OF WOUNDS. These vary in extent and nature. The instrument by which they are inflicted, the violence attending the injury, and the nature and importance of the parts divided, or in the neighbourhood of the wound, must all be attended to, for, from an accurate knowledge of these circumstances, the treatment of the case comes to be conducted accordingly. Wounds are divided into incised, punctured, bruised, and lacerated; that is, into such as are inflicted by a sharp-edged, sharp-pointed, or an obtuse body. In the first kind, there is greater or less effusion of blood, according to the size and number of the vessels divided. Some extend but a little way beyond the subcutaneous cellular tissue, and are consequently attended with but slight bleeding; others penetrate to a greater depth, and occasion hemorrhage from a large vessel, or other alarming symptoms, by having reached some important organ; others, though not of so great a depth as the former, may still, on account of their mere extent, be accompanied with very considerable loss of blood from a number of small branches. It is seldom that fatal effects immediately follow external wounds; but they may and do occur when bloodvessels of the first class only are cut. They are most likely to prove suddenly fatal when the arteries are only partially divided, and when the large veins accompanying them are also involved. When the artery is cut through, its extremities retract, effusion takes place into the sheath and compresses the orifice; the formation of a coagulum within the vessel is thus promoted, and the hemorrhage arrested. But, when a portion only of the circumference is divided, the blood continues to flow through the aperture and onwards, as if into a smaller ramification of itself, no retraction or contraction of the vessel can occur, coagulation is slow, and the bleeding profuse. I have seen a wound of so small a vessel as the internal mammary prove almost instantaneously fatal. Wounds of the large internal vessels for the most part prove immediately fatal; as wounds of the heart, or the large vessels passing to and from its cavities, at the root of the lungs, or at the upper part of the liver. When the heart, or the vessels within the pericardium, have been divided, it can be readily understood how life should be immediately destroyed, since the blood effused into the cavity of the pericardium by its pressure completely arrests the action of the heart. But occasionally punctured wounds, in such situations, have not been followed by instant death. In such cases, alarming symptoms occur at the time, but subside, and the patient may for some time suffer no uneasiness, but afterwards expires suddenly during muscular exertion, or perhaps in a fit of violent passion. Blood must have been effused into the pericardium at the first, causing symptoms of, or actual, syncope; but then the aperture in the vessel had become obstructed