(From through, and seco,to cut). Dissection. The cutting up a body,with a view amining the structure of the parts. See Anatomia.

It is scarcely an object of a work of this kind to teach the minutiae of anatomy, or, of course, to enlarge on the methods by which it may be most satisfactorily learnt. We rather design this article as subservient to forensic medicine, which is an object of considerable importance, and, in general, too much neglected by authors and professors. We shall add, however, a few observations on this subject, for the assistance of the younger practitioners; we trust not without their use.

At the conclusion of the article Chirurgia we spoke of the necessity of frequently using the knife to attain a dexterity in accommodating the hand to every little change of direction; and we would now extend the advice by recommending, as frequently as possible, the dissection of those who die of disease. In the theatres of anatomical investigation, some days have generally elapsed before the body can be obtained, and some further time is necessarily lost before all the cavities can be examined. Exudations, in consequence of this delay, often take place; the blood vessels, if distended, assume a livid hue, and give an unfaithful idea of the real appearance of the parts, so that the practitioner does not learn to distinguish disease when it really occurs. If the dissection of diseased bodies be often practised, some of the sound parts will show the young practitioner their natural appearance, and, in turn, he will see every part in its proper colours.

In such circumstances, his dexterity may be improved by the introduction of probes, bristles, or other instruments, into the different cavities. The probang and catheter he may thus be able to introduce more readily, He may learn to pass a tent to the upper part of the nose, by conveying a string through,it to the back part of the fauces; an operation on which, in haemorrhages of the nose, life may depend. In fact, the young surgeon should take advantage of every opportunity of increasing his readiness in executing every operation which he may be ever required to perform.

Another circumstance of no little importance is, that he will learn, in the subject recently dead, and not injured by hasty and rough conveyance, to see the situation of different viscera with respect to the external organs. He will find, for instance, that at the scrobiculus cordis many important parts meet; the stomach, the gall bladder, and the colon. Each may produce pains there; and it should be his object to discriminate those which are owing to diseases of the different organs. He will learn also from the diseased state, what deviations some-times take place in these respects. The stomach will be dragged down by a disease of the epiploon; the abdomen filled by one of the ovarium, etc. Each dissection, by careful observation, will thus afford a lesson either of instruction or caution.

Dissection, when necessary to ascertain real diseases, or to detect crimes, should be conducted with the greatest care. In the first instance, the pains are often distant from the seat. We remember a case where pain was almost exclusively confined to the region of the navel; the disease was a scirrhus pylorus: another which the best surgeons pronounced to be a scirrhous prostate; it was a stone impacted in the pelvis of the kidney: of a child whose complaints were attributed to a diseased liver; it was a mesenteric obstruction. Instances of this kind, and many we might add, will inspire a cautious distrust, and the propriety of a doubtful opinion, when originally offered. Yet nothing is more common than to find the most positive decisions. At this moment we have cases pronounced to be a wasting of the liver: a dropsy of the womb; and a polypus of the uterus; the sources of which arc either unknown or evidently mistaken. Should such bodies be ever opened, the physician and his science will be disgraced, except by some frauds which, we fear, are too common Deviations from the common structure have been made by art; and it is always easy to find, in any circumstances, what we wish.

When it is the object to detect crimes, dissection becomes an object of considerable importance. The life of an innocent person may be the sacrifice of ignorance, inattention, or presumption. The principal inconveniences we shall enumerate, as they occur in the greater cavities. In the head, the surgeon is often called on to decide on the cause of death. This may have occurred in a paroxysm of passion, and an accidental rencounter; and death may have arisen from apoplexy, or a blow. In each case, the vessels will be turgid, especially if intoxication, a frequent attendant, has concurred. In such circumstances, it is necessary to know that the vessels of the brain in a healthy state are usually very conspicuous. If no considerable external injury, no inflammation corresponding to the part where a slight or probable blow may have been afflicted, are observable, it may be concluded that the patient did not die from violence. Even general inflammation, though considerable, will scarcely justify the contrary opinion; nor an abscess, if at the basis of the scull, its most common seat, support a different conclusion. On the contrary, a trifling, and even an inconsiderable blow, either on the temple or on the upper orbit of the eye, where the bone is thin, may be fatal; and in such circumstances, the most minute examination of the brain and its bony envelope is essentially necessary. The point of a small sword against the upper part of the orbit has been fatal, by penetrating the brain, though the organ of vision has escaped.

In the chest, blows and wounds, though violent, will not always be fatal.; but, in this part of the body, the effects are generally obvious, and no doubt occurs that merits any elucidation.

In the stomach, we are often left in uncertainty. Blows at the pit of the stomach have been sometimes fatal, without leaving any trace. The effect, on this organ, is similar to concussion on the brain. Inflammation seldom points out any evident cause; and death, without any alteration of the structure, ensues.

Greater are, however, the difficulties when poison is the suspected cause of death; and it is necessary that every practitioner should be acquainted with the internal appearances of this organ. Fortunately, the taste of the most dangerous poisons soon guards a person from any permanent injury; and, of others, the effects are strikingly obvious. The idea of Mr. Hunter, that the gastric juice dissolves after death the substance of the stomach, and occasions erosions in it, is found to have no foundation; and it is a proof, among a thousand others, how far a preconceived opinion influences the most accurate observers. Lead, copper, and arsenic, can be ascertained by their most appropriated tests (see Venenum). The vegetable poisons arc too nauseous to escape the organs of taste, and the animal influence other organs. On the intestines we see only the effects of stimulant poisons, of inflammation, and its consequences. Wounds and bruises offer no subject of remarks, as they are sufficiently obvious. Yet sometimes, in severe bruises, the effects, for instance, of military punishment, an abscess forms below, rather than on the part affected, and is occasionally the cause of death.

In cases of death, in real or supposed puerperal cases, it is absolutely necessary to know the appearance of the organs in a state of health, and in the puerperal state. A woman sometimes dies apparently from poison, and the supposed inducement to this rash act is suspected pregnancy. The cause is, sometimes, with difficulty decided in the early months. If the period of menstruation is at hand, the uterus will assume the appearance of early impregnation, and we once saw it at a different period, though the hymen was entire. The appearance of an uterus, lately gravid, ought also to be known, as it may be sometimes necessary to determine whether a person, who has voluntarily terminated her existence, may have been lately delivered. For two months, at least, and very often much longer, the appearance of a corpus luteum in the ovarium is decisive

In cases of puerperal fever, the subject has been greatly confined by those who have described -the appearances on dissection, being imperfectly acquainted with those of the puerperal state. The natural fulness of the uterine vessels has been styled inflammation, and the coagulable lymph a purulent discharge.

In dropsy in tympanites, as well as in the puerperal state just described, the vessels are peculiarly full, and give the suspicion of previous inflammation where none has existed. Adhesions often take place in chronic cases, in the last moments, or soon after death, and excite an unfounded suspicion of an inflammatory disorder having preceded. In real inflammation of the peritonaeum, it is thickened, pulpy, and opaque.

A neatness in opening a body and again sewing the wounds, can be judged of by every one. The body should not be too much exposed. In dissecting the head, the integuments should be cut across from ear to ear. They may then be replaced, without disfiguring the subject. To examine the thorax, the cartilages of the ribs should be divided on each side, after dissecting off the integuments and the muscles, near the sternum, which may be turned back; and from the scrobiculus cordis, an incision should be made to each ilium, to examine the state of the abdominal viscera. When these viscera are taken out, ligatures should be made on every canal, previous to dividing it. The parts should be carefully replaced, and the integuments sown with what is styled the flat stitch. See C. Bell's System of Dissection.