To the surgeon, anatomy is eminently what Bacon has so beautifully said that knowledge in general is: it is power—it is power to lessen pain, to save life, and to eradicate diseases, which, without its aid, would be incurable and fatal. It is impossible to convey to the reader a clear conception of this truth, without a reference to particular cases; and the subject is one of such extreme importance, that it may be worth while to direct the attention for a moment to two or three of the capital diseases which the surgeon is daily called upon to treat. Aneurism, for example, is a disease of an artery, and consists of a preternatural dilatation of its coats. This dilatation arises from the debility of the vessel, whence, unable to resist the impetus of the blood, it yields, and is dilated into a sac. When once the disease is induced, it commonly goes on to increase with a steady and uninterrupted progress, until at last it suddenly bursts, and the patient expires instantaneously from loss of blood. When left to itself, it almost uniformly proves fatal in this manner; yet, before the time of Galen, no notice was taken of this terrible malady. The ancients, indeed, who believed that the arteries were air tubes, could not possibly have conceived the existence of an aneurism. Were the number of individuals in Europe, who are now annually cured of aneurism, by the interference of art, to be assumed as the basis of a calculation of the number of persons who must have perished by this disease, from the beginning of the world to the time of Galen, it would convey some conception of the extent to which anatomical knowledge is the means of saving human life.

The only way in which it is possible to cure this disease is, to produce an obliteration of the cavity of the artery. This is the object of the operation. The diseased artery is exposed, and a ligature is passed around it, above the dilatation, by means of which the blood is prevented from flowing into the sac, and inflammation is excited in the vessel; in consequence of which its sides adhere together, and its cavity becomes obliterated. The success of the operation depends entirely on the completeness of the adhesion of the sides of the vessel, and the consequent obliteration of its cavity. This adhesion will not take place unless the portion of the artery to which the ligature is applied be in a sound state. If it be diseased, as it almost always is near the seat of the aneurism, when the process of nature is completed by which the ligature is removed, hemorrhage takes place, and the patient dies just as if the aneurism had been left to itself. For a long time the ligature was applied as close as possible to the seat of the aneurism: the aneurismal sac was laid open in its whole extent, and the blood it contained was scooped out. The consequence was, that a large deep-seated sore, composed of parts in an unhealthy state, was formed: it was necessary to the cure that this sore should suppurate, granulate, and heal: a process which the constitution was frequently unable to support. Moreover, there was a constant danger that the patient would perish from hemorrhage, through the want of adhesion of the sides of the artery. The profound knowledge of healthy and of diseased structure, and of the laws of the animal economy by which both are regulated, which John Hunter had acquired from anatomy, suggested to this eminent man a mode of operating, the effect of which, in preserving human life, has placed him high in the rank of the benefactors of his race. This consummate anatomist saw, that the reason why death so often followed the common operation was, because that process which was essential to his success was prevented by the diseased condition of the artery. He perceived that the vessel, at some distance from the aneurism, was in a sound state; and conceived, that if the ligature were applied to this distant part, that is, to a sound instead of a diseased portion of the artery, this necessary process would not be counteracted. To this there was one capital objection, that it would often be necessary to apply the ligature around the main trunk of an artery, before it gives off its branches, in consequence of which the parts below the ligature would be deprived of their supply of blood, and would therefore mortify. So frequent and great are the communications between all the arteries of the body, however, that he thought it probable, that a sufficient supply would be borne to these parts through the medium of collateral branches. For an aneurism in the ham, he, therefore, boldly cut down upon the main trunk of the artery which supplies the lower extremity; and applied a ligature around it, where it is seated near the middle of the thigh, in the confident expectation that, though he thus deprived the limb of the supply of blood which it received through its direct channel, it would not perish. His knowledge of the processes of the animal economy, led him to expect that the force of the circulation being thus taken off from the aneurismal sac, the progress of the disease would be stopped; that the sac itself, with all its contents, would be absorbed; that by this means the whole tumor would be removed, and that an opening into it would be unnecessary. The most complete success followed this noble experiment, and the sensations which this philosopher experienced when he witnessed the event, must have been exquisite, and have constituted an appropriate reward for the application of profound knowledge to the mitigation of human suffering. After Hunter followed Abernethy, who, treading in the footsteps of his master, for an aneurism of the femoral, placed a ligature around the external iliac artery; lately the internal iliac itself has been taken up, and surgeons have tied arteries of such importance, that they have been themselves astonished at the extent and splendor of their success. Every individual, on whom an operation of this kind has been successfully performed, is snatched by it from certain and inevitable death!

The symptom by which an aneurism is distinguished from every other tumor is, chiefly its pulsating motion. But when an aneurism has become very large, it ceases to pulsate; and when an abscess is seated near an artery of great magnitude, it acquires a pulsating motion; because the pulsations of the artery are perceptible through the abscess. The real nature of cases of this kind cannot possibly be ascertained, without a most careful investigation, combined with an exact knowledge of the structure and relative position of all the parts in the neighborhood of the tumor. Pelletan, one of the most distinguished surgeons of France, was one day called to a man who, after a long walk, was seized with a severe pain in the leg, over the seat of which appeared a tumor, which was attended with a pulsation so violent that it lifted up the hand of the examiner. There seemed every reason to suppose that the case was an aneurismal swelling. This acute observer, however, in comparing the affected with the sound limb, perceived in the latter a similar throbbing. On careful examination he discovered that, by a particular disposition in this individual, one of the main arteries of the leg (the anterior tibial) deviated from its usual course, and instead of plunging deep between the muscles, lay immediately under the skin and fascia. The truth was, that the man in the exertion of walking, had ruptured some muscular fibres, and the uncommon distribution of the artery gave to this accident these peculiar symptoms. The real nature of this case could not possibly have been ascertained but by an anatomist. The same surgeon has recorded the case of a man who, having fallen twice from his horse, and experienced for several years considerable uneasiness in his back, was afflicted with acute pain in the abdomen. At the same time an oval, irregularly circumscribed tumor made its appearance in the right flank. It presented a distinct fluctuation, and had all the appearance of a collection of matter depending on caries of the vertebræ. The pain was seated chiefly at the lower portion of that part of the spine which forms the back, which was, moreover, distorted; and this might have confirmed the opinion that the case was a lumbar abscess with caries. Pelletan, however, who well knew that an aneurism, as it enlarges, may destroy any bone in its neighborhood, saw that the disease was an aneurism, and predicted that the patient must perish. On opening the body (for the man lived only ten days after Pelletan first saw him) an aneurismal tumor was discovered, which nearly filled the cavity of the abdomen. If this case had been mistaken for lumbar abscess, and the tumor had been opened with a view of affording an exit to the matter, the man would have died in a few seconds. There is no surgeon of discernment or experience whose attention has not been awakened, and whose sagacity has not been put to the test, by the occurrence of similar cases in his own practice. The consequence of error is almost always instantaneously fatal. The catalogue of such disastrous events is long and melancholy. Richerand has recorded, that Ferrand, head surgeon of the Hotel Dieu, mistook an aneurism in the armpit for an abscess; plunged his knife into the swelling, and killed the patient. De Haen speaks of a person who died in consequence of an opening which was made, contrary to the advice of Boerhaave in a similar tumor at the knee. Vesalius was consulted about a tumor in the back, which he pronounced to be an aneurism; but an ignorant practitioner having made an opening into it, the patient instantly bled to death. Nothing can be more easy than to confound an aneurism of the artery of the neck with the swelling of the glands in its neighborhood: with a swelling of the cellular substance which surrounds the artery; with abscesses of various kinds; but if a surgeon were to fall into this error, and to open a carotid aneurism, his patient would certainly be dead in the space of a few moments. It must be evident, then, that a thorough knowledge of anatomy is not only indispensable to the proper treatment of cases of this description, but also to the prevention of the most fatal mistakes.

There is nothing in surgery of more importance than the proper treatment of hemorrhage. Of the confusion and terror occasioned by the sight of a human being from whom the blood is gushing in torrents, and whose condition none of the spectators is able to relieve, no one can form an adequate conception, but those who have witnessed it. In all such cases, there is one thing proper to be done, the prompt performance of which is generally as certainly successful, as the neglect of it is inevitably fatal. It is impossible to conceive of a more terrible situation than that of a medical man who knows not what to do on such an emergency. He is confused; he hesitates: while he is deciding what measures to adopt, the patient expires: he can never think of that man's death without horror, for he is conscious that, but for his ignorance, he might have averted his patient's fate. The ancient surgeons were constantly placed in this situation, and the dread inspired by it retarded the progress of surgery more than all other causes put together. Not only were they terrified from interfering with the most painful and destructive diseases, which experience has proved to be capable of safe and easy removal, but they were afraid to cut even the most trivial tumor. When they ventured to remove a part, they attempted it only by means of the ligature, or by the application of burning irons. When they determined to amputate, they never thought of doing so until the limb had mortified, and the dead had separated from the living parts; for they were absolutely afraid to cut into the living flesh. They had no means of stopping hemorrhage, but by the application of astringents to the bleeding vessels, remedies which were inert; or of burning irons, or boiling turpentine, expedients which were not only inert but cruel. Surgeons now know that the grand means of stopping hemorrhage is compression of the bleeding vessel. If pressure be made on the trunk of an artery, though blood be flowing from a thousand branches given off from it, the bleeding will cease. Should the situation of the artery be such as to allow of effectual external pressure, nothing further is requisite: the pressure being applied, the bleeding is stopped at once: should the situation of the vessel place it beyond the reach of external pressure, it is necessary to cut down upon it, and to secure it by the application of a ligature. Parè may be pardoned for supposing that he was led to the discovery of this invaluable remedy by the inspiration of the Deity. By means of it the most formidable operations may be undertaken with the utmost confidence, because the wounded vessels can be secured the moment they are cut: by the same means the most frightful hemorrhages may be most effectually stopped: and even when the bleeding is so violent as to threaten immediate death, it may often be averted by the simple expedient of placing the finger upon the wounded vessel, until there is time to tie it. But it is obvious that none of these expedients can be employed, and that these bleedings can neither be checked at the moment, nor permanently stopped, without such a knowledge of the course of the trunks and branches of vessels, as can be acquired only by the study of anatomy.

The success of amputation is closely connected with the knowledge of the means of stopping hemorrhage. Not to amputate is often to abandon the patient to a certain and miserable death. And all that the surgeon formerly did, was to watch the progress of that death: he had no power to stop or even to retard it. The fate of Sir Philip Sidney is a melancholy illustration of this truth. This noble minded man, the light and glory of his age, was cut off in the bloom of manhood, and the midst of his usefulness, by the wound of a musket bullet in his left leg, a little above the knee, "when extraction of the ball, or amputation of the limb," says his biographer, "would have saved his inestimable life: but the surgeons and physicians were unwilling to practice the one, and knew not how to perform the other. He was variously tormented by a number of surgeons and physicians for three weeks." Amputation indeed was never attempted, except where mortification had itself half performed the operation. The just apprehension of an hemorrhage which there was no adequate means of stopping, checked the hand of the boldest surgeon, and quailed the courage of the most daring patient—and if ever the operation was resorted to, it almost always proved fatal: the patient generally expired, according to the expression of Celsus, "in ipso opere." How could it be otherwise? The surgeon cut through the flesh of his patient with a red hot knife: this was his only means of stopping the hemorrhage: by this expedient he sought to convert the whole surface of the stump into an eschar: but this operation, painful in its execution, and terrible in its consequences, when it even appeared to succeed, succeeded only for a few days; for the bleeding generally returned, and proved fatal as soon as the sloughs or dead parts became loose. Plunging the stump into boiling oil, into boiling turpentine, into boiling pitch, for all these means were used, was attended with no happier result, and after unspeakable suffering, almost every patient perished. In the manner in which amputation is performed at present, not more than one person in twenty loses his life in consequence of the operation, even taking into the account all the cases in which it is practised in hospitals. In private practice, where many circumstances favor its success, it is computed that 95 persons out of 100 recover from it, when it is performed at a proper time, and in a proper manner. It seems impossible to exhibit a more striking illustration of the great value of anatomical knowledge.

But if there be any disease, which, from the frequency of its occurrence, from the variety of its forms, from the difficulty of discriminating between it and other maladies, and from the danger attendant on almost all its varieties, requires a combination of the most minute investigation, with the most accurate anatomical knowledge, it is that of hernia. This disease consists of a protrusion of some of the viscera of the abdomen, from the cavity in which they are naturally contained, into a preternatural bag, composed of the portion of the peritoneum (the membrane which lines the abdomen) which is pushed before them. It is computed that one sixteenth of the human race are afflicted with this malady. It is sometimes merely an inconvenient complaint, attended with no evil consequences whatever; but there is no form of this disease, which is not liable to be suddenly changed, and by slight causes, from a perfectly innocent state, into a condition which may prove fatal in a few hours. The disease itself occurs in numerous situations; it may be confounded with various diseases; it may exist in the most diversified states; it may require, without the loss of a single moment, a most important and delicate operation; and it may appear to demand this operation, while the performance of it may really be not only useless, but highly pernicious.

The danger of hernia depends on its passing into that state which is technically termed strangulation. When a protruded intestine suffers such a degree of pressure, as to occasion a total obstruction to the passage of its contents, it is said to be strangulated. The consequence of pressure thus producing strangulation is, the excitement of inflammation: this inflammation must inevitably prove fatal, unless the pressure be promptly removed. In most cases, this can be effected only by the operation. Two things, then, are indispensable: first, the ability to ascertain that the symptoms are really produced by pressure, that is, to distinguish the disease from the affections which resemble it; and secondly, when this is effected, to perform the operation with promptitude and success. The distinction of strangulated hernia from affections which resemble it, often requires the most exact knowledge and the most minute investigation. The intestine included in a hernial sac, may be merely affected with colic, and thus give rise to the appearance of strangulation. It may be in a state of irritation, produced, for example, by unusual fatigue; and from this cause, may be attacked with the symptoms of inflammation. Inflammation may be excited in the intestine, by the common causes of inflammation, which the hernia may have no share in inducing, and of which it may not even participate. Were this case mistaken, and the operation performed, it would not only be useless, but pernicious: while the attention of the practitioner would be diverted from the real nature of the malady; the prompt and vigorous application of the remedies which alone could save the patient, would be neglected, and he would probably perish. On the other hand, a very small portion of intestine may become strangulated, and urgently require the operation. But there may be no tumor; all the symptoms may be those, and, on a superficial examination, only those, of inflammation of the bowels. Were the real nature of this case mistaken, death would be inevitable. Nothing is more common than fatal errors of this kind. It is only a few months ago, that a physician was called in haste to a person who was said to be dying of inflammation of the bowels. Before he reached the house the man was dead. He had been ill only three days. On looking at the abdomen, there was a manifest hernia: the first glance was sufficient to ascertain the fact. The practitioner in attendance had known nothing of the matter; he had never suspected the real nature of the disease, and had made no inquiry which could have led to the detection of it. Here was a case which might probably have been saved, but for the criminal ignorance and inattention of the practitioner. Whenever there are symptoms of inflammation of the bowels, examination of the abdomen is indispensable: and the life of the patient will depend on the care and accuracy with which the investigation is made.

But it is possible that inflammation may attack the parts included in the hernial sac, without arising from the hernia itself. The inflammation may be produced by the common causes of inflammation; there may be no pressure: there may be no strangulation: the swelling may be the seat, not the cause of the disease. In this case, too, the operation would be both useless and pernicious. Now all these are diversities which it is of the highest importance to discriminate. In some of them, life depends on the clearness, accuracy, and promptitude, with which the discrimination is made. Promptitude is of no less consequence than accuracy. If the decision be not formed and acted on at once, it will be of no avail. The rapidity of the progress of this disease is often frightful. We have mentioned a case in which it was fatal in three days, but it not unfrequently terminates fatally in less than twenty four hours. Sir Astley Cooper mentions a case in which the patient was dead in eight hours after the commencement of the disease. Larrey has recorded the case of a soldier in whom a hernia took place, which was strangulated immediately. He was brought to the "ambulance" instantly, and perished in two hours with gangrene of the part, and of the abdominal viscera. This was the second instance which had occurred to this surgeon of a rapidity thus appalling. What clearness of judgment, what accuracy of knowledge, what promptitude of decision, are necessary to treat such a disease with any chance of success!

The moment that a case is ascertained to be strangulated hernia, an attempt must be made to liberate the parts from the stricture, and to replace them in their natural situation. This is first attempted by the hand, and the operation is technically termed the taxis. The patient must be placed in a particular position; pressure must be made in a particular direction; it is impossible to ascertain either, without an accurate knowledge of the parts. If pressure be made in a wrong direction, and in a rough and unscientific manner, the organs protruded instead of being urged through a proper opening, are bruised against the parts which oppose their return. Many cases are on record, in which gangrene and even rupture of the intestine, have been occasioned in this manner. When the parts cannot be returned by the hand, assisted by those remedies which experience has proved to be beneficial, the operation must be performed without the delay of a moment. To its proper performance two things are necessary. First, a minute anatomical knowledge of the various and complicated parts which are implicated in it; and secondly, a steady, firm, and delicate command of the knife. In the first place, the integuments must be divided; the cellular substance which intervenes between the skin and the hernial sac must be removed layer by layer with the knife and the dissecting forceps; the sac itself must be opened: this part of the operation must be performed with the most extreme caution: the sac being laid open, the protruded organs are now exposed to view. The operator must next ascertain the exact point where the stricture exists; having discovered its seat, he must make his incision with a particular instrument—in a certain direction—to a definite extent. On account of the nature of the parts implicated in the operation, and the proximity of vessels, life depends on an exact knowledge and a precise and delicate attention to all these circumstances. How can this knowledge be obtained, how can this dexterity be acquired, without a profound acquaintance with anatomy, and how can this be acquired without frequent and laborious dissection? The eye must become familiar with the appearance of the integuments, with the appearance of the cellular substance beneath it, with the appearance of the hernial sac, and of the changes which it undergoes by disease; with the appearance of the various viscera contained in it, and of their changes: and the hand must pay that steady and prompt obedience to the judgment, which nothing but knowledge, and the consciousness of knowledge, can command. Even this is not all. When the operation has been performed thus far with perfect skill and success, the most opposite measures are required according to the actual state of the organs contained in the sac. If they are agglutinated together—if portions of them are in a state of mortification, to return them into the cavity of the abdomen in that condition, would, in general, be certain death. Preternatural adhesion must be removed; mortified portions must be cut away: but how can this possibly be done without an acquaintance with healthy and diseased structure, and how can this be obtained without dissecting the organs in a state of health and of disease?

It has been stated that the progress of strangulated hernia to a fatal termination is often frightfully rapid; in certain cases to delay the operation, even for a very short period, is, therefore, to lose the only chance of success. But ignorant and half informed surgeons are afraid to operate. They are conscious that the operation is one of immense importance: they know that in the hands of an operator ignorant of anatomy, it is one of extreme hazard: they therefore put off the time as long as possible: they have recourse to every expedient: they resort to every thing but the only efficient remedy, and when at last they are compelled by a secret sense of shame to try that, it is too late. All the best practical surgeons express themselves in the strongest language on the importance of performing the operation early, if it be performed at all. On this point there is a perfect accordance between the most celebrated practitioners on the continent, and the great surgeons of our own country: all represent, in many parts of their writings, the dangerous and fatal effects of delay. Mr. Hey in his Practical Observations, states that when he first began to practice, he considered the operation as the last resource, and only to be employed when the danger appeared imminent. "By this dilatory mode of practice," says he, "I lost three patients in five, upon whom the operation was performed. Having more experience of the urgency of the disease, I made it my custom, when called to a patient who had laboured two or three days under the disease, to wait only about two hours, that I might try the effect of bleeding (if that evacuation was not forbidden by some peculiar circumstance of the case) and the tobacco clyster. In this mode of practice, I lost about two patients in nine, upon whom I operated. This comparison is drawn from cases nearly similar, leaving out of the account those cases in which gangrene of the intestine had taken place. I have now, at the time of writing this, performed the operation thirty-five times; and have often had occasion to lament that I performed it too late, but never that I had performed it too soon."