No. 793.

LONDON, SATURDAY, NOVEMBER 10, 1838.

COURSE OF

LECTURES ON THE BLOOD,AND ON

THE CHANGES WHICH IT UNDERGOESDURING DISEASE,

Delivered at the College of France in 1837-8,BY

M. MAGENDIE.

LECTURE VII.

Effects of pressure on the parietes of the blood-ressels.—Considerations on transfusion.-Action of pain in increasing the pressure.—Fleets of galvanism.—Nature oj the buffycoat of the blood.-Differences between thefluid in and out of the body.—The fibrineof the blood diferentfroin that of muscle.-Effects of bloodletting.GENTLEMEN :-If you take a caoutchouc

tube, and force into its cavity more liquidthan is required to fill it accurately, its wallsyield, and are dilated. In proportion as

you add fluid, the distension increases ; inother words, the interior pressure augmentsin the direct ratio of the volume of the in-jected liquid. Now, it appears to me quitenatural, that the arteries should be subject-ed to the same physical law ; nevertheless,this is a view which, I admit, stands inmuch need of confirmation. I have alreadyattempted, in your presence, to increase thepressure, by adding to the mass of theblood ; but the mercury, instead of rising inthe trials I made, underwent a considerablefall. It seems probable that the oppositionbetween the anticipated and real results ofthe experiment, is to be, attributed to thenature of the liquid injected. The volumeof the blood was, no doubt, rendered moreconsiderable than before, but the energy ofthe heart’s contractility was diminished by ithe presence of water. My injection hadthe same effect as the diluents used in prac-tice, for the purpose of moderating the vio- lence of fever; the augmentation of theaqueous part of the blood weakened tb e

force of impulsion of the left ventricle, andthe pressure in consequence became lessthan previously through the entire system.I propose resuming this experiment to-day,but in a modified form ; instead of introduc-ing water, or any other debilitating fluid,into the circulation, I will make use ofblood drawn from an animal of the samespecies as that on which our experiment ismade ; in fact, we will practise transfusion ;and it affords me some satisfaction to havean opportunity of performing that operationbefore you,--one which enjoyed, in formertimes, the highest degree of reputation, andwhich has now fallen into the most com-plete discredit. Nevertheless, circumstancesmay arise wherein it would be proper tohave recourse to it: I have myself manytimes injected medicinal fluids directly intothe veins of the living subject. At the pe-riod of its discovery the operation of trans-fusion was received with a degree of enthu-siasm bordering on frenzy. Some impru-dent essays, however, made on our own

species, were followed by the most dis-astrous results, and then the new disco-very, on- which a multitude of natteringillusions had been founded, was abandonedwith as much inconsiderateness as it hadbeen practically adopted.

I am of opinion that there was too muchhastiness shown, both in the acceptance andin the subsequent total- rejection of this lastresource of medicine. It would be indis-pensably necessary, before introducing thetransfusion of blood into the regular prac-tice of surgery, to submit its performance tostrict rules, due attention being also paid tothe physical properties and composition ofthe liquid employed. The globules havenot the same volume, or form, in differentanimals; the degree of coagulability oftheir blood is not uniform. If the blood beintroduced by one process the circulationcontinues free ; if by another, its continu-ance will become physically impossible.Here, as in every other experimental essay,it is right to study the results of the opera-tion in animals, before we venture to applyit to man.There are two principal methods of per-

forming transfusion ; in the one the blood, if

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allowed to pass immediately from the vessels Iof the animal that supplies, into that of theanimal intended to receive it; in the otherit is first coliected in a vase of some sort,and then injected. The latter method ismore generally adopted than the former,’because it is easier of execution, and allowsthe operator to measure the quantity offluid transfused. In the present instance Iintend employing it. I must, however, ob-serve, that so great is the plasticity of theblood, especially in dogs, that the mere con-tact of the metal of the syringe srtflices todestroy its fluidity, and, in consequence, torender it inapt for circulation. Still, as it isnot our present object to investigate the mo-difications produced in the living hydruna-mic apparatus by the composition of thecontained liquid, but simply by its volume,the circumstance adverted to will not seri-ously interfere with the results of our expe-riment; so that, instead of introducing theextremity of one vessel by t sort of invagi-3aation into the interior of another, I willuse an intermediate instrument ; I will alsomodify, to a slight extent, the ordinarymode of proceeding in another way. In-stead of venous I will inject arterial blood,take;t fr<)m an animal of the same species,into the vascular system of this dog. Thiswill, I believe, be the first instance in whichthe influence of the volume of the circulat-ing liquid on the interior pressure support-ed by the vessels, will have been directlyexamined. The contractility of the ventri-cular fibres ought, in theory, to remain un-changed ; to undergo neither augmentationnor decrease of energy, because the bloodconveyed to the heart will be neither moredebilitating nor more exciting than habitu-ally.Here arc two dogs, of about equal

strength, oniyone is older than the other.The right carotid of both has been laidbare, and the instrument applied to each byM. Poiseuille himself. In order to avoidtiresome circumlocution?, in describing theexperiment, we will call the dog from whichwe abstract the blood No.1 ; and the ani-mal into which we inject it No.2. Thejugular vein of the latter has been exposed,and a canula fitted to receive the point of asyringe introduced into its cavity. Thecolumns of mercury stand unmoved, be-cause the cocks have not yet been turned.I now turn them ; the mercury in both os-cillates pretty accurately between the samepoints. Thus, we have in

No. 1. 75-1 n00; 75&mdash;100; 70&mdash;90; 65&mdash;95 millimetres.No.2. 70-105 ; 75&mdash;105; 65&mdash;100; 60

&mdash;105 millimetres.It appears, then, there is no very marked

difference in the height to which the mer-cury rises in the two cases. If both animalsbreathed isochronously, in such manner thatthe movements of inspiration and respira-

tion should exactly correspond, it is proba.hle that both scales would mark the same

degree. I had forgot to tell you that theleft carotid of the dog No. 1, has been laidbare, and an opening made in it, for the

purpose of receiving the mouth of thesyringe. These preparations were madebefore the lecture, for they would havetaken up too much of our time, had theybeen adjourned till the time of performingthe experiment. There is another advau.tage gained thus,-the animals have hadtime to recover, to a great degree, from thestate of agitation into which they vvere

thrown ; besides, the operation is so simple,that it is quite enough to have seen it per.formed once, hi order to understand itfully.

I now aspire some of the hlood containedin the carotid of No. 1, by raising the pistonof the syringe. The latter fills; and, in.deed, to produce this result, there is nonecessity for any effort on my part; for suchis the energy with which the heart drivesthe blood forward, that the piston is raisedat each contraction of the ventricle. Thismight even serve as a means of estimatingthe force of impulsion of the blood, though,of course, the information thus obtainedwould be only vaguely approximative com,pared with the mathematical precision ofthe results obtained with M. Poiseuille’sinstrument. I, therefore, called youratten-tion to this phenomenon rather as a curiousoccurrence, than as one susceptible of anyimportant application. The syringe is nowtilled. The scale marks

No. 1. 60-85 ; 55-95 ; 70&mdash;80mill.I inject the blood into the jugular of the

other dog ; we haveNo. 2. 70--100 ; 65&mdash;90; 70-90 mill.There is no very marked difference in the

height of the two columns. We have, so far,acted with too little liquid to produce anyvery notable effect. It would even appearthat a slight fall, instead of a rise, has takenplace in No. 2. I will repeat the injection.The capacity of the syringe I employ maybe estimated at about four ounces. Theblood had no time for coagulation, for it re-mained a few seconds only in the instru-

ment, and the latter had been previouslywarmed to the temperature of the blood.The syringe is now filled a second time.The mercury oscillates betweenNo. 1. 70&mdash;100; 50&mdash;65 ; 60&mdash;75; 60-M

millimetres.The fall is very slight. The column acted

on by the heart a-ad blood of the other Mi’mal, gives

No. 3. 65&mdash;95 ; 70-100; 75&mdash;95; 60-90 millimetres.The contents of a third syringe are now

transfused. The scales indicateNo. 1. 40&mdash;70 ; ;, 60-85 ; 60&mdash;75 mill,No. 2. 70-100; 75-100 ; 60&mdash;95 mill

There is clearly some diminution of prei,

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sure in the dog supplying the blood ; hut itremains uniform in the receiving animal. Inow fill the syringe for the fourth time, andinject its contents into the jugular. WefindNo. 1. 60&mdash;80; 50&mdash;65; 33&mdash;55 ; 45&mdash;70;25-50 mill.

No. 2. 75-90 ; 70-80 ; 70&mdash;90 ; 60-95 ; 70&mdash;95 mill.Consequently, the increase and decrease

of the mass of the blood are not proportionalto the height of the columns of mercury. Thepressure is sensibly diminished in the ani-mal which we have rendered almost anemic ;it is normal, or perhaps slightly lowered, inthe dog whose vascular system has been dis-tended by our injections. These results arenot literally such as I had announced thatwe should probably obtain ; but we willrecur to the experiment, which must berepeated before it can be considered to havefurnished precise conclusions incapable ofbeing controverted.The degree of frequency of the pulse of

the two animals is remarkable ; that of thedog No. 2, bfats only 72 a minute ; that ofNo. beats 150 in the same time. The fre-quent contractions of the heart, in the lattercase, are to be explained by the constantnecessity for a new supply of liquid felt byevery part of the economy, and by the main-tenance of the equilibrium of the currentsof blood. The frequency and extreme Ismallness of the pulse, in cases of abundantloss of blood, have been noted by all ob-servers ; they are even very valuable signs of a certain internal haemorrhage. I shallnow let the blood of the animal, from whichwe have already drawn so much, flow freely,A large opening is practised in the carotid.The mercury stands atNo. 1. 25-30 ; 25-27 ; 20-30 ; 23&mdash;25 ;

20-25 mill.You perceive that in proportion as the

blood flows the pressure diminishes. Ineed not explain to yoa why the jet of the liquid grows so feeble; it is perfectly natu-ral that its force of progression should de. crease in the direct ratio of the weakenedenergy with which the muscular fibre con-tracts. I now tie the vessel, in order toprevent the animal from perishing of hoemor-rhage. I must confess that, in spite of thepositive information acquired through M.Poiseuille’s instrument, I am at a loss whatopinion to hold respecting the agency of thehlood on the pressure of the walls of the ar-teries. What a few days past appeared tome decided, seems to me now far from pos-sessing that’character. The mercury, it istrue, fell to a considerable extent in the dogwhich we deprived of almost all its blood ;but it did so at the close of the experimentonly, at a time when the vascular systemhad retracted, in virtue of its elasticity, andceased to be dilated by the currents ofblood, :

Now, in the physiological state, the arte-ries are not only full but distended ; wecannot, therefore, legitimately conclude thatthe same condition of things exists in thatstate as in the experiment I have made be-fore you. As the physical conditions arenot the same, the phenomena produced mustalso differ. Although my theory has, per-haps, not been demonstrated to be whollyfallacious, yet I cannot conceal from myselfthat I took an erroneous view of the influ-ence exercised by the increase of the massof the blood. First, I injected water intothe veins, and the mercury fell. I was sur-prised at this result, but, in reflecting on it,fancied I might justly ascribe the diminish-ed arterial pressure to the debilitating ac-tion of the liquid injected. There might, Iwell knew, be some other cause, which Iwas unable to discuver, and this was a

point, I also knew, on which experimentalone could decide. I consequently madethe necessary experiment, and from its re-sult it would appear that, in truth, the volumeof the blood has only a trifling influence onthe force with which the column moved bythe heart presses on the coats of the arteries.I dare not draw a premature inference froma single fact, but we have just seen that thegradual injection of more than a pound ofblood did not increase the elevation of the

mei-etipy ; far from this, towards the close ofthe experiment it oscillated below its nor-mal level.These questions, Gentlemen, are not can-

vassed in our most recent works on physio-logy ; nay, more, they are not so much asmentioned in them. The authors of thosebooks are too fully occupied in discussingthe part to be assigned to the vivifying fluids,the materials of reparation, assimilable princi-ples, &c., to spare time for the considerationof hydraulic phenomena. In this matter,therefore, we have no authority to refer to,and must, for the time being, be contentedwith the evidence of our first essays. Butdo not suppose that a candidate for gradua-tion would do well in giving proof of know-ledge of this kind to his examiners; bewould not be understood. No; but let himtake the internal maxillary artery, for exam-ple, from its origin, follow it through all itsflexuosities, name all its branches, and enu-merate the anomalies to which it is subject,and he will be sure to receive unanimouspraise. If he were asked to describe thefunctions of the fifth pair, it is true that ht:would be sorely embarrassed ; but he candescribe the course of the corda tympaniwith unerring precision, and institute mostlearned antitheses between the thick andshort, and the long and slender branches.This factitious knowledge is just what iscalculated to make a brilliant show at ex-aminations. If it B.’ere even obtained bydissecting, something might be said in itsfavour ; but, in the majority of cases, ana-

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tomy is studied by plates, as geography bymaps; and, provided proof be given of acertain share of memory, the rest is of noconsequence. But to return; you see, fromthe uncertainty we feel respecting the modi-fications induced in arterial pressure, by thevolume of the blood, that all study on thematter has heretofore been neglected. Never-theless, there is no question more inti-mately connected with the practice of medi-cine. Whether you prescribe diluents, orremove blood by venesection, you alter themass of the living liquid in circulation, andhence produce, inevitably, certain mecha-nical results. We know that in many casesthe pulse becomes less frequent and strongafter one or more bleedings ; but practi-tioners are contented with the simple know-ledge of the fact, without looking for its

explanation. I am of opinion that we shallnever obtain really scientific notions on

these points, until a totally new view hasbeen taken of them. The modifications en-

suing in the frame are the consequences ofchanges produced in the volume and compo-sition of the liquids; hence the hydronamicphenomena of the body must be studied be-fore the vital.

Before quitting this subject for the pre-sent, allow me to bring to your recollectionsome experiments, elucidating the influenceof agencies, of quite a different character, onthe pressure of the blood. In those experi- ments, which were made on the venous I,trunks, we saw that the arterial pressure is ’,not modified by the physical condition of thetubes, or of the contained fluids alone. Weascertained that in the circulating system,as in the ensemble of systems, constitutingthe animal economy, vitality claims a sharein the regulation of the organic functions.Every moral impression and strong sensationreacts on the heart, and alters the rhthymand energy of its contractions. We allknow that anger and fright, for example,betray themselves to the bystander by thesudden change of colour in the features.According as more or less blood flows to-wards the capillary system the face reddens,or grows pale; it is justly termed the mirrorof the passions, because on it are reflectedthe modifications that occur in the vascularapparatus.

It had already been shown by M.Poiseu-ille, in the case of frogs, that any consider-able pain increased the internal pressure inthe vessels; I repeated the experiment, youwill recollect, on a dog, in order that youmight have ocular proof of the fact. Theanimal had already served us for some ex-periments, and, to save it the torture of anew operation, I made my observations onthe eighth pair, which was bared by awound exposing the carotid. The sensibi-lity of the pneumogastric nerve is, youknow, far from being exquisite. When Iraised it on the director this fact appeared

very distinctly, for the dog gave no evidenceof feeling the contact of the instrument,Indeed, as I have already had occasion fre.quently to observe, the sensibility of thatnerve is extremely variable. You will not,in all probability, find two species amonganimals, nay, two animals of the same

species, in which the eighth pair possessesa perfectly identical share of sensibitit;.In some it is enough to touch the nerve toexcite cries and convulsive movements; iuothers you may irritate, and even lacerateit, without the animal appearing to be con.scious of what you are doing. It is a stillmore curious fact, that the sensibility of thetwo nerves differs in the same animal. Youmay cut the vagus nerve on one side, and nosign of suffering be manifested; whereas,if you divide its fellow, the section deter.mines all the symptoms of acute pain, Iknow not on what this difference depends;but, in fine, the nerve under considerationmust be esteemed to be endowed with onlyslight sensibility in the dog. I made theexperiment under the idea that the varyinglevel of the mercury would point out moreaccurately even than the movements of theanimal itself, the degree of sensibility of thenerve.

The scale, previous to the experiment,marked from 20 to 22 millimetres; the respiration was regular, and performed withfreedom. I compressed the nerve with apair of forceps ; no evidence of much feelingfollowed ; the animal remained quiet. On

increasing the pressure considerably, hestruggled violently, and the mercury rose to

35, 45, 38, 40, 35 millimetres ; but I was ata loss what share in the elevation I shouldascribe to the contractile force of the heart,and what to the movements of expiration.It was certainly possible that the ascent ofthe column was more immediately causedby the play of the respiratory organs thanby the increased impulsion of the heart.However, you know that pain borne insilence acts quite as powerfully on the cir.culation in men, as when accompanied withthe most noisy demonstrations; frequently,indeed, stifled suffering deranges the func,tions of the heart to a greater extent thanthat which is clamorously expressed, with-out any attempt being made to struggleagainst the instinct that causes us to uttercries when suffering physically. Nothingof this kind was, of course, to be apprehended in the case of the animal on whichI experimented ; he cried out when he feltpain, and ceased to do so when he ceased tosuffer. His arteries, indeed, complicatedthe problem I was trying to solve, and prevented me from forming an accurate esti-mate of the energy of the ventricular fibre.On repeating the compression of the nervethe column rose, though the animal did normake any considerable struggle; now itstood at 30, 28, 35, 40, 37, 43 millitnetree,

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The pulsations of the heart became frequentaud tumultuous ; the stethoscope, appliedto the precordial region, transmitted distinctshocks to my ear, which were audible evenby the persons surrounding the animal.The respiratory movements became accele-rated, so that it would have been impossibleto draw any rigorous conclusion from this

experiment, had not its results been con-firmed by a crowd of previous observations.I finished by dividing the nerve. At theinstant the section was performed the animalmoved slightly, and the mercury rose a fewdegrees. All then became calm, exceptthat the respiration, as a matter of course,grew difficult, because the eighth pair pre-sides over the function of the pulmonaryapparatus. The surface of the column

stood, with little variation, between 20 and22 millimetres.

I followed up this experiment by inquir-ing into the influence of galvanism in thisway. It is my wish, as far as possible, toperform perfectly new experiments, for bydoing so both you and myself are equalgainers. Every one knows the sensationdetermined by the contact of the electricspark; but no one had thought of studyingits eflects on the general circulation, thoughit was plain these might furnish a curioussubject for investigation. I drove two pla-tiua needles into the animal, one into thecervical region, the other into the middle ofthe thigh. The two poles of the battervwere brought into communication withthese needles, so as to produce an electriccurrent through the tissues. The plan ge-nerally followed in practice is to apply theconducting wires to the surface of the inte-guments, and so induce a sudden commotionof the whole frame. In pathological casesI prefer electro-puncturation by means ofneedles placed in the course of the nerves ;l’am, in this way, more certain of the actionof the electricity, especially as I can limitit at pleasure. In the instance I am speak-ing of I made use of only ten pairs, lest thebattery should be too strongly charged.They were quite sunicient to produce aspowerful an effect as was desirable. Themoment I touched the needle with the wire,the animal gave a convulsive start, rapid aslightning, and the mercury rose a! the sameinstant to 55 millimetres. The rapidity ofthe ascent was so great, that it could notpossibly be ascribed solely to the efforts ofthe animal. Something must have actediubtantaneously, and directly on the walls ofthe vessels.We may conjecture the phenomenon to

be explicable as follows:&mdash;Muscular actionfavours the passage of the blood into theveins, as is clearly shown by the accelera-tion of the flow of blood from an openedvein at the bend of the elbow, by the move-ment of the muscles of the forearm. Now,if the muscles exercised energetic pressure

at the same moment on the entire venoussystem, the force of progression of the cur-rents of blood would increase to an enor-mous extent. This is, I fancy, just whathappened in my experiment. An electriccurrent traversed the tissues, and the coatsof the arteries and veins being pressed onall sides, pressed, in their turn, on the liquidthey contained. All authors who havewritten on tetanus, have described the pulseto be tense; hard, and vibrating. I have nodoubt but that these peculiarities depend onthe pressure exercised by the blood on thewalls of the vessels. To prove this experi-mentally, we should apply the haemodyna-mometer to an animal poisoned with nuxvomica.An equally curious phenomenon, bearing

on the present question, was some timepast observed by M. Poiseuille, in thecourse of his researches. A dog had beentightly attached to a table, to serve for someexperiments on the pressure of the vessels.The instrument was applied, and the mer-curial column stood at rest in its interior.Suddenly the mercury rose several inilli-metres without the animal’s having madeany considerable movement, or very deepinspiration. To what, think you, was thissudden ascent owing ? To a sudden

twinge of pain? ’? No, Gentlemen, far frombeing caused by a disagreeable, it was pro-duced bv an erotic sensation. The fact is,that a bitch in heat was at that momentbrought into the room, and her presenceawakened in the animal the instinct ofcopulation. It was a moral impression, andnot physical suffering, that, in this instance,modified the circulation of the blood.’ But to return to our more immediate studyof the properties of the blood in the humansubject. There is at present, Gentlemen, inmy wards at the Hotel Dieu, a young fe-male, aged nineteen, whose parents forcedher, two years ago, to marry againsther will. The consequence has been the

development of violent hysterical symptoms.The paroxysms occur frequently in the courseof the day, and while they last the patientsuffers under frightful delirium, and the

strangest hallucinations. She fancies shesees her mother approach to strike her ; hercountenance then expresses horror and af.fright ; at one moment she appears to try todefend herself, at least some broken wordsseem to indicate this ; at the next she turnssuppliant, implores her tormentors to spareher, and, bursting into tears, throws herselfinto the arms of the persons about her. Itwould, I think, be impossible to render withmore fidelity and expression the differentsensations she experiences. The most con-summate actress could not equal her in thevarying play of the physiognomy, on whichone may read in turn despair, dejection, andgrief, so truthfully depicted, that one longsfor the skill of the painter. This poor pa.

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tient fancied that loss of blood would relieveher. Aware of the influence of the moralover the physical being, in affections of thiskind, I yielded to her desire, rather to sa-tisfy her, than from any conviction of theefficaciousness of the proposed remedy. Hereis the blood extracted ; the serum is to theclot as 37 : 26. The proportion of the for-mer is evidently very considerable ; and, inaddition, the consistence of the clot is but

slight. Both agree in showing the existenceof a remarkable modification in the liquid.As I have already repeatedly told you, Ihave no intention of referring all diseases toan alteration of the blood. I am not a par-tisan of exclusive systems, and, therefore, Iwill not draw any inference, for the present,from the facts we now observe. I simplynote them as appearing very curious ; weshall, possibly, be glad to avail ourselves ofthem at a future period.

I now turn to a point which I consider ofsome importance, especially as a particularview respecting it has been strenuouslyurged in favour of the doctrine of inflamma-tion. I allude to what has been termed the

buff of the blood. It has been asserted (andamong others, by Rasori, in a long work onphlogosis) that this is the inflammatory ele-ment par excellence, and that it is never

wanting under certain given conditions, suchas during the existence of pleurisy, preg-nancy, &c. This notion, advanced perpe-tually, and defended in several thick vo-lumes, appeared to me to deserve seriousexamination. We should, above all things,seek for truth ; and, therefore, though I seenothing in the buff but so much fibrine, whichas it is lighter than the colouring matter ofthe blood, rises to the top and forms into amass, I would almost say organises itselfon the upper surface of the liquid,-still Iset about searching for this appearance inthe assigned conditions. With this view Ihad four or five gravid women bled at dif-ferent periads of pregnancy ; three of themwere affected with pleurisy, and yet in nota single instance did this buff show itself.Was the inflammatory element afraid to faceme? The fact is that I found no such thing,no matter how anxiously I searched for it.However, I should add that the modificationin the coagulating process, which producesthe buffy coat, depends on a variety of cir-curnstances. Thus, although inflammationevidently exist, if the opening made in thevein be narrow, or if its parallelism with thewound of the integuments be imperfect, andthe blood flows slowly ; or if the receivingvessel does not present a wide, and, accord-ing to others, a narrow, surface to the air,the buff refuses to show itself, and remainsconcealed within the cells of the clot. How-ever, I propose to continue vigorously myinquiry into this matter; for the service donethe science by overthrowing fallacious theo-ries, which interfere with its progress, is not

inferior to that of making useful dirce.verier.Here is another specimen of blond, drawn

some days ago, which has caused me con-sideralle embarrassment. It comes from a

young Savoyard girl, aged twenty-three, re-cently arrived in Paris. She was admittedwith some symptoms of the fever called eu.tero-mesenteric, or typhoid, such as injec.tion of the conjunctiva, general uneasiness,pro&tration, colic, and vomiting. Still theblood removed by a first and second vene.section seemed of a normal character; at

least, yon may see that the modification, ifany exist, is not appreciable. I thereforefelt uncertain about the diagnosis, and, atall events, I think the disease will not provedangerous. The blood shall also undergo aspecial examination, and the issue of theaffection will show if I have been in erroras regards the diagnosis.You remember, I trust, the case of the

female asphyxiated with the fumes of char.coal, whose lung we examined a few dayspast, and have not forgot tht- fluidity of herblood. I purposely return to her case, be-cause a singular phenomenon was ascer.tained respecting it after our separation. 1never before met with a similar peculiarity,not even in cholera patients. Her blood is

notably acid ; you perceive that it reddenslitmus paper. I cannot be sure that thischaracter proceeds from the entry of carbo.nic acid gas into the circulation, but ventureon this explanation of its existence, as aplausible hypothesis, worthy of further exa.mination. The exact analysis of the liquidmight, perhaps, give us some positive infor-mation on the point. We will try, at allevents.

In pursuing our study of the blood wemust constantly keep in view one fundamea.tal fact, namely, that the blood in the livinganimal is quite a different fluid from thatextracted from the body. Medical observersand chemists have, in general, paid too littleattention to this difference. By studying theliquid in the laboratory alone, they have in-creased the perplexity of many points, andin their statements almost all of them are atvariance with each other. In truth, there isa vast difference between the fibrine while

circulating with the blood, and when sepa-rated from that fluid. Besides, the bloodpresents itself in two very distinct conditions,even when removed from the body. In somecases it forms a compact mass, its superiorsurface being of a bright-red colour, thelower part blackish; in other instances it

separates into two perfectly distinct parts,- one solid, called the clot; the other liquid,known as the serum. Although our meansof investigation cannot be made applicableto the blood, except when removed from thebody, nevertheless we will improve on thosewho have preceded us, by not confoundingit with the fluid that traverses our organs.

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It is from this view of the subject, and onjust grounds, that very meritorious observ-ers, among others Professor M&uuml;ller, ofBerlin, have distinguished the liquor sangui-nis that circulates in the vessels, from theliquid which separates from the blood whenextracted from the body. Thus, when weexamine such vessels of an animal underthe microscope as are sufficiently transparentfor the purpose, we distinctly perceive aninfinite number of globules, borne along bya rapid movement, rolling and slipping overeach other; and we see, besides, betweenthe mass in motion, and the walla of thevessel, a space almost destitute of globules,and filled with a colourless transparent fluid.This fluid is the liquor sanguinis, whichholds the globules in suspension duringlife. It is probable that, by examining theblood while performing its various offices,we should succeed in discovering some ofthe phenomena of its organic composition.Unfortunately such study is rendered almostimpossible from the absence of favouringcircumstances; we are reduced to verylimited observations on small animals, inwhich some of the organs are transparentenough to allow the eye to follow the dif-ferent movements, and catch the form of theglobules under the microscope. Very youngrats and mice, and bats, are almost the onlymammiferous animals on which these expe-riments may be made with any success. Atthe present moment the rigour of the seasonhas benumbed the latter animals,and I havenot been able to procure any. It is impos.sible to conceive why the phenomena of theintimate composition of the blood are enve-loped in such complete mystery : it wouldseem as though Nature took pleasure in hid-ing their essence from us, precisely becauseit is a matter of such paramount importanceto comprehend it. The liquor sanguinis is,no doubt, in reality serum, but serum whichholds in suspension, or in solution, the

coagulable matter or fibrine of the blood.Fihrine, by.the way, is an improper term, andought to be replaced by coagitline; this is,possibly, not unobjectionable, but it would,at all events, prevent us from confoundingunder the same denomination two differentsubstances, the fibrine of the blood, and thefibrine of muscle. Chemists fall into a pal-pable error in regard ing these two princi-ples as identical ; and the proof that theyare not so, in addition to the absence of re-semblance in their physical properties, is,that compared in respect of their alimentaryqualities, they differ widely. I have demon-strated, by direct experiment, that the fibrine of blood is but slightly nutritive, whereasthat of muscle is extremely so. The serum,again, is the liquor saizguinis deprived of itsfibrine ; the latter becomes organised, differ-ing herein from the albumen of the blood,which always forms into an amorphous massUIIder the action of heat and the acids. When

removed from the vessels part of the serumsolidifies, the rest remains liquid. Such isnot the constitution of the circulating fluid.The study of the clot presents similar diffi-culties. In the living blood, as it might becalled, there is a liquid holding particles insuspension ; but if you receive some of thisblood into a vase, a clot will form and theglobules disappear, while within the vas-cular tubes they move in the midst of a vis.cid liquid, endowed with properties withwhich you are acquainted. In a vase poli-diGcation takes place : one of the elementsof the liquid, the fibrine, becomes organ-ised, and imprisons the globules in its cellu-lar structure. In the living subject theserum contains the globules and fibrine insuspension; removed from the body thatliquid bathes a clot composed of fibrine andglobules.

Here, then, are points of material differ.ence. Still, of the two parts, the serum andthe clot, into which the blood separateswhen out of its natural tubes, examine thelatter, and you will tind that the liquid dis-solves the globules. The fibrine will aloneremain, and you will be astonished at itsminute quantity, compared with the dimen-sions of the clot, and the enormous numberof globules it contained. The fibrine, whichmight be termed the basis of the clot, is, iuthis isolated form, worthy of the most seri-ous attention. It, alone, is at once the causeand the agent of the solidification of theblood. The latter is one of those pheno-mena placed on the confines of vitality andphysical endowment, and one which might,in a certain sort, be compared to the sym-metrical transformations undergone by mat-ter called crystallisation. However, thesetwo kinds of organisation must not be con-founded ; if you examine one of thesemasses of parenchymatous fibrine under themicroscope, you will detect a regular con-formation in it resembling the forms assum.ed by organised matter, such as ramifica-tions and areolae, intermingling and anasto-mosing in an infinity of ways. The clot,then, the insula of the ancients, must not belooked on as inert mass, but as a fibrinousarborescent matter, forming the basis of afinely and delicately organised parenchyma,and differing essentially from the albumen,the solidification of which is the simple re-sult of a chemical or physical agency. Butthe functions of the fibrine do not stop here.It is to be found again, with the same chaoracters, in the coagulum that obliterates di-vided arteries or veins : it is to be traced inthe formation of adhesions, of false mem-branes, and of cicatrices; and it is t) beseen deposited in layers at the surface ofsolidified wounds. Under all these condi-tions it is organised ; its arborisations are

converted into pseudo-membranes, and thesefalse membranes become canaliculated, form-ing vessels permeable, in their turn, by the

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liquid that produced them, and of which !,they originally helped to constitute the sub-stance. ’

Much has been written on the cicatrisa-tion of tissues divided by the cutting instru-ment. The growth and adhesion of granu-lations, the effusion of coagulable lymph,and the organisation of new vessels, have all of them given rise to important researches. One thing remained to be done, namely, toexamine the influence of the composition ofthe blood on the rapid or slow, complete orincomplete, formation of cicatrices. Now,the animals I had defibrinised were welladapted for experiments on this point. Ichose a dog for the purpose, from whom Ihad successively removed several portionsof fibrine (this, by the way, is an experi-ment to which I shall call your attention at Ia future period) ; he was greatly reduced Iin strength ; still he was not so much pulled Idown as to be unable to survive an opera-tion. I made a longitudinal incision throughthe skin and some depth of muscle in theanterior and middle part of the neck. Theblood that escaped from the divided vesselsappeared more liquid than usual ; it did notcoagulate on the blade of the bistoury. Iunited the lips of the wound accurately bythe twisted suture, and the animal was leftto himself. He died yesterday evening,having survived the operation a few daysonly. Here is his body, which I now pro-ceed to examine. We may, before begin-ning, indulge in a few conjectures, as weshall be enabled to verify them immediately.The main question is, did union by the firstintention take place? Opinions might be di-vided on this point. For my part, I believethat such union was impossible, because theblood contained no fibrine, and had, there..fore, lost its power of solidification. I ex-

press my opinion thus distinctly and unre-servedly, because, even if it be erroneous,it cannot leave any wrong impression onyour minds, as the autopsy will at once cor-rect it. I now shave away the hairs sur-

rounding the wound. The blood, which hadby its desiccation glued its lips together,masks their appearance, and prevents usfrom seeing if they have really united. How-ever, if I may judge from what I can alreadyperceive, there is no real adhesion. Thetissues are discoloured, dry, and hardly atall swollen. In the situation of the pointsof suture, there are, no doubt, a few cellu-lar bands; but these are rather isolatedfalse membranes, than an exact adhesion ofthe two surfaces of the solution of conti-nuity. The cicatrisation of the wound, there-fore, could not be accomplished ; and every-thing seems to show that, if the fibrine hadbeen completely withdrawn from the blood,there would not have been any points evenof apparent union. You will often see

wounds of bad character in the hospitals,which remain stationary for weeks or months,

resisting all the efforts made to hasten theirprogress to a cure. We may dress themwith stimulants, cover them with powderedbark, sprinkle them with the chlorides, butall in vain ; no improvement follows. Thecase alters when, as is sometimes done,leeches are applied in the neighbourhood;the effects are then soon perceptible,&mdash;butwhat are they ? ? The rapid extension of theulcerated surface both in length and depth !But let the patient be placed in favourablehygienic condition ; let a strengthening dietreplace that to which he had been confined,and his strength returns; his face regainsits colour; the wound assumes a vermillionhue, and advances quickly to cicatrisation.The consequence deducible from these factsis too evident to require me to expatiate onit. Do you not see that the therapeuticalmeans employed were useless, so long as

they were calculated to act on the solidsalone, but that they at once became effica.cious when the liquids had been modified’The explanation of this is simple, As thesolids draw from the blood the materialsproper for their cure, they continued in adiseased state, so long as that liquid wasitself altered, and could not furnish thosematerials. From the moment its normalcomposition was restored to the blood by asuitable regirnen, there was nothing to im.pede cicatrisation.

I made another somewhat similar experi.ment on this animal. I tied a large vesselwith the intention of examining it after acertain time to see if a coagulnm was formed within it. It is not very uncommon toobserve recurrence of haemorrhage after thefall of a ligature ; and it seems possible thatthat serious accident might be prevented,if ifwe had more accurate notions on the coagu.lability of the blood. I consequently applied a ligature to the right carotid; let ussee if it is obliterated in such a manner as

to be capable of resisting the heart’s im’pulse. I cut away a piece of the artery, inorder to slit up its walls, and examine itsinterior with gteater ease. You see thatthere is no trace of coagulum; for I cannotgive that name to a few granules which lieon, without adhering to, the internal mennbrane of the vessel. The ligature had al-ready nearly cut through its walls ; had theanimal survived a few days longer secondaryhaemorrhage must have taken place.This rapid view of the subject will allow

you to form a notion of the importance of thestudy of this organisable material, whichreconstitutes, reproduces by itselfalone, allthe tissues of the economy. We will pushour researches respecting it as far as possi-ble, and shall probably obtain results, bothof a physiological and therapeutical kind,more precise in their character than those

we now possess.! I have now to inform you of the presentcondition of some animals submitted to va-

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rious experimental treatments. All these

experiments refer to questions of the deep-est interest, such as, among the rest, the re-lative proportion of the serum and clot. Inthe blood of a healthy and robust male theserosity may be estimated as forming a fifthor a fourth of the whole; it abounds withtibrine and globules. In women and chil-dren the serosity constitutes one-third of themass. But these proportions vary accord-ing to the age, temperament, and species ofnourishment of the individual, as well as avariety of other circumstances. My objectis to determine what proportion between thetwo elements is incompatible with the con-tinuance of life. This is an experimentalproblem completely. In the hope of solvingit, I have placed different animais in circum-stances fitted to give useful indications re-specting it. We know that successive bleed-ings, closely following each other, augment the proportion of serosity, and induce vari-ous disorders, and finally death. I havesubmitted one animal to this species of treat-ment. The quantity of serum increases also,from the abundant use of drink; at least,this is a notion generally admitted by medi-cal men. But once again, we are remindedthat we must not prejudge results; our pro-phecies are constantly exposed to be provedto be false. Here, for example, is an expe-riment well calculated to make us cautiousin this respect. I have had two ounces ofblood taken from the animal before me everyday, and replaced by an equal quantity ofdistilled water. I fancied I should havehad to present you a specimen of blood richin serum, and containing a small proportionof clot. The reverse is, however, the truth ;it contains, to all appearance, scarcely anyserum. I presume, however, that the serumis really augmented in quantity, but thatsome cause or other prevents us from appre- Iciating its increase. Perhaps it is retainedin the substance of the clot. A third ani-mal is also bled daily ; he is given plenty toeat, but no drink. At the second bleedingthe serum was found increased in quantity,and it had, besides, lost its limpid appear-ance. A fourth animal has abundance ofdrink, but no solid food ; his blood containsas much serum as clot. Here is the productof the seventh venesection practised on theanimal about which I have already morethan once spoken. Although he eats anddrinks as much as he likes, his health ismaterially affected ; a notable change hastaken place in his gait, habitudes, and tem-per. The mucous membranes have grownsingularly pale,-a peculiarity which hasbeen long noted by veterinary practitionersin appreciating morbid symptoms. Whenhe is bled now, syncope follows. I have nodoubt but that an affection of the lungs willsoon come on, and speedily put an end tohis existence.Finally, here is the subject of an experi-

ment of a different kind. I injected somefrog’s blood, the globules of which areovoid and provided with a central nucleusinto the veins of this little animal. I amanxious to see whether they will becometransformed, so as to acquire the charactersof the globules of mammiferous animals.The subject of the essay is, as you perceive,in good health, and does not appear in anyway affected by this new species of trans-fusion.

UNIVERSITY COLLEGE HOSPITAL.

ABSTRACT OF LECTURESON THE

EXCISION OF JOINTS;BY MR. LISTON.

Delivered October, 1838.

LECTURE I.THIS was the first clinical lecture which

Mr. Liston gave this session. He said hehad few opportunities of’meeting the stu-dents as a lecturer; there was, indeed, littleencouragement for him to do so, exceptthat feeling of pleasure and satisfactionwhich every one must experience in the im-parting of knowledge to others. No kindof instruction was equal to clinical instruc-tion, in which the pupil might see practisedthat which was described to him. But forthe full benefit of clinical teaching, it wasnecessary that the cases should be recentand fresh in the minds of the students ; oldcases raked up, after a long period, werecomparatively useless. The subject he hadselected for the present lecture was that ofdiseases of joints, a variety of which caseshad lately been in the hospital. The diseaseof the joints requiring resection or amputa-tion, might occur in a variety of ways, in allor any of the tissues entering into the for-mation of the articulation; or it might bethe result of injury to the soft parta in theneighbourhood ; thus injury of the knuckle,or a bruise, might be followed by abscessesforming along the member, and the articula-tion become diseased. The same fact heldgood with respect to the larger joints; thedisease, however, in these instances, gene-rally commenced in some part of the appa-ratus of the articulation itself. The signsand symptoms of disease, as affecting thedifferent structures, were, at the commence-ment, generally sufficiently distinct ; Lutafter a time the whole of the structures be-came involved, and the signs, of course, al-tered. The disease most frequently com-

i menced in the synovial membrane of thearticulation, and was of a chronic charac-ter. In this case there was often so much

swelling, that the form and exact situationof the joint was, with difficulty, ascertained .Sometimes, particularly in the knee and