The larger the area of skin burnt, the more grave is the prognosis. Burns of the abdomen and genital organs are especially dangerous. Young children are specially liable to die after burns.
XI.—CONTUSED WOUNDS AND INJURIES UNACCOMPANIED BY SOLUTION OF CONTINUITY
If a blow be inflicted with a blunt instrument, there is produced a bruise, or ecchymosis, of which it is unnecessary here to describe the appearance and progress. A bruise may be distinguished from a post-mortem stain by the cuticle in the former often being abraded and raised. When an incision is made into the bruise, the whole of the subcutaneous tissues are found to be infiltrated with blood-clot, and there is no clear margin. In the case of a post-mortem stain the edges are sharply defined, not raised, and, on section, mere bloody points are seen which are the cut ends of the divided blood vessels.
XII.—INCISED WOUNDS AND THOSE ACCOMPANIED BY SOLUTION OF CONTINUITY
These comprise incised, punctured, and lacerated wounds. In a recent incised wound inflicted during life there is copious hæmorrhage, the cellular tissue is filled with blood, the edges of the wound gape and are everted, and the cavity of the wound is filled with coagula.
Lacerated wounds combine the characters of incised and contused wounds. They are caused by falls, being ridden over, machinery crushes, bites, blows from blunt weapons, etc. The wounds heal by suppuration.
Punctured wounds come intermediate between incised and lacerated. They are greater in depth than in length, being caused by sword or rapier thrusts. They cause little hæmorrhage externally, but death may be due to internal hæmorrhage. They may be complicated by (1) the introduction of septic material adhering to the instrument; (2) the entrance of foreign bodies which lodge in the wound, not only carrying in septic matter, but acting as mechanical irritants; (3) injury to deeper parts, which may at the time be difficult to detect.
An apparently incised wound may be produced by a hard, blunt weapon over a bone—e.g., shin or cranium. It is often difficult to distinguish between a wound of the scalp inflicted with a knife and one made by a blow with a stick. A puncture with a sharp-edged, pointed knife leaves a fusiform or spindle-shaped wound. A wound from a blow with a stick might be of this character, or it might present a jagged, swollen appearance at the margin, with much contusion of the surrounding tissues. If the wound is seen soon after it is inflicted, examination with a lens may disclose irregularities of the margins, or little bridges of connective tissue or vessels running across the wound, and so be inconsistent with its production by a cutting instrument. Lacerated wounds as a rule bleed less freely than those which are incised. Symptoms of concussion would favour the theory of the injury having been inflicted by a heavy instrument. Again, it is often difficult to decide whether the injury which caused death was the result of a blow or a fall. A heavy blow with a stick may at once cause fatal effusion of blood, but this might equally result from fracture of the skull resulting from a fall. The wound should be carefully examined for foreign bodies, such as grit, dirt, or sand. The distinction between incised wounds inflicted during life and after death is found in the fact that a wound inflicted during life presents the appearances already described, whereas in a post-mortem incised wound only a small quantity of liquid venous blood is effused; the edges are close, yielding, inelastic; the blood is not effused into the cellular tissue, and there are no signs of vital reaction. The presence of inflammatory reaction or pus shows that the wound must have been inflicted some time before death, probably two or three days.