= ■ j{- '■ ■-• ■ ■ ;if^TipV ^v;''$" :---^if:' ;-:^i''::': ^>'"---':.. '. --SfliM *y?5$!fe4f ■••■ \:-yl--- "i i;\' i • f V-y'•• ■ ■ ■■-■ NATIONAL LIBRARY OF MEDICINE Washington X CHARLES BELL'S SYSTEM OF DISSECTIONS. A SYSTEM OF DISSECTIONS, EXPLAINING THE ANATOMY OF THE HUMAN BODY, WITH THE mnmt of 2Dtgpfa?tngti)e gmn> THE DISTINGUISHING THE NATURAL FROM THE DISEASED APPEARANCES, And pointing out to the Student the objects most worthy of attention: BURLYGA COURSE OF DISSECTIONS. VOLUME I. BY CHARLES BELL. First American from the third London Editioi}. BALTIMORE: Published by Samuel Jefferis, No.312, Market-Street. P. Mauro, primer. 1814- .. - £o\zl TO THE GENTLEMEN ATTENDING THE MEDICAL CLASSES IN THE UNIVERSITY OF MARYLAND. IN reflecting upon the manner in which a young man should pursue the study of physic, it has appeared to me that much more error and confusion have arisen from the hasty and indiscriminate manner in which the different branches have been at- tended to, by tlje greater number of stu- dents, than i'rom want of talent or of that preliminary education so essential to the correct comprehension of any of the scien- ces. Instead of commencing by studying attentively the elementary principles* which vi constitute the basis of that science so impor- tant to them, because contemplated as form- ing the future occupation of their lives, they launch at once into the more abstiuse and complicated branches, of which no man can have a clear conception, unless he has pre- viously acquired an intimate and correct knowledge of the structure of the human body, In the ordinary course of medical prac* \ice we meet with many diseases which would be wholly unintelligible to the physr cian, unless he were accurately acquainted with anatomy. It is therefore sufficiently evident, that a minute knowledge of the structure of the human body, will be high- ly important to you even after you have completed your studies. But this species pf Knowledge will appear still more impor- tant when viewed as connected with your peculiar situation, In this country the de- partments of medicine and surgery are not separated from each other and occupied by different persons as in Europe, but are If qui certain local causes, so completely in- vii terwoven, as to render it necessary that the same individual should perform the du- ties of both. If, therefore, a knowledge of anatomy be an essential preliminary to an accurate view of medical diseases, its im- portance must rise still higher in your esti.. mation, when you recollect that you will be compelled to combine, with the knowledge and judgment of a physician, the duties and qualifications of a surgeon. For these and other reasons of a similar nature, I have been induced now to recom- mend to your notice, this small work, writ, ten expressly for the purpose of facilitating the study of anatomy, and composed by one, who stands so pre-eminent in the pro- fession, as to require from me no eulogy* His numerous works testify his merit, and will always remain a lasting monument of the genius and erudition of their author. Thei( System of Dissections" was first pub- lished in the folio form, and the observa- tions illustrated with splendid engravings. After having undergone two editions, it was vin conceived by the author that the work, aln though in the hands of most medical mem could not be rendered, from its expence, so extensively valuable to students, for whose use it was for the most part original- ly intended. He was therefore induced to bring forward a third edition in two small duodecimo volumes, and he was encouraged in this determination from having observed, that several small works were published not only upon his plan, but containing mat- ter peculiar to the " System of Dissections," and that these works, from their size and cheapness, were eagerly sought after by students. The work now offered, is printed from the third London edition, and has never be" fore appeared in the United States. It was my intention originally to have added some notes and commentaries, but upon further reflection it seemed to me, that the work was in itself so truly interesting, valuable and free from fault, that any thing which I might be able to add to it, would not only ix be of little importance, but would be detri. mental by increasing the size of the book, and thereby the expence. As it is, you have it emanating from the author himself who alone is capable of improving or in. creasing its value. Upon perusal you will find, that he has not only shown you, the method of dissect" ing and learning the anatomy of the body in all its forms and bearings; but that to this he has added valuable and important observations on the diseases, both medicai and surgical, of the different organs \ and along with these the morbid anatomy and pathology of each part. In every point of view, " The System of Dissections" is to be considered a truly original work, and one invaluable to the student of physic. It may be supposed by some of you, per- haps, that I recommend this work to your attention, from partiality or prejudice, from my having been educated under the care and direction of the author; but I dis- X claim all such Incitements as tliiesc; for although I have a thousand motives for re- collections of a friendly nature, or for bene- fits conferred on me, yet rest assured, that as my only object is your improvement, so I shall never offer you any advice, but what I may conceive to be the best and most useful. I remain, gentlemen, Your sincere friend, WILLIAM GIBSON. Liberty street, December 4,181S. PREFACE. IN the study of every science, it is ne- cessary to present to young men such gene- ral views of the subject as may give them a lively interest in the pursuit; direct their inquiries to the points of real importance • and confirm in them manly and steady re- solutions to persevere in learning the details and minutiae. These details, though in themselves disagreeable and tedious, are absolutely necessary ; and no one who aims at useful knowledge, will acquiesce in gene- ral views, without endeavouring to follow up and complete the investigation, by study- xu ing the details from which they ought to follow, as legitimate conclusions. In no department of science is attention to these two parts of study more indispen- sable, than in Anatomy; for while the details are intricate, they are often individually of the most serious importance to the life of man; and the general result, the economy of the human body, considered as a whole, is highly eurious and interesting. The common elementary books are often represented as sufficient for the student, and as comprehending the whole of Anatomy. But the object of such books is not practi- cal anatomy, by which is to be understood the investigation, and knowledge of the dissected body. The descriptions are not adapted to the limited and successive views which in dissection we must have of the parts : they cannot be implicitly followed as guides. On the contrary, the anatomy of the parts implicated in a great operation, xni must be collected from different parts of the work—muscles from one place, blood-ves- sels from another, and nerves from a third. The descriptions too, will often be found insulated, and defective in such views as can give a lively interest, or any knowledge of the mutual dependence of the parts* Now it is quite right that elementary books should contain simple introductory and connected views ; but the fault lies with those who would apply such works to wrong uses. From the arrangement necessary to their plan, the descriptions cannot be im- mediately compared with the dissected 'body. Dissection is the study of anatomy in the detail; and in books subservient to this study, more attention should be paid to the relative situation and contrast o"l parts, than to general views and rapid de- scriptions of the vessels or nerves. Thus. more general and connected compends are essentially necessary, but they are to be Vol* I, B XIV taken as merely introductory to the study of anatomy by dissection. That the common books are not fitted to be assistants in dissection, every one must allow who has taken the knife into his own hand, or been attewtive to the operations in a dissecting room. He will soon learn that in dissection it is not the want of minute description that is so much to be deplored, as the want of arrangements and plans on which to proceed. How often is it found that young men who have begun their ana- tomical labours with a sincere conviction of the importance of the study, and with the most determined resolution to combat all difficulties, have, for want of plan, gone to work in a manner so disorderly, that they have been soon bewildered, and forced to re- nounce in despair a pursuit which, with their views better directed, would have been easy and certainly most valuable to them. XV The object of this work is to assist the student in acquiring a knowledge of practi. cal anatomy; in gaining a local memory of the parts ; in learning to plan them on the dead subject; and in representing them to his own mind upon the living body. In ac- complishing this design it has been my ob. ject to present an ai'rangement adapted to the purposes of dissection; to give a short but a preeise and accurate detail of the anatomy; to show how the parts are to be laid open, and how they are to be dis- tinguished in dissection or avoided in oper- ation ; to explain the consequences of each part to the great functions of the body, and to mark the diseases to which it is liable, and the appearances which characterise that disease. It has been my principal object to direct the thoughts of the dissector to matters of practice, being well convinced that the questions of practice are for the most part XVI best discussed when the dissected body is before him. For the execution of a plan of so much importance, much allowance must be made, for the subject is extensive and difficult, and the illustrations are to be drawn from the whole range of the science. A small volume has been lately published 'On the plan of this system of dissections, and the author has endeavoured to incor- porate in it much of what is peculiar In this work. The sale of that volume has proved that the folio size is at least very inconve- nient. It has therefore been thought right to print this edition in a portable form. With many alterations and amendments the author offers this third edition to the student of anatomy, hoping that, if the cheaper and more portable form of the book may at first attract attention, he will in the xvii perusal discover that there is something more in the science than can be taught by books, or than can be contained at least in a pocket volume; and that he will find his first studies facilitated, and the importance of a further prosecution of the science enforced. London, 11, Leicester street, Leicester square, October, 1809. B2 mxrtmtutu Dissection consists not merely in the management of the knife ; it implies also a knowledge of the methods of injecting and preparing the parts, of in- vestigating the structure of the viscera, and of present- ing them for demonstration. For this reason 1 shall enumerate here the chief circumstances to be attended to as introductory to a common couisc of dissection, that they may be concentrated, and the anatomy freed from needless repetition. Practical anatomy, like all arts in which an aptness and dexterity ol|the hand is necessary, is to be acquired not hastily, nor by pre- cept ; but an ease and certainty in its operations can be attained only after much labour. All therefore which is necessary at present, may be said in a few- words ; and I shall, in the first place, give some ad- vice on the management of injections, and the means employed for facilitating the dissection and demonstra- tion of minute parts, and then point out the course of study to be pursued in the dissecting room. Of injecting.—Injections have led to many use- ful discoveries Jin anatomy ; but it is to be regretted, lhat experiments in the dead body have been too hn- I licitly trusted to, in accounting for the functions of living bodies. Physiologists seem, indeed, to have heroine bolder in the extravagance of their theories, XX relying on supposed proofe *by injection. Yet in spite of every disadvantage, the art of injection has contri- buted to the rapid advancement of our surgical know- ledge. In the choice of the subject, the bodies of young persons are to be preferred, as much fitter for the injection of the arteries, and for minute injection: for while their blood-vessels have an elasticity and strength which enables them to bear the push of the injection by a kind of elastic resistance they give warning of the danger of rupturing the coats. In injecting the bodies of old persons, the piston of the syringe goes at first easily down, then stops, and if forced, most probably bursts the vessels, driving the injection amongst the muscle-., and confounding the dissection. When any of the trunks burst in this way, the tension being ta- ken off, their coats contract upon the warm injection, and they remain half tilled. In old age, this want of elasticity becomes vcrv re- markable. There is often a kind of stiffness and rigidity, as if the co;its of the vessels were corrugated ; a degree of that state in which we find the aitciies when ossified, or when concretions are formed in their coats. If only some coarse injection is to be thrown into the great ve -els to shew their course, it does not much signify how it is clone, or what injection is used, or what means are employed to facilitate the passage of the injection. But if the vessels are to be injected minutely, it is necessary previously to heat the subject well, by laying it in warm water, or ap- plying steam to the surface. This is of more conse- quence than even the choice of the subject ; for, as t;ie injection is intended to be fluid when warm, so as to pervade easily the minute vessels, and upon becoming cold to congeal and remain solid ; it is necessary that the vessels be heated to prevent the sudden chilling of the injection : be ides this healing XXI of the body softens and relaxes all the mass of flesh, and brings it to a more suitable state for admitting in- ject ion. But it ought to be remembered, that, if the paits be overheated, especially where the vessels to be injected lie exposed, there is danger of corrugating the coats of the vessels, and making them quite triable and tender. The common practice in the injection of the great vessels, is, to take first equal parts of brown and white spirit varnish, coloured with the same paint that is used for the coarse or wax injection; and this fine varnish injection, being moderately heated, and thrown in before the wax injection, clears its way, and moderately heats the vessels, so that they do not rea- dily cool or retard the wax injection which is to fol- low. Even when using minute injection (which is size, coloured with vermilion) for the purpose of de- monstrating the minute vessels, although the hard injection is thrown into the vessels after it, simply to htop the regurgitation of the warm and liquid size, and to retain it in the minute extremities of the ves- sels, yet it happens that the wax injection runs very minutely in this way. Size injection is the least ex- pensive, runs more minutely, gives always a chance for beautiful specimens of minute injection, and can be pushed to any quantity, even till the skin of the limb becomes quite tense, without rupturing the vessels, or those vessels at least by which the coarse injection. can escape. By this means, the vessels are dilated, the limb made warm and moist, and the wax injection flows easily into the arteries, whilst the size es- capes with the slightest piessure into the cellular tex- ture. Care ought to be taken to exclude air and water iiom the arteries previously to the injection, least they should retard it, or break the continuity of the wax in the arteries when cold : but often, upon an emer- gency, equally good injections of the arteries may be made by throwing in abundance of warm, water be- XXII fore the wax. This, however, is not a practice to be followed; only it shews that it is rather the mixture of water or air along with the injection in the syringe, which is to be avoided ; for, in that case, they will certainly be mixed in the vessels, and, upon cooling, the wax will be found broken and interrupted. As to the veins, on the contrary, if there be any air or water in them previously to throwing in the injec- tion (at least in the extremities, where, on account of the valves, it is necessary to inject from the branches towards the trunks), the injection is then confined to the great vessels ; and the air or water, not being al- lowed to escape by exudation, must remain interrupt- ing the wax. The most eflectual way of avoidirg'the mixture of air with the injection in the syringe, is, after having drawn it full, to hold up its point. This allows the air to rise to the top; and before introduc- ing the nozzle of the syringe into the pipe, the pis- ton should be pushed gently, till the injection appears at it. Of the Injection of Veins.—The success of the injection of veins depends entirely upon their being well washed with warm water, and repeatedly dilated, as they are for the most part foul with coagu- lated blood, especially in o d, people ; although, in other respects, the veins of old subjects are in the best state for injection, being enlarged and varicose. The coagula must frequently be drawn out of the mouths of the larger veins befoie introducing the tube.5 If the veins of the thigh and leg, for instance, are to be injected, the tube should be fixed in a small vein upon the fore part of the foot, near to the great toe ; and a stop- cock should also be fixed into the external iliac vein within Poupart's ligament. Then the blood must be washed out by throwing in tepid water from the tube atthe toe ; first, with the stop-cock open ; and after- wards when the veins are a litle cleared, the stop-cock at the top of the thigh is to be stopped, and the veins XXU1 a little distended, and the limb immersed in warm water. Before injecting, the veins must he completely empti- ed by opening the stop-cock, and stroking up the thigh. The coarse injection should be thrown in while the limb is thus completely warm, and without any fine injection being thrown in before. Dunne the injection, the stop-cock at the groin should be kept open, ond some one placed to turn it when the injection; appears at the mouth of the vein.—In this way, the air or water will be driTenfreely before the in- jection ; and veins which would otherwise remain emp- ty, will be filled ; for by the dilatation, the valves lose their power, become too small for the diameter of the vessels, and allow the injection to go backwards into the branches. In filling the arteries with coarse injection, when extravasation or rupture of the vessel happens, it seems strange that the rupture is commonly in the trunk, and not in the smaller branches, since we know that the strength of the larger vessels is owing to their greater elastic resistance, whilst that of the lesser arteries ari- ses from their muscular power which must cease in the dead body. But there is an obvious reason for this; the rapture of the arteries often happens from using the injection too hot ; and as the great heat of the injection is in part corrected before it gains the extre- mities, they are not effected by it; while the root or trunk of the vessel being perpetually exposed to the hot stream, its coats are corrugated, and burst. Be- sides, as the injection, when it cools, plugs up the smaller branches, the force .of a heavy and unwary hand is exerted upon the trunks, where the injection, being yet fluid, they are dilatable. Accordingly we find, that, in throwing in cool and fine injection, the rupture is always towards the extremities. I'Yoin all this it may easily be understood why at first the piston is to be pushed slowly and gradually whilst throwing in the fine injection ; insinuating the XXIV fluid into the more delicate vessels, which arc very easi- ly ruptured ; scarcely pressing at first, but allowing the piston to go down with its own weight, and gradu- ally increasing the force. The coarse injection again is to be thrown in with a smart push. This is the great delicacy in injection ; and to accomplish it without danger ofrupturing the vessels, is to be learnt only by practice. There are still other things' which require attention, viz. the tying of all the vessels that may have been opened, and the fixing of the tube securely in the mouth of the vessel. When the injecting pipe is in- troduced into the vessel, it cannot he retained there by a simple knot, without a chance of its slipping off during the injection, or, if tied firmly, of cutting the coats of the vessel. Therefore alter the ligature is drawn upon the artery including the tube, the ends of the ligature should be brought over the wings of the tnbe, and then carried round so as to include that part of the ligature which reaches from the mouth of the tube to the wing ; and being tied there, the former knot is at the same time tightened and the mouth of the artery drawn up upon the barrel of the tube. THE COMPOSITION OF THE INJECTION. Coarse Injections—The coaree injection is composed of the following ingredients : for good com- mon injection, tallow, one pound, resin, one pound wax three ounces, Venice turpentine, two ounces spirit of turpentine, one ounce. Or bee's wax, sixteen ounces resin, eight ounces, turpentine varnish, six ounces The' wax and tesin give hardness and consistency • and the varnish u added to give it pliancy. A coarser com- position may be made with tallow, wax, spirit of tur- pentine, and oil, coloured with the coarser pi^ts • „r simply tallow and red lead, maybe u-ej when the pari* XXV are not to be preserved. These colours are generally used : vermilion, king's yellow, flake white, smalt, verditer, verdigrise, lamp black. They should be mixed with the terpentine varnish, and then added to the wax when melted; the injections should always be heated in an earthern pot set in boiling water, for water will not take a degree of heat to injure the co- lour, and the chance of accident by fire, is, by this means much diminished. The injection should not be thrown into the vessels while too warm, for it will hurt their coats : the degree of heat should be such, that the finger can be allowed to remain in it for a little while. For fine injection to be thrown in before the coarse; equal parts af white and brown spirit varnish is commonly used. For minute injection, painters' size coloured and strained, serves every purpose; a finer size may be made of isinglass. An injection to be used cold, and which is well adapted for class demonstration, or where the dissection is intended merely to demonstrate the vessels, without preserving them, may be thus made;— take red lead and linseed oil, and mix them till they are of the consistence of putty, add a little turpentine varnish, then a little spirit or turpentine, lastly, just hefore injecting it, sprinkle a little water into the mix- ture and agitate it. This injection runs very minutely, and for preparations there may be added fine vermilion to heighten the colour. Preparations of bones.—It has already been observed, that the limbs or any part of the body, are easily dilated by the minute injection, in consequence of its escaping into the smaller vessels. This must in some measure be prevented when it is intended to dis play the minute vascularity of membranes and joints, and more especially the vascularity of bones ; for while the injection freely escapes into the dilatable cellulai membrane, it will never penetrate into the more rcrif' Vol.. 1. C *' XXVI ing parts, as the bones and cartilages, therefore, when a minute injection of the bones and cartilages is intend- ed, a bandage must be rolled from the toes to the up- per part of the limb, not very tight, but so as to restrain the enlargement of the muscles and cellular membrane by the force of the injection. In this way, the minute vessels are filled, yet little extravasation allowed ; for there is an equal resistance in the soft parts and in the bones, and the parts partake more equably of their na- tural proportion of the colouring fluid. By this pre- caution, the bones may be very successfully injected, so as to show the stages of ossification. And not in sound limbs only, but in cases of diseased bones, with open ulcerated surfaces, I have succeeded in the in- jection, by firmly bandaging the limbs ; when, other- wise, the injection would readily have escaped, and important morbid preparations have remained useless. The minute vascularity of a bone is to be shown, after injection, by a long maceration of it in diluted muriatic acid; which, by dissolving the earthy part of the bone, leaves the fibrous part (in the interstices of which the earth was deposited) flexible, and without any character of bone but the form. In this state, it is like cartilage, soft and yielding, but fibrous, and the vessels will not be more discernable than before. The bone is to be thoroughly dried, and then plunged into a glass of clear spirit of turpentine; when, as soon as the spirit penetrates the cells, the bone be- comes quite transparent, and the vessels easily distin- guishable, branching through its substance. In|cor. roding shells to show the glutinous basis in which their earthy part is laid, spirit of wine, with a little of the acid dropped into it, has been used, by which the delicate web is preserved, whilst the other parts are taken away. In the same manner, in the maceration of bones, when the maceration is expected to be tedious, it may be necessary to add spirit of wine to the menstruum to prevent the size in the vessels from being resolved xxvii and washed away.—The most beautiful preparation of bone is the simple section of the cartilage, or apo- physis, in young subjects, where the injection has run minutely, and while the nucleus of bone is still small and red with injection.!" This nucleous is seen hying in the middle of the cartilage, with the vessels crowding from the surface towards the centre, and terminatfng in the bone ; or perhaps only a small and delicate artery is seen pushing into the centre of the cartilage, and ter- minating in a point the beginning of a future bone. The cartilages in this state, when cut in thin slices, and suspended in spirits of wine, are beautiful; or when those slices are dried and suspended in spirits of tur- pentine, the cartilage becomes so transparent that it is with difficulty discerned in the fluid, ajnd nothing is seen but the nucleus of bone, with the arteries beauti- fully ramifying to supply it. Or the nucleus of bone maybe tinged by solutions of some of the metals in acid, while the cartilage will remain perfectly white. Such preparations may be infinitely varied, forming the most beautiful examples of the changes going on, not only in the bones, but, by analogy, in the whole body. The marrow, also, may be displayed, after injecion, by maceration in water; or by slitting up the cylin- drical bones, and preserving them in spirit of wine. When such a section of a bone is dried, and put in oil of turpentine, the vessels supplying the marrow bags, being collapsed to the side of the bone, are seen in great profusion. The structure of bone is demonstrated, independ- ently of injection, by maceration and burning. By exposing bones gradually to a red heat, and so placed that they may be equally supported, the animal part is burnt away, while the earthy part remains behind, a calcareous phosphat, retaining the figure of the bone, but deprived of its gluten and fibrous part, which gave it strength. This is just the reverse of what XXV111 takes place in the corrosion with the muriatic acid. In the one case, the animal fibre is burnt away, leaving the secreted bony part in its original figure ; in the other, the calcareous or osseous part is dissolved in the acid, the softer parts (which, when endowed with Kving properties, were capable of secreting this earthy part from the blood) remaining undissolved. These preparations, therefore, should be contrasted. If a bone is hurnt, and then put in acid, it is entirely destroyed. If, threrefore, after burning it completely, warm wax be poured into its cavity, and it then be corroded in acid, the cells will be elegantly cast in wax. For example, to make a cast of the intricate passa- ges of the temporal bone, with a view to demonstrate the cavities of the internal ear, we first enclose the temporal bone in Paris plaster, leaving open the mea- tus externus : then dry it thoroughly by the fire and heating it gradually, throw it into the fire. When the bone is calcined take it out and pour melted lead into the passage of the ear, lastly break, off the Paris plaster, and put the bone into the muriatic acid, and you have a peifect cast of all the cavities of the ear. Of Corrosions.—Corroded preparations arc the most elegant of all, but require great care. They are generally made of the injections of the solid viscera ; as the heart, lungs, liver, kidney, and spleen. Harder injection than common is required for these, and no minute injection need be thrown in before. If the in- jection succeed, the only other circumstance which requires care, is that we place the part while the injection is yet warm, as it is intended to re- main, and where the corroding acid may be easily applied. When the fleshy part is dissolved, it is to be gently washed away by the agitation of the water ; and it should not be attempted to be lifted out of the water till entirely freed from the parenchymatous matter, which, by its weight, might break the delicate branches. The menstrua are the XXlX muriatic and nitric acids ; the latter of which M. Sue found a more perfect menstruum, and less apt to af- fect the colours of the injection or minute vessels. Compositions of glass may also be used in making casts of many parts, as they admit of a great variety of transparent colours ; the soft parts and the bones be- ing hurnt away, while the paste is acquiring its glassy surface. Of wet preparations.—In preparing morbid parts, there are often appearances, curious and im- portant, which cannot be preserved. Often in ex- amining the parts, the colour is the only criterion by which the nature of the disease is to be determined ; and this it is often impossible to preserve. Recourse must be had to painting, to give the lively tints which alone remain of the disease, &c. But even here in- jections may be of much service, as a means of making the parts more beautiful or natural, and more exten- sively useful, by preventing that confusion which is so often found in wet preparations having no distinctions of colour. Even in organic affections of the heart, lungs, intestines, &.c. injection gives a splendour and consequence which the real importance of these parts would perhaps claim in vain ; and in preparing such parts, great expertness may be acquired in giving them natural or beautiful tinges, by injecting the ves- sels with coloured fluids. In preserving thick fleshy parts in spirits, it will be necessary to inject spirits into their vessels; which thoroughly pervading them, tend greatly to preserve them. Liquors for preserving preparations have been much boasted of since the time of Ruysch ; but to clean and unadulterated spirit of wine there can be no objection. It must, however, be diluted arcouling to the delicacy of the parts l^o be immersed in it. Sometimes when very delicate membranes are put up in pure spirits, they will be found next day shrivelled and shrunk up to the top of the jar : but by saturating XXX the spirits with sugar, they lose this property, and the membrane hangs loosely in the jar. The glasses con- taining such membranous parts should be allowed to stand some time before being finally closed : for though the membrane, being full of water, when first put into the spirits, hangs elegantly enough ; yet, when it has parted with its superabundance of water, and re- ceived the spirit, it will become so light, that it will swim upon the surface, and require little hooks of glass to be put to its lower parts to weigh it down.— Wet preparations often require to have the spirits changed upon them several times beforejthey are finally put up, to prevent the possibility o.f their tinging the spii its after they are closed : Or, perhaps, it may be necessary that the parts should be stuffed, or held out in particular postures, till they be so hardened, that they may ramain unsupported in the jar. For this purpose diluted muriatic acid and nitrous acid combined,is sometimes used ; or the diluted nitrous acid simply ; or a solution of alum and common salt. These give the parts firmness and strength to support themselves in the glass. Care must always be taken to macerate the parts well previously, and to free them entirely from blood. When delicate membranes are to be injected either with quicksilver or with fine size, instead of tying all the vessels by which the fluid may escape, I have found it necessary only to sear the edges of the mem. brane with a heated iron; or, after having fixed the tubes, the common method is to dry the edges all pound, while the middle part is kept soft and moist. When it is required to demonstrate the vascularity of a part where there is no opportunity of injecting it, if membranous, the blood may be detained in the vessels by quickly drying and varnishing it. The blood, when extravasated, or when (as in the piles) preter- naturally collected in vessels, may be coagulated by a solution of allum ; or blood inflamed parts may be XXXI coagulated by distilled vinegar. In other instances, as in preparations of the lacteals, their natural fluids may be coagulated and preserved by plunging them suddenly into stiong spirits. To demonstrate the rete vasculosum of the retina, a drop or two of solution of caustic alkali, may be put into the spirits, by which the matter of the nerve is dissolved or made transparent, when the vessels of the nerve make the most beautiful exhibition. Demonstration of minute parts.—There are many parts of the body "which it is impossible to keep for any time in their original beauty, and these the most dilicate and interesting ; as the organs of the senses, and all minute neivous parts, the villi of the intestines, the comparative anatomy of insects, the incumbated egg, &c. The ready demonstration of such delicate parts in the fresh subject is the truest test of the abilities of the practical anatomist; for there is more delicacy and nicety required in exposing these parts, and more real benefit to be derived from it, than in making the more lasting preparations.—The minute stucture of many of these parts must be dissected and unravelled under water, where the loose and floating membranes display themselves ; while, out of the wa- ter, they would lie collapsed and undistinguished. In such investigations, I have found nothing of so much service as jelly made strong and quite transpa- rent. When a delicate part is completely dissected (suppose it to be the coats of the eye,) place it in the jelly as it is becoming firm, and hold out the parts; and they will be retained, elegantly displayed, either for demonstration or for drawing. In some instances, (as in dissecting the eye and ear,) freezing mixtures have been employed, which allow the frozen parts to be dissected without the fluids escaping. It is not always with the knife that we must expect to dissect and separate the minute and transparent organs, but frequently the object is best XX XII attained by blowing betwixt the lamina : as of the pia mater, the capsule of the lens, the cellular coat of the intestines, &x. In anatomising insects, two small and very delicate hooks are used, by which the parts are to be torn asunder; the attempt to dissect them" with the knife will be quite vain. It is by this means that Mr. Ma- cartny has succeeded so well in his preparations of comparative anatomy. Boiling and maceration are often employed to de- monstrate the muscularity of parts ; as the course of the fibres in the heart. The course of the fibres in the bladder may also be shown, by^ distending it, and plunging it suddenly into boiling water. In this way, also, the coats of arteries, the retc mucosum of the skin, &c. maybe demonstrated. Immersing the skin in boiling water before injection, is said to make the villi stand out more from the sui face. Although im- mersing in boiling water will not separate membranes into their layers, sometimes alternately macerating them in cold and warm water will do it, or macerat- ing till puti efaction takes place, and then plunging the part into boiling water, as is done to separate the roinea. Boiling gently with a solution of nitre and allum is i sed to render evident the muscularity of membranous i arts. The solution makes the muscular fibre of a red colour : but, perhaps, minutely injecting the parts is a n ore natural and eflectual method ; for, altera suc- cessful injection, the muscular fibres of the bladder, for instance, being very vascular, become distinguishable. r ervous memm-anes, as the expanded nerve of the eye and ear, the septa of the vitrous humour, and the membranes of the egg, become opake when vinegar is poured upon them. Without this, the latter cannot b«*. distinguished. To prepare for the demonstration of the brain, 1 have been in the u^e of injecting it minutely with XXXU1 line size, which even if it happen to be soft, will give firmness, and enable one to display the parts better. The brain and nerves, by being exposed to the oxygenated muriatic acid, arc made firm, immersed in a solution of corrosive sublimate and spirits, the brain is hardened and can be preserved. But to preserve preparations of the brain, spirit of wine, corrosive sublimate, and nitric acid combined, make the best liquor. Of the Lymphatics. — The injection of the lymphatic vessels is the most difficult part of practical anatomy. The subject taken for lymphatics, should be under twenty-ffW^ears of agej and dropsical.—The apparatus in the shops is fit for every purpose ; generally however, the tube of glass is too thick, which makes it heavy and unwieldy when filled with mercury. A provision of very fine forceps, scissors, lancets, nee- dles, and thread, should be at hand, and the assistant must be equally ad.oit with the anatomist.—The mercury must be pure, and the globules leave no tract behind them. Supposing that an extremity is to be injected : the veins and arteries should be previously injected. It is placed with the upper part of the limb a little inclined downward. The integuments are to be dissected off; the common cellular membrane left; lines will be per- ceived small as the most delicate nerves, but without their white opacity, and taking a course somewhat obliquely, crossing the cutaneous veins, below the ancle and on the wrist. It will be difficult to introduce the point of the smallest tube, unless we proceed in this way. Having discovered a lymphatic, a delicate needle and thread is put round under it; then with very fine scissors cut the filament half through. The scissors 1 use in preference to the lancet, as by snipping the lymphatic a little obliquely, an opening is made which is more easily found than a puncture. We may now inflate the vessels by the small blow pipe"; XXX1V making the stream of air play on the punctured part of the vessel; but I never do this. I introduce into the ves.-el the delicate steel poker, if it enters smoothly and without resistance, I know that it has found the vessel; if it is pushed on with difficulty, that it is mak- ing its way amongst the common cellular substance. When the poker is introduced, I then take the pipe with a high column of mercury and make the stream play along the poker, when the mercury never fails to enter the lymphatic) and now I he point of the tube easily enters the distended vessel, when the poker is to be withdrawn. The mercury should be allowed to flow freely: from one small vessel, on the wrist or foot, six or ten lym- (ihatics may be filled on the thigh or arm. With simi- ar precautions other vessels are to be sought and filled. If we have to inject lymphatics betwixt the glands and trunk of the system, the pipe maybe plunged into the glands so as to fill its cells, from which it will pass or may be pressed into the second set of vessels. The lymphatics of any subject may be injected. We have them here injected and dissected for the lectures tn that subject, in whatever body may offer in the rooms at that time, but when there is much fat the dis- section of them is difficult, and to preserve them it is absolutely necessary that the subject shall be thin and anasareous. When a limb is injected, it should be laid hori- zontally : we begin the dissection on the lower part, when we have dissected the vessel to some extent, a very fine thread is tied round it and this ligature is' repeated as we proceed up the limb, at the distance of five or six inches. When a vessel of perhaps three feet in length, is left without this interruption to the mercury, it cannot be expected that when the vessels dry, and the valves consequently shrink, the coats of the vessels will bear so high a column'. It XXXV will always be remembered that it is the heighth of the column, not the quantity of mercury in the tube, or in the vessels, which governs the force with which it presses at the lower part. At all times, but especially when the coats of the vessels have dried it is necessary to keep the preparation in a uniform temperature. If the heat be increased the vessels will burst : if they are prepared in a warm temperature and removed into a colder place they will shrink. I strongly recommend to the student the perusal of Sheldon's introduction on the preperation of the Lymphatic Vessels. OF A COURSE OF DISSECTIONS. - I advise the student to make himself perfectly mastei of the Bones, before he take part of a muscular sub- ject. When he takes the knife first in hand, his ob- ject ought to be, to learn to use it with ease and free- dom ; to acquire a mobility of the wrist and fingers. The assistant will first put him on a fleshy part, teach him to lay the edge of the knife to the indivi- dual fibres, and cut always in the course of the fibre. When he can make a clean dissection of the gluteus. muscle lifting the integuments at once, leaving the fibres distinct and clear of cellular membrane, the next step is to know the nature of cellular expansions, and the aponeurosis of muscles. He will find for ex- ample in dissecting the tendons of the abdominal muscles, that they are covered with thin layers o;' membrane, he will mark how all muscles are covered with these, and the demonstrator will take occasion to point out the necessary consequence of inanima- tion or the growth of a tumour or the prot usion of a hernia upon these layers of cellular membrane. In the dissection of muscles and fasciae a lar j;e knife XXXVl with a full convex edge, should be used : but in the dissection of nicer parts, in following the nerves for example, small and straight, or lancet pointed knives are necessary. Besides the common hook and for- ceps, if the student be going to enter on minute dis- section he should order the hook knives and forceps for the extraction of the cataract, he cannot expect that the instrument maker will give him fit ones under an order for dissecting instruments. During the dissections of the muscles, the mechan- ism of the joints, the classification of the muscles, their effect in fracture, and dislocation, their anatomy as it regards hernia, &c. ought to be the object of study. When the student is master of the muscles, he enters upon the dissection of the Nerves. While the dissection of the muscles gives ease and freedom to the hand, the dissection of the nerves gives niceness and delicacy. During a 'course of dissection of the nerves, we have two subjects of inquiry, connected with our sub- ject : the one surgical strictly; the other patholo- gical.—The connexion of the nerves with the arteries, and the places where it is likely or probable that they may be tied when the surgeon uses his needle to secure bleeding arteries are to be noted. We must know the distribution and the precise course of the nerves of the extremities. We must observe the branches which account for the various sympathies, and the consent of parts. We must contemplate that wonderful tissue of nerves forming the system of the viscera.—In short, if we do our duty while we are dissecting the dead body, we shall take into consideration such pheno- mena of the living system as may correct the inaccu- rate and too mechanical notions which we are apt to receive from mere dissection. To the surgeon, dissection of the arteries is notmerely most necessary, but quite indispensable. Both XXXV11 heart and head must be wrong when a young man al- lows himself to be put in situations of great responsi- bility, without having dissected the arteries, and thought maturely of the chances of war, and of the equally great variety of open, and oblique, and torn wounds of the great vessels, which occur in domestic life. During dissection, there are many little operations which should be practised, and which are neglected. The introducing for example, of probes into' the ducts ; as into the nasal duct, and into the ducts of the salivary glands; the introducing of instruments into the nose and throat, and into the eustrachian tube : the use of the prbbang, and of the catheter, &c.—Knowledge and dexterity in such points, often prove more useful, as being oftener required, than the greater operations of surgery. In dissection the integu- ments are to be preserved that they may be laid down 4 on the parts again, otherwise in the intervals of dis- .,. section,.the surface contracts a mucus, and gets dry and foul: a wet cloth, which by evaporation may keep the body cool, is indispensable, in tne warmer days. In conclusion, I venture to affirm, that the difference betwixt a young man that promises to be one who will improve his profession, ahd'him who is mere- . 1 ly tolerated as a practitioner, is this, that the one seeks every occasion to be informed of what is going forward •'in the dissecting room, while the other supinely does his task, and requires his certificate in writing. The first body which the student dissects for the arteries may be done in the common way, as for mak- ing dried preperations. But after he has ascertained the principal bearings as it were of the great trunks in their course; and has made himself master of the brunches of the arteries, their classification, and num- ber, and proportional size; there remains a depart* -. ment of study which is to bring him nearer to the circumstances of actual practice. He ought to dissect Vol. 1. D xxxvni a body with the arteries uninjected, that he may know them by their appearance and relations, as they will be in the living body where else, he will sadly feel the want of the wax to inform him of what is artery, vein, 3 and nerve ! In this department of his study he should attend particularly to the depth of the vessels, the fascia by which they are surrounded, the muscles which a>e to be separated in order to penetrate to them, fie precise bearing of the artery to such points of none, or to the courses of tendons, as may stand him good in the living body ; and lastly he ought carefully to observe the relation of the artery, vein, and nerve ; where he may dive boldly with the needle ; where cautiously separate the artery before he ties it. A SYSTEM OF ^i$$ttmn$. DISSECTION OF TUB ABDOMINAL MUSCLES. THE dissection of the abdominal muscles is often the first that a student sees ; and if it be carefully done, he is astonished to find the fleshy mass of the body separated into so many distinct parts, and is pleased with the appearance of the muscles exposed in all their beautiful variety of shapes and colours, the smooth- ness of their surface, and their silvery expanded tendons. But he conceives all this to be the simple expo.-itioii of the parts, not the effect of persevering labour ; and if accustomed to the clear demonstration of a class dissection, has no idea of difficulty in the task. He feels the difficulty of dissection only when he takes the knife in his own hand, directed by that vague knowledge alone, which is, I fear, too common, and which consists more in a facility of repeating descrip- tions, than in a precise and clear idea of the situation i of the parts. To begin a course of private dissections with such light ideas of the difficulty and importance of the task, and so poor a notion of practical anatomy, must produce in the student that disappointed and irritated state of mind, which is but ill calculated to , cany him on with prescvcrance. He will find that thcie are many little observations to be made, and inich accurate knowledge to be acquired of the ap- J>earance of parts, of vessels of cellular substance, ^ a^cia and tendons, before he can go on confidently, and be sure of the course of his knife. t No dissection ought to be begun without maturely } considering the parts which lie concealed, and all that is most worthy of labour. Following this method, I shall first describe the general outline of the parts to be dis- 1 sected ; and, secondly, the order of the dissection, ., and the points that ought to arrest attention*. * FIRST STAGE OF THE DISSECTION*. In the first dissection there is only one muscle on each side of the belly to be dissected; for the outer g oblique muscle covers all the others. 1 The obliques externus abdominis arises by trian- gular fleshy slips from the lower edge of :the eighth 1 loweimost ribs, its muscular fibres proceed down- wards obliquely over the cartilages of the ribs, and also obliquely downwards over the free space betwixt the borders of the chest and the spine of the ilium. J Terminating its muscular part abruptly, it sends its ! * The reader mw.t novo be informed, that only One prin- cipal circumstances ojdie anatomy, are described here ; he otogfttto readthh before dissecting, and if during dissection he requirestke origin or insertion of muscles, or thename of „ an artery or nerve, he can con ,ult the appendix. Pages 41 -44 missing Pages 41 -44 missing 45 situation of this aponeurosis, and its propable changes in disease, sacrifice it to a more important demonstra- tion, or leave it on one thigh, while you proceed with the dissection of the other. Thus taking away these confused parts, expose neatly the ligament of the thigh. Dissect the artery and vein in the angle of the groin, where they lie imbedded. Then dissect- ing delicately with your scissors, under the ligament, you find proceeding from the upper part of the femoral artery, two branches ; the arteria circumflexa ilii, and Jthe epigastric artery. The first of these you find running back along the inside of the ligament, to- wards the ilium, to inosculate with the ilio lumbar artery ; the latter is the more important, the epigastric, artery. It runs upon the inside of the tendons of the abdominal muscles, making its way to the rectus muscle, on the inside of which it climbs, even till it r>inosculate with the internal mamary, which is the first branch of the subclavian artery. In this.course it crosses the upper pait of the ring, and crosses be- * hind the spermatic cord. Now, you observe that the femoral hernia, coming down on the inside of the femoral artery, the epigastric artery and the spermatic cord must pass before the neck of the sac, so as to hinder the free incision of it when strangulated ; and you see how difficult it must be to cut thread by thread exactly jn the middle point betwixt the epigastric artery and the cord, especially when you recollect how different the state of these parts is in hernia. These are parts of such importance, that you ought I to consider them in every possible light. You see that the direction of the inguinal hernia must follow the course of the cord, that it will be nearer to the pubis, and higher up : that the seat of the femoral hernia is in the flexure of the groin ; and that if the hernia is not very large, and the parts swelled, the ' ring, and the cord from the ring to the testicle, should 46 be free. You have to observe how the arch, which is formed by Poupart's ligament, over the vessels and muscles coining from within the belly, is filled up with . fat and cellular substance, and how the vessels lie im- bedded in it. You find the vein lying more towards \ the pubis than the artery, and the small inguinal branches of the artery rising to supply the inguinal glands ; These arteries sometimes bleed profusely in opening buboes in the groin. SECOND STAGE OF THE DESSECTION. ■ Having paid equal attention to the dissection of the muscles of both sides of the belly, you proceed thus: dis- sect off the serrated origins of the external oblique muscle from the ribs, and from the space between the ilium and false ribs, and detach it from the obli- quus internus which lies below it. You will re- collect that the obliquus internus ascends from the ilium, spreading its fan-like fibres in a direction which • forms an acute angle with the fibres of the external muscle which you are dissecting off. Continue to separate the exte nal and internal oblique muscles, till you find them firmly attached by their tendons to the linea semilunaris. Betwixt them there is interposed some loose cellular substance, which mars the beauty of the lower muscle if not carefully dissected away ; ^ and you find them connected by the branches of the arteries and Veins piercing them to gain the skin and cellular substance. Observe the origins of the ' * obliquus internus abdominis from the spine of the ilium, and apparently also from the mass of mus- cular and tendinous origins of the muscles of the r^ack (you will find it very difficult to desscct its origins from the spine as described in books.) Those fibres of the muscle which originate from thebackpart of the spine of.the ilim, fun directly upwards to the carti-" 47 lagcs of the false ribs. From the fore part of the ilium its fibres are continued more in a direction across the belly, and from its lowest portion which runs direct- ly downwards in the direction of the external oblique, you find it sending off, behind the external ring, a delicate fasciculus of fibres which invest the sparmatic" vessels, and (brm the origin of the cremaster muscle. . The belly of the internal oblique muscle ends in an uniform edge, and its tendon is finally inserted into the linea semilunaris : but here it is to be remembered, that some anatomists have described its tendon as splitting into two layers, one forming, with the external oblique, the outer part of the sheath of the rectus; the other forming the inner part, with the tendon of thetransversalis abdominis. This inner oblique muscle, when dissected, should be left in its seat, and the outer muscle replaced over it. Then making an incision by the side of the linea alba, which opens the sheath of the rectus, you dis- sect it back towards the linea semilunaris. In doing this you must separate carefully the sheath from the tendinous bars of the rectus muscle, for at these parts they are firmly blended together. Towards the bot- tom of the sheath, you find the pyramidal muscle running up from a broad origin upon the os pubis, to an acute point inserted into the linea alba. The two py- ramidal muscles rising together, one on each side of the middle abdominal line, form a cone that is sometimes observable, shining through the strong sheath which covers them. These parts being completely dissected, return them to their former place; and having con- tinued the dissection of the muscles of the other side exactly in the same manner, proceed after this method. The teudon of the internal oblique muscle is to be cut from its connexions with those of the other' mus- cles at the linea semilunaris : then dessect the muscle back towards its origin upon the spine of the ilium; 48 and laying it over the haunch, you have an opportu- nity of observing the course of the transversal!* abdominis. You find its fibres running across the belly, more in the direction of the external oblique, than in that of the last dissected muscle. You see it arising fleshy, from six of the lower ribs, upon their inside, (which has allowed some anatomists to de- scribe minutely its digitations with the diaphragm;) and tendinous, from the mass of muscles upon the loins. It runs a little round towards the side, where the strongest part of the muscle is formed. It arises likewise from the spine of the ilium, and even from the outer part of the ligament of the thigh. It is in- serted into the linea alba having previously connected itself with the linea semilunaris. It will be observed, that towards the lower part of the belly, this muscle appears deficient, and the bowels are seen through the peritoneum, the outer surface of which is covered with much confused cellular substance, and unlike its smooth inner surface, which is applied to the intes- '• tines. SUBJECTS FOR CONSIDERATION DURING THIS DISSECTION. ' These parts being thus dissected, can be demon- . strated in such various views, and with such quick. succession, lifting and replacing them, that they can- not fail to be effectually understood. And having carefully observed their strict anatomy, no one can be A at a loss to recapitulate their general character and j uses. j It may be observed in the skeleton how great a ^1 space there is to be covered from the edge of the tho- ^M rax to the brim of the pelvis, and backwards to the \ spine; and recollecting, that in this space are con- - tained the soft viscera of the abdomen, and that these | must be sustained by an elastic and yielding covering, 1 49 it will be understood how this covering, whilst it supports the viscera, and yields to and assists the ope- ration of the diaphragm, must support and poise the whole trunk upon the pelvis ; and that although the muscles of which it consists be thin and delicate, yet, having so great a lever as the edge of the thorax, while the centre of motion is at the spine, it bends the upper part of the body with great force. The following Heads and Observations I have con- sidered as necessary and important to press on tlie Student's attention. I. 1. The abdominal muscles are muscles of respira- tion. 2. They are muscles of the trunk. 3. They rompress and sustain the viscera. II. 1. The Student ought to consider how as mus- cles of respiration, the distinction in the manner of breathing becomes a symptom of disease. 2. How we endeavour to substitute the action of these muscles, and the diaphragm, for the external muscles of respi- ration, in fracture of the ribs and sternum, &c. III. 1. The question, are the viscera of the abdomen suffering an unceasing pressure ? Is a very important one. 2. And when on this subject, we are called upon to consider how the effect of pressure of the ab- dominal muscles becomes a diagnosis in diseases of the abdomen ; 3. The effect of pressure taken off by the deliveiv of the child, or by the drawing off of the water in ascites ; 4. The destruction of hernia as they may proceed from weakness in the tendons, or where they are brought down by powerful exertions ; 5. The sympathy of these muscles with the bowels ; 6. How they are early effected in tetmus, and even lacerat- ed in the violence of the convulsion in this disease. IV. 1. Collection of matter sometimes form in the interstices of these muscles, or in the cellular mem- !-iane on the outside of the peritoneum. 2. The Vol I. I'. 50 nature of the sinuses which form amongst their layers should be thought of. These are the heads of subjects worthy the con sideration of the dissector. He will then comprehend how very much more is to be learned than can be taught by a porter in a dissecting room. DISSECTION OF THE INGUINAL RING AND LIGA- MENTS, OF THE THIGH, WITH THE VIEW OF UNDERSTANDING THE ANATOMY OF HERNIA. But there remains still a very curious and interesting part of anatomy to be studied, viz. the manner i:i which the spermatic cord, and the vessel of the thn.h, are allowed to make their escape without endangering the protrusion of the viscera. Where the tendon of the external oblique muscle is de- scending to the os pubis, it splits to form an opening for the spermatic cord. On the first stage of the dis^ section, to examine Tthis opening, let the student at- tend to the dense layer of cellular membrane which covers it, for this membrane forms one of the coats of ' hernia, when it takes place here. The fasciculi of fibres, forming the sides of this opening, are called the pillars of the inguinal ring. The form of the opening is that of a very acute angle on the outward and upper end towards the pubis, it is larger and round, at their insertion into the os pubis, the columns tlecus-a'.e. I have used the common expression, and have said, that the splitting of the tendons forms the ring; weie it so exactly, the action of the muscle would draw tight the opening, and compress the vessels of the cord : contrasted with the many minute description'-? of this part, which have been given since, I am not ashamed to transcribe what follows from p. Ill, of the edition of this book published in 1S00. "The ligament of the thigh is formed bv the ten- don of the external oblique, muscle of the abdomen. 5J taking a firm hold of .the spinous process of the ilium, and stretching over the muscles and arteries of the thigh to the os pubis. On the outer part, as it rises from the os ilium, it is firmly tied down by its connexion with the fascia of the thigh. In its whole length, but chiefly as it approaches tbepubes, it is not the rounded tendon which, from viewing it on the outside, we should expect ; but it is turned in and inserted into the os pubis with a flat broad horizontal tendon. The consequence of this, is, that at the point towards which the viscera must gravitate in the erect posture of the body, it is very strongly secured : and that the effort of the viscera to protrude is not made under the arch or ligament, but above it; since the margin of the tendon spreads thus horizontally to be inserted into the os pubis. "The spermatic cord lies as in a groove formed by the ligament as it approaches the os pubis ; and as the extremity of the ligament forms the lower pillar of the ring, an exit is, by a peculiar yielding or twisting of its more outward fibres, allowed for the cord, with- out diminishing the strength of the femoral ligament, which, by its horizontal sheath stretching backwards, is firmly inserted into the bone. Thus the spermatic cord is not exposed to the compression of the two pillars of the ring ; for as the lower pillar of the ring ^is the extremity of the femoral ligament, as from its connexion with the bones it is immoveable by the action of the abdominal muscles, and as this lower pillar holds the cord in a kind of flat groove laid ho- rizontally on the os pubis, its outward fibres only yielding to allow the cord to escape, the consequence is, that the upper pillar (which spreads its fibres on the outside of the lower) does not, when made tense by the abdominal muscles, compress the cord against the lower one. On the other hand, the security of the abdominal ring depends upon the obliquity of the 52 passage, and upon the pressure of the viscera not being made in the diiection of the cord, but laterally." Now let the dissector make an incision from the linea alba two inches above the pubes to the lower spinous process of the os ilium, through the tendon of the external oblique muscle : he has then to dis- sect down the lower part of the tendon, to observe, the internal apparatus of the spermatic passage, lleie he may observe the course of the internal obti the cord. Now 1 have a circumstance of the anatomy to point out, of much importance. I am going to ob- ject to Mi. Cooper's history of the internal ring. The subject is before us ! I cannot misrepresent, though i may misinterpret. Let the profession determine, whether I do this in enmity to one, who most 53 liberally bestows his praise on others, or from that commendable spirit of investigation which it is my du- ty to recommend and enforce with my pupils. When the internal muscle is dissected off the cord, there is behind the muscle a layer of cellular substance, which surrounds the cord, in which the rav "deferent, and ves- sels of the testicle, descend under the peritoneum and scatter to their destinations : on the inside of the vas de- ferens the epigastric artery and its sheath of cellular membrane will be felt. Here is the internal ring of Mr. Cooper. Instead of this condensed cellular membrane, he describes a fascia having a slit to allow the spermatic vessels to pass. Mr. Cooper says, that this fascia is the guard against hernia, but admits that in some sub- jects, it appears as condensed cellular membrane only. It appears to me, in its natural state, not strong enough to cause strangulation, and especially as it is a guard against hernia, so will hernia take place where it is weak only. In my last edition, I have said, that " I have found in operating on inguinal hernia, that the contraction wai not in the ring, but in the peritoneal sac, fully two inches within it." Ap. p. 5. This I still hold as the true opinion ; when the peritoneum is pushed over the spermatic vessels, by the protrusion of an intestine, it passes under the inner muscles, and around upon the outside of the epigastric artery. The epigastric artery is pushed inward, the cellular mem- brane accumulated by this yielding, is pressed and condensed : but sometimes it will not allow the further shifting of the neck of the hernial sac inward, and the condensation and thickening of the peritoneum and cellular membrane are such as to form, indeed, a ring, which may strangulate the gut; and I may add, though this is no place to enter more fully into the explanation, the sudden turn which the intestines take round the arterv, is the^cause of the strangulation. When Mr. Cooper says, surgeons have very gene- rally believed that the aperture was continued into E 2 54 die abdomen immediately behind the ring, he does great injustice to the profession, and pays a poor com- pliment to the surgeons with whom he is more imme- diately connected. When the student has made this dissection of the ring from without, he may take an opportunity of laying down the whole flap of the abdominal paries over the thigh, and examine the ring by lifting the peritoneum from the inner layer of muscles,—here he is to distinguish the fascia, which comes up from the iliacus internus, and lines the abdominal muscles, then tracing the spermatic vessels and the vat deferens through this fascia, he has to dete mine whether or not it be stiong enough to account for the strangula- tion of lid nia, whether it deserves the name of fascia, or layer of cellular membianc. Of the dissection of the femoral ligament. —Another very curious piece of anatomy must be studied, before we leave the consideration of the ab- dominal muscles. The dissector makes incisions upon the integuments of the lower part of the belly and top of the thigh. In taking the skin from the tendon of the external oblique muscle, he has to observe a thin but pretty firm web of cellular membrane. It is very useful to obse.ve this membrane, but not very accurate to call it fascia or aponeurosis.* It will be found to cover the ring and spermatic cord, towards the pubis. To- * T/teten.i fascia, s/iould be confined in its signification to the sheaths, which cover, and as it were, swathe the mus- cles of the limbs. Aponeurosis, meant the tendon of a musclespread out into a membrane ; but now the difficulty is to say, which is aponeurosis, which a web of common cellu- lar membrane? however, if we be willing, we may distin- guish a tendinous expansion by the silver-iike l'rilf the fibres, while the layers by membrane, composed of t/u common cellular texture condensed, want thissplendour. 55 Wards the outer and upper part of the thigh, it mingles with the fascia lata, and on the middle of the thigh, it is dissipated and lost in the fat glands and cellular membrane, which lie over the femoral artery and vein. Having dissected the fascia lata, which is on the out- side of the thigh, and observed the manner in which it mingles with the sheath of the great vessels, and turns in to unite with the femoral ligament, he may open the sheath. In proceeding to dissect away from the groin the glands and fat, we shall find a few delicate superficially distributed neives coming from underthe ligament of the thigh. We shall find also, that the cellular membrane which surrounds the great vessels forms a condensed bed, independently of an aponeuro- sis upon the subjacent muscles. The inner surface of this cellular membrane is strong from the interlacing of fibres. It covers and invests the great artery and vein. The same condensed cellular membrane is con- tinued behind the vein and artery ; and by pulling up these vessels, after dissecting it from before them, the branches may be seen piercing it like the vessels of the heart going out from the pericardium. All the vessels in the body are moie or less supported in this manner by sheaths of cellular membrane ; but it is at such places as this in the groin that it becomes a great object insurgical anatomy. Now the director has occasion to lay aside his knife, and with the point of the finger to feel the connexion betwixt this sheath of cellular membrane and aponeu- rosis, and the ligament of the thigh ; in endeavour- ing to push his finger up into the belly by the inside of the vessels of the thigh, he feels the shaip edge of a ligament, when he pushes his finger deep and again withdraws it, the circular edge of this ligament, can be seen. I have for several years demonstrated this as the part strangulating in crural hernia; such of my pu- pils as belong also to the Borough school, insist upon something more. If there be, I stand corrected; but if this be claimed as a discovery by any man, I pointedly 56 object to it. The ground for drawing my pupils' at- tention to this has been this. They have said, Since the eord lies in the groove formed by the lower part of the tendon of the external oblique, is not the cord in danger of being cut in the operation for femoral hernia? My answer ha-, been, so it would appear, if the sur- geon was to take his notions of the suite of the parts in hernia, from the clean dissection of the Poupart ligament : but when he comer, to operate, and puts his finder into the neck of the sac, lie feels a sharp edge of ligament which extends from the Poupart liga- ment. Again, in substantiating the explanation of the cause of strangulation, viz. that for the most part, it was not the narrowness of the o :ening under the ligament, but the sudden an^le of the gut when forced out from the groin and made to ascend on the face of the abdominal tendon ; I have had occasion to demonstrate this liga- ment as causing the sharpness of the angle. In the internal view of the ligament of the thigh, there is a difference in my manner of demonstratingthe connexions of the tendons of the abdominal muscles, which I state with diffidenee after the very full investi- gation of this piece of anatomy, by ^others. In the first appearance of the psoas abscess in the groin, and the tumour of the femoral hernia, there is a striking difference which long since made me endeavour to dis- cover the cause. I have accounted for this from the insertion of the psoas parvus, where it was present, and from the attachment of an aponeurosis, which I have observed going off from the psoas magnus, where there was no lesser muscle. The psoas muscle is described as being inserted into the os pubis or the junction of the os ilii and os pubis, and as being a muscle which assists the psoas magnus, my observation has led me to describe the psoas parvus, as a muscle guarding the connexion of the abdominal muscles; and when this miuJ.c is wanting, I have shown the 57 going off of a fascia from the psoas magnus, which connected itself with the inner edge of the ligament of the thigh, so as to close the abdomen, and, as I have alleged, excluded the iliac vessels from the abdominal cavity. Hence, I have explained, that pus descending from vertebrae, passes on the outside of this fascia or aponeurosis, and by the side of the iliac vessels, but when hernia takes place, it is on the inside of the iliac vessels, because on the inside of this fascia. Further, when I have taken occasion to shew the manner in which the abdominal viscera were enclosed and supported ; I have never failed to mention the psoas muscles with the abdominal muscles, the dia- phragm, and perneal muscles. After the dissector has attended tothese connexions of the psoas muscles, with the abdominal muscles, he ought' to dissect and examine the inner edge of the ligament of the thigh, and the termination of the tendon of the rectus. DISSECTIONS OF THE VISCERA OF THE ABDOMEN. FIRST DISSECTION. Of the Manner of opening tfie Body, and observing t/ie general situation of the Viscera. AS the great use of dissection is to acquire, the know- ledge of the parts in the living body, it is proper, be fore opening the belly, to read the general description of the paits ; to learn the boundaries of the abdomen ; the situation of the diaphragm, encroaching upon the cavity of the thor ax ; the track of the intestines; and the pi ice of the more important viscera;—how the liver and stomach are received within the margin of the ribs, and guar ded by them ;—how the arch of the colon winds round under these ; and how the small intestines are collected in a group under the navel. It is of importance to mark the situation of all these parts, and to conceive which would be wound- ed by pointed instruments, pushed in various direc- tions. A degree of accuracy in the knowledge of the 59 seat of the viscera will thus be acquired, which is of the greatest use both to the physician and sur- geon. In opening the belly*, if the operator be not jtoo finically inclined, a simple crucial incision is made ; one cut from the scorbiculus cordis to the pubis, keep- ing the left side of the navel ; and another crossing it from the spine of one ilium to that of the other, coming below the navel. In doing this, the only care should be to avoid cutting the intestines, by raising the integuments from the viscera, after the first punctute. Having thus laid open the belly, it will be seen whether the preconceived ideas of the situation of these parts be correct. In private dissection, when the abdomen and breast are to be opened, one incision from the throat to the puhis will lay open both cavities sufficiently. The following are the points to be observed, and which will lead without confusion, to a full de- monstration of the whole. I. The great arch of the colon, mounts up from the os ilium of the right side, crosses the belly under the edge of the liver and brim of the thorax, and descending again upon the left side, sinks under the small intestines, and rests upon the wing of the os ilium ; thus surrounding the small intestines, which lie together in the middle of the belly. 2. The stomach will be found in the left hypo- thondriumf, retired under the ribs, and covered by the arch of the colon. 3. The omentum will be found proceeding from the stomach and colon, which lie contiguous, and stretching down over the small intestines, a delicate and expanded membrane, loaded with fat. * I speak here, as if another body iverc bestowed on this demontlration ; bid here is no neccm.itif for it. * <■ '•! annir the space under the cartilages of t/ie ribs. 60 4. The liver will be seen with its edge under the marT oin of the ribs, and towards the right side. Such is the general appearance upon the first open- ing of the abdomen. Jiut as one part of the intesti- nal canal may happen to be more inflated than another, this regularity will sometimes be disturbed. The stomach may be distended, and the colon contracted and empty ; consequently, instead of the colon being the prominent part, it may have subsided, and be scarcely distinguishable from the small intestines, while the stomach may push out its sides from under the liver and the ribs of the left side : or perhaps the stomach and colon may have both receded, by the expansion of the smaller intestines. Now, in this state of the intestines, if an attempt be made to unra- vel them with the hands, there is every probability that they will be tumbled into greater confusion and disorder. It should be remembered, that in the exami- nation of all the?e parts, the colon is the sure guide; for the caput coli is fixed down by thepeiitoneum to the loins, upon the right side ; and from this the colon can be always traced up under the stomach, and above the small intestines. This transverse portion is called the arch of the colon, and if you puncture it, and introduce a small blow-pipe, and blow it up, then eveiy thing seems to take its true place. As the colon swells up, it shews its ligamentous bands, and the cells so peculiar to it. It is seen rising before the stomach, de-cending upon the left side, and under the small intestines, and finally tied down by the peri- toneum to the loins upon the left side, forming at this place the sigmoid flcxture of the colon, which is the last portion of this gut. From this point to the anus, the continuation of the intestine is the rec- tum. In this first display of the viscera, there is a very partial view of the intestines : only a part of the coloti, jejunum, and ilium is seen ; and tt» trtje the. whol" 61 length of the alimentary canal, this natural appearance must be deranged. Course of, the Intestines.—Having found the great curvature of the stomach, and the arch of the co- lon connected by the omentum, separate them, by de- taching the omentum from its connexion with the colon, and lay the great intestine down over the small intestines. You then find the stomach lying obliquely across the upper part of the belly, towards the left side, a conical bag, bent upon itself ; so that the two ends approach, forming on the under side a greater and on the upper side a lesser curvature. The great- er curvature presents itself in this view of the parts. The cardiac orifice, or entrance of the oesophagus, lies out of sight; and even the pylorus, the lower orifice, recedes out of sight when the stomach is dis- tended. Towards the left side, under the ribs, and hanging on the great curvature of the stomach, you find the spleen of a dark and livid red colour. You see the duodenum, the first intestine, taking a turn upwards from the pylorus, stretching a little to the right side, then turning upon itself, and descending under the mesocolon towards the right kidney. Ob- serve how it is bound down at this point ; observe also its situation with regard to the stomach and liver, and arch of the colon ; and remember that it is here within this space that it receives the pancreatic and gall ducts, and from its size and the circumstance of these secretions being poured in here, this has been called rentriculus secundus. Neither of the ducts can be seen in this stage of the dissection, the pancreas itself being obscured in the cellular substance at the root of the mesocolon, but you may feel it under the stomach, a hard conglomerated mass, stretching directly across the spine. The extent of the duodenum is from the orifice of the stomach to the place where the gut emerges from under the mesocolon. It lies before the emulgent vessels, before the aorta. Vol. I. F 62 and upon the last vertebra of the back. It is larger than any of the other small intestines, and , sometimes is very greatly distended. Turning up the colon and omentum, fixing them over the brim of the thorax, and pushing down the small intestines towards the pelvis, you find the duode- num coming out from under the colon, but still tied close to the spine by the peritoneum, or lining mem- brane of the abdomen. After a little space, the in- testine extricating itself from the ligamentous folds of the peritoneum, is seen rising up, and coming forward and is called the jejunum. You have now to unravel the small intestines, which lie below the arch of the colon, as they at first present themselves to you. The small intes- lines are the duodenum (which you have already exa- mined,) the jejunum, and the ileon. These two last comprehend the whole length of the small intes- tines below the mesocolon, the lower end of the ilium terminating in the caput coli, or beginning of the great intestines. The jejunum, is so called from being found more empty than the ileon ; but this must not be trusted" to. It is said also, that it is of a redder colour, and more vascular and more abounding in the valvular processes of its inner coat ; but this distinction may be rejected with safety, as authorised by Ilaller. In prescribing the limits of these two intestines, ana- tomists are reduced to the necessity of supposing them to be divided into five parts ; two of which they give to the jejunum, and three to the ileon ; which showing the necessity of an arbitrary division, is thereby decisive of its inutility. It is sufficient to observe, that these small intestines may be pretty regularly divided into two masses, especially when inflated ; that the upper portion, and that more to the left is the jejunum, while the lower is the ileon ; and that the situation of this last exposes it more to hernia, especially on the 63 tight side. Very generally the portion strangulated in hernia of the rightside, is about a foot distant from the caput coli. Where the ileon enters the caput coli, there is a soft pendulous projection of the inner coat, forming a valve at the termination of the ileon. When the caput coli is inflated and dried, this valve appears like two transverse membranes, standing obliquely across the intestine, the one projecting over the edge of the other ; matter endeavouring to pass from the large intestines into the ileon, shuts the transverse slit. The great intestines form the last division of the intestinal canal. Tracing the intestines according to the course of the food, the first turns, or the con- volutions of the portion nearest to the pylorus, are situated further down in the belly than the last turns of the intestines ; and these you find even lying contiguous to the stomach, as the great arch of the colon. The great intestine-, differ in their functions and use from the others, and seem to be the receptacle of the matter which has already run through the more active small intestines. They form few convolutions ; but being very capacious, although short, they fill a great space in the belly. They arc commonly divided into the ccecum colon, and rectum ; but it is surely better to divide them into the colon and rectum, and to subdivide the colon, as consisting of parts having a variety of shapes, and very different in their situation, into these three portions : First, the caput coli where the colon is tied down to the loins of the right side, comprehending the valve of the ilium, the ca-cum, or properly, the beginning of the colon, and the appen- dicula vermiformis lying in the space under the right kidney, and in the natural situation of the parts, hid by the covolutions of the intestinum ileon. Observe then upon the outer side of the coecum a little appen- dage, like a twisted earth-worm, and thence called appetidicula vermiformis. Secondly, from the caput coli you trace the colon, mounting upwards over 64 the face of the kidney, and connected with it by cel- lular substance. A little further up, you find it tinged with the bile (shewing that it has lain conti- guous to the* gall bladder) and then going across the upper part of the belly, forming the great arch of the colon. In this part, and its whole course, you will observe its peculiar shape, notched into cells by the ligaments of the colon ; which, running in the length of the gut, slip their fibres into the interstices of these cells, and seem to form them by constricting the gut. Thirdly, the colon then descends upon the left side, and going backwards under the stomach and spleen, into the left hypochondrium, and then descending over the kidney of this side, it is connected with it, and is again tied down, but less perfectly than on the right side, forming some remarkable turns out of the general direction, and this part is called from the sigmoid flexure of the colon. The last division of the intestinal canal is the rectum. Drawing aside the intestines, which rest in the hollow of the pelvis, you find the great gut continued down from these convolu- tions directly, (as its name would imply) to the amis, before the sacrum, and inclining to the incurvation of that bone. The liver.—Replacing the intestines, you hav« to observe the situation and general figure of the liver. You find the upper surface convex, answering to the concavity of the diaphragm. The under surface is ir- regularly concave, answering to the parts it has to re ceive ; it is thick backwards, and on the fore part laps over the stomach and colon with its thin edge. Its li- gaments rather connect it with the neighbouring parts, than support it: and these connexions are disposed so as not to interrupt its gentle motion in respiration, but tie it to the diaphragm, the moving part. The peritoneum.—A subject which ought to be studied in this the natural situation of the bowels, is t"he peritoneum, and the knowledge of this membrane 65 must include much of the general anatomy of the ab- domen. It has been invariably the custom of anato- mists to pay great attention to the course of mem- branes, not only in the belly and breast, but in the more delicate organs, and to trace them in all their windings, deriving one inflection or process from another. But one may easily conceive how all the investing membrane or surfaces of the viscera and muscles, and of all the variety of parts contained in the belly, were formed at the same time. And here in the abdomen all the surfaces of the intestines of the liver, of the parietes of the belly, or inner surface of the ab- dominal muscles, have one common nature. They are all smooth, polished, and continually exuding a serous fluid, which allows one part to glide easily upon another, and to lie in contact without adhering. And as the contents of the belly, though all within one common cavity, do not lie loose, but are attached, the whole surface must be continuous. Now every part of the body, as it differs in structure or use from that to which it is contiguous, is separated from it by a substance differing somewhat from both, viz. the cellular texture This substance is elastic, divid- ing one vessel from another, and one muscle from another; without which there would be no action allowed in vessels, nor motion in muscles and their tendons ; but the whole body would remain a solid and inactive mass. We find in the belly (as in the stomach and intestines, and in the bladder) one layer of mem- brane separated from another, where they differ in stiucture and economy, but the outer layer or sur- face of all the contained parts in the belly has a com- mon nature, which differs in its properties from the parts which it covers, whether the muscles of the ab- domen or the intestines, and ifcis separated from them bv hvterstitious cellular substance, and appears, upon careful dissection, a distinct membrane, viz. the peri- toneum, l! this is to be considered in the light of a F 2 66 separate membrane, involving all the bowels in its doublings, then its demonstration is to be followed in this manner : it is seen lining the abdominal muscles which have been laid back, it can be traced from the lower flap over the os pubis, reflected over the bladder, and again running down betwixt the bladder and rec- tum, then embracing the rectum, and connecting it to the spine, and while it gives easy access to its blood vessels, involving them in its duplicature. When you put down your hand behind the bladder, you find that you can proceed but a little way ; your finger is impeded by the membrane being reflected from the bladder upwards over the rectum, thus separating the viscera of the abdomen from the pelvis. There is no cavity, as it is called in the pelvis, but the parts aie connected by loose cellular membrane, and it is the motion of the abdominal viscera which requires the general smooth and investing membrane. In the upper part of the abdomen, is seen in the same manner the peritoneum continued from the muscle over the inside of the ribs, and under surface of the diaphragm ; reflected from the diaphragm upon the liver : and forming the broad or middle ligament (liga- mentum suspensorium,) which reaches down from the integuments of the abdomen, and is inserted into the upper surface of the liver, in a line with the great fissure which is on the lower surface. You may ob- serve in the edge of this, a hard round ligament, better felt by the fingers than seen ; it proceeds from the umbilicus, and is the remains of the great umbilical vein, which in the foetus came from the placenta. Drawing aside the colon and small intestines of the ri;^ht side, to have a view of the right lobe of the liver lying deep in the hypochondrium, you may see the .lateral ligament of this side, thin, but ligamentous, and fo, im-d like the others by the peritoneum reflected from the surface of the diaphragm. And when you look up under the diaphragm, holding down the liver, you 67 see an extensive attachment betwixt them, formed by the peritoneum which, including a circular portion oftheliyer, is called the coronaiy ligament of the liver. It cannot be conceived that these ligaments support the weight of the liver, they are in themselves de- licate, and all the ligaments and processes in the belly, partaking of the nature of the peritoneum, are gradu- ally elongated upon the slightest extension. But were they in every respect calculated to support the liver, their insertion into its soft substance would be unable to bear its weight; it is the equable pressure of the abdominal muscle tbat supports it, and all the viscera of the belly. And it may be observed, that the great peculiarity both of the abdomen and thorax is, that the lungs in the one, and the intestines in the other, containing each a proportion of air, give an uni- form and elastic resistance, while the vessels in the limbs and other parts of the body act under a more in- cumbent and sluggish weight. The mesentery, mesocolon, and ligaments ofthe colon, are formed thus : the lining membrane of the inside of the belly, when it comes to the spine, mounts over and covers all the parts that lie contigu- ous to the spine ; inventing them on the fore part, but leaving them at their attachment to the back, involved in cellular membrane. In this manner are situated the kid- neys, the great vessels, the thoracic duct, Sic. These may be considered as without the peritoneum. But indeed all the contents of the abdomen may be con- sidered as equally without ttie peritoneum, for they lie as if they had forced themselves forward from the connexion with the back, carrying the peritoneum before them. The intestines a ein this situation; the peritoneum coming off from the backbone ami loins, on either side of the vessels which go to supply tiie intestines, includes the ve-.sels in a double membrane, the mesentery, which, when it reaches the intestine*, se- 68 parates again, and, stretching over the gut, forms its outer or peritoneal coat. In the same manner is formed the mesocolon of the great intestine, answer- ing the purpose of the mesenteiy of the small intes- tines . Yet this method of explaining, although in a cer- tain degree it may give a clear and precise idea of these parts, may be carried too far, and become intricate. The omentum, that delicate, and in many instances pellucid membrane, loaded with much fat, which first presents itself on opening the body, is described by anatomists as consisting of four layers ; for being a double membrane (which can be demonstrated by blowing it up,) and each of the membranes being formed by the peritoneum coming off in a double layer, the one from the stomach, and the other from the arch of the colon, they thus reckon it, as consisting in all of four layers of membrane. From its con- nexions, this the great omentum has received the name of gastro-colic omentum. Its connexions and double layers are best demonstrated by introducing a large blow-pipe under the great vessels going to the liver, pointing it towards the left side, and blowing it up. It may be traced on the left side to the spleen, which it connects with the obtuse end of the stomach running round to the cesophagus, and being continued even into the lesser omentum. This lesser omentum is found by laying down the stomach, and exposing the under surface of the liver. It is a membrane of the same nature with the last; running back from the lesser curve of the stomach, reaching from the cardiac to the pyloric orifice, and spreading backwards to the liver. It forms thus a web, concealing the little lobe of the liver and the pancreas. In injecting the sto- mach, this membrane ought to be carefully preserved, as it is supplied with arteries from the coronary arteries of the stomach. There is yet another division of the omeniu.m, the omentum colicum, which is 69 continuous with the great omentum, arising from the right side of the colon, and ending conically above the ccecum. The smaller masses of fat which are at- tached to the great intestines are the appendiculae epy- ploicae. I. EFFECTS OF DISEASE IN DERANGING THE ABDOMINAL VISCERA. On this subject it is of importance to study the na- ture of inflammation, of adhesions, and suppuration, and the almost uniform consequence of disease upon the peritoneum. It will be easy, when this knowledge is acquired, to unravel the diseased • viscera, which, without it, must appear confused and intricate. Active inflammation should be distinguished from turgidity of the vessels ; for often a fulness of the veins mechanically produced, is described as an active in. flammation in the brain and in the pleura, and still oftener in the abdomen. In dropsy, in violent disten- tion of the intestines, in tympanites intestinalis, and after child-bearing the veins of the intestines and pe- ritoneum are often found distended with blood. But in real inflammation, there is a suffused redness, the peritoneum becomes thickened, pulpy, and less transparent, and the blood is also of a brighter red colour. As the eye becomes dry and painful and inflamed when the eye-lids are forcibly kept open and prevented from spreading the secretion upon its surface; so, when the enveloping membrane of the viscera is exposed, the natural secretion of its surface is destroyed, and the surface is irritated and inflamed. Or, by inflam- mation from any other cause, the secretion is destroy- ed ; the parts lying in contact are no longer kept sepa- rate ; the secretion is changed into a deposition of coagulable lymph and they unite. Adhesion!is produced in thepeiitoneum and in testines in a wonderfully short time: and the smooth membrane, when it is torn from its new connexions, appears cellular ; or, upon being cut, thickened and solid ; or if the surface have, undergone severe inflam- mation (without being allowed to form these adhe- sions which are so frequently the consequence of in- flamed peritoneum,) its surface becomes ragged, and numerous floculi of new membranes are formed upon it. When the inflammation has been violent as in strangulated hernia, purulent matter is sometimes found lying on the surface of the intestines. In long continued chronic inflammation, the peritoneum is covered with opaque white bodies. In diseases where inflammation has spread among the viscera, it is generally understood that the peri- toneum is the original seat of the inflammation. And according to this idea, it appears upon dissection, that the intestines do more readily than the muscles participate in the inflammation of the peritoneum. The muscles are indeed guarded in some measure by the loose cellular substance, which separates them from the peritoneum. But this does not satisfactorily ac- count for what in the above view appears to be so great a difference between the sympathy of the intestines and that of the muscles with the peritoneum. The true ex- planation seemes to be, that the disease or inflammation is in general communicated, not from the peritoneum to the intestines, but from the intestines to the peri- toneum. It is the disease of the intestines which produces those deadly symptoms that are said to mark inflammation of the abdominal cavity ; however, there are diseases in which the peritoneum is peculi- arly the seat of inflammation, and this inflammation of the peritoneum, produced by any external cause, is dangerous by propagating its inflammation to the bowels, or from the great extent of the cavity, the in- terminable surface, as it were, along which the inflam- matory action is propagated. 71 In investigating the seat of disease in the abdo- men, the dissection is very simple. These are the stages : Make a crucial incision, at once laying open the ca- vity ; or, if in a female, make your incision so as to lea^e a triangular flap to fall over the parts of gene ration, by continuing your longitudinal cut no fur- ther than the umbilicus, and from that point, making an oblique incision on each side, towards the project- ing point of the ilium, forming thus three triangular flaps. Then observe whether the parts are in their natu- ral situation ; examine the omentum, the stomach, the spleen, the intestines, and then the liver and gall ducts. Then separating the stomach and colon, con- nected by the omentum, raise the stomach, and ex- amine the pancreas, cutting up the adipose membrane, examine the kidneys, by making a section of them. Then following the ureters, examine the contents of the pelvis, &.c. In making up your case, the diseased appearance, will of course be first described, but the viscera in general, which may be natural, should be enumerated, that the reader may not imagine things were forgotten. The history of this dissection should be kept perfectly pure of all reasoning. This in general, is the order of a dissection of these parts for the investigation of the cause of death ; but it is proper, in the following remarks, to keep to the order of the demonstrations already given. I shall first, therefore, consider those viscera which lie in the upper parts of the belly, and are seen upon folding down the colon and small intestines. II. DISEASE IN THE OMENTUM. Under the title of omentum extra sedem, there is no end to the varieties to be described, but in fact, this fs the explanation. It is a membrane in its natuial 72 state loose and floating, reaching into the furthest corners of the abdominal cavity ; and if there be in any part an inflammatory tendency, this membrane is pi one to assimilate with the action and to adhere. Thus if theie be disease about the pylorus, there the omentum is collected and massed into a tumour; if there be obstruction of the colon, the omentum forms tumour there ; if there be disease in the womb, though seated deep in the pelvis, this membrane will have formed an attachment to the fundus of the uterus ; if there oe an hernia it is more than an equal chance that the omentum forms a part of it. From this dis- position to attach itself and to assimilate with disease it is os all the parts in the abdomen, the least frequent* ly to be found in the natural state. We find it inflam- ed, gangrenous, morbidly loaded with fat, wasted as by putrefaction, scirrhous, steatomatous, entangled with hydatids, and its cavity distended with fluid. III. OF THE DISEASED A1VEARANCES OF THE STOMACH. The stomach and spleen being minutely injected with size, they are to be taken out and carefully exa-" mined. Notwithstanding the very peculiar and impor- tant office ot the stomach,in performing the first change in the assimilation of the food, yet no complicated ap- paratus appears ; it is a membraneous bag similar to the other parts of the canal. 1. The distinctions of the great and lesser extremities, are naturally dwelt upon. 2. The attachment to the former-of the spleen by the vusa brevia, is noted as demonstrating this to be the place of the most important function. 3. The muscu- lar coat of the stomach will of course be traced from the oesophagus, and the motion of the stomach consi- dered in digestion, in rumination, in the borborygmus; its sympathy with the diaphragm in vomiting, 6iC. 7*. 4. Then the other coats will fall to be dissected, the seat of inflammation considered, as for example, how it may be confined to the villous coat, or be evi- dent also in the vascular coat. 5. If the dissector ever means to consider himself as entitled to speak befoie a jury, he will be led to consider the distinction of ul- ceration of the inner coat of the stomach from poison, and that destruction and softness the effect of its own juices, for during life, the property of life in the coats of the stomach, prevents the action of the gastric juice, but if a person be suddenly cut off during health, nothing prevents the secretion of the stomach, which is intended for the food itself acting on the stomach. 6. He will think of this necessary effect of acrid matter acting on the living stomach, viz. that there will be vas- cular action excited, and inflammation or extravasated blood around the spots. Thus, I have seen death from swallowing caustic alkali, where with the black- ness of the inner surface, the substance of the sto- mach was much thickened; and so also in poison of concentrated acid there is the same appearance. In those dying from swallowing an inordinate quantity by spirit, I have found the inflammation attended with re- markable spots of extravasation in the coats. In conse- quence of the poison of arsenic, with the erosion, there is much redness from inflammation and extra- vasated blood. 7. In hydrophobia, from the bite of a rabid animal, I have found large spots of an inflam- mation like erysipelas about the cardiac orifice. 8. In cancer of the stomach, there is sometimes an appear- ance of glandular thickening of the walls of the stomach with ulceration on the inside, it is sometimes like soft cartilage on the inside, or there is a fungous or cancer- ous tumour, hanging into its cavity from the coats of the stomach. 9. I have also met with that very peculiar ulceration of the stomach, which leaves an opening in its side as by the thrust of a svvovd, and by which t!ic content of the stomach escape When " Vol. 1 > the abdominal integuments must also be tied, care being taken to include all the principal branches, as the epigastric aiteiy. And if, at the same time, the 91 thigh is not to be injected, the external iliac artery must be tied, and a cord drawn round the thigh. To inject the thigh minutely from the aorta in the tho- rax, requires a force that might probably burst the unsupported vessels of the intestines or stomach.* The intestines should be kept under warm water, or heated with sponges. The stomach also and blad- der should be filled with warm water; and it should be remembered, that if the stomach be once distended too far, it will never be made to assume any thing of a natural appearance again. The cceliac arteries are those in which rupture is to be expected. By this injection, all the ai teiies of the stomach and intestines, with the hepatic arteries and those of the pel-is and bladder will be filled, while, at the same tune, the membranes will be minutely injected. Injection of the veins.—The veins also must be injected before the intestines are unnecessarily hand- led. There are r.o valves in the veins of the intestines. The liver may be injected from the ramifications of the veins in the mesentery ; or the minute extremities iuthe intestines may be injected from the trunk of the porta. To find the porta as it enters the liver, the stomach should be held down, and the smaller omen- tum cleared away from betwixt the stomach and liver. The vein is then found covered in part with cellular substance, running obliquely across the spine, and parallel to the biliary duct- If uncertain of its situa- tion, the substance of the liver may be pressed gently with the hand, or the blood urged along the veins of the intestines, when the vena portae will rise fi om con- tusion, a large dark blue vein. * By injecting from the thorax, muck is sacrificed to tfte arteries of the viscera. When the thorax is not to be opened the injection may be made from tfte femoral arteries, while the aorta is tied above the cceliac ; but the injection air ways runs better from trunk to branch than in thi. rstro~ gudc course. 92 If the veins of the intestines are to be injected, the tube may be inserted into the trunk of the vena porta near the liver, and pointed downwards. But to in- ject the whole system of the vena portae at once, a tube should be introduced into the ilio-colic vein. This branch is easily found, as it has its name from being subservient to the caput coli, and that part of the intestinum ilium which joins the colon, or the angle formed by the joining of the ilium and colon. It is only necessary, therefore, to fold back the small in- testines from the right os ilium, and to expose the caput coli, and follow up the veins till they have as- sumed a size large enough to admit the tube. After puncturing and introducing the tube, there should al- so be a ligature put upon the vessel behind the tube, to prevent the injection from coming round and escaping. Before throwing in the injection, these veins should be repeatedly syringed with warm water, especially those of the liver. In throwing in the mi- nute injection, it maybe made to run more into the vessels of the intestines by pressing gently upon the trunk of the vena porcae. The vein cava abdominaUs, and the veins coming into it from the liver, may easily be injected by tying the cava above the diaphragm, close to the. right auricle, and injecting from the femo- ral or iliac veins. DISSECTION. The small intestines are now to be taken away, by folding the colon over the margin of the chest, and searching for the beginning of the jejunum, whe.e the small intestine comes out from under the mesocolon, and where it is connected to the spine; then the intestine being tied here with a double ligature,* it should be *An int'stm". to b? rut, m'isifor cleanliness, he tied with a double ligature, so t/iat when cut, the 'two ends may be tf cut betwixt the ligature*i&nd the gut should be se- parated from the mesentery, from this point down- wards following the convolutions of the small intes- tines, and leaving only a small portion of the ileon attached to the caput coli. The intestines will now take a very simple form; only the colon and rectum, and the stomach, lying behind the colon, will be seen, and the duodenum coming from below it; and the course of the jejunum and ilium may be followed from the projecting portion of the duodenum along the edge of the mesentery, till the small intestines end in the caput coli. The whole of the great intestines are to be left. Dissection of the mesenteric arteries.— Here tlie student must go to the Appendix, and read the branches of the abdominal aorta. The colon should be blown up, and kept forming a full arch ; then the vessels of the colon and of the rectum are to be dis- sected, and those of the mesentery, which lie in the middle. These comprehend the distribution of the upper and lower mesenteric arteries. The superior mesenteric artery supplies the small intestines, which have been cut away, and the right side of the great gut, which remains. Its trunk is found coming out from under the mesocolon and stretching over the duodenum. The inferior mesenteric artery is much smaller in its trunk, and less extensive in its distri- bution. It supplies the left side of the colon and the rectum ; a branch runs down over the os sacrum into the pelvis, from which the whole artery has got the name of hcemorrhoidal—See Appendix. close. In the same manner, wften examining tfte diseased inner couts of the intestines, or tfieir co?itcnts,portions in dif- ferent parts oftiw ca)ial should be taken out in this way, and .slit up in a flat bason ; we thenseethe state of the contents, and tfie diseased state of the coats is better displayed. t 94 The dissection is to be begun with the loose mc*en- tery,by dissecting off the peritoneal coat and fat from the vessels. These arteries of the <*luall intestines have no appropriated names, but compose one mass of innume .ibie branches, forming, before tiny reach the small intestines, frequent anastamoses and arches, by which the capacity ot the branches combined must be wonderfully increased in proportion to that of the single trunk from which they arise. From ttic upper mesenteric artery, upon the right side, three branches are given off to the colon. The arteuia ilio-colica, whose ramiii. ations connect the branches which go to the small intestine, and those which go to the colon. It runs down in a direction to the caput coli, and last turns of the ilium. Its branches upon the small intestines inosculate with those branches of the superior mesenteric, distributed to the small intestines in general ; and, upon the great intestine, it inosculates with the second colic branch of the superior mesenteric artery; viz. The coi.ica or \tra which will be found running from the root of t.;e superior mesenteric artery across towards the right side of the colon, where it begins to rue over the kidney, inosculating largely with the last branch downwards and upwards with The colica media.—Tnis branch goes directly upwards f.om the trunk of the upper mesenteric arteiy, as it comes out u uier the me ocolon. After running a little way upon the mesocolon, it divides-; and the division goinrr towards the right side, makes a large circle 1 ion ti.e ' iesoo'on, and forms agreat inosculation wr.h tin : .-t colic artery, while the other divi ion, going towards the left side makes such another sweep, and joins with the left colic artery, which is a branch f.o.n the lowcf mesenteric artery. These two branches of the median colic artery give, off numerous ramifi -ations, which supply a great extent <.' ofthe middle part of the colon. 95 The inferior mesenteric__The branches of the inferior mesenteric artery 'are easily found. The dissection may Tie made backwards, from the hcemor- rhoidal artery lying upon the back part of the rectum. Proceeding up along the gut, numerous branches are found distributed to that part of the intestine which forms the sigmoid Hexture. These are derived from the uppermost branch of the lower mesenteric, and as it supplies the left side of the colon, it is called the colica sinistra ; it communicates with the median colic branch of the upper mesenteric artery and com- pletes a great circle of inosculations, reaching all the length of the intestinal canal.* Of the accompanying veins seen in this view of the intestines.—The branches of the veins run here in company with the arteries, however different they may be in the direction of their trunks. Therefore the names and distiibution of the one set of vessels being known, the other must be known also : for all vessels should be named from the parts to which they are distributed, and not from the trunks from which they are sent off; their distiibution being con- stant, their derivation irregular. The veins, as seen in this view of the parts, preserve auniform course ; their varieties consisting only in the direction of the trunks in which they are gathered to form the vena portae. Returning then upon the demonstration of the arteries. The hemorrhoidal vein, rising from the back of the rectum, may be easily found, the venm cell a situ tra, coming from the left part of the colin, * In tfte direction of the lower mesenteric artery, its root it found entangled by the nerve of the lower mesenteric plena, formed by branches from the sympat/ietic, by favnrhe, from the superior mesenteric plexus, and great cirlhc pl"xu •. The. lower myenteric plexus, surrounding tfie trunk of the artery, send* branch-is out alonj the mi- s.'n'cni to the lit side of the colon, and to the rectum. at. the vena colua meaia, following the artery of that name and returning the blood from the arch of the colon; the vena cotica dcxtru, towards the right side of the colon, and the vena ilio colica, from the caput coli, then one great branch is scmi promiscuously di- vided among the small intestines, and returning their blood to the vena portae. These veins are farther traced in the next view of the intestines. THIRD DISSECTION OF THE ABDOMINAL VISCERA. Containing the Direction of tfte Cwliac Artery of the. Trunk of the Vena Portw of the Arteries and Veins of tfie Stomach of the Liver, Gull-ducts, and Pancreas. Separate the arch of the colon from the stpmach and lay it down. There is now much difficult dissection. The stomach will be seen lying under the projecting liver ; the spleen towards the left end of the stomach : and the pan- creas under it, lying directly across the aorta, reaching from the spleen to the duodenum, and involved in the root of the mesocolon. The cceliac aitery supplies all these parts lying in this uppei division of the belly, above the mesocolott It is the second artery of the abdominal aorta, comin'; off at the point where the great artery seems extricating itself from the diaphragm. It comes directly outfr«m the aorta; a short trunk quickly dividing into branches. The best way to dissect this artery, is to lay down the stomach and to dissect away the lesser omentum from betwixt the liver and stomach. The cceliac artery is then found, dividing at once into many branches ; and as they depart in different directions from one point as from a centre, this is called the axis arterice caliaca. The arteria coronaria ventriculi will be found g»ing off towards the left side, and spreading largely over the upper part of the stomach. If, in dis- J secting it where it goes off from the trunk of the cceliac, it is found to be larger than the other branches, then it may be expected to send a branch to the liver, and should be more cautiously dissected in that direction, vizk a little to the right, and then upwards, till it be lost in ti^fossa ductus venosi of the liver. When there is no branch sent to the liver, it holds its course to the left or superior orifice of the stomach. Here it divides into two "branches : one of which encircles the cardiac ori- fice, and inosculates with the gastroepiploic artery above the spleen ; the other runs down the lesser arch of the stomach, sends a branch over the broad side of the stomach, and, continuing its course, inosculates with the pylorica, or coronaria dextra. (See, in the Appendix, the table of the cceliac branch of the aorta.) In tracing these branches upon the lesser curvature the stomach, we find several nerves, they are branch- of the eighth pair of nerves, or par vagum, which is the neive of the stomach. The arteria splenica arises from the trunk, or axis of the ^celiac artery. It passes under the stomach, and along the borders of the pancreas, where it gives off the pancreaticae parvulae. Continuing its serpentine course it gives the vasa brevia to the stomach and small branches to the mesocolon. When it reaches the spleen, it makes a curve in its bosom, and enters it Vol.1. I J 38 in several branches. It sends off from its branches in the spleen a more considerable branch to the stomach ; which inosculating with the gastroepiploic artery is called the gastro-epiploica sinistra. The artery of the spleen is tortuous ; certainly not to allow the dilata- tion of the stomach : it is not the force of the blood in the artery which curves it, or makes it tortuous ; nor does the tortuous form seem a provision for breaking the force of the blood, as the vein also is tor- tuous. I have elsewhere assigned a reason for this.* The arteria hepatica runs in a direction oppo- site to the splenic artery, towards the rig^bt side. After ^ havina run some way in the direction ot the trunk of the vena portae, it divides, nearly at the same place into four branches, which spread over the trunk of the vena portae. First, there is sent off the arteria gastro- epiploica, so named from its chief branch ; or some times called the duodeno-gastrica, from that brancb of it which goes to the duodenum. This artery descend- i ing under the pylorus to gain the great curvature of the stomach, with its accompanying vein, catches the eye while the viscera are yet entire. It is seen beautifully distributed to the stomach and omentum ; and reach- ing the left and obtuse end of the stomach, it inoscu- lates largely with the splenic artery. As this gastro- epiploic artery runs across the under side of the duo- denum, the pancreatico-duodenalis is sent off. It inns down the intestine, and sends a considerable branch along the pancreas. • The hepatic artery after sending off this branch, almost immediately divides into the right and left he- patic branches; and from the left branch is sent off the coronaria dextra, which turning backwards, spreads its branches upon the pyloric end of the sto- mach, inosculating with the proper coronary of the superior orifice, and with the pyloric arteries, which are numerous and important twigs from the surround- ing greater arteries. This artery sometimes comes * See Anatomy, vol. iv. v. 134, $-c. 99 oft" from the trunk of the hepatic artery (as in the plan of the cceliac.) The left hepatic ar- tery climbing upon the vena portae, enters the liver, and, separating into branches, continues at- tached to the great vein, and is distributed within the liver to the whole of the left lobe, the lobe of Spige- lius, and part of the right lobe. The right hepatic branch, passing under the hepatic duct of the liver is distributed to the right lobe of the liver and the gall- bladder. In djissecting the root of the cceliac artery and the aorta, betwixt it and the superior mesenteric artery much confusion arises, from the meshes of the cceliac plexus, and the branches coming to it from the semilunar ganglions of the splanchnic nerve, a division of the sympathetic nerve, and from the eighth pair upon the stomach. From this plexus an im- mense number of smaller nerves are sent out, forming lesser plexus, along the mesentery to the duodenum, liver, spleen, &c. but plans for the dissection of these nerves will be given in the succeeding part of this work. Of the vena port*.—The vena portae is formed by the gathering together of the veins from the intes- tinal canal, and from the spleen and pancreas of the solid viscera. Near the liver these are collected from three great branches, answering to the cceliac, upper and lower mesenteric arteries. The trunk of the vena portae lies obliquely across the spine. The branch ^swering to the cceliac, is the splenic vein. It forms one of the great arms of the vena portae in the belly ; it is carried in the direction of the main trunk ; it ga- thers the blood from the spleen, stomach, pancreas, and omentum. The veins coming up from the lower part of the belly answering to the mesenteric arteries, are the mesente- rica major, and the mesenterica minor. All the veins from the mesentery, and from one half of the co- lon, meeting together, form the first of these ; which, 100 from its size, is the most important vein of the intes tines. Its branches run in company with the extremi- ties of the superior mesenteric artery, as they are spread from the duodenum, along the track of the intestines to the middle of the colon. It joins the trunk of the vena portae. The vena mesenterica minor carries back the blood from the left side of the colon, and from the rectum, accompanying the lower mesenteric artery in its whole cou'se : and from the branch which mounts up upon the back of the rectum, it has been called the^haemor- rhoidea internea. This vein joins sometimes with the splenica more commonly with the mesenterica major. As the great mesenteric vein goes up under the duode- num, it receives the veins of the pyloric orifice, and those answering to the pancreatico-duodenal artery: and as the trunk of the vena portae runs across the spine towards the liver, it receives the veins from the right side of the duodenum, and lesser arch ofthesto mach, answering to the lesser coronary or right coro- nary of the stomach, then mounting obliquely up- wards and towards the right side, it enters the porta of the liver, and dividing into two great branches, forms the great sinus of the liver. In dissecting these veins, there is much cellular substance to be cleared away ; and it is not easy if the injection be at all brittle, to dissect upon their thin coats without cutting them, or breaking the injection. As the vena portae approaches the liver, it runs Mr rallel to the ducts and the hepaiic artery. They are here included in one sheath of cellular substance, viz. the capsule of Glisson. This was formerly thought to assist the circulation of the blood in the liver, by giving a pulsation to the vena portae. The vena portae, then, is a vein performing the of- fice of an artery in the liver, by distributing in it that blood which it collects from the arteries of the intes- tines. But the proper veins of the liver, the branches of the vena cava hepatica, return their blood directly to the 101 heart. These in their extremities are distributed much like the vena portae ; but upon dissecting the under surface of the liver, they are found, when gathered into trunks, to tuinaway from the porta, and run up towards the attachment of the liver to the diaphragm, and enter into the inferior cava very near the heart. The gall-bladder will be found on the under surface of the liver, half sunk into the substance of the gland; and when tbe liver is in its place, it is nearly horizon- tal. It is touched by the duodenum and colon, as their toeing found tinged with bile in bodies opened after death, demonstrates. The hepatic biliary duct comes from the substance of the liver; runs by the side of the great vessels ; and is large compared with the cystic duct which does not come off directly from the gall-bladder but turns up a little upon its smaller end before it descends to meet the other duct, which it does at an acute angle. They run some way together before they join to form the ductus communis chole- dochus. This common duct, separating from the vena portae runs down, obscured by the pancreas be- hind the duodenum, and betwixt the lamina of the mesocolon ; then entering the coats of the duodenum, it runs some way betwixt them before it opens into the cavity of the gut* ; it generally enters by the same mouth by which the duct of the pancreas enters, al- though sometimes they enter separately. The gall- bladder and ducts may be injected from the common duct, or by piercing the bladder ; and all the ducts may- be filled, by introducing the pipeinto the back part of the bladder, soasnotto injurethe appearanceofthe prepara- tion. Thenerves of the liver are very minute. They come from the eighth pair, and great sympathetic : they run in two divisions, viz. with the hepatic artery before, * To understand the nature of the entrance of the biliary and pancreatic ducts, open tfte duodenum, andexamine it in ivatcr. 1 '2 102 and with the vena portae behind. There are likewise some twigs from the anterior plexus of the stomach. As the opening of the common duct into the intestine is apparently the easier passage, how is the bile collect- ed in the gall-bladder ? The use which is naturally suggested to us, is, to prevent the perpetual discharge of the bile into the intestine, and to reserve it to be mixed with the food as it passes the duodenum. But it is not easy to determine how this is done ; whether by the distention of the intestine, and consequent pressure upon the gall-bladder ; or by the contraction of the gut, and consequent opening of the mouth of the duct; or whether it be not an irritation of the mouths of the ducts themselves, by which the dis- charge into the intestine is regulated, and even the se- cretion promoted. A calculus in the common duct must, if not discharged, disorder the whole system ; but the cystic duct being smaller and more valvular, concretions formed in the bladder if they pass the cys- tic duct, can generally pass the common duct. When there are calculi in the hepatic duct, the ducts which ramify in the liver must be enlarged ; while the ducts below must shrink, and even the bladder and cystic duct must shrink. When the cystic duct is Jobstructed then the gall-bladder shrinks ; and when the com- mon duct, then it is enlarged. There are cases of cal- culi making their way out by the umbilicus, and leav- ing a little ulcer discharging a yellow lymph. This happens by the enlargement of the gall-bladder, and its adhesion to the enteguments. In the Memuires de Ciiirtrgie a case is given by Petit; who was so bold as to operate upon a circumscribed tumour presenting at this place; from which he extracted a calculus, and relieved his patient from extreme agony. But for the most part, those extraordinary cases of knives cut from the stomach, and bodkins from the groin, and stones from the gall-bladder, which at first seem impo-sible, are 103 but the opening of a superficial abscess, where tbe foreign substance having gradually made its way out wardly is almost protruding ; and it is only in such a state of the parts that the operation can be performed. There arc instances of woi'ms getting into these ducts from the intestines, and even nestling and adhering in groups. I. OF THE VESSELS OF THE ABDOMEN, AND THE CIRCULATION OF THE LIVER. The vena portae, which receives the blood from the arteries of the abdominal viscera, is like the other veins of the body, comparatively of a larger size and thinner in it* coats than the arteries. It gathers its branches into one great trunk : (but when it has got into the liver, though it retains the character of a vein in the thinness and inactivity of its coats, yet it assumes the office of an artery ; for it again divides into branches ; and its blood does not flow from its extremities towards its trunk, but, like that of an artery, from the trunk towards the extremities. To account for this further propulsion of the blood, the muscularity of the coats of the vein, and the al- ternated action of the abdominal muscles, is suggested in almo: t every book. But the coats of a vessel, though endowed with muscular power, can give no assistance in propelling the contained fluids, unless an alternate action be allowed. Sow the veins having no pulsation, their muscular fibres contract their diameter only till the force of contraction is equally opposed by the force of the circulating blood and they then become like rigid tubes. If, therefore, the mus- onlar fibres of the veins are proved to exist, and sup 104 {ios-d to accelerate the blood, a pulsation must be al- ow :d also. Ingenious men may perplex even the plainest truths ; bui that the veins have no pulsation cannot be long a question, when the action of the tu-art and vessels is attended to. The uniform flow of blood in the veins is generally accounted for, from the supposed effect of the blood in a vein receiving the imprlse of the heat by channels of unequal lengths. But though this may account for it, perhaps a still more satisfactory reason may be drawn from consider- ing the consequence of the action of the two accelerat- ing powers, the heart and arteries. The pulsation of the heart, by a gradation offerees, which it would be tedious to explain, is continued into the extremities dfthe veins. This is a fact acknowledged by all who wonder how the veins, like the arteries, do not answer to the stroke of the heart. The blood is carried forward to the beginning of the veins by the contraction of the heart, at the same time that the arteries are dilating : and the arteries being dilated, they immediately con- tract and push the r blood into the veins, which, alter- nating with the contraction of the heart, causes not an interrupted stream or pulsation, but a continued flow. Tne arteries beat because they receive a pulsation from the heart's contraction ; but the veins being beyond the arte.ies, receive the force of contraction both of the heart and arteries ; and these succeeding each other without interval, make a continued stream in the veins. To use a familiar example, they are in the situ- ation of the nozzle of a double bellows. If it were asked of those who say that respiration mcchani. ally assirts the circulation of the blood in the abdomen, whcthei these veins are more compressed during the contraction of the abdominal muscles, or during that of the diaphragm ? they would hesitad* fo; t' :erc have been no experiments to ascertain whether th -. pressure upon the abdominal viscera be uniform or not. And surely, from considering the alternate 105 action of the diaphragm and abdominal muscles, the one receding while the other acts, we must conclude that there is an uninterrupted pressure, and before it can be said that even the violent efforts of vomiting and coughing compress the abdominal veins or accele- rate their blood, the state of the thorax in the same actions must be considered, and whether the pressure there be not equal to that in the abdomen. ("Sec Ob- servations upon the Action of the Diaphragm, Part III.) II. That a degree of pressure kept upon these veins by the abdominal muscles and diaphragm, is necessary, we know from an old observation of Bartholine, con finned eveiy day, that, upon opening the belly of a living dog, he observed the veins gradually swell, and become monsterously distended. There are frequent Opportunities of observing in the human body the con- sequence of this tension being taken off; as in the eva- cuation of the waters in dropsy and in childbirth, and even in the sudden discharge of wind from theintes- tines. In slighter cases, it is attended by a peculia r faintish feeling. Sometimes it prqves fatal. In one caserifecorded by the younger Du Verney, the operator, mistaking for dropsy" an habitual distension of the in- testines with air, pushed his trochar into their cavity : the" air rushed suddenly out, the abdomen became flaccid, and the patient died in a very short time There arc other cases, where the patient being wasted and feeble, a sudden discharge of wind while at stool has occasioned sudden death. But this e!>ect is in part to be attributed to the disordered respiration pro- ceeding from the relaxation and weakened action of the respiratory muscles. t 166 III. r It strikes me, that there is in this dissection much deserving consideration, which has yet escaped the notice of pathologists. 1. The first thing which must occur to us as a great peculiarity in the liver, is the number of its vessels, and then again, this vena portae may be considered as being the very re- motest part from the influence of the heart. If therefore, debility happen to be the disease of the vascular sys- tem, it is scarcely possible but that the liver must sutler i 1 the greatest degree. Hence the frequent complaints in the liver of those whose constitutions are exhausted.. 2. The liver, it must be perceived, depends for its blood in a great measure on the state of excitement of the stomach, intestines, spleen, and pancreas, and un- less the arterial system of the viscera be active, there must be a slow motion of the blood in the vena portae. 3. It is further evident that the secretion of the liver is the stimulus to the intestines. 4. As the liver, sto- mach, and intestines are thus mutually connected in function so are they united by nervous connexion and sympathy. These considerations explain more of the common diseases of the abdominal viscera, than the most minute account of the tubercles of the liver, b^t to follow the subject now, would lead us from our proper object. IV An inflamed liver is large, firm and of a purple co- lour ; but the peritoneal surface of the liver is often inflamed and thickened and adhering from a cause foreign to the viscus itself. When the surface of the liver is irregular, we expect tubercles in its sub- stance. These are most commonly the brown tuber- 107 cle, as it is called, being of a yellowish white, and solid. By their growth they seem to press upon and dimi- nish the capacity of the vessels of the viscus. The colour of the liver is as if surcharged with bile. When we consider that the bepatic extremities of the vena portae, are thus compressed by the tubercles, we com- prehend how scirrhous liver is generally attended with water in the abdominal cavity ; for it is probable, that the effusion takes place from the arteries corres- ponding with the intestinal extremities of the vena portae, as pressure upon the iliac vein, will produce cedema of the leg. The defective secretion of the liver if-probably the cause why the gall-bladder is contract- ed and empty. LAST DISSECTION OF THE ABDOMEN. The cavity of the abdomen will now be freed from all the confusion of the viscera. But still a tedious dissection is required to show the muscular and en- dinous parts of the diaphragm ; the passages for the vena cavi, the oesophagus, and aorta; to display the muscles of the loins, the, kidneys, and ureters,the vena cava, and the gene al distribution of the aorta. The diaphragm is the septum which divides the thorax from the abdomen. It arise* musci*!** from lOS the borders of the chest, and tendinous from -the ver- tebrae of the loins. But It has no insertion, unless the mediastinum be so considered ; its action is within itself; it moves no parts a* other muscles do by its contraction; it alters its own convexity, enlarges the chestand draws tight themembtane around the heart. Before opening the thorax, it may be seen how the mid- dle part of the diaphragm is retired up into the thorax, forming a large concavity which receives much of the abdominal contents ; and how it is sucked up and made tense by a vacuum in the thorax. In this state, if the thorax be opened or punctured, the diaphragm is seen to fall flaccid and loose. Observing this, the ., effect of the action of this muscle must be easily understood; that, by the contraction of its muscular part, the arch which it forms into the thorax ap- proaches to a plane, and consequently enlarges the capacity of the thorax, and allows the lungs to re ceive the atmospheric air. The great muscle of the diaphragm, as it rises from the borders of the chest on the inside, should be the first dissected. This exten- sive origin is to be followed round to the false ribs, • and where it approaches the spine, a kind of ligament is found passing from the twelfth rib to the,, vertebrae, forming an arch over the upper part of the psoas mag- nus. This ligamentum arcuatum, it will probably be found difficult to demonstrate satisfactorily ; for the fibres of the diaphragm here are strong, yet loose and flabby, and not easily dissected, as it lies under the kidney, and under much loose cellular substance, and soon becomes putrid. Down upon the spine, an irregu- lar sheath of tendons will be found lying flat and shin- ing, and arising from the ligaments of the lumber ver- tebra. These origins, or feet of the crura of the dia- phragm, may be counted : but it is more important to observe t'ie muscle connected with these tendons, viz. the smaller and posterior muscle of the diaphragm; and how these crura stretch over the aorta and surround 109 it; while, by the direction of their fibres, they are prevented from compressing the great artery. These muscular fibres after passing the aorta, mingle • but they again separate to give passage to the oesophagus, »nd again intersect each other above the oesophagus. The central tendon is the tendon of this great circle of muscle. The fibres composing it are intricate, and 'form irregular interlacements, which yet keep a won- derful similarity in different subjects. Through this central tendon the vena cava pierces, to go up into the thorax. Heie there are no muscular fibres, tie pas- sage being large and free. The fleshy muscle filling up the space at the side of the spine, is the psoas magnus. It is very strong, supporting the trunk upon the lower extremity,, and moving the thigh upon the pelvis. Its uppermost origin is from the last vertebrae of the back ; at which place it is covered by the diaphragm: from this point downwards to the sacrum, it arises from the transverse processes and sides of the vertebrae; which origins are concealed by its belly. It runs under Poupart's liga- ment out of the belly, and turns over the head of the thigh bone to be inserted into the lesser trochanter of that bone. The tendon of the psoas parvus will be found running down on the inside of the belly of the great muscle. The iliacus internus filling up the cup of the ala ilium, may be dissected at the same time, as it accompanies the psoas, and has the same insertion. . To follow these at present to their insertion, would be incroaching too much upon the dissection of the thigh. To dissect the great vessels of the belly when in- jected, u no very difficult matter for it is but clean- ing away the cellular substance from them. It may be observed how the aorta comes out under the dia- phragm. It enters the abdomen upon the left 6ido of Vol. I. K no the spine : but proceeding downwards, it shifts more t. wards the middle of the spine. T.ie vena cava in the upper part of the belly, as in the oreast, does not lie close to the back-bone ; but proceeds from below upwards, somewhat removed from the sjnne, towards the perforation of the diaphragm. 1'ite abdominal branches of the aorta may^iow be enuineiated. 1. The phrenic artery, sent oli as it passes under the diaphragm, or perhaps from the cce- liac artery. 2. The cceliac artery sent off to the sto- mach, liver and spleen. 3. The superior mesenteric artery. 4. The emulgents, one sent off on each side tj the kidneys. 5. The lower mesenteric arteiy, &.c. see Appendix. Be->ides these, the aorta gives off the lumbar arteries, which are seen dipping under the psoas magnus of each side. As the emulgent arteries go off from the aorta betwixt the superior and inferior mesenteric ar- teries, it happens that all the great arteries of the visce- ra are sent out within a very small space; and at this point aneurisms of the abdominal aorta are most fre- quently found. Before the emulgent artery enters the kidney, it gives off small branches to the glandula atrabilaiis (which is a small triangular body, seated like a cap upon the upper end of the kidney, and which dwindles in the adult,) and also to the fat surrounding the kidney. The parts surrounding the kidney likewise receive arteries from other sources, even from the phrenic arteries ; and besides each of the small glands attached to the kidney has an artery peculiarly its own coming from the aoita at the root of the upper mesenteric artery. On thefore part of the aorta will be found small twigs running to supply the lumbar glands. But the arteries which th ere is most danger of destroying, ai e the sper- matic arte ies, which are extremely small, running down parallel to the aorta. The left spermatic artery cdrnes more frequently from the emulgent artery than 11! from the side of the aorta ; the right more generally fioni the side of the aorta. The artery of each side, running down along the psoas muscle, is joined by i s accompanying vein from the emulgent or renal veins : then descending is courses round the brim of the pel- vis to the abdominal ring, where it meets the vas de- ferens as it is about to drop down into the pelvis' to join tht vesiculae seminales upon tlie neck of the blad- der. The emulgent, and consequently the spet matic' veins do not empty themselves, like the veins of the other abdominal viscera, into the vena portae, but into the vena cava inferior ; so do all the veins of the solid walls of the abdomen. The spermatic veins are the only vessels within the abdomen having valves, wnicb. is evidently a provision of their descent out of the ab- domen into the scrotum. To point out in this dissection, the nerves which must be cut; how the anterior crural nerve is compos- ed ; the connexions of the intercostal nerve ; and the uumerous and intricate branches going to the muscles of the loins and belly, would need a long description which would be useless since they must be more fully described in the other parts ; this has been carried beyond its due length. It may, however, be remem- bered, that to dissect these nerves completely, so as to have a comprehensive view of them, the ribs of one side must be cut far down, the diaphragm separated from the margin of the ribs on the same side, while it is kept attached at its tendinous origins f 1 om the lum- bar vertebrae, and held out so thatthe side of the spine may be seen in the thorax and down to the pelvis : then the kidney being lifted from its seat let it be held out, attached only by the ureters and emulgent ves- sels. In this situation of the parts, the sympathetic and its connexions with the spinal nerves, may be dissected in the thorax above the diaphragm : and the anterior branch or splanchnic nerve, sent off in the thorax, can be traced through the diaphragm to the 112 ganglious about the root of the cceliac artery ; and the continuation of the sympathetic nerve may be seen running neai the root of the ribs, down the spine As the sympathetic descends, it comes move towards thefoie part of the bodies of thg. vertebrae: here it receives additions from each lumbar ganglion, and sends at the same time numerous small b. anches ovter the great vessels, and finally ends in the plexus within the pelvis. PART II. CONTAINING THE DISSECTION AND MORBID ANATOMY OF THE BRAIN. •ISSECTION OF THE BRAIN. When the brain is to be dissected for the demon- stration of the anatomy merely, the head should be injected with fine size. The effect of this injection, is to give firmness to the brain, by which the dissec- tion is much facilitated, and the cavities, and vessels, and plexus are more elegantly displayed. But if the brain is to be dissected, to discover the seat of disease ; the head must not be injected, for by that means the colours of disease would be blended or totally de- stroyed. I shall now suppose, that a young surgeon has to make a dissection of the brain, and to give a report of the diseased appearances. I shall describe the manner of dissecting the brain ; the method of distinguishing the principal parts, and at the same time notice all the K 2 114 variety of morbid appearances which may chance to occur. An incision is carried from ear to ear cutting through the scalp. The skin is then dissected off the cranium and drawn over the face and over the occiput. The scull-cap is then sawn in the circle, on a level with the highest part of the ear, it is burst up and separated from the dura mater, and the head is finally placed for the nice dissection of the brain. The scissors may now be run along the longitudinal sinus, and the manner of the opening of the veins into it noticed, and the glandula Pacchioni and the trabecula or little pillars like tendons. The corda?. Willisiance ai e better seen on the inside of the dura mater. REMARKS ON THE FIRST STAGE OF THE DISSECTION. Very little consideration will teach us that much of the accuracy of a report on the state of the brain, de- pends on the attention which has been paid to the state of the circulation as indicated by the dissection. 1. Even before opening the skull, it behoves us to mark how far the vessels of the scalp are loaded with blood, and to remember, that there is often a fulness of the cellular membrane with blood and black dis- colouration, which is an effect of the gravitation of blood after death, and which may be on the occiput or temples according to the position of the head in death ; we must distinguish this from the effect of 'blows or inflammation. 2. On the observation of the difference in the quan- tity of blood without and within the cranium,, the nature of the disease, may, perhaps, rest to be ex- plained. 3. The size and form of thecraneum, may be wor- thy of attention especially in children. 4. The degree of resistance in raising the cranium; 115 may vary much, but this has relation to the age, &,c- anu the constitution of the bone, not to the disex-e of which the patient died. 5. The quantity of blood which escapes on raising the skull-cap from the dura mater : the colour and de- gree of fluidity is to be observed. The sinuses and the meningeal veins may be loaded with blood, so that the dura mater appears of a dark blue inclining to purple. It may be only moist with a thin watery blood; it may have the appearance of inflammation. 6. There is not necessarily a relation betwixt the inflammation of the dura and pia mater, or at least I may say, that the dura mater being properly the mem- brane of the bone and the pia mater, that of the biain, marks of increased activity of the circulation of the brain are apparent, when the dura mater is not affected. OF THE DISEASES IN THE BONE AND DURA MATER. Under this head I place such instances of derange ment as are not symptomatic of the state of the brain, viz. the immediate consequences of injuries on the head ; the secondary consequences ; the diseases inde- pendent of injury to the cranium. 1. In injuries of the bone with fracture, there re- quires little aid of morbid anatomy, to inform us of what is most important. We know when a blow has been recently received by the blood in the fissure or under the bone ; on the contrary, if there be in- flammation on the membranes the person must have survived the blow some time, if matter is in the fissu res or on the membranes, a considerable time must have elapsed. 2. When there has been a blow received, though 116 there be no fisure outwardly discernible on the crani- um, yet we look for the breaking in of the taWa valrica. 3. Although there may be no fracture, there may be extravasation of blood under the cranium, owing to the shock and consequent separation of the dura mater from the bone. 4- If a man has received a blow on the head, and after lingering has sunk, although there may be no frac- tuie, those appearances may present,—under the tumi- fied scalp, and betwixt the pericranium and the bone, t .ee is exuded serum, on the inside of the skull there is pas, for the dura mater has inflamed and separated from the bone and pus is betwixt them ; the dura mater is red, with enlarged vessels, the colour is bright and diffused : if the dura mater be thus affected, most assuredly the brain will have partaken of the disease. 5. A rare occurrence is a sharp spine of bone growing from the inside of the cranium, in consequence of a smart blow which has bruised the bone. I have seen such a spine as sharp as a prickel of a thorn. 6. the nature of the fungous tumours of the skull and dura mater, are not easily understood.* There are observed little bodies soft and like glands, which pro- ject from the dura mater ; and these may be so large, as to have corresponding pits in the skull-cap, but they are natural. The fungous tumour of the dura mater may be thus described ; there is a soft pulsating tumour under the scalp, in death it is found that the bone is deficient, and that this tumour is a fungus of the dura mater, the dura mater being examined from the inside, appears thick and very vascular, and the tu- mour adheres or is rather incorporated with the mem- brane. Sometimes the fungus has irregular pieces. * Memoires de VAcad. de Chirurg. torn. v. tumeursfon- gueuses de la Dure-mere ; see also the very interesting cases and obnervationi, Principles of surgery by J. Bell. vol. a. p. 2 ■ 117 of bone within its substance. Two of the first pathologists of the present age have declared such an ap- pearance to be the result of a tumour of the dura mater, destroying the skull, and at last bursting through it. I conceive it to be a disease of the bone, (of which the dma mater is a constituent part as much as the pe- riosteum of the common bone,) and that the eaith of bone being absorbed, there remains only the soft tumour of the membrane, and the vessels of the bone. It must be distinguished from fungus cerebri. Scrophu- lous tumours are said to have been found connected with the dui a mater. I never saw anything like this. 7. When in venereal caries of the cranium, the bone is destroyed with a circular opening, a fungous like tumour grows into the opening, but I have found it only a thick layer of coagulable lymph on dissection. When the opening by this caries is large and irregu- lar, I have found the dura mater cut, and a fungus cerebri the consequence. 8. Thickening of the dura mater is described but I have not seen it independent of disease of the skull. The dura mater adheres to the surface of the brain sometimes, but this is no cause of death, nor in my mind to be counted as the cause of symptoms unless there is accompanying inflammation. 0. Bone is found in the dura mater, in the falx and tentorium. The instances on record of mania cephalalgia, syncope, vertigo and convulsions, fi om ossified uura mater are numerous : but as I have often found them where during life there was no symptom even of uneasiness to mark their presence, I cannot give entire belief to these relations ; yet I will not deny that when these concretions press upon the surface of the brain, they may sometimes produce convulsion or insensibility. 118 SECOND STAGE OF DISSECTION. I speak now of the natural anatomy. The dura mater is now cut w'uh the scissors all around close by the bone, then it is turned up, when the falx is found to be a process of it, and to descend deep betwixt the two hemispheies of the cerebrum. 1. The nature of that adhesion which is betwixt the dura and pia macer near the longitudinal sinus is to be remarked. 2. The course of the veins of this surface of the brain and their manner of entering the sinus. 3. The deli- cate and transparent tunica arachnoides, is to be no- ticed, and the distinction of the firm opaque dura ma- ter, the transparent and colourless arachnoid coat, and the delicate but vascular pia mater. Now we insinuate the scissors horizontally betwixt the anterior lobes of the cerebrum, and cut the falx fiom the crista galli and frontal bone, we raise it out of the great fissure, and we turn the whole dura mater backward, and now see the whole upper surface of the cerebrum. 1. We see the reason of these great divi- sions being called hemispheres ; we recollect that tbe lesser divisions into three lobes are to be seen only on the lower surface, and that the cerebellum and me dulla oblongata are lying deep in the bottom of the cranium. 2. We separate the hemispheres, p-cssing them gently aside and cutting the entangling pia mater; we then see the artery t>f the corpus callosum. 3. We raise the arteries and then we discern a white body, the corpus callosum or commissura magna. The hemispheres being replaced, the knife is carried horizontally cutting off a section from one of the he mispheres. 1. Then the distinction of cortical or cineritious and medullary matter is observed. 2. The manner in which the pia mater descends betwixt the convolutions of the brain. 3. The vascularity of the 119 cineritious matter. 4. The open mouths of vessels and the spots of blood in t he medullary substance. DISEASED APPEARANCES ON THE SUR- FACE AND SUBSTANCE OF THE BRAIN IN THE SECOND STAGE OF DISSECTION. 1. The most frequent diseased appearance of these parts, is that of extravasated serum lying under the tu- nica arachnoides. In reading Bonet. I. i. s. i. de Do- lorc Capitis, we find many instances of serum and blood, and bile, lying on the membranes, and producing dolor, gravedo and cephalalgia. There is no trust to be put in this. I have found it in those dying of fever, of. drukenness, of hydrophobia, of hydrocephalus, of phrenitis, of serous apoplexy, in short it is a con- sequence of an increased activity of vessels. 2. We have, however, to remark whether this effusion un- der the surface, be attended with an inflammatory state of the vessels, or if they be empty. 3. While the outward delicate and transparent membrane is entire this fluid looks like jelly, and has been often des- cribed as coagulatedlymph. But coagulable lymph accompanies a truly inflammatory state of the mem- brane, while this is the effect of an increased activity of vessels, the first oftener follows blows on the head, the latier will be produced by such increase of circu- lation, as is consequent on excessive drinking, or after taking opium, or a fever, &.c* It is to be noticed, when coagulable lymph is thrown out upon the surface, * We find him attributing dolor capitis to tfte serum ex travasated on tfte membranes, or to the veins being loaded with black blood. The membranes of the brain, are not sensible. Sw/i appearance denotes rather that the patient's death has bcci preceded by oppression of the semes. 120 whether or not there be a mixture of pus with it, mak. ing it of a dull or turbid colour. 4. Tne ;>ia mater is the most apt to inflame of any membrane in the body on the contact of disease or from injury. We must care- fully distinguish betwixt the congestion Oi blood in the vessels and the true effect of inflammation. The bii^hter red, and especially when the redness is diffused in the interstices of the vessels denotes inflammation ; while the retarded circulation produces only turgidity of the vessels. 5. Va,a cerebriJlatulenta is a title of Lieutaud, and Morgagni has much to say on the same subject; if morbid anatomy be the knowledge of the effect of dis- ease in the body as seen after death, we have nothing to do with that title here. The air which we see lodging in the vessels of the brain is generated by che.nical agency alone, after death. The moment that air, thrown into the circulation of a dog or cat reaches the brain, all animation is extinguished, we cannot th -refore suppose that air exists in the vessels during the life*. 6. The convolutions of the brain are sometimes parti ularly distinct and hard. I have found this combined with water on the surface, and in the ven- tricles when the patient had been years in a state of fatuity. 7. Sometimes the substance of the brain is irregularly hard. Sometimes it is more than usually elastic. 8. 1 have dissected the brain, where I found that when the razor was drawn through it, it was torn up aud exhibited a number of hard tubercles". The whole cereHrum was thus diseased with irregular tu- bercles covered with numerous vessels. The child was long stupid and lethargic. In general, in all long con- * In Roneti sen. we have examples of the dura mater being blown up. Tfte observation ftere, will I fancy, equally apply to such appearance.—L. I. sec. 1. ob. xxxt. 1-21 tinned diseases of the brain, there is water in the vcn- 'tricles but I am inclined to think it a vulgar error in such cases to attribute the coma to the pressure of the waLer. 9. In the substance o>'the brain, weihay find small tumours or nodules, they can be felt with the lin- gers : I am given to understand they are frequent in epilepsy. 1 have found tumours of the cineritious matter of the middle lobe, but tumours, or nodules are more common in the medullary matter of the cere- brum and cerebellum. In the centre of these tumours $ have foud a disposition to suppuration. In this part of pathology, there is something not well understood : from the common opinion, we should be led to sup- pose that a tumour growing in the cavity of the crani- um, must press on the brain, and produce insensibili- ty, yet I have found the symptoms quite irregular, sometimes the patient would be for a time oppressed and revive from this state to relapse in the end into a worse degree of oppression : nay, I have found three tumours in the medullary substance of the cerebrum and cerebellum, where during the whole course of the disease, the child shewed a remarkably increased sen- sibility and quickness of apprehension. The sensibi- lity and the oppression of the senses and faculties de- pend on the state of circulation ; and disease, in the first instance, is attended by a slight increase of acti- vity in the circulating system, which produces increase of sensibility and perception, while a greater degree of the aiterial action will produce effusion of serum, and oppression. Were we at liberty here to carry the in- quiry further, I am confident this opinion could be sustained. 10. Abscess: 1. The brain is the part of the whole body the most apt to fall into inflammation and abscess, especially when the irritation is made through the hones and membranes. 2. When for example, there is a portion of the skull dead, the dura mater separates Vol. I. L 122 from it, and while pus is on the outer surface of that membrane, the inner surface adheres to the pia mater, pus is at the same time formed on the surface of the brain ; an abscess eating deep into the brain is the con- sequence. On dissection we rtietimes the spinal marrow, as well as the brain, is deficient.----From the scalp in these cases of mal- confoiination, there is commonly either a soft sac which hangs backwards, or a soft spongy tumour eel. Iular and full of fluid. A SYSTEM OF DISSECTIONS OF THE THORAX. THE present subject shall be divided in such a way that each branch of it may be comprehended in one dissection, or view of the parts, as they lie in the dead body : and those parts of the anatomy shall be chiefly dwelt upon which are useful in dissection, or in understanding the local or organic diseases. The two first dissections of the thorax naturally include the muscles and blood-vessels w ich lie upon the breast and lower pa. t of the neck ; then proceeding to the viscera, the appearance of the heart, lun.s and mediastinum, upon lifting the sternum, makes the second division ; next the manner of displaying the heart is to be explained ; afterwards the injection «f 136 the heart with the dissection of the great vessels pro- ceeding from it. Lastly, the morbid anatomy of the breast will solicit attention : first, aneurisms, and the diseases of the heart and larger vessels, vith the cir- cumstances which are to be observed in the dissection of those diseases; and secondly, the diseased appear- ances of the lungs, of the pleura, and of the cavity of the chest in general. It may however, be proper further to observe in this place, that in explaining the situation of the heart and great vessels, and the play of the lungs, it is impossible to overlook the deficiencies in the ac- counts that are given of the mechanical action of the heart and vascular system, and of the effect of respi - ration upon the action of the heart, or rather of the manner in which its effect upon the heart and veins is counteracted. And it surely will not be thought too great a departure from the plan and limits of this book to touch slightly upon these important points. ^ FIRST DISSECTION OF THE THORAX. 'Ike dissection c the muscles and blood-vessels which lie upon the atAae of tfte chest, and lower part of the neck. Nothing confounds a person more in dissection than an ignorancepf the parts which immediately sur- J Tound that upon w\ich he is employed : therefore, in explaining the dissection of the outside of the chest, it is proper to poin0ut, not only the muscles, and the branches of the rteties which lie upon the chest, but those likewise wi^ch lie in the axilla, and upon the neck, as being stictly connected with them in every useful inference o be drawn from the anatomy of the part. FIRST DSSECTION. Make an incision from tje thyroid cartilage down the middle of the sternum; and extending below the scrobiculus cordis; then mike an incision in the di- rection of the clavicle, and ?ver the top of the left shoulder. In dissecting the integuments of the breast, ca,. y tfie knife in the direction of the last incision ; by which the pectoialis major muscle and the deltoid muscle will be smoothly dissected in the direction ©f their fibres. M 2 138 No fascia will be found expanded over tie muscles which lie upon the chest; but the fibres '- tions of the Mucous Membrane 4>f the Bronchia, by Di Badham. 156 From examining the state of large arteries, cither when stopped by ligature or by an effort of nature, as in the formation of abscesses.it would appear that the for- mation of coagula depends much, if not entirely upon the coats of the artery. In ulcerated surfaces, and in the formation of matter (as in the present instance, in the lungs,) the coats of the artery, partaking of the inflammation in which it is involved, and which ex- tends from the surface ulcerated to the surrounding parts, form a clot by the exudation from the inner surface of the vessels, and partly from the mass of blood in its cavity.—And the clot thus formed has a firm hold upon the sides of the vessel, and an intimate connexion with it. It is the connexion with the surrounding parts which supports the arteiy of an aneurism, or ofa stump, after being tied. This con- nexion, by supplying its little vessel, gives support to its inflammation, and assists in the production ofa healthy clot. But if the artery be left exposed in the middle of an abscess, or left dissected from the sur- rounding parts, then that part which is exposed will have no proper clot or contraction of its coats ; but the coagulum which stops the bleeding will be found at that point of the artery which has a connexion with the surrounding flesh. If, again, the coats of a vessel tied in an aneurism be diseased, partaking of that ossified state which has already been fully described as accompanying the dilatation of arteries, they will probably be rendered by irritation un- susceptible of active inflammation: and upon the cutting of the artery by the ligature, there will be found .no proper clot formed on the artery coalescing with its coats, so as in time to form a com- plete union ; but, on the contrary, there is nothing to restrain the blood from flowing but the mechani- cal tying of the ligature, so that immediately upon the cutting of the artery by the ligature the blood escapes. It is certain, that in those dissections 157 described by Hallcr and others in which the mouths of the trachea and great vessels were seen projecting from a remaining bud of the lungs, the clots must have been formed a little within the mouths, and the vessels closed up in the common manner. Of concretions of the lungs__Earthy concre-1, tions, I would be inclined to say, are frequent in the lungs. Sometimes they are united with abscess in the substance of the lungs. They are found in irre- gular cysts, crumble easily in the fingeis, but take a stony firmness when dried. They grate upon the knife in dissecting the lungs ; and, it would appear, are sometimes found in the extremities of the branches ofthe trachea : the greater masses are near the trachea. I have seen them so large as to press upon the aorta and upon the trachea, turning them from their seat. Of blood extravasated in the lungs.—I have examined the lungs of those who have been suddenly suffocated from hcemoptisis. In a young man cut suddenly off in this way, the vessels in the neighbour- hood of an abscess had given away and filled the whole bronchiae, so that no air could be drawn into the air|cells. Of examining the trachea.—It will frequently be necessary to examine the inside of the trachea through its whole length, as it is often the seat of dis- ease. It may be necessary to examine it to know the cause of suffocation :—it may be compressed by tu- mours ;—it may be eroded by obstinate ulcers ; it may be ^inflamed, and polypous membranes may have been thrown out from its inner surface; or the co- agulable lymph in hamorrhagy may attach to the surface and being moulded to the branches of the trachea, be previous like a tube. When the trachea is to be examined, in order to trace a disease which is connected with the lungs, the incision may be continued from the thorax upwards upon the fore part of the neck, and the trachea laid bare :—and being cut below the thyroid cartilage (or even the Vol. I. O 158 whole larynx being dissected out,) it may be dissected from the oesophagus, and carried down to its bifurca- tion in the lungs ; it being kept at the same time at- tached to the lungs by its branches. It can then be opened upon its back part, and slit down its whole length, when any polypous membranes thrown out by inflammation may be distinctly shewn, and traced in their progress in the lungs. When the trachea is re- placed, and the incision upon the neck sewed up, the Body is left in no way unseemly about the lace ; which in private dissection must always be avoided. The dissection of the throat and its diseases are con- sidered in the succeeding part. Diseased appearances in the mediastinum.— The posterior mediastinum which surrounds the great vessels that run down the spine behind the great vis- cera of the thorax, is not unfrequently the seat of disease. The lymphatic glands which lie at the root of the lungs arc sometimes diseased; they are en- larged ; or gritty matter is found in them which grates upon the knife ; or they are found in a state of sup- puration. Their disease will perhaps account for some ofthe symptoms which may have occurred du- ring life ; for they may be found to have compressed the trachea, the oesophagus, or the greart vessels, the aorta, thoracic duct, or vena azvgos. When the conglobate glands are affected in one part, it will be commonly found more or less a general disease in the thorax, in the course of the aorta and iliac vessels, in the mesentery, &c. When abscess forms in the posterior mediastinum, it has no outlet, and it has been known to make very strange and exten- sive sinuses amongst the cellular membrane, even to have continued its course until it presented in the usual place of lumbar abscess, at the groin. 1. The anterior mediastinum differs in no res- pect as to its diseases from any other deposit of cellular membrane where there is much fat and many ('glands 159 and blood-vessels. 2. (It is subject to inflammation and the formation of abscess. Matter here has destroyed and rendered carious the sternum, forming a soft tu- mour, with fluctuation above the bone. In such cases the pulsation of the heart being communicated to the matter, an aneurism has been presumed, and the patient terrified with the idea of sudden death. 3. Although I have said that matter may destroy the sternum, yet I believe it is oftener the reverse, viz. that the scrophu- lous disease of the sternum fills the anterior mediasti- num with matter. 4. A hydrops mediastini is spoken of, but it must be a singular occurrence. 5. The thymus has been found schirrhous, and concre- tions have been found in it, but 1 have seen no in- stance of the disease of the thymus. A great accumulation of fat here has been consi- dered as a serious disease, and even upon dissection assigned as the cause of death. The premature accumulation of fat upon the viscera may be considered as a disease, though in old people it is natural. This load of fat upon the viscera is the last stage which the adipose membrane undergoes from the foetus to old age. But the appearance of the fat, and the place of its deposit, are more changed than its quan- tity. It is hot drawn from the extremities to the heart and v iscera, but from the surface to the interior parts. In the foetus, when the firm and unelastic integu- ments are dissected off, the muscles are left bare, and the further dissection is easy, the fat being firm and insulated, and external chiefly. Here the delicacy and neatness and beautiful form of the muscles and ten- dons will be as much the object of admiration as in the adult. The integuments of the foetus in deli- very is its great strength. In a youth, whose limbs have become shapely, the fat is more equally diffused over the interstitious cellular membrane, the dissec- tion becomes more difficult. And in old age it has become still more tedious and impracticable ; for 160 every part oozes out oil, and the dissection can never be freed from fat. The fat, which to the infant gave unformed rotundity, and to the middle age symmetry and shape, has left the integuments, and is more equally distributed ; it is now more accumulated about the internal parts, and more intimately blended with them. The fat does not remain in the cells any length of time, but like the rest of the body, it must suffer a pepetual change ; be resumed into the circulating system, as subservient to other uses, whilst the cells are at the same time filling with a new deposition. It is natural to suppose, that the state of the fat changes with that of the solids, and has a strict connexion with the ecomony of the body. Yet how insufficient is that explanation of the accu- mulation of fat about the viscera which assigns to it the use of rendering pliant and easy of motion these important parts, which are now stiff and inactive with old age ! it is to suppose the most important viscera ofthe body to be greased like the wheels of an engine. The membranes of the body, though loaded with fat, are not oily upon their natural surface : the attri- tion of surfaces in an animal body is prevented by their own secretion : and the animal oil, though it escapes, upon the adipose membrane being slit up, yet in the living body it cannot transude, to oil the moving parts. It is not long since the opinion was enter- tained, that the fat was laid in the track of the coro- nary vessels of the heart, to preserve them from those diseases to which the arteries were liable in other parts of the body, and the evil consequences of which would be manifold in the heart. The pericardium is a strong white and compact membrane ; smooth upon the inside towards the heart; never adhering to the heart but in disease ; and moistened with a continual exudati n. It supports the heart in its place, allows it free motion in its 161 natural play, and restrains it in its inordinate actions. VV hen we lay open the pericardium (by slitting it up on the fore part,) and expose the heart, the right ventricle protrudes ; the right auricle is towards us ; the left auricle is retired, and its tip is seen lapping round upon the left ventricle : from under this tip of the left auricle, a branch of the coronary vein and artery proceeds down to the apex of the heart. The course of these vesseh may serve as a mark of the division of the ventricles by the septum, by which the cavities of the heart may be laid open ; for they run parallel to the division of the two ventricles by the septum, and a little to the left of that division. If this mark, or the natural division of the ventricles, be not sufficiently distinct upon the outside of the heart, by grasping the heart in the hand, the left ventricle will be found firm, fleshy, and resisting ; whilst the right ventricle is loose, and feels as if wrapped round the other. But these marks, by which the heart isdo be dissected, will be afterwards observed more particu- larly. Following up the right ventricle to the root of the artery disemboguing from it, we find the artery be- twixt the two extremities of the auricles ; then it seems to turn -entirely round under the arch of the aorta ; but it sends only the right pulmonic branch under the aorta, while the left goes to the lungs of that side. The aorta, again, seems to rise from the middle of the base of the heart, and takes a turn forwards from the left ventricle, which lies in a manner behind it/ Even in the uninjected state of the heart, it can be observed how it is placed towards the left side of the chest, and how in its position, in regard to the ventri- cles, it is oblique too ; as that ventricle which is call- ed the right is almost diiectly forward, whilst the left is behind, and almost completely hid by the right ventricle. It may also be seen how both ventricles 0 2 162 rest upon the diaphragm, making the lower surface flat, as if moulded by its own weight, and forming its obtuse and acute margins; its point or apex being turned forwards, and towards the left side, so as to strike its pulsation upon the jo ning of the cartilagin- ous and bony part of the fifth rib. Holding the pericardium from the right auricle, the inferior cava is seen coming up through the dia- phragm, and the superior cava coming down from the upper angle of the pericardium, and behind that part of the aorta which is within the pericardium. A probe can be introduced behind the superior cava ; in which case, the probe will be insinuated betwixt it and the veins going fiom the right lung to the left auricle. Upon lifting the heart from its place, and pressing up- on the back part of the pericardium, it astonishes us at first to find the back bone projecting so far foiwards, and resisting the finger. These marks are very useful in txamining the parts in disease. It is useful to ob- serve the situation ofthe heart in the breast because, being held in the same position when it is taken out of the body, the manner of laying it open can be simply described, and the description of its diseases easily understood. In tracing the pericardium up to its connexion with the great vessels, it is found to be reflected from those vessels over the whole heart, and to form the outer covering of the substance of the heart. But here it is more delicate, and ofa totally 'different na- ture from the proper pericardium. When this mem- brane which covers, the heart is considered as the peri- cardium continued and prolonged, we are obliged again to explain its situation, when entire, by the awkward supposition of a sac, emptied and laid upon the heart. In which case, the outward layer would represent the pericardium ; and that which was in contact with the heart, the membrane of the heart itself. That the connexions of the pericardium may 163 be understood, it is only necessary to lay it open ; but to demonstrate it more completely, a tube and stop-cock may be introduced by a small puncture, and the paricardium strongly blown up : then the layers of the mediastinum may be dissected a little off it, and the connexions at the root of the great vessels shown, with its vessels, nerves, &c. It may be observed, in regard to the pericardium, that the heart is never what we would call completely filled ; that is to say, the ventricles and auricles are not distended at once ; but the action of these alter- nating with one another, the pericardium, instead of being alternately distended and relaxed, must, in the reoular actions of the heart, be much more stationary than we are at first aware of. So, in injecting the heart though the pericardium, being entire, may restrain the too great enlargement of the auricles or ventricles, yet it is no measure of the quantity of in- jection to be thrown in ; and it can give no assurance ofthe heart being filled with its natural proportion of / fluid ; for either the quantity which belongs to two ofthe cavities of the heart may be divided among the S four, or if all arc filled to the utmost of their natural distention, the investing pericardium must be stretched beyond its due extent. DISEASED APPEARANCES OF THE PERI- CARDIUM. 1 Upon opening the breast, there is always more or less water found in the pericardium. When the ouantity is considerable, it is commonly accompanied Sh/drothoTax.or with general dropsy : the colour of theVid takes a tinge from the blood after death in the same way as macerating the heart in water 164 would colour the water, though the cavities of the heart were tied up. 2. The pericardium is supposed to have a greater proportion of water, because it has a greater degree of motion ; but the additional explanation of Mr. John Hunter, viz. that the water may also fill up the inter- stices betwixt the rounded surfaces, though ingenious as applied to the pericardium, does not mark a differ- ence betwixt other cavities and the pericardium. Even the smaller collections of water in the pericardium are frequently accompanied with similar collections of water in the other cavities of the breast, and even in the belly ; but water, if contained in the pericardium, is at once observed ; while the smaller quantities of water in the cavity of the breast sink behind the lungs, and are not distinguished. Extravasations of water into the pericardium are common in all lingering diseases, where the strength of the system is much exhausted some time before death. It is probably thrown out in the last feeble efforts of life. It is observed, that how- ever much water there may be contained in the peri- cardium, still, upon dissection, this membrane is not found distended, but appears rather loose about the heart. This may happen from a deficiency of blood at this time in the heart, while in the living body the heart, during its utmost distention, may have been closely embraced by the pericardium. 3. Indeed I believe that all sacs containing fluid are less stretched on dissection than they were during life, and I imagine this proceeds from the function of the absorb ents continuing longer than that of the arte rial system. 4. In the pericardium there are often found spots of extravasation, the effect probably of recent inflam- mation. Sometimes the inflammation is more gene- rally diffused over its surface ; or we find adhesions formed at different points betwixt the heart and peri- cardium ; and it happens, also, though rarely, that 165 the adhesions are complete in all the extent, uniting the pericardium with the whole surface of the heart. 5. Exudation of coagulable lymph is frequent within the pericardium. The lymph thus thrown out being by inflammation connected with both sur- faces (with the heart and with the inside of the peri- cardium,) is found drawn curiously into fibres ; or perhaps taking a firmer hold upon the heart, and forming no communication with the pericardium, it is found adhering to the heart with an irregular and spon- gy surface, or sometimes it is curiously reticulated. 6. The pericardium is liable to a more permanent disease. It becomes thick, so as to be easily sepa- rated into layers like the coats of arteries. And al- though we should not suppose such membranous surfaces as the pericardium liable to such a disease, it has been found studded over with white schirrous tumours, containing pus. Matter, too, is found upon the surface of the heart; for it is subject to ulceration. I have seen it irregular and foul, with disease upon the surface, and covered with a viscid matter ; so that it seemed won- derful that the patient could have existed for a mo- ment. In such a case as this, we may naturally ex- pect to find the lungs adhering to the outside of the pericardium, and the pericardium to the heart. 7. I have seen a fracture of the ribs, form exten- sive sinuses with caries, affect the lungs, communi- cate disease to the pericardium ; the pericardium was thickened, and contained much matter within it, a small opening communicated betwixt the sac of the pericardium, and an extensive abscess in the lungs. The substance ofthe heart too was diseased, the outer membrane greatly thikened, and a greenish, thick, and adhesive matter was upon its surface ; yet here, in the last days of the man's illness, there were no 166 peculiar symptoms, nothing differing from a common hectic fever. 8. I have found the pericardium transparent ;it was in a case of angina pectoris. 9. When the blood is found extravasated into the pericardium, it would appear that it is sometimes dif- ficult to distinguish the rupture from whence the blood came ; whether it was from the root of the aorta, from the erosion of the ventricles, or from the coronary veins or arteries. And in all ruptures it will be frequently necessary, after carefully examining the coats, to wash the heart out with warm water, and to syringe it gently into the great vessels, observing carefully from whence it jescapes. When blood is extravasated into the pericardium, it does not support the action of the heart by its resistance to dilatation; but, on the contrary, the more that the pericardium resists, the more it must encumber the action of the heart: and when at last the disease proves fatal, it is by the extravasated blood suppressing the action of the heart ; for in proportion as the action of the heart is great in propelling the blood betwixt the heart and pericardium, so must the compression of that blood be in resisting the future dilatation of the heart. OF OPENING THE HEART TO DEMON STRATE ITS INTERNAL STRUCTURE ;— AND OF DISSECTING THE COATS OF ARTERIES. Supposing the heart to be rudely cut away, with its vessels short, and to be held nearly in the position in which it lies while in the body, these marks may lie observed : 167 First, The pulmonary artery is before the aorta; and these vessels are in a direction crossing each other. Secondly, Upon the left side of the pul- monary artery, the tip of the left auricle appears ; and under it a vein and artery, descending to the apex of the heart. Thirdly, the right auricle lies behind, and towards the right side of the aorta : a Sirincipal vein and artery are seen emerging from the at at the base of* the ventricle, and under the margin of the auricle ; they likewise run down to the apex of the heart. If the great arteries have been cut close to the heart, the play of the semilunar valves may be observed by looking down into the vessels, and rais- ing the valves by blowing upon them with the blow- pipe. Of the right auricle.—A small part of the trunk of the vein should be left unopened; for when it is entirely slit up, it will not be always easy to dis- tinguish the mouth of the vein, nor, consequently, the situation of the parts as relative to the course of the blood. Introduce a probe or blow-pipe into the lower cava, carrying its point to the projecting part of the auricle, which lies contiguous to the root of the aorta. Using this as a directory, the auricle may be slit up by which the Eustachian valve, and every important part, will be avoided. Con- tinuing to hold the heart nearly in the same situation in which it lies while in the body, the remains of the foramen ovale may be seen in the partition di- viding the two auricles. This fossa ovalis is .an irregular depression, of an oval fo> m, with its border especially upon its upper part) elevated into a ring. Its margin is white, and has somewhat the appear- ance of tendon. Within this there is a circle of those fleshy fibres which form the musculi pec- tenati of the auricle; and the membranous part in the middle, which performed the office qf a valve 168 in the foetus, is white and firm. This membranous part seems continuous with the margin upon the lower part, while, upon the upper part it goes behind the margin of the fossa : and here it may be examined with the probe, if the valve be still open, which it sometimes is. If the lower cava, where it expands into the auricle, be held open, or if the vein be slit up with the auri- cle, then, by extending apart of the auricle upon the left side of the vein, there will be seen a membrane stretching from the inner side of the margin of the foramen ovale, round upon that half of the root of the vein nearest to the opening of the auricle into the ventricle. This is the Eustachian valve : it is like a duplicaturc of the inner membrane of the auricle. Behind the Eustachian valve is the opening of the great coronary vein ; which vein running round the margin of the left auricle, gathers the smaller corona- ry veins. The little semilunar valve on the mouth of this vein was likewise first described by Eustachius.—. Several mouths of small veins may be observed near it, and having all little pellucid valves covering their mouths. The opening of the auricle into the ventricle is to be observed, viz. osteum venosum. Annalus venoms. When the auricle and ventricle of the right side are laid open, the circular margin of the valves being en- tire, the play of these tricuspid valves may be observed by holding out the auricle, and allowing the ventricle gradually to sink in water, when the valves will rise, and close the opening into the ventricle. Of the right side of the heart.—To open the right ventricle, an incision may be made from the root of the pulmonary artery down to the apex of the heart, parallel with the right branch of the left coronary arteiy and its accompanying vein, which comes out from under the left auricle, but a little io H 169 the right of those vessels. By a cut made in this direc- tion (care being taken to cut no deeper than the thin sides of this ventricle,) none of the columnoe carncae will be cut; for the ventricle will be opened exactly to one side of the septum of the heart : and being then enabled to see what parts are to be cut, the incision may be continued round the base of the heart, by the root of the pulmonic artery and margin of the right auricle : or the first incision maybe continued round the point or apex of the heart, so as to lay it open as if it were cleft or split from the apex. The action of the semilunar valves upon the pulmo- nary artery being examined from below, that artery may be slit up, and the inside of the right ventricle be displayed. Of the parts seen upon opening the right ventricle.—First an irregular column of flesh is seen rising from that part of the ventricle which is laid back, and dividing into eight delicate cordae ten- dineae ; and these are again expanded into a broad tendon, which is the anterior division of the tricuspid vajye. From a little mammillary process of flesh, near the valves of the pulmonic artery, and where the surface of the ventricle is smooth, there is sent out, in three divisions, a great number of delicate cordae ten dineae ; and which are also connected with this an- terior division of the valve. The next division of the origins of the cordae tendineae is from the septum of the two ventricles; from which they arise by separate little pillars of flesh. And, again, from the hindmost part of the ventricle there is a strong pillar of flesh, having a double origin from the two opposite sides of the ventricle, and to which the great posterior division of the membranous valve is attached. The transverse connexions betwixt these muscular attachments of the valves should be observed. From these three divisions of this circle of membrane which surrounds the opening from the auricle into the ventricle, it is Vol. I. P 170 called the tricuspid valve. It must be considered ra- ther as the ventricular valve of the right side, than as the valve of the auricle ; in the same way that the valve in the great artery is called the semilunar valve of the aorta. The smoothness of the ventricle towards the open- ing into the pulmonic artery may be observed : and the pulmonic artery being slit up, the three semilunar valves of this artery will be seen. These valves are more frequently perforated in the edges than those of the aorta. ' Of opening the left side of the heart.— Introduce the blade of the scissors into one of the pub inonic veins, and insinuating it into the part of the au- ricle which projects by the sides of the pulmonic arte- ry, slit it up. Little is to be observed in this auricle : the mcsculi pectenati are not so strong nor so evident upon its inside as those of the right auricle. The pulmonic veins open almost always into four mouths ; those from the right lungs being closer to- gether than the left branches. To expose the left ventricle, make an incision as far towards the left side of the vein which runs down from the tip of the left auricle to the apex, as the in- cision made to lay open the right ventricle was to the right of these vessels. In opening this ventricle there is less fear of cutting upon the columnae carneae, or upon the septum ; as the right ventricle, being open, the septum is seen, and we can cut immediately on the other side of it; while the columnae are collected in the further side of the ventricle, round the opening of the auricle, and are not much exposed to the knife. Con- tinuing the upper part of the incision round under the projecting auricle, slit up the aorta to show its valves : in doing which, that branch of the left coro- nary artery which comes out under the margin of the left auricle, must be cutthrough. When this ventricle is laid open, that part which is towards the-eptum is 171 very little rugged with the interlacements of the co- lurnnae canieae, especially towards the opening into the arteiy. The fleshy columns,on the contrary, which are connected with the mitral valve (that valve which prevents the retrograde motion of the blood into the left auricle), are thick and short, and confined in a coiner of the ventricle ; nor do they spread their roots so extensively as those of the right ventricle. Two larger masses of these muscular columns, by which the valves are connected with the sides of the ventricle, may be observed. That which is before the other may be cut from its root, and thrown back with the portion of the valve to which it is connected. The connexions of these valves are so much alike in every essential circumstance to those of the right ventricle, that a description of the effect of the con- traction of the muscular columns will apply equally well to both. Turning our attention to the semilunar or sigmoid valves, we may observe, (hat in the child they are deli- cate and loosely floating membranes, variegated in part by a white opacity ; while their edges are at some places so transparent, that there appears often to be real deficiencies of the valve near the edge, when there is none.—There are, however, such deficiencies some- times. In the adult, these valves acquire greater firm- ness and strength, and are opaque. Behind each of these valves are seen the lesser sinuses of the aorta. The use of those cavities behind the valves has been often considered, but not satisfactorily explained : my opinion of their use is, they are intended to prevent the possibility of the valve being forced against the sides of the artery by the blood flowing from the ven- tricle. If no such provision were made, the blood would, upon the reaction of the artery, have'no power upon them to throw them down upon the ventricle But by this sinus or cavity behind each of the valves 172 they are held as if in the middle ofthe stream of the re- trograde blood; and in its first movement backwards, they are forced together so as to prevent the regurgita- tion ofthe blood into the ventricle. The mouths of the coronary arteries open behind the two valves which are upon that side ofthe aorta, contiguous to the pul- monary artery. It is disputed whether these semilunar valves effect the passage of the blood into the coronary artery. But though the valves were thrown so close upon the sides of the aorta as to close the mouths of the coronary arteries during the systole ofthe heart, still that quantity of blood, which is behind the valve upon its being thrown back, would as effectually be propelled into the coronary arteries as if no valve in- tervened. See, below, Diseases of the Heart. OF THE ACTION OF THE TRICUSPID AND MITRAL VALVES;—AND OF THE EF- FECT OF THE CONNEXIONS OF THE COLUMNiE CARNEiE. The disputes and variety of opinions about the action ofthe tricuspid and mitral valves have arisen from the supposition, that the columnae carneae were merely the attachments of the cordae tendineae to the flesh of the ventricles. And upon this supposition of their inactivity, the whole attention was bestowed upon the contraction of the ventricle and the ap- proaching or retiring ofthe apex ofthe heart from its base during its action. Nor does it seem ever to have been considered what is the peculiar connexion of the roots of the columnae carnece to the parietes of the ventricles, or what effect the dilatation of the K3 cavities of the heart must consequently have upon them. But since those connexions of the membranous valves of the auricle are only in part tendinous, while much of their length is muscular (viz. the columnae carneae,) it is natural to suppose, that those muscular columns are synchronous in their action with the sides of the heart itself, with which they are intimately blended. While the action of the auricle is dilating the ventricle, and the cavity of the ventricle is distend. ing in every direction, the cordae tendineae will be stretched, and the attached muscular columns will be relaxed, while the heart itself is relaxing. And it may be observed, that in whatever direction the ventricle is dilated (whether in its transverse or longitudinal diame- ter,) the connexions of the little muscles attached to the valves are such, that they must be extended and relax- ed. Again, during the contraction of the ventricle, the columns of Lower contracting also (the muscular fibres of both having been excited by the distention of the ventricle) as the apex of the heart approaches the base to which the valve is attached, the cordae tendineae are shortened by the contraction of their muscular attach- ments :—and by this means the valves are restrained from being inverted, and the blood from escaping backwards into the auricle from the contracting ventri- cle. This explanation of the action of the columnae car. neae does not rest upon the presumption of the elong- ation of the heart in its axis ; which is a disputed point. For if the connexion of these little muscular columns be attended to, it will appear, that their elongation and relaxation must take place during the filling of the heart with blood, in whatever direction the ventricle is dilated by the influx of blood. For instance, in the right ventricle, the larger pillars con- 174 nected with the valves have their base rising from the three opposite sides of the heart ; and the lesser col- umn^ run in a direction across the cavity of the heart, —or cross bridles may be observed, which, being fixed into the longitudinal columns, must elongate their fibres upon the dilatation ofthe ventricle in width. And it may be observed, that by the contraction of the fleshy roots ofthe chief columnae they have a greater combined effect upon the point, or pull it through a greater space, in a middle course, directly in the axis ofthe heart, than if the column of muscle attached to the valve ran in a direct course from the valve to the apex of the heart. And it will readily be conceived, that the relaxation of the muscular power in these de cussating fibres ofthe columnae carneae, will allow an equal latitude to the lengthening ofthe cordae tendineae (inversely as their powers of contraction,) when the heart is dilating by the influx of blood from the con- tracting auricle. It will (by this explanation) be at once understood, how very imperfectly experiments, by filling the dead heart with water, will illustrate the play of the valves in the living body. OF THE DISSECTION OF THE COATS OF ARTERIES. To prepare the coats of ^an artery neatly, it should be injected with coloured tallow, and its coats dissected and pinned out; or the dissected coats may be trans- fixed with a strong bristle, to keep them separate.__It is then to be preserved in spirits. To show its inner surface, it may be opened, the injection picked from its cavity, and its sides held separate. Even where wc have to examine diseases, as in aneurisms, in os- 175 sifications ofthe coats of the arter'cs of the rxtreini- ties, in stumps after amputation, or in diseased lungs, &.c. we may still have the vessel injected. For the manner of demonstrating the muscularity of arteries, Imust refer to the Introduction, p. xiv. There are, four coats in an artery ,—the outer cel- lular coat—the muscular coat—the inner cellular coat —and that coat which forms the inner surface of the artery. To dissect the more numerous divisions ofthe coats, as described by some authors, the chief depen- dence must be placed upon the outer cellular coat; for this coat maybe separated into layeis making up any number of coats, while the others are more dis- tinct, with something like a natural division between them. Tne common cellular substance, which surrounds the arteries loosely, more or less, through the whole body, forms sheaths, which, in the dissection of some parts, it is necessary to preserve. Of this kind, is the sheath which surrounds the carotid artery, jugular vein, and eighth pair of nerves, in the neck. When an ar- tery is cut across, it contracts and buries its mouth in the sheath. It is very necessary often to show the situation of vessels in regard to the bed o> cellular sub- stance and fat, in which they lie. Indeed nothing is of more consequence to the surgeon; for if we are taught the anatomy ofaccurately dissected muscles on- ly, and of injected vessels cleat ed from all confusion, we can scarcely hope to recognise an artery in an operation on the living body. In a demonstration, therefore, if the students have not seen the whole pro- gress of the dissection, some part of the a.tey should be left in its native confusion. The EXTERNAL CELLULAR OR VASCULAR COAT. —By this coat the artery is connected with the parts in which it lies imbedded. It is covered in the great cavities by the general investing membrane, as the 17G pleura or peritoneum. The small arteries which ra- mify upon the larger trunks of arteries (the vasa vasOrum) ru.i chiefly in this external coat. These arteries are not, in general, derived from the larger vessels on which they lie, but come from some ofthe surrounding smaller branches of arteries. They are to the great arteries as the coronary arteries are to the heart." They supply and nourish the coats of the arter- ies, while fie column of blood in their cavities seem to have no such effect. To prepare these subordinate vessels, they must be injected minutely (while they lie in situ) with size, or fine varnish injection, of a light 'colour, or o:'pure white. If after this minute injection a coarser and dark-coloured injection be thrown into the trunks, the light-coloured and fine injection will be pushed onward, while the coarse injection fills only the trunks ; making thus a contrast between the large vessels and the ramifications of the vasa vasorum upon its surface. The artery, when thus injected and pre- pared, may be dried and varnished or preset ved in spirits. The outer cellular coat of any artery may be separat- ed into many layers; easily into three layers. These layeis are gradually, as they proceed inwards changed in their nature from that ofthe general investing cel- lular membrane, and are at last incorporated into a more regular coat, which has been called the tendinous coat ; it is dense, white, and elastic; and has much more toughness than the inner coats. It may be use- ful to observe, that it is this coat, according to Hal- ler, upon which depends the tortuous shape of arte- ries ; and that when it is taken off, the arteiy loses its peculiar character. It is to be understood then, that while the inner surface of this coat, viz. that which is contiguous to the muscular coat, is more accurately defined, its outer surface seems imper- ceptibly to degenerate into the nature of cellular sub- stance. j;/ I he muscular coat.—Having dissected these outer layers, the muscular coat appears. Its fibres run in circles round the aitery ; no fibres run in the length ofthe artery. The circular fibres ofthe muscu- lar coat do not pass in the whole circle. On attempt- ing to trace any single fibre, it may be found to make a complete circle round the artery ; but, on further examination, the circle is made up of segments of fibres irregularly combined, the extremities of which are intermixed, and seem lost among each other. The inner cellular coat.—In dissecting a dis- eased artery, with concretions formed in its" coats, the concretions are, upon lifting the muscular fibres, found situated in the inner cellular coat if, indeed, it deserves the name of a coat, since it is rather a connecting medium betwixt the muscular and the innermost coat of all. This inner cellular coat is difficult to be demonstrated;—but by slitting up the artery, and tearing off its innermost coat, the existence of this one may be shewn ; it appears, also in flie ossified state of the artery, when the concre tions are seen under the muscular coat upon the outside, and adhering to the innermost coat upon the inside. In a recent and healthy vessel, there is great difficulty in dissecting ortearing off the inner coat, unless a degree of putrefaction has taken place. The inner coat is dense and smooth ; it pos- sesses considerable elasticity, though it is not so tough as the outer coats ofthe artery. OF THE APPEARANCE OF DISEASE IN THE COATS OF BLOOD-VESSELS. Before speaking of the diseases of the arteries, I think it necessary to say a few words on the effect of ligatures on them. The experience of the" dissecting 179 room teaches us that if, in preparing for injection, we tie the arte.y too tight, we feel the ligature sud- denly yield, and we find, on examination, that the inner coats have been cut, and only the outer coat remains entire. If we are inattentive to this, the injection Will escape here. 1 have made this j the foundation of a caution to the surgeon, to take care in tying an arteiy, especially if it be diseased, that he do not thus cut it through. Mr. Jones, in his treat- ise on tiemorihagy, has drawn a very different, and, I think, an unwarrantable conclusion on this subject. He will have the artery cut by the ligature that it may adhere. " In the case of an artery, we perform an operation on it, to put it in the state of a simple wound, : i. e. in a state in which adhesion may take place ; and this operation consits in the application of the ligature, which, when propeily applied, cuts through the internal and middle coats of the arteiy, keeps their cut surfaces in contact, and affords them an opportunity of uniting and cicatrizing, as other cbt surfaces do, by the adhesive inflammation," "It is well known, that, generally speaking, we can only obtain union by the first intention, in clean and sim- ple incised wounds ; consequently, it is only in such wounds of the arterial coats that we can reasonably except it ; and hence it is obvious that we should take the utmost care to use the ligature of the form, and to apply in the manner, most conducive to the formation of such a wound." In the first place, 1 deny that cut surfaces adhere more readily than a natural surface, in a state of in- flammation. The effect of the ligature ought to be the inflammation of the coats of the artery, and the preservation of the inner surface in contact. Much as 1 admire the ingenuity of Mr. Jones, yet an cxpe riment has been made in my rooms, [which throws more light on the subject than twenty experiments of cutting the arte y. A ligature was put about an 179 artery, quite loose, and without obstructing the blood, in due time the clot was formed, and the coagulable lymph was thrown out, and the artery obstructed. Vet, from fifty such experiments, uni- » formly successful, it would be madness to say that, in tying an aneurismal artery, we were not to draw tight the ligature, but only leave it there surrounding and causing inflammation of the artery ! I conceive it little less rational, because cutting the inner c ats of an artery,in brutes is followed by the closing of the artery, to say, that in an operation of aneurism we were to draw the ligature till we felt the giving way of the inner coats. This subject I should be happy to pursue further, but I am limited to the mere expression of dissent to such dangerous doc- trines. Both arteries and veins are liable to have con- cretions formed in their coats ; but in the veins it is an uncommon disease, and, apparently, the concre- tions are different in every respect from those found in the coats of arteries. Concretions in the arteries have been long a subject of inquiry ; and it is one which indeed involves much matter of practical importance in its discussion. The inner cellular coat is more particularly the seat of ossifications, or more properly, of con- cretions. Steatomatous tumours, also I have ob- served originating in the cellular substance, bchi: d the inner coat of the aorta, and partiallv filling up the arteiy. The aorta has been totally obliterated by such tumours, and the circulation carried on by the iaosculalion of the thoracic and epigastric arteries, by the inosculations betwixt the^ phrenic, an 1 cceliic, and mesenteric arteries, liu.b^e we em con:cive that | the minute brandies of these extended arteries could perform this circulation of the blood through the pel- vis, and thighs, and legs, we must recollect, how 180 slowly such obstruction approaches, and how unlike the instantaneous obstruction in the tying of arteries. Pus is described by some authors as found in this internal cellular membrane ; but it is more probable, that it was that kind of matter which surrounds the concretions. Of concretions.—In accounting for dilatations in arteries, too much importance has been given to concretions, while the general state of the artery,has been overlooked : concretions are more of the nature of an accompanying evil; and only one of many forms which diseased arteries assume. These concretions are situated betwixt the inner membranes of arteries and their muscular coat. They are of two kinds. More generally, they appear upon the inside of the artery, yellow and irregularly concreted tubercles ; and upon the injection and drying of the arteiy, they raise its surface into irregularities. It is in this state, that, upon opening them, they arc fiequently found surrounded with matter, thick, and of the same colour with the concretions. This led Haller to the explanation, that these ossifications, as they are com- monly called, are concreted from a fluid matter depo- sited ; in opposition to the opinion, that the matter is formed in the surrounding coats by the irritation of this foreign substance causing ulceration. Were this fluid matter produced by ulceration, we could not conceive that the arteiy should be able to sustain the force of the blood for an instant, or what limits should be set to the ulceration. This matter surrounding the concretions was observ- ed by the older anatomists ; but was considered rather as a circumstance confirming them in their opinion ol the concretions being true bone ; for this they consi- dered as the marrow. In the broad scales, which more resemble bone, this fluid matter is seldomer found. Such broad 181 scales are frequently found almost completely sur- rounding the artery, without any dilatation or aneuris- mal enlargement of the artery ; while the more irre gular tubercles are common in the enlarged arteries. Often we find the whole arteries of the pelvis and thigh, with thin coats, so full of ossification, that they stand rigid and open when dried. Rupture, from the scales formed in the coats of ar- teries, happens very seldom in the great arteries of the trunk. From the cases on record, it would appear, that the fair rupture of the aorta takes place more frequently within the pericardium, and at the root of the heart. I have known it happen in the posterior mediastinum. It is wonderful that the larger trunks of arteries, where they lie in an even course, are sometimes sur- rounded with scales of these concretions, while yet they seem to perform their functions. Ossifications in the lower part of the aorta and iliac, and femoral ar- teries, are very frequent without dilatation. These instances would alone teach us how passive the great trunks of arteries are, compared with the extreme branches. Ofthe cause of aneurisms—In aneurisms of the great arteries, the coats are found thickened, firm, and easily separating into layers, almost constantly, with concretions formed in them, and with their elasticity remarkably diminished. These ossifica- tions have been always assigned as the cause of enlargements of the arteries; but the degree of the enlargement, and its place in the artery do not seem affected by the ossifications. If these ossifications caused the enlargement of the artery, by acting me chanically by attrition and destruction of its coats, they would produce, not a gradual and extensive enlargement, but a partial and sudden one; such as we find in the extremities. It has been said, that the ossifications in the coats of aiteries occasion Vol. I. Q. 182 greater resistance to the dilatation caused by the action of the ventricle of the heart; and that this resistance exciting the heart to greater action, it becomes at last so gieat as forcibly to dilate the artery. A strange subtilty, to make the strength of the artery the cause of its being overpowered. It is said again, that these ossifications destroy the muscular coat of the artery ; and, consequently, rendering it incapable of with- standing the stroke of the heart, it ceases to second the stroke of the heart, and sufieis itself to be dilated. But the muscular coat of an artery is not that which resists the passage of the blood, or rather the dilata tion occasioned by the force of the ventricle; the muscular coat is alternate in its action with the heart. Duiing the contraction ofthe heart it is in lelaxation, and it is only when the heart intermits its action that the muscularity of the greater arteiies acts in resistance to the muscularity of the extremities; whose combined power would repel the blood back to the ti unks, and dilate them, were the greater trunks not enabled to resist by the additional action of their mus- cular power. The power of resistance in the aiteries near the heart to the blood propelled from the ventri- cle, depends on their elasticity. This is a power which yields, yet resists. By its yielding, and yet its uni- form inci easing resistance, even to the utmost stretch of its elasticity, it subdues that shock which the great vessels would otherwise receive from the sudden exertion of the heart. Now we obseive, upon dissecting the coats of dilated arteries, that the whole functions of the vessel must be impaired; the coats are thickened ; are easily divisible ; and have lost their elasticity. And upon examining the length of the aorta, when thus diseased, it is found dilated ; not uniformly where the ossifications are most nu- merous or longest, but often where there are no hardenings or concretions in the coat; on the other hand, whole tracts of ossification will be found with- 183 out any dilatation of the artery. In this state, the ar- teries can no longer dilate upon the action of the heart, and uniformly resist and contract again; but, on the contrary, there is a more solid and inert resistance to the impulse of the heart, their coats being thick and unelastic: so that every contraction of the heart gains a point in the permanent enlargement of the artery, which (unlike the dilatation of elasticity) is never regained. Thus, although the artery be actual- ly strong in its coats, and dilated and filled with firm coagula of blood, yet will the impulse of the heart gradually encroach upon this inert resistance. While the thin and limber coats of the natural arteiy will re- sist the heart's action, never yielding in the slightest degree through a long life. Cause of dilitations being more freo.ue.nt in the curvatures of arteries.—The arteries are more generally dilated at their curvatures, or where branches are sent oft". The reason of this is evi- dent, if we allow the above explanation of the cause of dilatation in general. Those who have paid much attention to the structure of arteiies, have found, that where an artery sends off a branch, or takes a sudden turn, its coats are strengthened to resist the action of the blood, which must be greater at these points : and as this increase of strength must consist in a more powerful elastic and pliant resist,. ance to the current of blood propelled by the heart, combined with su-;h a proportion of muscular power as to react equally with the rest of the canal; so, on the other hand, when the coats of the artery become diseased, they bring the artery to the slate of a rigid tube ; and the force of the heart becomes more quickly perceptible at those points which are most exposed to the current of the blood, and where that power, which formally resisted in a greater degree, is now reduced to the same state of inactivity with the rest of the tube. Thust we find dilatations more fre. 184 quent in the curvature of the aorta, at the root of the great vessels going to the head and arms ; and in the belly ; at the cceliac, and emulgent, and mesenteric aiteries ; or at the joints. Of aneurisms in the extremities.—This ex- planation of the cause of dilatation may be extended to the aneurisms of the arteiies in the extremities; where we almost constantly find the enlargement of the artery at the part wheic it lies in the great joints, as in the groin or ham. But in the aneurisms of the extremities there is often another cause of dilatation, which arises from the mechanical effect of the con- cretions in the coats. In dissecting the tumour of the artery, it is frequently found not to be a uniform dilatation of the coats of the vessel, but the artery is seen upon one side of the tumour, and resembles that aneurism which is formed by the puncture of the vessel, and by the blood escaping from it into the surrounding soft parts, and forming a sac. Wherevt~ I have had an opportunity of examining the artery, it was much ossified and diseased above the tumour ; a circumstance always to be dreaded in attempting the operation when it is an aneurism of the dilated coats. These concretions in the coats form gradually; and they adapt themselves to the shape of the artery in the prevailing posture of the limb. If the leg be for the most part stiff' and rigidly extended, upon any violent exertion the arteiy is bent, and its coats torn upon the edges of these concretions. On the other hand, if the limb e shrunk up and contracted, the artery being at the same time diseased in much of its extent, mere may be formed a scaly concretion, o: ii curver form, answering to the bend of the artery at thejohil, as in the ham or groin; and in this case a violent attempt to stretch the leg will rupture the artery, since it must bring it to an angle differing 185 from that of the scale which has been formed in its coats. There are cases of this kind upon record. More particularly of- the great aneurisms in the breast—While slight dilatations are very frequent in the aorta, as it proceeds from the heart, and in its great arch ; it is universally observed, that dilatation of the pulmonic artery is very rare. When the dilatation of the aorta has proceeded a certain length, it rapidly increases. It seldom happens that the artery is much diseased near the heart, without being in some degree enlarged through the whole length of the aorta. Aneurism never is in its com- mencement a local disease. But when the dilatation of the artery has proceeded thus far, it generally, at some one point, gives way more easily; so that the di- lated sides of the artery are pushed towards the root of the neck, or, being forced directly forward in the chest, come in contact with the sternum. The bone for some time interrupts its progress ; but by the con- tinned impulse from the heart, the coats of the artery seem to be worn away in the pulsation against the bone; while, on the other hand, the periosteum and membranes which cover the bone are entirely destroy- ed, and the bone itself is absorbed. Or sometimes the dilated sac of the arteiy, stretching widely under the sternum, finds a less resisting passage betwixt the cartilages of the ribs, destroys their membranes, and, protruding, raises a beating tumour externally upon the breast. When this happens, there are generally two tumours ; the tumour of the one side appears be fore that of the other, and commonly they rise upon each side of the sternum, about a hand's breadth below the clavicle. Dissection.—To examine the state ofthe parts, we may proceed thus : dissecting off the integuments fiom the breast in the usual way, they may be laid back until the tumours on each side of the sternum are com- pletely laid bare. But it may happen,that when the dila- Q 2 186 tation has proceeded freely in this direction, the skin (if it have not actually burst) is stretched and in- flamed, and has become as it were one substance with the sides of the cyst, and cannot therefore be dissect- ed off. When the integuments are still loose, upon taking them off, the pectoral muscle is found with its fibres thinly scatte ed over the protruding sac, and strengthening it ; and the sacitselt appears to be com- i osed of condensed cellular membrane, with sonic- thing like the natural coats of the arteiy forming its inner layer. If it be intended to make a preparation of the dis- eased paits, the sternum being loosened from its at- tachments, the heart may be taken out alongst with it, and afterwai ds displayed with the dilated artery pushing through the insterstices of the ribs. It, how- ever, seldom happens that we can be thus far masters of our time in dissection. When the sternum is raised in the common way, the tumour of the aorta is found adhering with a broad circumference to the under side of the sternum : this must be cut through, and with the coats of the aorta we must cut much hard coagulum of blood. Upon examining the under side of the sternum, the bony part of the sternum will in general be found wasted by the blood. Sometimes the cartilages, also, are found wasted; but they seem better to resist the blood. The blood must affect the bones by exciting tbe absoiption, or preventing the deposition of the bony matter, by its mechanical action. Upon exa- mining the aneurismal sac, it will be found greatly thickened, irregular, with white callous scales or tuber- cles, imbued with a matter resembling pus ; and, upon the inside of the sac, lamellated clots, partly resem- bling membranes, partly concreted blood, will appear. Upon turning the attention to the heart, it will, I ihink, be found small and firm in its texture, and forced lower down in the breast. Upon looking 187 down into the dilated aorta, the valves appear thicken- ed and white with concretions. In thus describing the manner of examining these aneurisms of the great arteries, the most common cir- cumstances attending them have been detailed ; yet a great variety of appearances may present themselves to us. The clots which fill up the great bag ofthe tu- mour should be examined, that we may acquire some idea of their progressive formation ; for this may per- haps explain some ofthe symptoms during the patient's life, as the sudden subsiding of the tumour, its more suppressed pulsation, &c. Or the tumour of the ar- tery may be found compressing the trachea or lungs, or encroaching upon the cava, or in some more im- mediate way affecting the respiration or the circulation ofthe blood. When the aneurism forms in the poste- rior mediastinum, the tumour pushes out by the side ofthe vertebrae of the back. Of the veins.—Dilatations of the veins near the heart never happen but as a consequence of the dilata- tion of the light side ofthe heart with blood ; and in that case it is not a permanent increase of size in the veins, but a dilatation from the occasional fulness, caused by the difficulty of circulation in the heart :— I have not seen the veins near the heart enlarged or varicose. A remarkable diminution of size in the veins near the heart is moie common. I have found the su- perior cava no larger than a goose-quill. I had no op- portunity of obseiving the effect of this during the pa- tient's life: but the size or fulness of the heart seemed in no way affected by it. There are instances of the great veins being quite impervious ; a fibrous polypus-like matter, or hard fleshy substance, or a fatty medullary-like substance, filling up their cavities. And that they were imper- vious during life was confirmed in these instances, by the smaller veins being dilated to carry the blood ; in one case, the spermatic vein in the belly ; 188 and in another instance, the vena azygos in the breast performed the office of the cava. There have been found in the lesser veins (in those of the pelvis, and parts of generation, it would appear, more frequently) little stony concretions, round, and sometimes move able. Ruptures, too, of the great veins are said to have happened ; but this is a very rare occurrence. I have seen, however, a tumour seated upon the abdo- minal cava, which seemed to have destroyed the coats of the vein ; for a spongy tumour projected into the cavity ofthe vessel, and the blood seemed to have ex- uded into the tumour which covered all the roots of the cceliac, upper and lower mesenteric arteries. The peculiarities in the veins of the extremities come after- wards to be considered. FIFTH DISSECTION OF THE THORAX. Of the injection and dissection of the heart and adjacent vessels. Old subjects should never be taken for the purpose of preparing any of the viscera: for the fat is in old ige accumulated about the viscera, both of the abdo- men and ofthe thorax. Nor is the fat deposited here 189 derived from the extremities : for although the limbs of old people seem during life, shrivelled and lean, yet the oil contained in them makes them also useless for preparing:—although dried with the utmost care, they sweat out giease, which mixes with and dissolves the varnish ; and they never make clean nor lasting preparations. If the heart, therefore, has much fat accumulated about it, there should be no hesitation in sacrificing it as a preparation, to the attainment of some other point of inquiry as the examination of its internal structure. To make a good injection ofthe heart, it is necesa sary to have the coagula well washed fiom its cavi- ties ; to have it well heated ; and to pay particular attention to the filling of the coronary vessels, upon which the beauty of the preparation much depends. The coronary veins, and even the arteries, may be injected separately, by introducing a long tube down the cava and aorta ; or the fine injection may be thrown in in this manner; while they are filled with the coarse injection, at the same time that the cavities of the heart are injected. By this means the surface of the heart is beautiful, the minute ramifications of these vessels being filled wfth colours answering to the colour of the injection in the right and left sides ofthe heart. The right side of the heart will be most advantageously injected from the left jugular vein, or the injection may be made by any of the other large veins. From any of these, the right auricle and ventricle, with the pulmonary artery and coronary vein, will be filled. The left side of the heart may be injected from the aora below the diaphragm, or from the axillary or carotid arteiies of either side. By this injection all the arteries of the breast will be injected ; the coronary arteries ; the left ventricle (by the wax breaking dow n the valves of the aorta ;) and from the ventricle the wax will find its way into the left auricle, and into the pulmonary veins. If in 190 .filling the heart, the injection, by flowing down upon the vessels in a full stream, should raise the valves, cither in the aorta or, in its passage into the auricle irom the ventricle, the valves may, by kneading or rregularly compressing the heart, be moved from t heir hold, and the injection have access to the whole side ofthe heart : but to prevent the possibility ofthe valves of the aorta being shut by the injection, they may be lacerated by introducing a probe down the aorta ; or a tube may be introduced into one of the pulmonary veins, though this will be seldom neces. sary. In injecting the veins, the vena cava may be tied above the diaphragm, or it may be tied below the liver, by which the venae cavae hepaticae will be filled. The thoracic duct may also be inected. If sought for in the abdomen, it will be discovered at its dilated part, at the root of .the mysenteric vessels ; or upon the left side of the aorta, where one of its branches runs under the aorta ; it is then seen going up under the diaphragm, along with the aorta, and upon its right side, close to the spine. In the thorax, it may be discovered running up betwixt the aorta and the vena-sine-pari. If it lie collapsed and undistinguish- able, it may be raised by blowing into some of the glands upon the root of the mysentery, or into those upon the course of the external iliac vessels or even into those without Poupart's ligament in the groin. It must be injected with a different colour from the veins, that it may not be confounded, in the thorax and at the root of the neck, with the branches ofthe veins. In injecting the heart when out of the body, the numerous branches of the subclavian arteries and veins, and the intercostal arteries coming off in the whole length of the aorta must be tied. And to make sure that all vessels are tied, except those into which the tubes are to be introduced, let the 191 heart and lungs be laid in a flat bason, and covered with water ; then, by blowing into the principal trunks, all the open mouths of arteries will be easily detected. OF THE VESSELS TO BE TRACED IN THIS DISSECTION. In the first place, the pericardium being dissected off, all is made clear for the dissection ofthe heart and great vessels :—then the fat which obscures the coro- nary vessels is to be dissected away;—the great coro- nary vein is to be shewn encircling the base ofthe heart, and emptying itself into the right auricle :—the right and left coronary arteries are also to be display- ed : they need little dissection, but upon the base ofthe heart. In dissecting betwixt the aorta and pulmonary artery, there may be observed a kind of ligament between them, which is the remains of the ductus arteriosus. The branching of the pulmonic ar- tery to the lungs of each side being dissected, and the right branch followed under the arch of the aorta, and the branches of this artery and the pulmonic veins, displayed for some way ramifying in the lungs —we must proceed with the aorta as it rises from the heart, where it is called the ascending aorta. In young subjects, the thymus must be attended to : it is to be lifted from the pericardium and great vessels, and folded over upon the neck. Its blood-vessels will be found coming out from the root of the inter- nal mammary artery of each side, and attached to the thyroid or tracheal veins. Upon the top, or utmost convexity ofthe aorta, three important arteries are sent off on the right side: the arteria innominata which quickly divides into the right subclavian and right carotid aiteries ; the middle artery is the carotid of 192 the left side ; the other is the subclavian artery of the same side. But the superior vena cava, and the trunk common to the jugular and subclavian veins of the left side, cross before these important arteries*. The superior vena cava, shooting up from the right auri- cle, snd having escaped from the pericardium, is joined upon its back part by the vena azygos. This vein coming forward in an arch from the spine, upon which it creeps to one side ofthe aorta, and before the intercostal arteiies, pours its blood, (gathered from the back part of the chest) into the superior cur- rent of blood. The vena cava, having got a little higher than the arch of the aorta, stretches a great arm (the left subclavian vein) across the top of the chest, and before the root of the arteries which go to the head and arms. This branch, dividing into the internal jugular and the subclavian veins, receives the blood from the left side of the head and neck, and from the left arm : and at the angle formed by the joining of the internal jugular and subclavian veins of this side, the thoracic duct empties itselfinto the circulating system. OF THE LESSER VEINS—The vena mam- maria interna of the right side joins the upper part ofthe superior vena cava; upon the left side joins the subclavian vein, opposite to the cartilage of the first rib. The diaphragmatica superior, or peri- * As the right auricle of the heart lies upon the dia- phragm, the inferior vena cava must be very short. If the vena azygos hud emptied itselfinto tine vena cava at this place, it must have climbed upon the diaphragm, and joined the cava within the pericardium. It follows the general course ofthe veins ofthe thorax, which go to terminate in the branches of t/u; superior vena cava wliere t/iere is more easy access to them. 193 cardio diaphragmatica, on the right side, joins the vena cava at its bifurcation ; on the left it joins the subclavian below the mammaria. The thymic a, on the right side, sometimes joins the vena cava; sometimes the gutturalis or thyroid vein, or some neighbouring branch : on the left side it empties itself into the subclavian vein. The right pericardiac vein enters the root of the right snbclavian vein : on the left side it joins the subclavian \ cin, or the dia- phragmatica, or the mammaria interna. The thyroid vein, or trachealis, or gutturalis of the right side, is inserted into the bifurcation ofthe vena cava: on the left side, into the upper and back part ofthe left subclavian. The distiibution of these veins is des- cribed in their names. It is for the most part very re- gular ; but their communications with the larger veins are very inconstant, and differ in each side as the great trunks are different There is little use for a minute knowledge of these vessels, unless that we may be able to tic them in injections. OF THE LESSER ARTERIES—The subcla- vian artery is the great source of the numei>ous smaller arteries which ramify in the thorax, upon the mediastinum and pericardium, and upbn the under surface of the sternum ; and of those also which seem to come out from the thorax to be distributed upon the root ofthe neck and shoulder. The internal mammary artery ofthe right side is the first branch which the subclavian artery of the right side gives oft" after parting with the carotidi It is seen running upon the inside of the cartilages of Hie ribs near the sternum : It supplies much of the contents ofthe thorax anteriorly, and inosculates with the epigastric branch of the femoral artery upon the abdominal muscles.—It gives off the arterle thy- Micffi, it sends branches through the ribs to the mus- cles and integuments. See Appendix. Vol I. R 19+ The inferior thyroid artery is the second branch of the subclavian artery, and is subdivided into these branches; it ascends towards the throat. See Appendix. The vertebral artery, going from behind the subclavian artery, enters the vertebral hole of the sixth vertebra of the neck. The SUPERIOR INTERCOSTAL ARTERY, with its accompanying vein, can scarcely be dissected while the contents of the chest are in their place, as it lies close to the joining of the upper ribs with the spine, and comes from the back part of the subclavian ar- tery. AH these arteries are more accuratly described in the Appendix. In preparing for the dissection of these vessels, the reader may observe the general distribution of the nerves, and mark the points at which they are com- plicated with the arteries and veins. See that part of the work which treats of the dissection and general course of these nerves, from the base of the skull through the neck, thorax and abdomen. To continue the dissection of the aorta, as it lies upon the spine deep in the chest, the lungs, and even the heart, would need to be taken away, to have a full demonstration of its branches, which are but few and insignificant. Bat by folding back the lungs from one side of the chest, any thing important may be sufficiently observed. Or the ribs may be cut down on the left side, and the parts in the posterior medi- astinum carefully dissected. The bronchial arteries ; the oesophageal and intercostal ; the oesophagus, and eighth pair of nerves ; the thoracic duct, Ssuc. 195 GENERAL VIEW OF THE ACTION OF THE VASCULAR SYSTEM, AND OF THE AC- TION OF THE DIAPHRAGM AS AFFECT- ING THE HEART ;—BEING INTRODUCTO- RY TO THE DISEASES OF THE HEART AND VESSELS. There are a few leading points in the action ofthe vascular system, which being acknowledged and kept in view, will enable us to examine with advantage the morbid appearances in the heart and adjacent ves- sels ; or their preternatural structure, as in monsters, or in the imperfect animals. And as the appearances which we have to expect in morbid dissection are perpetually varying, to proceed at once to a detail of those appearances, without settling the principles upon which our estimation of their importance is to be formed, must expose us to continual difficulties. It is necessary to recollect the situation of the heart in relation to the surrounding parts, and to consider how its motions are regulated. When the diaphragm, which divides the thorax from the abdomen, is pulled down, and the thorax is expanded, and tbe lungs consequently dilated, it is natural to inquire, What effect this expansion will have upon the heart, or at least upon the great veins and auricles ? As they lie within the sane cavity with the lungs, they also would be dilated, or their action in some measure affected, by the vacuum* thus *// will not be understocd that I mean here a separation betwixt the lungs andthein ide of the thorax and an actual vacuum, but simply tfte tendency which tfte dilatation of the tfiorax has to expand any cyst whose cavities can be filled from sources external to the thorax ; as the lungs, by the atmospheric air drawn through the trachea. 196 formed in the thorax, were there not a particular me- chanism to counteract it. By the connexion of the mediastinum with the heart, by its reaching to the upper part of the thorax and surrounding the great vessels, and by its being stretched over the pericar- dium, or rather intimately connected with it, and for i.ing its outer coat—it embraces the cavities and tubes which circulate the blood. By this means, the heart i-> so situated, that the effects of that dilatation of the cavities, by which the lungs are inflated, is counteracted in as far as regards the heart :—for the mediastinum, being connected firmly with the diaphragm, and the diaphragm contracting only upon its lateral parts, its efforts upon the mediastinum must pull the membranes closer about the heart, in prpportion to the increase of capacity ofthe thorax, and to the tendency which the heart would other- wise have, in consequence of that increase, to suf- fer dilatation. This may seive as some explana- tion of the heavings of the chest, when by violent exercise, or in any other way, the blood is sent into the right side of the heart in increased quantity ; for while an increased velocity in the circulation of the blood requires a proportional increase in the action of the lungs, the compression of the heart and vessels, when the diaphragm acts strongly upon the mediasti- num and pericardium, makes us instinctively struggle to procure the necessary dilatation rather by the ex- pansion of the ribs than by the action of the dia- phragm. If the lungs arc thus dilated by the ex- pansion of the thorax, then the diaphragm does not need to be so violently contracted, and, consequentlv, the pericardium and mediastinum do not so strongly compress the heart, veins, and right sinus. This mechanism in the thorax brings the gre t ves- sels in the breast more to a balance with those in the belly, and other parts ofthe body. An increase of the velocity of the blood in circula- 197 tion must be accompanied with a proportional increased action in the lungs, because this increase of the quan- tity or velocity ofthe blood passing through the heart, i»;an increase of its stimulus, which must be accompa- nied with a proportional increase ofthe power of action or irritability ; the scource of which is in the|lungs, and which, thiough the medium ofthe blood, is bestowed upon the heart. Were not the heart thus invigorated to greater action, an increased flow of blood through it would exhaust its powers, and a load of blood be lorced into its cavities, which it would be unable to propel forward as happens in experiments upon the lungs ofanimals,when theartificialbreathingis stopped.* Upon examining the situation and connexion of the superior and inferior cava, it i» evident that they ai e not so large, in proportion to the arteiies, as the veins in other parts of the body are ; and that the blood must consequently pass thiough them with * 1its said, that t/ie blood, as a local stimulus, could not produce that regulat ity which the heart has in health, nor thai n i egularity which we find in disease. But the blood ojjccts the heait tn two ways ;—just, by stimulating it to exertion, in consequence ofthe mere distention of its cavi- ties :—and, again, by bestowing upon it, in its circulation through the coronary vessels ( as in every other part ofthe tidy,) life and the principle of activity. Jf hen blood unveutilated, unimpiegnated utth new pr operties (or de- puted of that change, whatever it may be, which the lungs ^reduce upon it, j gets access to the coronary vessels, it more quickly dissipates the energy of the heart than if the heart were allowed to exhaust itself, deprived of all circu- lation. It is of consequence to oher vc the appearance of the blocd circulating m thecor onary vesselsin eiperiments hfen the action of the heart in living animals. This is not u matter foreign to the present subject; it is mpossibie to L.at.unt for the way in which the blocd is found distributed m the system ajter death, without considering it. R 2 198 greater force or celerity, since the diameter of the veins, compared with that of the arteries, must be the measurement of the comparative force with which the blood passes thiough them. At the bottom of the jugular veins, and at the mouth of the axillary or subclavian veins,* we find valves placed, which defend them, as they enter the thorax, against the regurgitation of the blood from the chest into the upper extremities and head, when the contents of the chest may (in consequence of any irregular action peculiar to the respiiatory organs, as coughing or sneez- ing) be under severer pressure than the veins in the extremities.f That it is not to prevent the back stroke of the auricle that these veins are guarded by valves, we may presume; since there are no valves * Are we to consider the dilatation in the great veins of the neck as a provision agaiwt congestion in the head from any irregularity in the circulation of the chest, and as ad- mitting a kind of deposit here of that blood which would stilt more subject the head to the load of repelled blood during violent coughing, Sec. ? In violent Jits of coughing the contents of the chest are under violent compression during the convulsive expiration ; but, preparatory to that convulive expiration, and after it, the mastoid muscles and platyma muscle are in violent action as a mu cle dilating the chest, tine head being fixed; they must compress this di- lated vein, wfach lies immediately under it ; and as the blood in this vein cannot enter the head again, it it forced into the superior cava.—See what is further said'of the action ofthe abdominal muscle . f In dissecting subjects in ivhich there are enlargements ofthe heart, or where palpitations oftluz veins of the neck have formed a symptom oftftisdhease, and where the peri- cardium is found dilated, Sec.—it i; of consequence to exa- mine the state of relaxation ofthe diaphragm, the valves of the veins in the neck, the valves in the heart, and the general relaxed state of the membranes in the thorax, as explaining the symptoms of the disease during life. 199 guarding the pulmonic veins from the action of the left auricle, and since there are no valves in the lower cava. This last circumstance suggests to us the pro- bability, that in every irregular motion in the action of respiration, the compression upon the vessels is the same in the abdomen as in the thorax ; for if there were a possibility of a greater compression in the thorax by any voluntaiy exertion of the body or irregularity of respiration, the lower cava would have been defended likewise with valves. And it will appear, from a review of the action of the abdominal muscles and diaphragm, that the veins in the thorax and abdomen do in all actions suffer like degrees of compression. Let it be considered for a moment, what would be the consequence upon the viscera of the abdomen, if, during a fit of coughing, their vessels we.e liable to as violent distention as we sometimes sec in those of the face. That the com- pression upon the vessels of the thorax, and upon those ofthe abdomen, is the same, will further appear fiom this consideration, that when the abdominal muscks act strongly, the diaphragm yields, which prevents the greater compre sion of the abdominal viscera. On the contraiy, when the diaphragm reacts and resists, then the force resisting (viz. the diaphragm) being equal to the force of the abdomi- nal muscles, it follows, that the portion ofthe cava which is in the thorax is as strictly compressed by the mediastinum as the cava in the lower belly is by the abdominal muscles. Again, if the diaphragm acting should be supposed to compress the vessels rcund the heart, it must be remembered, that its con- traction pulls strongly upon its origin, or insertion, only ace01 cling to the resistance which its action meets with : i'.nd as the mediastinum may almost be considered as the insertion of this muscle, if the ab- dominal n.Ubclcs do not react, the mediastinum can- j;ct tc too btiongly compressed, and the abdominal 200 muscles, when they do react, compress the lower cava with an equivalent torce. If the pressure were not equal in the breast and in the belly, but greater in the breast, then would the blood be occasionally repelled from the breast, and accumulated in the abdomen*. It comes next to be considered, what is the power which dilates the auricle : and what is the conse- quence of the action of the auricle upon the column of blood in the veins ? The great use of the auricle is to prevent the action of the ventricle upon the circle of blood contained in the vessels from propelling the blood round upon the ventricle, even whilst yet in its state of contraction. For when the ventricle contracts, it throws forward into the beginnings or extremities of veins a quantity of blood, besides what dilates the arteries ; and a portion of the column of blood in the veins nearest the heart is consequently driven forward and fills the auricle.f That the dila * In violent coughing, straining, sneezing, Sec when- ever, in short, the thoracic and abdominal muscles art exerted, stagnation i s lid to be produced in the veins near the thorax. This, it may be observed, can never be brought directly to the test of experiment, unless in the veins of the neck; because these actions cannot be produced when tfte breast of an animal is laid open. Tfie opinion has arisen from seeing people coughing violently with the face turgid with blood ; but this is caused by the difference ofcompres. sion in the thorax, and in the head and arms, and does not prove that there is any difference of compression in the belly and in the bread. And the greater turgidity of the face than of the arm- is probably occasioned, partly by ike action of the muscles of the neck (ehiefly by that of the platysma myoides, which covers the externaljugu~ lar vein, and is in violent spasmodic-like contraction dur- ing violent coughing) and partly because any dilatation of the vei>el< of the head muit be externally only. f In examining monsters, and in dis ecting the more im- perfect animals, the great principle which must keep the 'J 01 tation of the arteries is not sufficient to account for the quantity of blood sent out by the contraction of the ventricle, is apparent from the flow of blood being continued in the veins during the contraction ofthe heart and dilatation ofthe arteries :—and that quantity of blood which is more than sufficient to dilate the arteries, and continues to flow in the veins, would,it is evident, distend the sides of the veins, were not the .'.uriele, at this -time, relaxed so as to allow an easy exit from the veins of this addition to their column of blood. This free exit to the venal blood, in the di- rection of the axis ofthe veins, prevents an additional lateral pressure. It is perhaps more difficult to explain why there is not a regurgitation of the blood, or dilatation of the veins, upon the reaction ofthe auricle. For though the force and quantity of the blood sent from the ven- tricle be so much more than sufficient to keep the veins dilated to their stationary diameter as to dilate the auricle also, there is still to be accounted for that portion ofthe blood delivered by the ventricle, which was sufficient to fill the arteries, and which continues to be forced on during the contraction of the auricle, with which the contraction of the artery is synchro- nous. The question comes simply to this, at what time, or by what power, does this quantity of blood, which blood in an uninterrupted circulation ought to be remem- bered, viz. tl& alternate action and relaxation of the mus- cla, fibres ofthe arteries ; their elastic power being only subservient in resisting, and in throwing the contraction of one set of muscular fibres upon that which it to follow, tliat t/iey may be dilated, and aguin, in their turn, react. An artery cannot circulate t/te blood either in a monster or a worm without some part oftfie circle alternating wit hit in action and relaxation. 202 is sent out by the ventricle, and which is more than sufficient to dilate the auricle, and stimulate it to con- traction, return to the ventricle? Does the blood, even during the contraction of the auricle, still force itself onward by the effort of the arteiies to contract, not in opposition to the contracting auricle, but act- ing in aid ofthe auricle, to distend the relaxed vent- ricle? Or does the quantity of blood, which is by the contraction of the arteiies propelled into the veins, distend the veins through the whole body during the contraction of the auricle, and when the blood may be stopped from entering the heart ? The first of these seems to be the truth ;—because, by supposing the contraction of the arteries still to carry forward the column of blood in the veins so as to flow through the auricle into the relaxing ventricle, the whole quan- tity of blood sent out from the ventricle is account- ed for without any pause or stop in the whole cir- culation*. This seems to agree the best with our observations on living animals : and it accounts for * from observations on tfie heart's motions in living mnimals, when influenced by artificial breathing, Mr. Hunter concludes," That the auricles are only reservoirs capable of holding a much larger quantity than is neces- sary for filling tfte ventricles at one time, in order that the ventricles may always have blood ready to fill them." Tftis is tfte opinion which is carelessly adopted in all books in which any explanation is given of thbi. But it is perfectly clear, that since there is a quantity of blood sent out from the ventricles, sujpci-rtt to dilate the arteries as well as tfte auricle, there must, upon the relaxation of tfte ventricle and action ofthe auricle, be a quantity of blood aqual to that which dilated the vessels returned into the ventricle, besides whutis supplied by the auricle ; and the contraction ofthe auricle, connotft omit ■ own stores, sufficiently dilate the ventricle, without there being, in'.he aex, rotndof actions, a deficiency of blood sent by the auricle into the ventricle. 203 the lateral pressure of blood upon the sides of the veins being at all times equal. And if the combined power of the arteiies cannot force a portion of the column of blood, equal to their contraction, into the ventricle during the contraction of the auricle, then not only must it be allowed that the contraction of the auricle is stronger than that of the arteries, but that it is so even when its whole side is as if opened by the relaxation of the ventricle. It is evident, then that the relaxed ventricle is the only opposition to the flow of the blood from the veins into the heart during the contraction of the auricle. Were we to account for the quantity of blood sent out by the ventricle, by supposing a dilatation of the veins to take place, we must allow a stoppage, or retrograde movement i in the great veins, which is contrary to the facts every day before us ; and besides, this sup posed dilatation of the veins (which maybe imper- ceptible, being so small a quantity of blood diffused over the whole body) must be accompanied by a greater compression upon the blood of the veins at one time than another ; which should be easily ob- served. It may be well to consider, how very small any dilatation of the veins, occaioned by such an insuf- ficient cause as is generally assigned, must be ; and the investigation will at the same time take away from the support which might be derived to the above opinion from the observations of those who have seen even violent pulsation in the veins, and conceived it to be occasioned by the action of the ventricle, and to be synchronous with the pulsation of the arteries* *Mr. Hunter says, " I think I have seen the difference ofthe projection so grvat, that it hardly could arise from that cause alone ;" viz. the lateral dilatation ofthe accom- panysng arteries.—And he adds, "The large veins near the fit art .'.irc a puliation, which arises from the coutraction 20t The pulsation in the arteiies is occasioned by the whole quantity of blood sent through them, in the direction •f their axis, lengthening them, in opposition to their elasticity, and causing them, to form contortions or curves. This is well illustrated in the pulsation ofthe heart against the side; which is in fact the pulsation ofthe aorta, not ofthe heart, and is caused by the effort of the aorta to lengthen itself and to fo~ m a more direct line, carrying the heart as on its point. It is illustrated also by the contortions of the arteries of living animals : as in the membranes of the chick in ovo, by the pulsating bud of an artery when tied in our operations :—and it gains additional proof from considering the very small dilatation which an artery must suffer in any one point touched by the finger, though the dilatation of the whole taken together is con iderable. It is not, therefore, the degree of dilata- tion which we feel in the pulse, but the shock given to the column of blood by the action of the of the heart preventing the entrance of the blood at that time, and producing a stagnation. Thii I saw in a dog," Sec. The incomutency of this iv evident. He finds a di- latation of the triu.i synchronous with the dilatation of the arteries, viz. by the contraction of the ventricle : and, again, when tfiey should unload themselves of thh blnod which dilates them, they are precluded by the acticn ofthe heart preventing tfte entrance of the blood, andformlng a stagnation. And, in opposition to both these observation'!, he say i, in the same page, that in some fevers the arteries contract, and the veins dilate alternateli/. Having an un- settled wwk'riur opinion, he makes observations in direct contradiction. All observations in experiments upon the dilatation of the vena cava n"ar the heart, the effect of artificial breathing on the action ofthe heart, and stagna- tion of tfte blood by expiration, are inaccurate ;for by the opening of the breast tJte whole actions i:c the thorax'rr ■■' be completely deranged. 205 ventricle. Before adopting the opinion, then that the reaction of the arteries should perceptibly dilate the veins, or convey a pulsation to them, it must be re- membered, that the veins, either during the contrac- tion ofthe heart, or during that of the arteiies, do not receive the impulse of the same quantity of blood which gives the pulsation to the arteries ; but if they should be supposed to dilate during the contraction of the ar- teries, they receive only that which is spent in the dilatation of the arteries ; and if they are supposed to be dilated during the contraction of the heart, then are they dilated by the blood sent from the ventricle, which remains after the dilatation both ofthe arteries and auri cle. To all this must be added the very great differ- ence of capacity of the veins and arteries;—we must consider that many veins of a greater size accompany a single artery in the extremities and how immense the capacity ol the veins is in many parts of the body ; as the sinuses of the head, the great veins in the neck, abdomen, and pelvis. How little effect that quantity of blood which dilates an artery in a (degree impercep- tible to the sight) should have, when thus dispersed in the greater capacity of those veins, which is triple, or even quadruple, that of their accompanying arteries, must be at once acknowledged. But further, a pulsation, supposen to be transmitted to the veins, would differ from that given to the arteries, in this—The pulsation of the arteries is great near the heart, because their elastic resistance is great, and the force ofthe current of blood sent forth from the heart is propelled violently in a narrow channel: and the elas- tic resistance of those greater arteries throws the force ofthe blood forwards unexpended into the smaller ar- teries, which have a less degree of resisting elasticity, and a diameter (the caliber of their branches beiii<* taken collectively) infinitely greater than the trunks : and asthosebrancheshave,astheyrecedcfrom the heart, an Vol. I. S 206 addditional muscular force in proportion to the loss of their elastic risistance, which muscular power is then in a state of relaxation, that portion of the blood which is expended upon the dilatation of the arteries, is bestowed upon their extremities chiefly ; and the extreme arteries again react by their muscular power, in exact proportion to their degree of dilatation—and thus they become the most active agents in the circu- lation. But if the greart arteries near the heart were dilatable in a great degree, it would retard the circula- tion; because the force of the ventricle would be expended upon their dilatation where there was no need for it, since the dilatation is a provision for an additional muscular power, to be exerted in accelerat- ing the motion of the blood. We see, then, that the arteries dilate as they proceed ; but they form a cone with its apex in the heart; that the blood must move more slowly onwards in the extremities ; and that it loses, in a proportional degree, its impulse from the heart. The effect of the contraction of the arteries upon the veins, differs from that ofthe heart upon the arteries, in this, that the effort of the heart is accumu- lated to a point, and the whole blood of the body is propelled through a narrow channel : that the con- traction ofthe extremities ofthe arteries, on the other hand, although great, when taken in its combined ef- fect, yet being diffused over the whole body, and the action upon the veins being through their innumerable extremities, and the quantity of blood returned by the veins, during the impulse of the heart, not being equal to that which passes through the aorta, the blood in its passage through the veins cannot have the same effect in causing a pulsation with the current of blood through the aorta. Those who conceive that there is a pulsation in the veins, and who argue from what they have ob- served of the beating ofthe v.ins, or the leaping of 207 the blood from them when punctured, as from an artery, besides overlooking the effect of the alternate action of the heart and arteries, do not seem to have considered what effect this great degree of ac- tion in the veins of the whole body would have, upon their insertion into the right side of the heart : for perceptibly to dilate the veins, would take a quantity of blood greater than is sufficient to dilate the auri. cle ; while, by their account, this pulsation is occa- sioned by the same power which causes the pulsa- tion of the arteries, viz. the ventricle. Now this is the same with saying, that the contraction of the right ventricle of the heart dilates the arteries, dilates the veins, and fills the auricle ; and in this state the quantity of blood delivered from the heart is left, without accounting for the manner in which an equal quantity of blood with that which fills the arteries and veins returns to the ventricle from which it was propelled. When are the veins supposed in this case to be emptied ? It must be during the contraction, not only of the auricle when the exit of the blood is more difficult, or, as the greatest supporters of this opinion say, is absolutely stopped ; but also during the contraction of the arteries upon the other ex- tremity of the veins, which probably produces a great- er effect upon them than even the action of the heart, which is more remote. The most essential difference between the veins and arteries consists in the different velocity of their blood. The quantity of blood under the active influence of the heart and arteries, at the same moment, is amaz- ingly small, compared with that in the veins : but in any length of time, the quantity passing through the arteries will be equal to that passing thiough the veins ; for the veins have the blood slowly moving in their large cavities, while in the arteries it is sent quickly through their narrow channels. The blood in the veins approaching the heart, is received as in a 208 vortex, pushed in an instant through the right side of the heart, driven through the circulation of the lungs, has its properties invigorated, and in an instant, is sent through the whole body, comes in contact with the parts with which it is to act, is angain deposited in the veins, where for a time it lies inactive, or sluggish- ly moving through their dilated cavities. If it were not for this distribution, and if the heart and arteiies could not draw supplies from the more inert mass of blood in the veins, our lives would be still moie liable to eveiy accident, and a trifling loss of blood would be fatal. It may be of importance to consider, as connected with the animal economy, from what proceeds, or to what tends, the increased quantity of blood in the dilated veins of old people, and whe- ther it corresponds with the diminished velocity of the pulse, &e. From the nature of the subject, this account may appear prolix or confused. In the apparent simplicity of the heart's motions, there must be many actions in unison with each other, while yet in description it is difficult to convey an idea of the accuracy with which every action is adapted to that which is to follow. But it may be useful, in concluding this subject, to give a short recapitulation of the mutual action of the heart and blood-vessels. The contraction of the ventricle delivers into the artery a quantity of blood, which quickly pervades the rigid trunks, and is sent into the more pliant mus- cular extremities, which are then in relaxation. These arteiies dilate through their whole length, but chiefly in their small branches. Besides the quantity of blood dilating those arteries, there is enough sent from the ventricle of the heart to continue the pi opulsion of the blood into the veins, which, displacing a pro- portional quantity from those veins which lie near the heart, propels it into the auricle, and dilates it. By this means the auricle is dilating during the con- 209 traction of the ventricle : again, upon the relaxation of the ventricle from its action, the flow of blood is continued into the veins by another power, viz. the contraction of the arteries. By this contraction, the quantity of blood sent out by the last pulsation, more than was sufficient to fill the auricle, is continu- ed forward with great force ; a force as great as that exerted by the auricle: it consequently enters the relaxed ventricle along with that blood which is sent in by the contracting auricle ; and so a mass of blood, equal to that sent out by the pulsation of the heart, is sent again into the ventricle. The flow of the blood through the inosculating branches of the arteries and veins (which must be considered as the ultimate intention of the circulation) is slow and uniform, allowing a reciprocal action betwixt the fluids and solids ; and is yet sent to the heart in such a manner, that the alternate action of the muscular power, the efficient cause of the circulation, is atone time allowed relaxation, and is at another stimulated to action. See peculiarities in the Vessels of the Extremities, in that Part which contains the Dissections of the Thigh, &c. FURTHER APPEARANCES OF DISEASE IN THE CIRCULATING SYSTEM. Although, during life, the heart seems the most frequent seat of disease, the most distressing symptoms, and all the feelings of misery and oppression, seeming to be concentrated there ; yet organic diseases, or such derangement of the natural structure as comes un- der examination in the dead body, are far from be- ing common. This is to be ascribed to the more lively sensibility of the heart, and its strict depen- dence upon the reciprocal actions ofthe whole system : 210 so that while the feeling of disease in the heart is common almost to a necessity in eveiy more universal disease, its organic derangements are comparatively few. OF DISEASE IN THE HEART. I have never seen inflammation of the heart, unless from wound or the communication of disease from the bones or the lungs. Nor have I seen abscess in the substance of the heart, far less mortification. The heart has burst and suddenly killed the person, but this is very rare : blood has been found in the peri- cardium where no orifice could be discovered in the heart or vessels. There are no two appea. ances so common, and so much connected, as a bloated, soft, and watery state of the body, and a soft, flabby, and enlarged heart—where the heart seems in sympathy with the languid and dissolved state of the body. Such a state of the heart may be expected when the complexion has been of a pale and leaden colour, with langour of all the bodily functions, and a gradual loss of strength; the pulse becoming weak and small, accompanied with frequent faintings, and sense of weight and oppression at the heart. The consequence ofa disordered state of the functions of the lungs upon the heart, and the loss of that recipro- cal connexion which is kept up during health, must often give rise to symptoms which are ascribed indis- criminately to the heart. When the breathing is gra- dually stopped, in experiments with artificial breath- ing upon living animals, the heart becomes languid in its actions, and swells up with blood which it is un- able to propel. The blood undergoes its changes in the lungs imperfectly, and in this state is received into the circulation, and is sent into intimate union with the whole body. The effect of this contaminat- 211 ed blood is* immediately perceptible upon the heart, -^ not that it is less capable of irritating the heart to action, but that it is incapable of bestowing the princi- ple of action upon it, through the medium of its circu- lation in the coronary vessels. Then the irritability ofthe heart is destroyed, the blood is pushed into the heart by those powers which are not so immediately affected by the loss of the most essential properties of the blood, and the auricles and ventricles are overpowered with blood. This is an experiment which we must consider as imperfect, but it may lead us by analogy to the axplanation of nearly the same phenomena in disease. When the powers of the system fail, when the action that must take place betwixt the fluids and solids is in any way interrupted, then is the delicate sensibility of every organ to its peculiar stimulus and action diminished. And when such an effect as thi& is produced upon the heart (and it must take place in the last stages of many debilitating and tedious dis- eases,) then does this state of the heart almost infalli- bly present itself upon dissection ; the heart is enlarg- ed, stuffed with blood, and flaccid in its texture, the aqua pericardii is in considerable quantity—and often the whole body is tabid. In this case, where the distention ofthe heart is habitual, the aorta is found remarkably small, being allowed gradually to contract its diameter, to suit the weak contractions of the heart ; but still the artery is not (as we should expect from this explanation) thick, as if its coats had con- tracted, but remarkably thin and delicate. Nor mus* we suppose, that the state ofthe artery is in contrast with that of the heart—the heart being diseased, while the artery is in a state of healthy contraction - for the artery suffers the same loss of power with the heart. The difference is, that much blood is sent in upon the heart, which it is unable to push forward, and its sides are thin and dilated, while in the aiteries there is a deficiency of blood—Were it possible to con- 212 ceive, that the heart should regain its healthy powers while the artery remained in this state, the artery would be too weak foif the powers of the heart. It must he remembered, that though the muscular power of the artery is weakened, yet a permanent dilatation will not be produced whilst its elasticity remains : for the arteiies in their contraction have not to combat with the heart, during its action ; therefore the ar- teries will not be peimanenlly dilated by the contrac- tu), i of the heart, unless when, as in their diseased state |in aneurism, they are incapable of contracting again by their elasticity : and whilst the contractibility of tne arte.ies remains greater than that of the veins, they will not be seen dilat*! in the dead body. We find, that when the heait is distended with blood, the right side of the heart is the most distend- ed. Tnis may be explained from the consideration of the difference betwixt the two circulations. The cir- culation through the body is the most extensive; and having greater power, must, upon the ceasing of the heart's motion, continue for a little to pour the blood into the right auricle and ventricle, while the left side of the heart has neither the same quantity of blood in the circulation of the pulmonary vessels, nor are these vessels so extensive, nor do they possess so great an elasticity, as the aoric system, and the extended veins of the "body. Neither will the thick and strong sides of the left cavities of the heart allow of distention so easily as the right. The blood in the great vessels of the body is forced in upon the right side of the heart, when, from failure of its powers, it is incapable of propelling it into the lungs, and from thence into the left side of the heart. In considering palpitations of the heart, we must remember, that the natural pulsation of the heart against the ribs is riot the dilatation or contraction of the heart itself, but the effect of its contraction upon the arch of the aorta, as explained by Dr. Hunter. But in violent palpitations of the heart, where it is 213 enlarged, and weakened in its' powers, and tbe aorta is small and insignificant, the palpitations have been sometimes observed not to be synchronous with the pul^e at the wrist, as the natural pulsations of the. heart are. In such cases, it may perhaps be the auricle which is affected with irregular motions when it is violently distended with blood; and the ventricles likewise being enlarged, the apex ofthe heart is forced against the ribs. From what I have seen, however, of the pulsation of the veins of the neck, I would say, thai it is impossible to determine whether the motion is at the same instant with the arteries or not. Palpitations or pulsations of the veins in the neck, and even of those in the arms, sometimes accompany enlargement and disease ofthe heart. To form a just conception of the cause of this pulsation, we must consider the peculiarities in the situation ofthe vessels near the heart. The pericardium, investing the ven- tricle and auricle, suffers little dilatation by the action of the heart :—its greatest dilatation is during the diastole of the ventricles ; because the space tilled by the dilated ventricles is somewhat greater than that of the dilated auricles ; yet the difference must be small. The mediastinum involving the pericardium sends its membranes round the great veins waich reach up- wards from the auricle and strengthens them. When, therefore, the veins in the thorax are dilated, and the whole heart enlarged, there must be a distention of these membranes likewise ; and the disease is not confined strictlv to the vascular system here, but even the diaphragm and involving membranes will be found relaxed, and the cavities dropsical. By the dilatation of the veins the action of their valves is affected ; they become too small for the diameter of the vessel, and the blood passes them. But the auricular valves, or those properly belonging to the ventricles, are not affected bv the dilatation of the veins ; their i elaxation must depend upon the elongation of their muscular 214 attachments to the inside of the ventricle. To cause a pulsation to be felt in the veins without the thoiax, a loss of power, both in the valves ofthe veins and in the valves ofthe heart, must have taken place :—be- cause, if the conclusion be right, though the valves ofthe veins at the lower part should have lost their power, yet while the extended circulating powers re- turn the blood with due vigour to the heart, the con- traction of the auricle will not be felt retrograde upon the column of blood in the veins : but if the heart and veins be dilated, and the tricuspid valve have lost its action, so as to allow the blood to recede again from the ventricle into the auricle during the contraction of the ventricle (the contraction of the latter being greater than the first,) the pulsation will be obscurely felt in the veins of the neck, beating synchronous with the arteries through the body. In examining these diseases of the heart, therefore, in dissection, or in considering the symptoms during life, much is left to be decided upon by reasoning from the symptoms. It may be required to decide, whether this pulsation be communicated to the en- larged veins by contiguous arteries, or by a pulsation from the auricle, or whether it be communicated from the ventricle, through the auricle and the column of blood in the veins ? or whether, again, the tremulous thrilling feeling in the veins may not be produced by the action of both auricle and ventricle ? In these diseases, the pulse is so iiregular, and quick, and feeble, that it will be difficult to say, whether the beating ofthe veins is simultaneous with that of the arteries (and consequently of the ventricle.) In dis- section, again, we have to examine the dilated state of the veins near the heart, and the state of their valves ; the de ,ree of relaxation over the whole mem- branes of the chest ; the state of the auricle ; the re- laxation of the ventricles, ofthe columnae earner, and of the valves of the heart. Dilatations of the cavities of the heart are impro- 215 perly called aneurisms ; but there have been cases which seem to have truly deserved the name, where the ventricles of the heart have at a point been dilated into a pouch tilled with coagulated blood. Of diseased appearances observable up- on openi'ng the heart.—To examine the diseases in the cavities ofthe heart, it is evident, that it must be dissected with as much care as for the demonstration of its simple anatomy. There is one circumstance, however, which may be remembered, that it may be required to exarfiine coagula or polypi of the heart, which may reach from the ventricles into the great vessels, the aorta, or the pulmonary artery. To de- monstrate these through their whole course, the cavi- ties of the heart may either be laid open while the heart is in the body, or the great arteries slit up, and the coagula withdrawn from them, and kept attached to the heart. And in this case, the coagula being strong, and minutely ramifying through the lungs or aorta, from a beautiful demonstration, when the ca- vities ofthe heart are opened, and their roots shown attached to the irregular inside of the ventricle, and the intricate interlacements of the cordae tendineae. That these polypi formed from the blood are for the most part formed after death, there can be little doubt; but still there are circumstances to be attended to which have induced many to believe that they are formed during life. They are found in layers, which argues a successive formation ; or they are attached to the sides of the arteries where their coats are diseased ; and their attachment does not appear to be accidental or owing to the simple coagulation of the blood. In many instances, however, where these coagula are remarkably firm, and such as we should suppose were formed during life, we find, upon examination, that the extremity, which is loose, lies in a direction con- traiy to the course ofthe blood ; a direction in which wc must be sensible it could not have rennined due- 216 ing life ; for it must have been driven in the direction of the current of blood, while the root was held near- er the heart. There must be coagula formed in dilated arteries; and to distinguish betwixt those which have been formed during life, and impacted in layers filling the dilated bag, and those which have been formed after deatn, is often impossible. Ilow, then, in the case of the coagula prolonged into the great vessels (which alone are called polypi,) can we expect to dis- tinguish what has been formed in the last feeble actions of the heart, from those which have been formed after death ? Wet e they ever formed in the vigour of the system, we should have had cases of some smaller part being torn from the trunk or stem of the polypus by the force of the circulation, and driven into some of the branches of arteries, so as effectually to inter- rupt the circulation of some important pait. No such thing happens, and the conclusion on the whole is, that they must be never looked to for the explanation of symptoms. In the annulus venosus I have found a stricture so narrow as just to admit the finger. Of the valves as subject to disease.—The muscular coat of the aorta is not continuous with the muscular fibres of the heart ; probably because their actions are alternate : but the inner coats of the arte- ries are continuous with the lining membrane of the heart, and the membranous valves in the heart: the whole inner membrane of the heart, and even the tendons of the tricuspid and mitral valves, are evident- ly subject to the same disease with the arteries. We see them partly of their natural colour, partly varie- gated with a more opaque whiteness, and increased in thickness. The semilunar valves of the aorta and pulmonary artery will be frequently found thickened and more opaque than usual. They are found ossified, too, or with a deposition of earthy matter. Upon opening thcsuiface, there will be seen several little distinct 217 *acs. The easy play of these valves must be much im- peded by this state of disease : they must become stiff and rigid instead of being pliant, and floating easily with the tide of blood. The extreme tenuity of these valves, and the netted appearance of their edges, would incline us to believe, that this also were a dis- eased state. But these deficiencies in the valves do not allow the blood to pass them ; they are only upon the edges, where the valves are in contact when inaction. The appearance being as common in children as in adults, teaches us, that these holes are not worn by*t trition. It does not appear that there is an instance of any part of an animal body being liable to such a waste : it is endowed with powers to counteract it. These valves have been found ruptured; and this we should naturally attribute to the force of the retrograde blodt^ '-■*■.*< - and thenoe argue a great force in the contraction bf the arteries. It is not impossible, however, that they might, when diseased, have been ruptured by the.vio- Jence of the heart's contraction occasioning a great degree of dilatation in the root of the aorta, which they (being uneiastic) might beuna,ble to bear. The m'r.al and tricuspid valves are subject to the '.>Jgijf same disease thickening, and to have concretions .'SjL-* formed in them. Their small tendons, too, if nar- *; [_- rowly observed, will be found partaking in the dis-vf;< ca.se. ■■.'-*■; There is yet one disease on which I wish to be mora"j*^ ':■ particular : theAngina Pectoris. JjT £ CASE OF ANGINA PECTORIS. Mr. G. A. is a tall and corpulent man of 50 years of ao-c, and though addicted to no access in di inking, is in the habit of eating heartily where his palate is indulged. He has on his facej probably in conse- quence of this habit, an eruption of those florid pimple> which s-.i commonly arise from frequent sur- t,* fc't He is a bachelor, of regular habits, and uni- Vol. I- T 218 formly takes his walk when the weather is favourable. He has been for fifteen years subject to dyspeptic com- plaints, and they have increased for the last two or three years. About the end of September 1793, he felt a pierc- ing pain strike from the under and fore part of his chest to his shoulders, and then along the arms ex- tending to the points of the fingers ; this was accom- panied with a very unpleasant and painful sensation of the stomach, and great depression of the mind. It continued a considerable time, and then gradual- ly left him. After this, similar attacks (as far as he recollects) frequently recurred, and of late he has many every day. They come at irregular intervals, and aie of uncertain duration ; but they are often brought on by fatigue. The pain in these attacks he finds alleviated, aiPHhe paroxysm, as he conceives, brought sooner to an end, by standing erect with his hands stietched above his head. He is also relieved by vomiting a \ff", sour acrid phlegm, which he frequently brings up in ■' mjuthfuls alter meals or bodily exertion. About T^W*.- three weeks ago, the pain became so unremitting and ■UaKKexcruciating, that he was obliged to stand for foity- ^WraP* eight hours before it abated. lie stood indeed so long, that he brought on oedema of the lower extremities ; .V*. at that time he took large doses of opium without any befiefit. He is troubled with flatulence and a costive belly, ««B^Hdns pulse is natural, and continues to be so during his ; paroxysm ; his£ppetite is not impaired, but he suffers so mufch after eating a hearty meal, that for some time he has lived abstemiously. He is neither ema- ciated, nor has he suffered diminution of strength; his spirits are equal, and he is constitutionally so cheerful, that wonderfully soon after his sufferings have ceased, he forgets them. He has submitted to a mercurial course, and has tried various tonic medi- -rjijt cines- He thinks the attacks are less violent, and 219 not so frequent when his bowels are loose; and he has had more relief from small doses of soda phosphorata than from any thing else. This is probably by lessen- ing the exertion at stool, for costiveness always brings on a paroxysm. May 1, 1801.—Soon after this report was drawn up, this gentleman, disappointed by our unsuccessful attempts, left off medicines entirely. The use of issues and purgative medicines was recommended, but he de- clined trying further remedies. We may further ob- serve, respecting his paroxysms, that he was general- ly so well in the forenoon, that he often walked many miles, and this he could do without difficulty, provided there was no acclivity in the way ; but after dinner he could not walk a hundred yards without bringing on a fit of his disease. Now, as he rather gained in ap- pearance of health, he bacame hardened to his suffer-. i:i^s, and paid little regard to the rules which were laid down for him. One morning when Dr. Cheyne called upon him, he congratulated him upon his looking so well. He ■"••■' had gone up stairs rather hurriedly, and on entering the room, begged that he might be excused for a little. His sufferings, he said were agonizing after the exertion he had made in ascending' the stair-case, but that he should soon be well. He raised his arms, and leaning on the chimney-piece, recovered in two or three minutes, and entered cheerfully into conver- sation. He regretted much that he could not dine with a friend upon some particular occasion, for now, he said, the slightest exertion after dinner brought on a paroxysm, and that he found his only safety in keeping his arm chair. He added, " my friends, misled by my looks, are always telling me that my complaints are imaginary ; but my sufferirtgs are past description, and must arise from some un- common cause; and of this 1 am so well convinced, that I wish my body to be opened when I die. I con 220 fess that 1 had a prejudice against this, but I have over- come it, fiom the hope that it may be useful in allevi- ating those dreadful sufferings in another." Soon after this conversation, this gentleman walked several miles, and returned home in very good spirits : he eat a hearty dinner, was cheerful all the evening, and, on going to bed, expressed great thanku.ii.ets for having escaped an attack after coming from his walk. This morning when his servant went to call him to breakfast he was lying in bed dead. As he was quite cold, it is probable that he died early in the night. May 2.—Dissection__When laid upon the table, the chest of this body was large and protuberant, and its appearance such as should have indicated good health. In the dissection, the quantity of fat accumu- lated about the body was observed to be very con- siderable, though the limbs were spare, as indeed is common in men of his age. When the sternum was lifted, the cellular membrane of the anterior mediasti- num was so much loaded with fat, as to obscure the heart and pericardium. When the pericardium was brou^nt into view, however, it appeared beautifully transparent, not thin, nor very delicate, nor as if dri« ed, but natural in every respect, except this very pe- culiar diaphanous appearance. The heart being exposed, its colour was very pale and somewhat leaden, unlike the fresh and fleshy colour which the heart usually presents. It was also much covered with fat. In the cavities of the heart there was nothing paiticulaiiy remarkable, further than that the mitial valves, and the beginning of the aorta were thickened, and had in thera specks of ossification. The semilunar valves were also thick- ened irregularly, but not so much as to impede their perfect action. On cutting through the substance of the heart, however, the knife grated on the ossifica- 221 tions of the coronary arteries. Upon a more particu- lar examination, a complete circle of ossification war* observed betwixt the coats of the coronary arteries, These concretions or ossifications pervaded the coro- naries to the extent of some inches, which was the more remarkable, as the greater vessels which in gene- ral precede the smaller ones in this diseased state were but very little affected. In the abdomen there were no marks of disease. The case which I have here faithfully detailed, in all its circumstances very accurately resembles many others which have been laid before the public; and it is this very conformity with cases related by physi- cians deservedly the most eminent, which makes me venture upon some general remarks relative to this disease. In the angina pectoris, the morbid appearances which, on dissection, most frequently occur, are the unnatural, or at leas* great accumulation of fat, and the ossification of the coronary arteiies. Whether the accumulation of fat be a cause of the symptoms or the mere consequence of the disease, may be questioned. But as fat thus accumulated in other instances gives rise to no symptoms like those which are peculiar to the angina pectoris ; and as, in some cases, the pa- tient has begun to be emaciated and dropsical while the disease continues, we must rest our explanation of the cause of these symptoms on the ossification of the coronary arteries. Physicians in speculating concerning the causes of the heart's motion, have too often confined their attention to some one of the many connexions or sympathies by which the union of the heart with the general economy is accomplished, so as to form one whole. Some have looked to the connexion of the brain and heart, as explaining the phenomena of the heart's motion ; others have tied and irritated the nerves of the neck ; others again have observe^ 222 the heart's sympathy with the lungs, or have thought of the compression of the nerves by the motion of respiration ; and, lastly, some have expected a solution of the difficulty from the circulation of the blood in the coronary vessels. In delibeiatcly contemplating the phenomena of the circulation we must not over- look any o: the connexions of the heart, yet there are views which must take the lead in discussion, and especially in explaining the symptoms of disease. Although there be a strict sympathy betwixt the brain and heart, the heart and lungs, the heart and stomach, the heart and diaphragm ; although the nerves, being pricked or compressed, accelerate or retard the heart's motion, and show that they are the medium of these sympathies ; yet the immediate de- pendence of the heart is on the circulation of the blood for the support of its action, and for the continu- ance of its sympathies and connexions. Whatever therefore interiupts, retards, or acceleiates the motion of the blood through the coronary circulation, must affect the action of the heart itself; and as we see, that in most diseases, and in almost evei y affection of the body or of tbe mind the heart is influenced, so when the heart is itself the centre of disease, the symptoms are unusually severe, the attacks irregular, and the depression of mind most remarkable. There is an anguish made up of bodily and mental suffering which attends no other disease. Although the blood circulates within the cavities of the heart, yet this circulation bestows no nourish- ment, and supplies not the muscular energy to the heart. For this purpose it is necessary that the blood should be carried into intimate union with the fibres of the heart through the coronary system. This may teach us the importance of attending to the ossification of these vessels in the investigation of the disease now under review. The ossification of the coronary arteiies must destroy their power of 223 action ; they can neither dilate by the impulse of the heart ; nor contract by their own muscular power in the same extent as formerly. In the case before us, there must have been very little, if any, action in the coronary arteries. While tl-.e circulation proceeds with perfect unifor- mity, this state ofthe coronary vessels will be attended with no bad effect; but when the body is active, and the circulation is accelerated, and the blood returns more rapidly, and in greater quantity, to the heart, then must the paroxysm commence; for in proportion to the velocity of the blood's return towards the centre of the system, the heart requires to be invigorated to greater action, and this is performed solely through the circulation in the coronary vessels. In this diseas- ed state, however, they are incapable of increased ac- tion, and hence arises the pain and anxiety, and at last the total interruption to the circulation. A SYSTEM OF PART IV. ANATOMY AND DISEASES OF THE PELVIS. DISSECTION OF THE PERINEUM, Or of the parts which are implicated in tfie operation of lithotomy, and in the diseases of the urinary passages and rectum. Previous to the dissection of the perineal muscles, the arteries of the pelvis and of the lower extremities may be injected, that the branches of the pudic artery, and their connexion with those muscles, may be un- derstood. The cavernous bodies of the penis and urethra should also be injected, and the subject placed upon the table, as the patient is held for the operation •f lithotomy. 2-25 FIRST STAGE OF THE DISSECTION. General view of the parts to be laid open in the first stage of the dissection.__In this dissection, as the muscles and delicate arteries to be demonstrated lie deep amongst much loose elastic cellu- lar substance, it is of some consequence to maik the depth and level ofthe parts. Because, although at first the student is circumspect, dissecting with cau- tion, yet gaining courage as he proceeds, and find- ing that he is only separating the cellular mcii.bi;ine, he plunges with more determined strokes of his knife, tiil at last he with much disappointment, finds the ex- ternal sphincter of the anus, or the trans veisalis UiU.-- cle, cut away, and the demonstration destioyed : like those surgeons who, being strongly impressed with the idea that deliberation is the characteristic mark of their ability, commence their operation withanaftected gravity of countenance and tedious cruelty ; while in the important stage all is indiscreet hurry and confu- sion. In both cases the celerity and success dcpti.d upon the knowledge of the points in which caution i-. required. The rectum having been ordered to be cleaned, a little barked hair may be introduced into the extremity of the gut, which will keep the anus gently protrud- ing during the dissection : or a cork with a loop at- tached to it being introduced, and the mouth of the gut tied upon it, the dissection will be much facilitat- ed, and the demonstration assisted, in consequence of the complete management we have of the gut; for wc shall thus be able to turn it in every direction, so as to show its connexions The reader may here, consult the Appendix, under the head Muscles of Perineum. The place of the erector penis being evident, since it rests upon the ramus pubis and crus penis, it cannot be destroyed, and should be our ii.it object in 226 the dissection, as serving, in some measure, for a guide in the dissection of all the other muscles. The next point in the dissection is the accelerator urinje : its place we cannot fail to find, as it sur- rounds the lower part of the spongy body of the urethra. In dissecting the external sphincter ani we have to recollect that it consists of loose fibres encir- cling the mouth ofthe gut, and lies immediately un- der the skin. This muscle is however, frequently missed in dissection, and it is indeed difficult to show- it neatly. A sure guide in the dissection of all these muscles, but chiefly of the transversalis perinei, is the tuberosity of the ischium : for the transversalis peri- nei, taking its origin from the tough tendinous-like membrane of the os ischium, runs directly across to the general point of union, lying about two inches deep in the elastic fat, which fills the space betwixt the anus and os pubis. By carrying the knife in the course of this muscle, it will not be unwarily cut across; its fibres being, in this manner, much more distinguished, and extricated from the surrounding cellurar substance. RECAPITULATION OF THE ANATOMY. Erector penis. A neat and delicate muscle arising from the os ischium ; stretches its muscular fibres over the lower part of the crus penis : and spreading its expanded tendon, gradually coalesces with the sheath ofthe crus penis. Accelerator urin;e, properly, ejaculator seminis. From a middle line, as from a common origin, the fibres, diverging, run obliquely upwards on either side, embracing the bulb and lower part of the corpus cavcrnosum urethrae with a coat of mus. cular fibres ; which, collecting into distinct tendin. 227 eus slips, are inserted into the crura penis. Perhaps,. considering its use, it were better to say, that, taking its origin from the body ofthe penis, it embraces and suirounds the lower part of the corpus spongiosum urethrae. Sphincter ani. The fibres of this muscle run in circles round the mouth ofthe gut; it can scracely be said to have an origin or insertion. It takes hold of the os coccygis behind, and is attached to the accele- rator urinae before : more intimately and immediately embracing the lower portion of the gut, are the stronger fibres of the internal sphincter. Transversalis perinei arises from the tupero- sity of the ischium, is inserted into the central point of union, where the sphincter ani touches the accele- rator urinae. Transversalis perinei alter. This slip had better been called obliquus, for it is a small slip of mus- cle, which, from the same origin with the last, as- cends to the side of the bulb and ejaculator seminis. OF THE BLOOD-VESSELS IN THIS STAGE OF THE DISSECTION. All the arteries seen in this stage ofthe dissec- tion are branches ofthe pudic artery. The pudic is sometimes named the external hemorrhoidal artery; bul, We find the external hemorrhoidal artery branching upon the extremity of the rectum, and en- veloped in the muscular fibres, surrounds the anus. The artery, which is prolonged by the side of the bulb ofthe urethra, and gives off twigs over the erect- or penis and crus penis, is a supreficial branch of the pudic artery. The transversalis perinei is a branch from the last artery, distributed in the cellular membrane, and to the sphincter ani*. • 22S The place of this artery is often supplied by several irregular branches. Feeling deep on the inside of the tuber ischii, vvc may feel the trunk of the pudic if it be injected with wax. The veins which arc seen in this dissection are the pudic or inferior hcemorrhoidal veins, and accompany the arteries. The nerves which appear in the course of this dis- section are the pudic nerves, coming from the second and third sacral nerves. They run sometimes over the transversalis perinei muscle ; more frequently below it: sometmes they come out in one bianch, sometimes in several twigs. But the veins and nerves arc of less consequence to be studied than the muscles and arteries. SECOND STAGE OF THE DISSECTION. Wc may now take away the transversalis perinei muscle, and expose the deep and strong transvei.-.: muscle, which is more important to the lithotomist than all the others. In the course of the dissection, wc have to observe the connexions ofthe levator ani : it will be seen coming down from the neck oi'the blad- der and triangular ligament of the urethra, and from the fibres of the sphincter vesicae ; and in stronger faciculi from the sides of the pelvis, converging to the anus, and mixing its fibres with tho-c of the inter- nal sphincter. Proceeding with the dissection, the muscles of the perineum and the ejaculator seminis are to be taken away and the deep parts exposed. If the arteries be injected, we have to observe these. ARTERIES. 1. Arteria Pudica Communis lying by the side of the ischium. 2. Irregular branches to the muscles and 2J9 ligaments. 3. Perinei transversalis, coming out into the cellular membrane. 4. Arteria Communis Penis,being the continued trunk, and this we may find dividing into, 5. A branch entering the bulb. 6. An artery which passes deep into the penis, being the Profound Propria. And 7. The Dorsalis Penis. Now, attending to the urethra and its connexions, we have to dissect round the bulb of the urethra, and observe the manner in which it hangs, as it were from the urethra. In tracing the urethra back from this place towards the neck of the bladder, we find what is called membranous part ofthe urethra, in dissecting which, we have to observe, what has been sailed the triangular ligament of the urethra ; it will appear as of a middle nature, Ibetwixt cellular membrane and tendon, surrounding the urethra, and connecting it and the prostate gland with the arch ofthe os pubis. It gives strength to the membranous part of the ure- thra.; and being perforated by numerous veins coming from the penis, it has been described as cavernous. In dissecting this part, it will be well to put a bougie into the urethra. VVe now lay bare the prostate gland, observing alwaysrthe thickness ofthe cellular membrane and the depth of the parts ; their, relation to the arch ofthe os pubis, and to the rectum, through which alone we can examine them in the living body. While these parts are exposed before us, there are many observations which ought to croud to the recol- lection., INFERENCES DRAWN FROM THESE SEVE- RAL VIEWS OF THE PARTS. Of the action of the perineal muscles.— 'I here is no combination o! muscles more curious, or more deserving of our attention, than that of the muscles or'the penis and rectum ; whether wc consi- Voi.. I. 'U 230 der the importance of the organs to which they a-s subservient, or the diseases with which they are con- nected :—yet both the natural action of those muscles, and their action and sympathies in the morbid state of the parts, have been much neglected ; and the uses or actions attributed to them are surely very far from the truth. Of the erector penis (Ischio-cavemosi Winslow.) —Is it not more natural to conceive that the use of this muscle is to brace the crura penis to the bone, than to adopt that explanation of its action which has gained it its present name ? Can we conceive any mechanism so well adapted to give firmness and occa- * sional strength to the hold which the root ofthe penis must have upon the bone, as that of a muscle par- taking of the same stimulus, inert when the penis is flaccid, and roused to action in proportion to the excitement of the penis ? To suppose it assisting the dilatation of the penis, by forcing the blood for- ward from the crura, is to attribute to it an action which would totally prevent erection, and not give firmness : the blood being excluded from the crura, could have no hold upon the os pubis. And the idea of its holding down the penis is (in spite of authority) ridiculous ; since the pubes or adipose membrane be- twixt the dorsum penis and os pubis, prevent further elevation, and render such an action in this muscle, unnecessary. Ejaculator seminis (Bulbo-cavernosi, Winslow.) —To understand the action of this muscle, we must recollect the relations of the bulb and lower portion of the cavernous body of the urethra upon which it acts. The corpus cavernosum urethr.e is a spongy body, surrounding the urethra from its mem- branous part under the arch ofthe os pubis to the glands. The glands is the enlargement of this body towards the extremity of the penis, whilst its lower part in the perineum is also enlarged to form the bulb. \ 131 Within this lower part the canal of the urethra is di, latable into what has been called the sinus urethra. Now this is strictly the operative part of the penis, and is raised upon the firmer support ofthe body of the penis, which alone, by its crura, has a firm hold of the os pubis. When the glands is excited, the whole parts of generation are brought into action :__ the vesiculae seminals more gradually empty them- selves into the urethra ; when the accelerator, being drawn into action, propels their contents forward by successive pulsations. It may be observed, too, that this action upon the bulb, though partial, affects the whole extent of the cavernous body of the urethra, and has the effect of contracting and making rigid that canal, so as to increase the force of the emission. r This muscle can have no power of accelerating the urine, though it may throw out the last drops which lodge in the sinus*. The erector and accelerator muscles are the only ones which can be conceived to have an independent action ; and the accelerator is very strictly connected with the transversalis and sphincter ani. In that action of the accelerator which has been noticed, the sphincter ani, the transversalis perinei, and the leva- tor ani, have a simultaneous action. The two first retain and steady the bulb of the urethra against the action of the accelerator ; whilst the levator ani, and muscular fibres about the neck of the bladder, compress the vesiculae, and, constricting the urethra, prevent a retrograde movement of the semen. Diseased action in these parts affecting the discharge of semen.—}. The thing most * In the Edingburgh Medical Journal, a gentleman has committed a blunder so gross and palpable, tn regard to the action of this muscle, in criticising apart of my work on surgery, that I think it right to leave him to his ucend thoughts. *232 necessary to be considered in the treatment of the diseases of the seminal organs, is the force of imagi- nation on the passion, since* of those who seek relief from impotency, many are suffering from the idea of imperfection, rather than actual disease. It may be sufficient to hint, that absolute conviction of success must precede the accomplishment, and that such an admiration ofthe object as would make her more than woman, makes a man less than himself. 2. An increased secretion from the vesiculae semi- nails, or prostate gland, is frequently a cause of terror to patients, when there really is no diseased secretion of the semen. 3. There are instances ofthe retention of the semen. Disease of the canal near the mouths ofthe seminal ducts, is apt to produce a retention of the semen. Sometimes it is passed slowly, and only as the erec- tion subsides ;"" sometimes it is thrown back into the bladder, and is discharged with the urine, which, for a time, it impedes. Strictures in the urethra do not produce this effect, unless they are very narrow. Petit, in the Academies de Chirurgie, gives in in- stances in which he cured the stricture and this com- plaint by incision. 3. There is a more singular case by M. de la Peyronie, ofa small tumour on the mouth of the ducts, which threw the semen back into the bladder, instead of passing it forward into the sinus of the urethra. 4. Much the same symptoms, I believe, are the consequence of ulcers having partially destroy- ed the accelerator muscle, when the power of expelling the semen from the sinus urethra is lost. 5. There are, I ttiink, more than one instance given of impotence, from too early a discharge, attributed to an enlarge mentand laxity of the seminal vessels. See Bonctus, lib. iii. sect. xxxi. ob. ii. & ob. I. Dc involuntaro seminis fluxu. We disregard all that is said on this subject by Bonetus. 6. In that affection of these parts which is consi- 233 clered as seminal weakness, an attention to their action and importance in the economy will, perhaps explain the nature ofthe disease. I should conceive, that the vesiculae seminales receive the semen, not strictly as reservoirs : but that in these vessels it may be mingled with their secretion, so as to form, when diluted, a quantity of fluid fitted to be acted upon by the muscles of generation. Were the semen poured only from the vasa dcferentia, there w ould be too small a quantity of fluid to be acted upon ; nor would there be the same chance, nay, scarcely the possibility, of impregnation. We know, that the prolific power of the semen is not lessened by dilu- tion ; and indeed we are assured, that by the violent excitements of the parts, the prostate gland and all the mucus glands of the urethra contribute their secre- tions. By dwelling upon this, it is meant to point out the distinction betwixt those affections of the jarts which are considered as seminal weakness, and any real affection of the testicle. The effect of in- flammations of these parts, weakness, and loss of tone, accompanied by the discharge from the urethra, or gleets, or, perhaps, diseased secretion ofthe ve-i- culae or prostate glands, will produce an increased secretion, a permanent or temporary laxity and debility of the secreting parts ; and their contents being accu- mulated, will be thrown out in straining at stool, or in the expulsion of the last drops of uiine, without implying any peculiar affection of the secretion of the testicle, or any more general debility of the system. 7. We must remember, however, that the seminal weakness spoken of frequently has no relation to the vesiculae or prostate, but in a discharge from strtcture and low chronic inflammation of the urethra. If there beany disease properly meant by the term, it is the frequent and uncontroulable discharge of semen. This is a complaint which gives great uneasiness; it nroceeds from too much irritability in the parts, and r no *.n is curci by the use of a bougie and strengthening medicine. 8. Of the action of the ejaculator seminis in case of stricture of urethra.—In reviewing books on this subject, there is so much assumed, so much addressed to the ignorant for selfish purposes, that, to avoid speaking intemperately of them, it is necessary to avoid the discussion. But the tollovving facts 1 must press upon the observation of the young surgeon, wnich 1 hope will enable him to arrive at the truth- No obstruction in a canal surrounded by muscles, is at any time entirely mechanical. Turn to what is said of suffocation for example; there the difficult breathing proceeds from the spasm of the glottis, and the cause of death is most generally the effusion in the lungs: herein the urethra, stricture or obstruction of any kind has its effect in disordering the consent which must exist betwixt the muscular fibres of the bladder and the urethra. I beg that it may be remembered, that when the detrusor uniinae acts, the muscle surrounding the neck ofthe blad- der and urethra must be relaxed, or at least free of any tendency to activity, before the urine can be dis- charged ; and that, if thee is disease in the urethia, or disorder in the bladder, the urine' wll not flow though the inclination to make it be strong. But without removing an obstruction, if by rubbing the perineum, or by introducing a bougie, or dashing cold water, a change shall be produced, and the usual relaxation of the muscular parts of the canal, and the natural sympathy be resumed, the urine will How. When a stricture will not give way to a bougie, by letting the bougie remain a little, it will at last pass, because, say authors, the spasmodic stricture at last gives way. Thefactis, that a continued gentle pres- sure will dilate a common stricture; but there is mo.e than this, often the muscular sheath of the 235 lower part of the urethra, formed by this muscle, the cjaiulator, and the muscular fibres which surround th,e neck of the bladder and membranous part of the uiethra, will, for a time, resist the introduction of the bougie, but at last yield. The reason will now be understood why, in introducing the bougie, when there is spasmodic difficulty, wc do it when the urine is flowing, or cause the patient to make the effort to pass urine at the time the bougie meets obstruction* ; lor if it be a spasmodic stricture, the action of the bladder will lc followed by relaxation ofthe canal, und the bougie will enter. Or action in the rectum__We shall, perhaps, come to admit that a relaxation takes place in the sphincter ani, if we consider the manner in which the intestinal canal acts through its whole length. One portion of the gut being in action, propels its contents to that which is below, which, relax- ing, receives them. Were there not a relaxtion in tiie lower portion, it would oppose itself to the con- traction of the upper part. In the same manner, the superior strength of the muscular fibres, surrounding the extremity of the rectum, is relaxed during the action of the rectum, which allows an easier expulsion of the faeces. It is from this peculiarity in the action of the rectum that 1 would explain the formation of piles in some in- stances, and the prolapsus ani. lrritatioivof the gut gives occasion to an almost imperceptible but con- stant effort to expel from the rectum ; and this effort is attended with a relaxation of the lower part of the "nt and of the muscles, which, in action, retain the parts, and counteract the pressure of the abdominal viscera and the occasional action of the abdominal inuscles. By continued relaxation of this kind the usual tension is taken off, the parts swell by the in- flux of blood ;x the internal membrane is distended with blood, and protruded, forming a species of the 236 hsemorrhoes. The same explanation holds good in violent straining at stool in costive habits ; and it should be recollected at the same time, that the con- traction made higher in the rectum, may more easily retard the returning venous blood than it can the more active play of the haemorrhoidal arteries ; thereby- causing a stagnation of the blood in the extremities of the veins. 2. Of intus-susceptio and prolapsus ani.— In the same manner we have to explain intus-suscep- tio and prolapsus ani. In the first instance, the gut being irritated at any point, the irritation causes a contraction, while in the superior portion of the ca- nal there is an effort to propel downwards : the con. sequence is, that the portion contracted by the irrita- tion is forced to slip into the lower portion of the canal. But how is it forced into the lower portion ? this is not well explained. It appears evident to me, that this is the effect of the longitudinal muscular fibres ; for a portion ofthe intestine, say six inches, being irritated, contracts ; this contraction is not in the diameter of the gut only, but in its length, so that it shall be only two or three inches ; the conse- quence of which is, that the internal coats are ga- thered together, and being turgid, with blood, they are pressed into the next portion of the gut; by this the contraction is increased and the disease continued. In irritable childhood this often happens. In prolapsus ani, that laxity of the internal mem- brane, which is the immediate cause, is frequently produced by irritation ; and the internal membrane being first protruded, the effort of expulsion being continued, the irritation increases, and a great part of the gut is inverted. When this accompanies dysen- teric affections or diarrhoea, where there has been vi- olent tenesmus and bearing down, it is a most dis- tressing symptom, especially when the counter indi- cations prevent the proper remedies. In cases where 237 there is local irritation (as from numerous ascarides in the rectum of children, or, as sometimes happens, from the stone in the bladder,) the temporary or per- h manent relief from the irritation must be the first ob- ' ject, while astringents are applied to counteract the effect of the loss of pressure. 3. In violent irritation of the rectum, as in long continued tenesmus of dysentery, the neck of the blad- der sympathises ; and what produces relaxation of the gut causes a strangury, or spasmodic constric- tion in the neck of the bladder, that derangement of which I have spoken above. This we shall readily conceive, when we recollect the strict relation which ^ subsists between the action of the rectum and that of , the muscles about the neck of the bladder in their T healthy state. The ejection of the contents of both is not allowed at the same time, but requires an alter- ' nation of action ; which certainly is in a great measure to be accounted for from the connexions of the leva- r tor ani; since this muscle, arising from the brim of the pelvis, sends its fibres down upon each side of the J neck of the bladder, and embraces it before it reaches the lower portion of the gut, into which it is finally i inserted. 4. It may be observed here, that in all such protru- sions, whether hernia or prolapsus ani, the most im- mediate bad consequence is the want of accustomed pressure upon the protruded part, which causes ful- ness and stagnation of blood. When prolapsus has taken place, the contraction of the sphincter and leva- tor ani tend to increase the evil, by drawing like a liga- ture upon the protruded gut.* 5. It is by such a view of the parts that we come to have a truer idea of the strict relation which they i have to each other ; of their sympathies in disease ; * The consideration of tfte diseases of these parts is re- sumed in a subsequent section. 238 and of what we should expect to feel in a morbid state, upon examining by the anus. Thus, in in- flammation of the neck of the bladder, or enlarge- ment ofthe prostate gland, the pain in making water— the frequent excitement to it;—the pain stretching up- wards to the kidneys, and extending along the penis to the glands—the pain upon pressure in the epigastri- um—the sensation in the rectum of a tumour, or of faeces ready to be expelled (which is occasioned by swelling of the prostate gland ;)—do in some measure recapitulate to us the anatomy and sympathies among the parts. 6. The student, in dissecting these parts, should naturally be led to inquire concerning the direction of abscesses which so frequently run amongst the cellu- lar substance ; of such particularly as may be con- nected with the urinary organs, the urethra, or neck of the bladder ; and of the fistula in ano, or such as run up by the side of the rectum. 7. The abscesses, forming amongst the celluhr membranes, become habitual- and stationary; be- ing long callous canals, which, by the condensation of the surrounding parts, acquire a smooth internal surface, and from which there is a perpetual discharge of matter. The leading principle, in the cure of all these com- plaints, is to discover the cause, and I will very con- fidently say, that it is either constitutional, or that it proceeds from obstruction in the natural passages. Remedies to the ulcer are useless. Of lithotomy.—1. Upon turning our attention to the presentation ofthe parts in these dissections, we find that the external incision in lithotomy must run in the direction from the arch ofthe os pubis past the anus, upon the left side of the perineum, and cutting directly through the transversalis muscle, cutting, also, a few fibres of the sphincter, and going deeper, or more pene- trating in the middle, so as to reach into the membra- nous part ofthe urethra apart of the levator ani is cut. 239 2. In laying open the groove of the staff", it is very awkward to cut the bulb of the urethra. It neverthe- less does sometimes happen, that it is not cut only, but minced with many transverse cuts. 3. The pudic artery is cut by carrying the knife too near the bone : it is often cut by the gorget. When the perineal arteiy is cut (and indeed it can hardly escape,) it does not interrupt the operation. 4. Some or all of these vessels bleed in the opera- tion of lithotomy, and choke up the wound with coa- gulating blood; so that the operation must be done much more in the dark than we should conceive from the view ofthe dissected parts. And this should teach ns how necessary a strong conception of the anatomy is ; not simply such an idea as can enable us to dissect the parts, but a knowledge also of the different parts by feeling, so as to be able to distinguish them during operation. OF THE SECTION OF THE PELVIS. The next dissection ought to give a lateral view of the parts contained in the male pelvis. The os pubis may be cut through about an inch from the symphy- sis, and the os ilium of the same side dislocated from the os sacrum. 1. The first thing to be attended to in this view is, the inflections of the peritoneum. 2. The relation of the bladder and rectum. 3. The exact situation of the bladder. 4. The turn of the ure- thra under the os pubis, and the place of the pros- tale gland and vesiculae seminalis. 5. The bulb and the membranous part ofthe uiethra, and the muscles and ligamentous substance which surround the urethra . (i. Further, the neck of the bladder and prostate gland ought to be pressed down fiom the arch'of the os pubis, and the minute muscles which surround the urethra and prostate gland dissected : viz. a supe- 240 rior arch of transverse fibres lying over the neck of- the bladder and the side of the prostate gland, and a posterior and weaker fasciculus mentiond by Santori- ni and Haller. The compressor prostatae (of Albinus) or levator prostatae Santorini, or prostatique superieur (of Winslow.) The levator ani must now be carefully examined, and especially such parts of it as being connected with the bladder, have been called levator vesicae proprior and communis. The muscular coat of the bladder ought also to be now demonstrated. 7. The action and sympathies of these muscles make a very necessary study, as I have hinted above, before we determine on the subject of obstructed urine. REVIEW OF THE PARTS AS SEEN IN THE SECTION OF THE PELVIS. 1. The bladder is, upon the upper and back part, covered with the smooth expansion ofthe peritoneum: on the lower and fore part, and contiguous to the lower portion of the rectum, it is imbedded in cellular membrane, in which abscess makes rapid progress. The bladder, upon distention, rises before the intes- tines, keeping close to the pubes, and carrying the pe- ritoneum before it; so as, when much distended, to appear above the os pubis, and to allow of its being punctured, or even to permit the performance of the high operation for the stone without piercing I he peri- toneum. As it rises, however, the lower part of the bladder does not proportionally protrude downward, but rather (in the subject) retires from the perineum as the bladder fills. 2. During dissection, the place and degree ofthe curve of the urethra should be carefully observed, as of the last importance, in all operations in the perineum. It may be obsei ved how strongly the membranous part '' 241 of the urethra, or that portion of it which is betwixt the bulb of the urethra and the prostate gland, is supported by the faciculus of fibres or ligamentum triangulare and how much dissection it requires to show Us membranous nature. In the healthy state of the parts, it seems almost impossible that such rudeness should be employed as to rupture the urethra with the catheter; yet this happens in the diseased state of the parts. The consequence of continued pressure of bougies, however, is that the urethra is at last perforated, because the bougie, being with dif- ficulty directed in the curve of the uretlna, makes its way into the interstice filled with cellular membrane, betwixt the neck of the bladder and rectum, and sometimes into the rectum itself ! forming a conrtant draining of urine into the rectum and exciting tenes- mus. 3. The prostate gland, which is seen sur- rounding the neck of the bladder, when swelled by any of the causes enumerated below, compresses the canal of the urethra : but a more complete obstruc- tion to the introducing of the catheter arises from its swelling irregularly, or pushing forwatds, so as to \ increase the sudden curve of the urethra, or to shift it ;;side. In the same manner, tumours, or even ab- scesses, by distorting the urethra, cause difficulty of passing urine. We see an instance of the distortion of ! the urethra causing retention, where the bladder is contained in the hernial sac. But in this case, much of the difficulty of passing urine aiises from a degree k of weakness in the bladder itself, and from its also having lost the co-operating pressure ofthe abdominal muscles. 4. The section of the pelvis may illustrate ano- ther circumstance much dwelt upon by Camper, viz. the point of the catheter being prolonged too far beyond that part of its curve which should » be adapted to the curve of the urethra ; the ■ \oi. 1. X 242 consequence of this is, that when it is fully introduc- ed, the point reaching the back part of the bladder pushes it before it; and the coats of the bladder, clinging round the catheter, prevent the urine from flowing ; or, if the instrument be continued in the bladder, there is great risk of the bladder being hurt by the point of the instrument. Cases have occurred of its making way into the rectum from the bladder. 5. It may be observed, too, how much ofthe blad- der is, in sounding, under the curve of the staff; how a stone, gravitating into the lower part, may be overreached by the staff or catheter, and no grating be felt but by forcing the convexity of the staff down- wards in sounding. The stone falling into this more depending part ofthe bladder, in the prevailing posture of the body, may form a lodgment there. This would undoubtedly more frequently happen, did the bladder always retain its natural pliancy and thinness of its coats ; but the consequence of the presence and irri- tation ofa stone in the bladder is a thickening and con- traction of the coats, which tends to prevent the for- mation of cysts. 6. In puncturing the bladder from the rectum, we see how the prostate gland being enlarged may be mis- taken for the bladder, and the trocar plunged into its solid substance. In puncturing by the perineum also, we must recol- lect, that if the diseise be in the prostate gland it is enlarged, so that there is a great probability that the trocar shall be passed into the substance ofthe gland, without penetrating into the bladder. I have seen an instance of the trocar in this opera- tion having passed through the urethra : upon with- drawing the stilet no urine flowed from the canula, because it had transfixed the urethra (which had been dilated behind the obstruction ;) but upon withdraw- ing the canula a little, and freeing it from the oppo- site side of the urethra, the urine flowed in full 243 stream. The canula upon this was further introduced again ; but, instead of taking its former direction, it slippled along the urethra, and found its way into the bladder by the natural passage. This appeared upon the dissection. In the subject we see how the bowels press down into the pelvis in the erect posture of the human body ; but we may obseive also, how the viscera of the pelvis, being more firmly connected by cellular membrane and constricting muscles, support the weight of the abdominal viscera ; that, by the combined power of the perineal muscles, levator ani, sphincter, and coc- cygeus muscles (the antagonists of the abdominal muscles and diaphragm,) the prolapsus of the parts is Erevented ; yet we can conceive in the female pelvis a ernia of some of the intestines, betwixt the vagina and the rectum, forming a tumour pushing down from the vagina ; or here sometimes a hernia may insinuate itself betwixt the bladder and os pubis, get- ting access to the throid hole ; nay, there are even in- stances of hernia protruding upon the hip from the sacro-ischiatic hole. Still another very useful view of the viscera of the pelvis may be had, by taking away the os sacrum and dissecting the parts, separating the rectum and blad- der, but preserving all the connexion of parts, and the muscles in their natural situation. The arteries of the pelvis will of course form part of the demonstra- tion. (See Appendix.) 244 FURTHER DISSECTIONS OF THE URE- THRA AND BLADDER. The bladder and penis being taken from the pelvis, and freed from all the muscles, we have to examine the spongy bodies of the penis, the prostate gland, the vesiculae seminalis, and the urethra itself. In the examination of the urethra we ought to be very particular. 1. When the urethra is opened, it has sometimes the appearance of having muscular fibres in its inner coat, but this is a deception, owing to the slight rugose state of that membrane when the penis has shrunk. 2. The next thing to be look- ed to is the lacun.e. They are very nune ous-on the anterior half of the canal. They are largest, too, on the side of the urethra next the body of the penis, which makes us, during the introduction of a bougie, bear the point of it, for the most part, against the lower side of the urethra. 3. The seat of gonorrhea is in the fore part of the urethra. Mr. Hunter said within a little way of its extremity. This is always the situation of the inflammation in the first instance, 1 presume, from the symptoms, and from Mr. Hun- ter's dissections. 4. I have dissected the parts in what I conceived to be a later stage of the disease, when I found that, within two inches of the termi- nation forward, the urethra was loaded with blood, but I saw, also, that the same inflammation was for the extent of two inches at the bulb. In stricture of the middle of the canal, I have found the urethra inflamed at the anterior extremity, and at the bulb in the same manner. 5. The following are very fre- quent circumstances in practice. A gentleman has a gonorrhea, he can force matter fiom the fore part of the canal until it is quite clear, and nothing flows, but, by pressing the perineum, a quantity of matter is 245 to be forced up greater than at first. Again, as I pass the small ball probe into the urethra, near the extre- mity, there is pain, and matter canv be brought out; in introducing the ball further into' the canal, there is no pain nor matter, but on passing it into that part which is near the bulb, there is great soreness, and matter is brought out. I have little doubt then that the inflammation either passes by sympathy, from its seat near the extremity, to the part ofthe urethra which is at the bulb, or that the inflammation making its progress along the canal subsides in the greater extent, but becomes fixed near the bulb, owing to the greater natural irritability of that part. 6. A discharge which resists the use of injections and is yet in the fore part of the urethra, will be found to proceed from the large lacunae. Being in a state of suppuration, the continued inflammation of the lacunae produces a hardening and swelling of the surrounding cellular membrane, so that it appears like a gland, both to the feeling during life and on dissection. 7. The pros- tata iNrERioREs, or Cowper's glands (see his Myc- tomia,tab. xix.) I am inclined to think they are an ef- fect of inflammation. I have often found them. I have found a gland on one side and not on another, but in general they are not to be found. Of stricture.—Strictures I have ascertained by dissection to be of several kinds. 1. The first is the simplest and most common and such as is represented in Mr. Hunter's plate—a portionjof the canal, not greater than the sixth or seventh part of an inch, has lost its elasticity and remains undilatable; on inspect- ing it narrowly, the disorder is seen not to be in the inner membrane of the urethra only, but in the sur- rounding membrane and sometimes the spongy body is drawn into a less compass, and is become dense and white. 2. The surface of a stricture is in general smooth, but I have found it curi- ously reticulated, and effect 1 have supposed of 216 ulceration in the part, yet when abscess forms by ulceration, it is behind the stricture. 3. I have seen a stricture where the patient died after the application of the caustic. One half ofthe stricture had been des- troyed, and, in place of the firm dense sides of the urethra, soft fleecy shreds hung from the surface. 4. The second kind of stricture is that in which a consi- derable portion ofthe canal has suffered by deposition of additional matter, which now depiives this part of its natural elasticity, and it remains irregularly con- tracted. 5. A third kind of stricture is where the ure thra is contracted, and the spongy substance wasted. On dissection, I have found a stricture of this kind two inches'in-length. 6. The spasmodic stricture is quite an improper term. The symptoms which have given rise to this term belong to another disease. When the death has been owing to the sudden in- crease of the stricture, or the interruption of the flow of urine by the falling forward ofa small calculus against the stricture, 1 have found that the whole tract of the urethra and bladder was greatly inflamed, and the inside covered withshreds of coagulable lymph ; the coats ofthe bladder loaded with blood, the ureters and kidney dis- tended and inflamed. 7. There is found a little serous effusion on the brain of those who die of obstructed urine. This is the effectof the continued irritation and fever, and is not of the nature ofa translation of excre- tion. 8. Fistula in perineo may become the subject of anatomical investigation, for, in the first violence of the disease, it sometimes destroys the patient, and, by tedious suffeiing, it often wears out the strength and constitution. Mr. Hunter held an opinion, that sometimes the mouth of the lacuna contracted, and that the secretion beinj, retained, a* in fistula laciymalis, an abscess fo.med on the con- 247 trary, I believe that, in all cases of fistula in perineo from disease, the origin is from the stricture of the urethra. On dissection, the circumstances to be at- tended to are the place of the uiethra, which has ulce- rated and its relation to the stricture, the state of the stricture in the urethra, the extent of the fistulous openings, and state of the cellular membrane ^of the perineum and about the neck of the bladder; the state of inflammation ofthe urethra, bladder, and kidnies— with a view of contrasting^ the appearances and symp- toms, and deciding on the manner of operating in simi- lar circumstances. I have not seen any thing like warts or tumours of the urethra. 9. A very valuable part of Mr. Hunter's book is his account of the diseases of the prostate gland : he describes the manner in which the gland swells in its greater mass which is below the urethra, so as to raise the canal. He ascertained that sometimes one side only is enlarged, so as to distort the canal, and particularly that there was a part ofthe gland seated behind, which swelled up even when the gland was not generally dis- eased, so that, projecting into the bladder like a valve, it obstructed the urine. The gland will therefore, be examined with a view to understand the cffeqts ofits disease upon the canal of the urethra which passes through it, and the manner of insinuating the catheter, past an obstruction of this kind. 10. In enlargements of this gland the constricting fibres upon the mouth of the bladder have a strange ef- fect in moulding it as it were, for while it enlarge-), the fibres protrude it backwards into the cavity of the bladder. 11. Dr. Baillie has found this gland with scrophu- lous pus in it. 12. The enlargement of this gland may sometimes not improperly be called a varicose enlargement; be 248 cause the enlargement is not so much of its substance as of the surrounding parts and circle of veins, which are in situation and diseases somewhat analogous to the haemorrhoidal vessels. 1 have seen in the neck ofthe female bladder as great an enlargement as in that of the male ; and in many cases, in dissecting diseased parts, to give a clear and distinct view, the tumour gradually vanishes, and, before we are aware, no mark of disease remains. But of this there is no danger in the most frequent kind of disease, the most incurable and distressing malady, the schirrous enlargement in old men. Too frequently, in the last stage of life, disease, and the debility of old age, falls upon the urin- ary passages, causing an irritability in the bladder and swelling of the prostate gland, and terminating life with excruciating agony. 13. Even when no mark of disease is apparent, yet, upon cutting into the gland, small chocolate-coloured stones, like seeds, are found filling up its ducts, or in little sacs. I have seen this gland stuffed with them like the gizzard of a fowl. OF THE DESCENT OF THE TESTICLE; OF THE MANNER OF DISSECTING; AND OF THE DISEASES ILLUSTRATED BY THIS PIECE OF ANATOMY. The descent ofthe testicle in the foetus is, in a phy- siological light, extremely curious, and almost inexpli- cable as a piece of anatomy. It is with some difficulty comprehended at first, but worthy of our utmost at. tention, as illustrating many important diseases; hernia, hydrocele, and all diseases of the testicle chord, and abdominal ring.—See our Anatomy ofthe Human Body. When a foetus is procured in which the testicles 219 ^ have not descended, it may be dissected with a view " to the followiug circumstances :__ 1. Tne testicle will be found in its progress down- ward from its original situation on the psoas muscle. 2. The peritoneum on the inside of the ring will ap- pear as if perforated ; into this a small probe being pushed, it will pass obliquely into the groin, and being cut upon there, it will be found to have entered into a process of the peritoneum, resembling the fin- ger of a glove. 3. The vessels will be observed run- ning to the testicle, and the vas deferens descend- ing, t. On the side of the pelvis under the peritone- um, and sL etching from the testicle towards the ring, the gubenaculum testis will be discovered. 5. If the testicle shall have descended, yet the process ofthe peritoneum, which projects before it into the groin, will still be open, and, by passing' down the probe into this process, it will come in contact with the testicle as it hung originally on the loins. If, on the other hand, the scrotum be now opened, the coats of the testicle will appear as in the adult state. After taking off the dartos, the vaginal coat will b« seen, and, on opening this, it will be found to be the same sheath or process of the peritoneum, into which the probe had been introduced, and, on fully exposing the testicle, the tunica albuginea will be understood to be the membrane covering the testicle, as it origi- nally hung on the psoas muscle. THE COATS OF THE TESTICLE OF THE ADULT, AND SOME OF ITS DISEASES ILLUSTRATED FROM THE ANATOMY OF THE TESTICLE OF 'Villi. FOETUS. Cause of the descent of the testicle.—It is utterly impossible to account for the descent of the testicle by any mechanical action, by the pressure of 250 the abdominal muscles, by the peristalic motion of the intestines, by the genaration of wind in them, or by gravitation :—for the foetus lies in the womb with the head downwards, the abdominal muscles are qui- escent, and the probability of occasional inflation in the intestines of the foetus is very small. Beside-, any general pressure would, at all events, more probably act upon some of the loose viscera, and produce rather a hernia than the regular descent of the testicle. The action of the gubernaculum is the more natu- ral explanation. It guides the testicle into its destined lodgment, and probably solicits it by a gentle action. Yet this action is unlike the action of other muscles, being unremitting whilst the testicle is within the belly ; and when the testicle is arrived without the groin, a relaxation must take place, allowing the testi- cle to descend into the scrotum. It is worthy of remark, that neither the spermatic vessels nor the vas deferens appear as if elongated or stretched,but retain their tourtuous waving figure. Under the title of gubernaculum testis, the fibres of the future cremaster muscles are included; and by many this muscle is thought to have the chief action in bring- ing down the testicle. The fibres of this muscle are with difficulty demonstrated in the human foetus ; but, from comparative anatomy, it is found that it is reflected from its origin :rom the transversalis abdo- minis upwards, following the gubernaculum. In this situation of the parts in the foetus, the cremaster muscle must lie behind the peritoneum; but in the adult, as that side of the peritoneum which is con- tiguous to the psoas muscle becomes (in the scrotum) the outer surface of the peritoneum which covers the chord, the cremaster becomes an outer layer of fibres embracing the chord. The exit of the testicle through the abdominal ring is certainly facilitated by the gu- bernaculum as a precursor. It altogether forms a 251 body of a wedge shape or pyramidal form (its base being upon the testicle) which must gradually dilate and till up the abdominal ring, and make way for the testicle. When the testicle is as yet far up upon the loins, the gubernaculum is slender ; by its contraction it becomes thicker ; and before tbe testicle has ar- rived at the outlet, it is little larger than the contracted and thickened gubernaculum which has preceded it. Situation of the testicle in its full de- scent.—As the testicle descends, the process of the peritoneum accompanying it changes by insensible depress. Though we see in a child upon one side v the testicle lying behind the peritoneum like the other viscera of the abdomen, yet, upon the other side, if the testicle have fully descended, we shall have some difficulty (from the additional layers of cellular mem- brane it has acquired) in dissecting the vessels from the peritoneum, to shew that the vessels run down behind the sac to supply the testicle. Shortly after the descent, the prolonged sac of the peritoneum coaleses wi;*^i and surrounds the spermatic chord, now composed of the spermatic vessels, the vas defe- rens, and the muscular fibres. These form one mesh; so that no passage remains previous from the cavity of the abdomen down betwixt the tunica vaginalis and the unica albuginea. Mr. Hunter was of opinion, that in those cases where the testicles remain in the belly, the testicles are diminutive, and more imperfect than those which descend into the scrotum. There is undoubtedly something defective in the testicle when it does not descend, and a tendency in it to form adhesion to the intestines indicates disease or imperfection, Of congenital hernia.—How widely different the causes ofthe descent ofthe testicle are from those of a rupture, appears from the rarity of the occurrence of the congenital hernia, or the pacing down of a portion of the intestine along with he testicle. 2.>2 This is veiy remaik able, when wc consider that a turn of the intestine is not larger than the testicle to which it lies contiguous, and that the testicle remains long in the very ring dilating it; yet by the peculiar me- chanism and interlacing of the fibres ofthe ring, the intestine is not allowed to follow. Indeed, I am of the opinion of the celebrated Wrisberg, that the con- genital heinia does rarely .happen but by a previous adhesion of seme of the intestines to the body of the testicle, by which it is drawn down along with it. Wrisberg found the ring, in several instances, so wide, and the parts so lax, as easily to allow the de- scent of a portion of the gut or omentum ; yet in these cases thei e was no hernia. Again, he found in other young subjects, where the testicle still remained in the belly, tfiat it had contracted adhesions with the omentum. And lastly, he found in a case of old congenita] hernia (upon opening the belly,) that a portion ofthe omentum seemed to be attached to the ring ; but, upon further dissection, he found it con- tinued down thiough the ring, and adkviing to the tunica albuginta of the testicle. In oti.er cases, he found the testicle so connected with intestinum ca-cum, that in pulling the one either way the other followed ; and, what he conceives to be a convincing pi oof, he found in one side of a subject a facicuius of fibres attached to the testicle, and inclosed in a duplicature of the peritoneum : while on the other side, though the ring was so wide as to allow the finger to slip in, there was no heinia. From these facts, he conjectures that the congenital heinia is, for the n.ost part, foimed in consequeue of adhesions betwixt the ttsticle and viscera ; and that the intes- tines, or omentum, are in.con. equence, drawn down along with the testicle. It is a curious circum- stance, if fully proved, that the testicle not only most unaccountably comes down into the scrotum 253 but that its tendency thither is so great as to pull down the intestine, and elongate the mesentery also. It would be an idle repetition to point out the me- thod of dissecting and investigating the congenital hernia, since the circumstances of its anatomy, and its character and peculiarities, have been alreadv detailed. The appearance of tbe more common rup- ture may perhaps be more opportunely illustrated here. Of inguinal hernia.—Although the abdominal ring be preternaturally wide, if the testicle shall have descended naturally, and the peritoneal sheath be closed, hernia congenita is for ever prevented; but if, upon any unusual exertion, a portion of the in- testine shall be forced through the ring, the old sheath is not opened, but a new sac of the peritoneum is forced down ; and though it take the same course with the testicle, it still, in all its stages, remains detached, and in a distinct process of the prolonged peritoneum. In an old case of hernia, and where the patient's death has not been occasioned by the rupture, the ring is wide, the intestine loose in its sac, and the testicle lax, hanging far down, and often much wasted. Upon laying open the integuments, the peritoneal sac of the hernia comes into view ; and when the chord and testicle are extricated in all their length, the preternatural sac has no marked limits, but seems gradually to coalesce with the chord, being enveloped in loose cellular membrane and vessel*. Upon dissecting up towards the abdomen, we find no ring, but the sac of the hernia gradually blended with tne tendon of the external oblique muscle ; which, stretching over the neck of the sac, is so closely mingled with it, that it is only distinguish- able from it by the splendor of its encircling fibres. To demonstrate further this preternatural connexion, we iav open the belly, and examine the state of the viscera ind the portion of the gut protruded ; we di» Vol. 1. Y 254 sect the peritoneum carefully on the inside, from the muscles and ring, showing how it forms a sac inclos - ing the hernia. We take notice of the oblique or direct manner in which the sac passes through the ring. We are careful to observe the natural appear- ance of the peritoneum, where it is remote from the ring, and on the contrary how it is thickened and united with the cellular membrane in the ring. Then we show the spermatic chord going down quite on the outside and behind this sac, andjthe obliquity of its coursefrom the abdomen ; we lay open the vaginal coat of the testicle, showing that the testicle lies distinct in its appropriated coats : and lastly, show the hernial sac distinct from the spermatic chord or coats of the testicle ; or ring of the tendon of the external oblique; and, as we raifA'the pillars ofthe ring fiom the neck of the sac, we are carefull to observe how the fibres are dispeied and expanded over the neck ofthe sac. Appearances of strangulated hernia.— In a strangulated heinia, where it has been the immedi- ate cause of death, though the essential circumstances of the anatomy remain the same, the occasional oc- currences are infinitely varied. Upon making an incision to lay bare the sac, it is found tense and firm, crowded with vessels, and thickened towards the ring ; but over the proper sac we notice the several lamina of the cellular membrane ; the marks of inflammation are great, and chiefly owing to tbe efforts {o reduce the hernia. Upon opening tbe belly, the intestines are found inflamed and distended ; pus and coagulable lymph is on the surface, by which they aie often slightly glued together. If the hernia has been large, tbe mesentery is elongated by the pulling ofthe intestines, and the viscera in much disorder, even the stomach having descended from its place ; so that sometimes in very large hernia the abdomen is left almost empty of the floating viscera. In a case wherethe intestines have been 1 educed eithei by the operation or taxis, the re- 255 duced portions are found lying within the ring ad- hering ; often sphacelated. Upon laying open the sac of the hernia if of old standing, it is found to consist of many layers, smooth as the abdominal peritoneum within, including most commonly the omentum, or a portion of the ilion in the sac. If the person has died of unreduced strangulated heinia there is bloody serum in it. The intestine is dark coloured, and has on it black or livid spots ; and on the surface, sometimes, coagulable lymph. The coagulable lymph marks this circumstance, taat inflammation of the protruded portion of the gut preceded the .strangula- tion. When a gut is strangulated, inflammation is over, and where it takes place suddenly there is no coagulable lymph. If the omentum have fallen down, it will have altered much of its nature, become firm and condensed, composed of hard pellicles of tat irregularly connected by membranes ; with frequent strings of adhesion, tortuous dilated veins, and gene- ral inflammation. If the strangulation of the gut have advanced far, then it is dark and mortified, with foul serum in the sac. Adhesions are frequent betwixt the doublings of the gut, mou| rarely between the gut and sac, on the outside of the ring. It would appear to me that the irregularity of the functions of the intestinal canal, the inflation or congestion of the protruded portion of gut; is the more frequent cause of strangulation, and of the worst symptoms, in old hernia ; and that the inflammation and constriction of the neck of the sac is secondary merely. Sure I am, that the intestine is seldom reduced by the me- chanical exertion ; but merely the flatus in the in- testine is forced into the intestines within the belly, and then the portion which had descended is drawn in by the action of the intestinal canal : and, again, it would appear, that frequently in attemptiug the re, duction, the mouth of the sac is pushed aside from the ring, and the reduction prevented. 256 When the strangulated portion of the gut gan- grenes, the fascia, cellular membrane, and glands of the groin, form one confused foetid mass, and air is generated in the cellular membrane ; all that can be done, I beKeve, in operating in the living body, is to lay the gut freely open, and leave it to nature : the upper part J of the canal being opened, the load is evacuated by this artificial anus. The patient has sometimes survived such an operation ; continuing to discharge the faeces by the groin. I have dissected the parts where the patient has lived some time with an anus at the groin. Both ends of the intestine arc found adhering to the peritoneum, and adhering and fixed to the passage of the abdominal tendons ; and, what is more important to observe, adhering to each other. I have conceived, that by an operation the course of the faeces may be directed into the old chan- nel again, but this is no place for the discussion. It is a curious resource of nature, by which the faeces spontaneously resume their natural course to the rectum, although a complete turn of the gut has been cut off. This is accomplished by the sides of the intestines, strictly included in the ring, or under the femoral ligament, forming an adhesion and com- munication with each other ; which is completed by the closing of the ulcer in the groin. This takes place more frequently in the small femoral hernia of women. 1 have given here a few hints, which I hope will be • sufficient to enable the surgeon to take advantage of his opportunity of private dissection. But for the full elucidation of this subject, he must turn to Mr. Cooper's work on hernia, the highest example we have of pathological research. Of hydrocele.—As in the last species of hernia the intestines take a new route, and are preceded by a distinct sac of the peritoneum ; so, in hydrocele, the tunica vaginalis testis being distended with fluid, the 257 original sheath is not again opened, but that part which envelopes the chord (now degenerated into loose irregular cellular membrane) remains entire, while the distended sac swells on all sides, but chiefly upwards, and before the spermatic vessels, conically. So that, upon laying open the sac in the operation for the radical cure by incision, the testicle is seen covered only by its proper tunica albuginea, unless when, by frequent tapping, a partial inflammation has been communicated to the testicle ; in which case, itvery commonly adheres to the fore part ofthe tunica vaginalis which had been punctured with the trocar. In hydrocele the water is green or yellowish, the tu- nica vaginalis is commonly thickened, and the testicle sometimes small and compressed, but sometimes, and indeed more frequently, larger and soft. To demon strate the anatomy of an advanced hydrocele, we inject the spermatic vessels, follow the chord down behind the sac formed by the dilated vaginal coat, fill the sac, by a small puncture, with spirits, and harden the whole in spirits for a few days ; then open the vaginal coat, to show the situation ofthe testicle; the prepa- ration may be preserved in spirits. I have in two cases examined the coats of the testicle after the use of the injection for hydrocele: in one ofthe instances, the two coats had adhered by the in tervention of a fleecy cellular substance ; the other had partially adhered, and where it did not adhere, the water was collecting. The diseases of the spermatic chord show us how completely it is changed in its nature from that ofthe peritoneum ; for its cellular structure sometimes Ire- comes the seat of dropsical swelling, forming a species of hydrocele : sometimes it appears like a collection of hydatids, yet neither communicating with the vaginal coat of the testicle nor with the cavity of the abdomen ; sometimes the hydrocele consist of only one or two vesicles : and, when the lower 258 portion ofthe chord is pressed, the swelling subsides, and retires to the cells in the chord within the ab- domen. Loose cartilages are sometimes found in the tunica vaginalis, a frequent occurrence is that of small soft bodies attached to the epididymis. FURTHER DISSECTION OF THE TESTICLE. To prepare the testicle for the demonstration of its structure, the chord must be kept very long, the spermatic arteiy and vein injected with different co- lt uied wax injection. Then the mercurial tube must be fixed into the vas deferens, and the seminal vessels injected. To demonstrate the lymphatic vessels, we may blow into the substance of the testicle by punc- turing the tunica albuginea, or we may force nieicuty into it, and by forcibly squeezing the testicle, the lymphatic vessels will be filled by the air or mercury. Or if the vessels and ducts be already known to the student, and he wish only for such demonstration as may enable him to understand the physiological opinions given during the controversy on this subject in the Thesis of Dr. Monro, De Valvulis Lymphaticis, and Medical Commentary of Dr. Hunter; let him only inject the spermatic arteiy with mercury, and observe the progress of tbe injection. First, the hv;inches of the arteries filling, the mercury will be seen returning by the veins ; then the lymphatics will be Middenly distended ; and lastly, the seminal vessels will be filled. 1 have no doubt that the mercury gets into the two last classes of vessels by bursting into the cellular membrane, and, at the same time, lacer- ating the branches, and entering the sides of these vessels. Whalconfiims me in this opinion is, that I l.ave filled the seminal vessels and epididymis, by thrusting a pipe into the substance of the testicle. 259 By such experiments, die fallacy of all proof of func- tion from the mere circumstance of dissection, is made apparcn t; for, in the filling the lymphatics by extravasa- tion, there is no more proof of their rising from the cellular texture, than ofthe arteries, veins, or seminal vessels doing so. Having considered the original situation of the tes- ticle ; the source of its arteries, veins, and nerves ; the progress of its descent; and hence seen the reason of iU extensive sympathies ; being, in fact, in all res- pects, as a viscus of the abdomen. Having dissected the vessels of the chord, opened the coats ofthe body of the testicle, and floated the delicate tubuli testis in water ; having traced these tubuli to the rete testis, where they are united on the dorsum ; followed the rete testis, and seen the manner in which the vascular cones, or vasa efferentia, were derived from it ; then traced the vascular cones into the epididymis, observed the manner in which this wonderfully convoluted ves- sel lay on the testicle, so as to recognize the parts' in the living body, the student is well prepared to consider the diseases ofthe testicle. I. Varicocele. The enlargement ofthe veins of the spermatic chord is a frequent disease, and yet we are apt to pass it over in dissection, owing to the col- lapsed state ofthe vessels. There is no disease more frequently met with in private practice. 2. Nor do I conceive this the place to speak of the inflammation of the testicle, nor of abscess in the body of the testicle. 3. The scrophulous testicle is described as if the sub- stance of it was degenerated into a white or yellowish curdy substance, mixed with pus. 4. 1 have found it enlarged, hand, and elastic, when covered with its coats ; soft and pulpy, and vascular, when the albu- ginea was opened. 5. But the most frequent appearance is scirrhous. It is enlarged, irregularly hard. When cut into, the tumour is found to be intersected with membranes, 260 which is theinternal character of true scirrhous, and in the center there are sometimes cells found. 6. The cancer of the testicle, resulting from the ulceration of this scirrhous enlargement, having its chief character in the liv ing body, we having nothing to do with here. 7. The testicle has been found both cartilaginous and bony. 6. The tvaginal coat of the testicle I Have seen so greatly thickened a s to be mis- taken for a scirrhous of the body of the testicle, for which the whole was amputated. 9. The testicle wastes, and almost totally disappeares. 10. It some- times remains in the abdomen, or slowly descends about the time of puberty, which is supposed by Mr. Hunter, with every appearance of truth, to proceed from some imperfection of the testicle. OF THE INVESTIGATION OF DISEASE IN THE PELVIS, AND OF THE MORBID STATE OF THE PARTS. In their diseased state, the parts in the pelvis should not be cut out hastily, or before attention be paid to such points as can alone be illustrated by an examina- tion of the parts in situ. After the jgreat operations, the spreading of inflammation to the bowels, the stage to which the inflammation has proceeded, the quantity of matter, and the course of sinuses near the wound should be observed :—then the parts being carefully washed, and the vessels perhaps injected (if the state of the subject will allow it, and if -• y be of conse- quence in the dissection, as after lithotomy), a freer in- ves'igation may be allowed. For example, in a case of lithotomy, we have to • observe the state of the intestines. If the patient has died soon after the operation, the degree of intlam- 261 mationramong the intestines, and their distention; if the patient has lingered, and died debilitated, the in- flammation will have subsided, and there will be ad- hesions amongst the intestines, inflation, and scybalae; the lower portion of the colon, at least, will be dis torted and inflated, and will be found to have preter- natural adhesions. We have to observe the direction of the incision; the state of the wound ; the sinuses, that too often stretch up from it by the side of the rectum, and the effects of which will be seen upon the peritoneum, by folding back the rectum from the sacrum. In dissection, after the operation of puncturing the bladder, or after a tedious case perhaps of retention of urine where the catheter has been used, the instru- ments should be allowed to remain : then the bladder being opened from above, we can observe their true place, see them projecting into its cavity, judge of their effects, and of the inflammation in consequence, and of their pressure and effects on the neighbouring parts or opposite side of the bladder. In taking out . the parts, the penis should be first separated from the pubis (which, by the by, may be done without leav- ing any apparent deficiency, by leaving the skin and glands,) the crura cut from the bone, and the whole forced down under the arch of the os pubis : then, pro- ceeding to the inside, cut all freely out, by carrying the knife close to the bones of the pelvis ; by which all the parts are retained for further investigation ha their natural connexions. Of the bladder.—1. Where there has been ob- struction of the urethra, the bladder is always greatly changed : if the obstruction has been sudden, the coats are little thickened, but the inflammation is great, the vessels are numerous, and there are many spots red with extravasation. 2. If it has been sudden and absolute, the bladder suffers astonishing dilatation; it does not burst; it is said to burst, bu$ 262 I have found one or two small holes in the fundus, with irregular black edges, and the urine escapes among the viscera and inflames them. 3. If the ob- struction has been of long standing, and gradually increasing, then the bladder is small, and the walls greatly thickened. 4. When stone is in the bladder, the coats are very often thickened, in consequence of the incessant irritation, and, if not inflamed yet, its inn«;r surface is covered with slime and mucus. 5. The inner turface of the bladder is found ulcerated, and abraded. 6. In those who die violent deaths, the bladder is found firmly contracted. 7. It is found in old people contracted considerably, and equally inca- pable of much dilatation or further contraction. 8. The inner surface of the bladder is, in some instances, diseased with fungous excrescences ; they ai e soft, spongy, and full of blood; and not nncommonly such tumours have deposited on them a calcareous matter, which, during the life of the patient, is with difficulty distinguished from a stone. 9. In some rare cases, stones have been formed in those tumours. There is an explanation of this. 1 believe that calcit-W" lous matter will adhere to a diseased surface, though it will not concrete upon the smooth and seci eting surface of the internal coat of the bladder. Thus, after lithotomy, I have found the lips of the incision into the bladder prominent, and covered with a cal- culous crust, but none where the secreted mucus was poured out. 10. It is a very rate occurrence to find the stone lying betwixt some of the stronger fasciculi of fibres. 11. I have repeatedly found the rectum of young children terminating in the bladder. 12. A portion of intestine will sometimes attach itself to the bladder, and in time form a fistulous commu- nication. We have to expect some curious and in- teresting cases of this kind from Dr. Cheston, of Gloucester, who is about to give us the result of his experience in morbid dissection. 265. The vesicul.e seminales seem to be seldom the seat of disease, though, from their situation behind the prostate gland, they must frequently be involved in the diseased state of the rectum and bladder. Some- thing of their affections has been already mentioned. Dr. Baillie has found them with scrophulous matter in them. They are said to have stones in them, and have suffered by scirrhous. Though not a viscus of the pelvis, yet, from its strict relation to the last subject, I am induced to say a few words on the morbid anatomy of the kidney. Of the kidney.—The varieties in the form and distiibution of the emulgent arteries and veins, and in the ureters and pelvis, and whole of the gland, are so fi equent, that they can scarcely be considered as curiosities. 1. Coagulated blood, or concreted mucus, frequent- ly forms the nucleus of calculi in this gland and in the bladder. The natural mucous secretion, which con- tinually exudes from the urinary passages, allowing no deposition from the urine to take bold upon them, * prevents the formation of calculi; but when a particle of dead matter lodges, concretion immediately forms around it. Urinary calculi may be the symptom of a more universal disease in the assimulating organs, or they may be only casually produced in the bladder by an accidental necleus of this kind. Small grains of sand are sometimes found, even in the tubular part of the kidney. But commonly they are found lying in the pelvis or calices, and very often they fill the whole pelvis, and ramify into the calices or infundibuli. Then the cavities are enlarged, and the substance of the kid- ney distended. Sometimes the natural appearance of the substance of the kidney is lost. 2. Suppuration following inflammation of the kid- ney, will form at one time an immense deposit of mat- ter, converting its substance into a sac of pus; at another, only partial ab-cesses are formed. Sue'h 264 collections have sometimes been evacuated by the ureters, causing in their course, before they got to the bladder, dangerous retention of urine ; or it may hap- pen that, by communicating with the colon, the mat> ter may be evacuated by stool. It may spread amongst the surrounding cellular substance, or it may even point outwardly to the loins. Such diseased action in the kidney has gone so far, that the whole substance has been destroyed, and its seat has been only marked by a more condensed indurated cellular substance. 3. The kidney sometimes acquires an enormous size ; or it becomes soft; or degenerates into an as- semblage of hydatids ; or perhaps a steatomatous mass. 4. Scrophulous tubercles have been seen in the kid- ney. 5. Dr. Baillie has found it scirrhous. We may be at once sensible, why, upon inspiration and expiration, or in going to stool, or in efforts to make urine, the pain of inflammation in the kiney be- comes more violent, when we observe its situation up- on the muscles ofthe loins and upon the diaphragm, and how it must be affected by the play of the latter muscle. We may understand, likewise, how, in in> flammation or enlargement of the kidney, a stiffness and numbness is produced in the thigh, loins, and testicle, in consequence of the contiguity of the ante- rior twigs ofthe lumbar nerves ; which, running down. wards, play upon the groin, fore part of the thigh, and testicle, b. In retention of urine from the obstruction of the ureters by stones, hydatids, or clots of blood, the ureters are sometimes so much dilated as to resem- ble a small gut; and they become, at the same time, tortuous, or are irregularly distended; and, in their partial dilatations, their internal coat is stretched across like a valve. Their coats, too, in all such cases, be- come thickened. Where there is no obstinate re- sistance, even the pelvis and ducts of the kidney be- come enlarged like a second bladder, and greatly in' gamed. 7. It is in this case only, in which i have pk 265 served inflammation ofthe capsuli ofthe kidney. 8. I have carefully examined the kidney in diabetes, bnt observed only that it was larger and softer, and the ves- sels proportionally enlarged and soft; that appearance which indicated increased activity, but not inflamma. tion. Of the rectum.—The rectum being a very glan- dular part, largely supplied with veins, and exposed •to a variety of exciting causes, is very subject to dis- ease ; and peculiarly to scirrhous thickening and con. ractions of its cavity. The contraction is in general about two inches from the anus. When such derange- ment proceeds to cancerous ulceration, it makes an ugly mass of dissection. 2. In the last stage of such a case, it will be found that the bladder is drawn into disease; that the surrounding cellular substance is hard and scirrhous, and that abscesses run through it, forming communications with the gut above the stric- ture. 3. It is subject to have soft spongy tumours growing in the inner surface. 4. The verge of the anus is the seat of piles. These are tumours of en- larged veins, with much coagulable lymph deposited around the veins. 5. The inner surface and margin of the gut is subject to descent and consequent ulcer- ation. 6. Spongy excrescences are frequent about the verge of the anus. They are, I believe, rarely cancerous. CX» OF VOLUME OKE. Dissections. Vol. 1. Beirr5 National Library of Medicine Bethesda, Maryland m~»Hm on Receipt = The volume had been bound in library buckram and was in good condition. The »e"ing appeared sound. The pages were acidic and discolored. ThTvolume had tears that had been mended with pressure-sensitive tape. Ii;:r^r.a^nr^ore^%!Har;erTndedTh:f;Ssawere UsUd'for^ubiUty. The head tall and pjge. were dry cleaned and nonaqueously *>"««•*