Fig. 25 (a), b (plate II.) represents a section of an infected exit aperture from a patient who died seven and a half days after its infliction. Two main points of interest are at once apparent: 1. The carrying forwards of the subcutaneous fat into the lips of the skin wound by the bullet. This illustrates the manner in which lightly supported structures are carried forward by the bullet, and throws some light on the mode by which vessels and nerves may escape by a process of displacement. This figure may be compared with fig. 25 (b) which shows a tag of omentum similarly carried forward by a bullet crossing the abdominal cavity and plugging the exit wound. 2. The second feature of interest is the amount of hæmorrhage into the subcutaneous tissue. In this respect the contrast between the exit and entry apertures is marked, since in the latter hæmorrhage is scarcely apparent. The presence of such hæmorrhages is explained by the same dragging action as the extrusion of the fat, and is of course dependent on consequent rupture of small vessels. It is of importance as predisposing the exit wound to more easy infection, and it accounts for the persisting subcutaneous induration more often detected beneath healed exit than entry apertures. Again, it suggests that the presence of blood in the deeper parts of the tracks may be the determining cause of the indurated cords often replacing them.
G. L. Cheatle.
Mauser Wound of Exit, 7½ days after infliction. Healing delayed by Infection. About 12/1.
Section of the exit segment of a Mauser wound, removed seven and a half days after infliction. Magnified twelve diameters.
The healing process has been delayed by infection.
There is no attempt at closure by a layer of epidermis, and the margins are not depressed.
The wound track is narrower than that seen in the entry wound plate I., and completely occluded by a plug of the subcutaneous fat which has been carried forward by the bullet in its passage. A small wedge-shaped plug of lymph indicates the position of the actual track at its termination.
Dragging on the surrounding tissue consequent on the extrusion of the plug of fat has ruptured some capillaries, and given rise to considerable extravasation of blood, which is seen as a darker layer in the deepest portion of the wound.