether1 #gd ,deep breathing1 #aj ,degrees of ansthesia1 #ca ,dental ansthesia1 #ed1 #eg1 #abh1 #aca1 #afc ,depth of ansthesia1 #cf ,dextrose in acidosis1 #aef ,difficulties of ansthesia1 major1 #adj minor1 #ch ,dilatation of pupils1 #e1 #ag1 #ce1 #ec1 #ff1 #abe1 #acf1 #ada1 #adc ,disease1 relation of ansthesia to1 #aff acute infectious1 #afh ,dislocations1 ansthesia in reduction of1 #afd ,dorsal position1 #aeg ,dosimetric method for chloroform1 #aad for ether1 #ij ,dott1 ,mr ,n41 direct laryngoscope1 #ajd ,douche method1 #bj ,dread 7see ,fear7 ,drop bottles2 chloroform1 #aag ether1 #hc ,drop method1 #cj1 #hc ,drugs for local and spinal ansthesia1 #agj to #agd ,e ,emphysema1 #afg ,empyma1 #afg1 #ahg ,enema1 before operation1 #db ,ether1 #gd1 et seq4 closed1 #gh intratracheal1 #if open1 #hc physiology of1 #ge rectal1 #ic warmed vapour1 #ij ,ether1 respiratory sequel of1 #aej ,ether tremor1 #ch ,ethyl chloride1 #abb1 et seq4 combined with nitrous oxide1 #abh freezing ansthesia by1 #bjj ,eucain1 #agd ,excitement 7see ,struggling7 ,extraction of teeth 7see ,dental ,ansthesia7 ,eye reflexes1 definition of1 #ca ,f ,face-down posture1 #aeg ,face1 adaptation of masks to1 #ba1 #eb1 #hd ,face-pieces for nitrous oxide1 #ea ,false ansthesia1 #da ,faradism of motor nerves in ansthesia1 #c ,fat patients1 #aeh1 #afe ,fatty changes after ansthesia1 #aec ,fear1 effects of1 #i prevention of1 #aa1 #dc1 #hh ,feeble patients1 #afh ,ferguson1 ,dr41 ,w4 ,j41 #hg ,fingers1 regional ansthesia for1 #ahd ,flame1 open1 dangers of1 #gd1 #ajd ,forceps1 tongue1 #bd ,food before ansthesia1 #db ,foreign bodies in the larynx1 #af ,freezing analgesia1 #bja ,fright 7see ,fear7 ,g ,gags1 #be ,gardner1 ,mr ,bellamy1 #bc1 #bd1 #hc ,gas and air1 #ed ,gas and ether1 #ach ,gas and ethyl chloride1 #abh ,gas-oxygen1 #fj ,gasping1 #dj ,genito-urinary operations1 #afh ,glossotilt1 #bd ,glottis1 spasm of1 #af1 #bj1 #bf1 #aje ,goitre1 ansthesia for1 #afj1 #ahe ,goitre1 exopthalmic1 #i1 #afg ,grey and ,parsons on shock1 #f ,guy1 ,dr ,wm41 #abh ,guy-,ross1 gas oxygen method1 #aca ,gwathmey1 warmed ether vapour1 #ij oil-ether1 #ic ,h ,hmorrhage1 as a factor in shock production1 #i observation of1 by ansthetist1 x1 #cg ,hmorrhoids1 local ansthesia for1 #aia ,harcourt1 ,vernon1 #aad ,head and neck operations1 position for1 #aeh ,head and neck1 raising1 #aeb lowering1 #aaj1 #ade extra pillow in deep chested patients1 #aeg ,heart1 failure in asphyxia1 #ag observation of1 #cg action of ether upon1 #ge of chloroform upon1 #aaj of ethyl chloride upon1 #abb failure of1 in secondary syncope1 #add ,heart disease1 ansthetics in1 #afg ,henderson1 ,yandell1 #aj1 #bi ,hernia1 local ansthesia in1 #ahi ,heroin1 #dd ,hewitt1 ,sir ,frederick1 #bb1 #ej1 #fb1 #ha1 #acg ,hill's direct laryngoscope1 #ajd ,hill1 ,prof4 ,leonard1 #aaa1 #abj ,hornabrook1 #hg1 #abc ,hydrochloric acid1 as an impurity in chloroform1 #aji ,hypnotics1 #ab1 #db ,hypodermic medication1 #ab1 #db ,i ,impurities of ansthetics1 #gd1 #aji1 #abb ,infiltration analgesia1 #age ,inhalers1 ,clover1 #gh ,clarke1 #fh ,guy1 #abh ,guy-,ross1 #acj ,hewitt1 #ej1 #fb1 #ha ,junker's1 #aae ,ormsby1 #ha ,paterson1 #eh ,rendle1 #ace ,inhibition1 vagal1 #aaa1 #adc ,intestinal obstruction1 #ada1 #ahi ,intranasal surgery1 #afj1 #aff1 #aib ,intratracheal method1 #if ,kelly's instrument for1 #ajj ,shipway's1 #aja ,inversion1 ,leonard ,hill's experiments upon1 #aaj1 #aaa ,j ,jactitations1 #ec ,jaundice1 #aed ,jaws1 clenching of1 #ae1 #bf falling back of1 #af operations upon1 #aff management of1 in ansthesia1 #bc1 #he ,joints1 ansthesia in dislocation of1 #afd ,junker's inhaler1 #aae ,k ,kidney1 position for operations upon1 #afh ,kelly's intratracheal instrument1 #ajj ,l ,labour1 ansthesia in1 #dd1 #afi ,lane1 ,sir ,arbuthnott1 #ad ,laryngeal stridor1 #af1 #bj1 #bf1 #dj1 #afi ,levy1 ,goodman1 #aab1 #ade ,light ansthesia1 dangers of1 in chloroform1 #i1 #aab ,levy's views1 #aac ,light reflex1 #cb ,local ansthesia1 #agj et seq4 ,lowering of head and shoulders1 #aaj1 #ade ,lumbar puncture1 site for1 #aif ,lungs1 ventilation of1 by normal breathing1 #if by intratracheal method1 #ig ,lymphatism1 #adh ,m ,malcolm1 ,j4 ,d41 #i ,marshall1 ,dr ,geoffrey1 #gj ,masks for chloroform1 #aaj for ether1 #hb for perhalation method1 #bh ,massage of heart1 #adh ,mechanical asphyxia1 #ae ,meltzer and ,auer1 on intratracheal method1 #if ,menstruation1 #afi ,micturition before nitrous oxide1 #ea ,mixtures1 ,c4 ,e41 #hd1 #acd1 #acg of nitrous oxide and oxygen1 #fj of nitrous oxide and ethyl chloride1 #abh ,morphine1 #ab1 #dc1 #aeb ,mouth1 breathing through1 #bb ,mouth1 operations upon1 #afe ,mouth props1 #bb ,mucus in air passages1 #dj ,musculo-spiral paralysis1 #aeg ,muscles in ansthesia1 ix1 #c1 #ai1 #cd ,muscle tone1 #c1 #ai1 #ec ,n ,nasal breathing1 #bc1 #aff ,naso-pharyngeal catarrh1 #aea ,nasal methods of giving nitrous oxide1 #eg ,nasal tube for ,junker's bottle1 #aai ,neck1 position of1 #bj relaxation of muscles of1 #ba posture for operation upon1 #aei tumours and inflammatory swellings in1 #g1 #aff ,nephritis1 influence of1 upon choice of ansthetics1 #gg1 #afh ,nervous system1 effects of ansthetics upon1 #b1 #ge ,nerves1 peripheral1 unaffected by ansthetics1 #c ,nerve blocking1 #ab1 #agi ,night-crowing1 #adh ,nitrous oxide1 #df with air1 #ed with ether1 #ach with ethyl chloride1 #abh nasal1 #eg physiology of1 #df contra-indications to1 #ef ,nitrous oxide and oxygen1 #h1 #ab1 #fj various systems for1 #fg1 #gj1 #acj for use in major surgery1 #gb with ethyl chloride1 #aca ,o ,obesity1 #aeh1 #afe ,obstruction1 intestinal1 #ada respiratory1 #ae1 #ada ,oil ether1 ,gwathmey's method of1 #ic ,oligmia in shock1 #aj ,omnopon1 #dd ,open method1 definition of1 #bh chloroform1 #aag ether1 #hc ethyl chloride1 #abc ,o',malley's technique for intra-nasal surgery1 #afj ,ormsby's inhaler1 #ha1 #acg ,over-dosage1 #cf1 #aaj1 #add with nitrous oxide1 #ed ,oxygen1 reduction in blood in ansthesia1 #bjf as a relief in asphyxia1 #bg to old patients1 #afe with nitrous oxide 7see ,nitrous ,oxide and ,oxygen7 with nitrous oxide and ethyl chloride1 #acj ,p ,paralysis1 musculo-spiral1 #aeg ,patella reflex in ansthesia1 #c ,percentages of chloroform and ether required in ansthesia1 #f of chloroform1 #aaa of ether1 #hf1 #ii1 #bja1 #bjd ,perhalation method1 definition of1 #bh ether 7see open ,ether7 ,phenomena of ansthesia normal1 #cc abnormal1 #ch of nitrous oxide1 #eb of ethyl chloride1 #abe ,pericarditis as a cause of death in ansthesia1 #afh ,phillip's artificial airway1 #bc1 #afj ,physics of natural respiration1 #if ,physiology of ansthetic drugs1 #a of asphyxia1 #ag of chloroform1 #aji of ether1 #ge of ethyl chloride1 #abb of nitrous oxide1 #df ,phthisis1 #afg ,pneumonia1 post ansthetic1 #aeg ,position in ansthesia1 #aeg ,positive pressure in nitrous oxide1 #eb in nitrous oxide and oxygen1 #ff ,post-chloroform poisoning1 #aec ,post ansthetic complications1 #aej ,pregnancy1 ansthesia in1 #afi ,preliminary hypodermic medication1 #aa1 #dc1 #aeb ,preparation of patient1 #db ,primary syncope1 #aaj1 #adc ,protection from shock by general ansthetics1 #h ,pulse1 rate in shock1 #f clinical observation of1 #cg ,pupil1 light reflex of1 #cb size of1 #ce in asphyxia1 #ag ,purging before ansthetics1 #dj ,q ,quinine and urea hydrochloride1 #agd ,r ,rebreathing method1 #ah in nitrous oxide1 #fh ,rectal administration of ether1 #ic ,rectal saline1 #db ,reflexes as a cause of shock1 #d1 #f order of disappearance of1 #c ,reflex1 conjunctival1 #ca1 #ce corneal1 #cb1 #ce light1 #cb1 #ce patella1 #c skin1 #cg ,reflex syncope1 #h1 #aab1 #ade ,regional ansthesia1 #agi ,renal disease1 #afc ,rendle's cone1 #ace ,repeated administrations1 #fj1 #aef ,respiration1 arrest of1 #adb artificial1 #adf blowing1 #cd1 #hi crowing1 #af depressed1 #ci1 #dc effect of morphia and chloroform upon1 #dc1 #hf normal1 #cd obstructed1 #ae1 #ada1 #aff ,respiration1 physics of natural1 #if reflex arrest of1 #ci ,respiratory abnormalities1 minor1 #ci major1 #ada ,respiratory system1 effects of ether upon1 #gf after-effects of ansthetics upon1 #aej ,rigidity of muscles in asphyxia1 #ai1 #ch1 #ci in second stage1 #cc ,s ,saline injections1 per rectus1 #db subcutaneous1 #ad ,schimmelbusch's mask1 #bh1 #aaf ,scopolamine1 #dd1 #ajc ,secondary syncope1 #ag1 #ach1 #adc ,secretion of mucus1 #dj1 #gf of urine1 #afh ,sedatives1 #ab1 #db ,selection of ansthetic1 #afb ,semi-open method1 #bh ,septic cases1 #i1 #fj1 #aef1 #afh ,sequel of ansthesia1 #ajj ,sex1 relation to ansthesia1 #afe ,shipway1 ,dr1 #ia1 #aja ,shock1 #e difference between syncope and1 #adb ,short1 ,mr ,rendle1 #aed ,sickness 7see ,vomiting7 ,sighing1 #dj ,sight-feed machines for gas-oxygen1 #gj ,signs of ansthesia1 #cf1 #ec1 #fe ,silk1 ,dr ,j4 ,w41 #bc1 #hg ,single dose ansthetics1 #cj1 #afc ,sitting posture1 #ba1 #aeh ,slow respiration1 #ci ,spasm1 muscular1 #ai of jaw muscles1 #ae of larynx1 #af1 #bf1 #afi ,specific gravity of chloroform1 #aji of ether1 #gd ,spinal ansthesia1 #aic ,stages of ansthesia1 #ca ,starvation1 a cause of shock1 #i of acidosis1 #aee ,status lymphaticus1 #adh ,stertor1 #dj1 #ec ,stimuli from field of operations1 #f ,stomach tube1 before operation1 #ada ,stovaine1 #agc ,stridor1 #af1 #bf1 #dj ,struggling1 #cd ,strychnine1 #adg ,subcutaneous saline1 #ad ,swallowing1 movements of1 #cc ,sylvester's method of artificial respiration1 #adf ,syncope1 #adb ,syringe for local ansthesia1 #agf for spinal ansthesia1 #agf ,t ,teeth1 danger of dropping of into larynx1 #af extraction of1 #ed1 #eg1 #abh1 #aca1 #afc ,teter1 ,dr41 on nitrous oxide and oxygen1 #fh ,thomson1 ,prof4 ,alexis1 #ab1 #aeh ,thomson1 ,torrance1 on intratracheal ansthesia1 #if ,thoracic operations1 local ansthesia in1 #ahf ,three-way tap for nitrous oxide1 #ej1 #abh ,thyroid gland1 see ,goitre ,time for operations1 #db ,time afforded by single dose ansthetics1 #afc ,tongue falling back of1 #af forceps for1 #bd operations upon1 #ig1 #aah1 #aff local ansthesia for1 #aia ,tonsils and adenoids1 #abg1 #aff ,trachea1 mucus in1 #dj pressure upon1 #ag ,trachetomy1 #adb1 #ahe ,tremor1 ether1 #ch ,trendelenberg posture1 #aeh ,tropacocaine1 #agc ,turner1 ,dr ,logan1 #abe ,u ,urine1 secretion of prevented by morphia1 #afh ,v ,vagus nerve1 #aaj1 #ade ,valved method1 features of1 #bi ,vapour method1 ether1 #ij ethyl chloride1 #abe ,vaso-motor system1 in shock1 #i in asphyxia1 #ag in nitrous oxide1 #df 7and see ,physiology7 ,veins1 large1 emptying into heart1 #aj engorgement of1 #bj1 #aea ,venesection in syncope1 #adg ,veronal1 #ab ,vicious circle of asphyxia1 #bj ,vital medullary centres1 #c ,vomiting1 #adj1 #aeb impending1 #ci1 #ada ,w ,war1 anti-shock1 measures in1 #aa lessons of1 #fa1 #aea ,warming ansthetic vapours1 #fb1 #ij1 #aja ,wedge for opening clenched jaws1 #be ,withdrawal of ansthetic1 for stridor1 #bf for breath holding and struggling1 #cd for syncope1 #ade ,,footnotes3 #a ,this can be done to a very limited extent indeed if the ordinary valves here described are used4 ,see page #fh4 #b ,a safeguard provided on some machines is a side lead from the oxygen supply direct to the facepiece whereby pure oxygen can be given if required4 #c ,the amount of oxygen in a cylinder is designated in terms of cubic feet4 ,a cylinder which would hold #ajj gallons of ,n#b,o1 will contain #cj cubic feet of oxygen4 #d ,in the figure the ,clover is shown with gas valves and #b-;gallon bag1 arranged for 8gas and ether40 #e ,trans4 xvii4 ,internat4 ,med4 ,cong4 ,sub-sect4 7vii47 ,part i4 #f ,journal ,amer4 ,med4 ,assoc41 ,sept4 #aiac4 #g ,trans4 xvii41 ,internat4 ,med4 ,cong4 ,sub-sec4 7vii471 ,part i4 #h ,trans4 xvii41 ,internat4 ,med4 ,cong41 ,sub-sec4 7vii471 ,part ii4 #i ,trans4 xvii41 ,internat4 ,med4 ,cong41 ,sub-sec4 7vii471 ,part ,i4 #aj ,the student should be careful to be sure that the bulb is attached to the inlet pipe3 if by accident it be slipped on to the outlet pipe1 the first compression of the bulb will eject a stream of liquid chloroform from the instrument4 #aa ,the author described this method in a paper read before the ,scottish ,branch of the ,british ,dental ,association1 and afterwards published in the ,journal of the ,association under the title 8,the ,edinburgh ,system of ,dental ,ansthesia40 ,to the use of this term ,dr ,j4 ,h4 ,gibbs1 of ,edinburgh1 took strong exception in a letter to the ,editor of the ,journal4 ,the author has and had no desire to convey the impression that this system was universally used in ,edinburgh1 but simply that it is the method taught by ,dr ,guy1 ,dean of the ,school1 to the students in the ,extraction ,room4 ,transcriber's ,notes3 #a4 ,obvious printers'1 punctuation and spelling errors have been corrected silently4 #b4 ,where hyphenation is in doubt1 it has been retained as in the original4 #c4 ,some hyphenated and non-hyphenated versions of the same words have been retained as in the original4 #d4 ,superscripts are represented using the caret character1 e4g4 ,dr4 or ,xxx4 #e4 ,italics are shown as xxx4 #f4 ,bold print is shown as xxx4