The question of the heat imparted to a projectile in its course and the possibility of its being sterilized by such heating are questions which have been carefully investigated. The heat of a bullet produced by penetration into a hard material will depend upon the striking distance and the density of the material. In the human tissues the heat attained by a bullet, even when penetrating a bone at short range, is rarely 100°C., while at long range it will scarcely amount to half of that. There is no accurate measure of the heat that may be engendered in its passage through the atmosphere, but the question is one of interest, in that it brings up the possible sterilization of the bullet and its capacity for destroying such septic material as it may carry in with it. A series of experiments made in Baltimore and elsewhere permit the following conclusions to be drawn:

1. The majority of cartridges in their original packages are free from septic germs, this freedom being due to the precautions observed during their manufacture.

2. As a result of this cleanliness the majority of gunshot wounds are not septic.

3. Such resistant germs as those of anthrax, when applied to the small bullet of a hand weapon, are rarely completely destroyed by the act of firing, and it is possible to infect an experimental animal with such a projectile.

4. The ordinary germs of suppuration are not always destroyed, and may also cause infection.

These conclusions may be epitomized in these two statements: that bullets from small hand weapons are not necessarily sterilized by the act of firing, and that they also may infect.

The principal features to be noted in a case of gunshot wound are the following:

1. Hemorrhage.

—Hemorrhage may be internal or external. When internal it is rarely so accessible as to permit of the saving of life, yet the effort should be made to ascertain the source of the hemorrhage, as only in this way can life be saved. For example: A patient may bleed to death from injury to an intercostal artery, an epigastric, etc., while in either case a very simple expedient would tend to save life. External hemorrhage is generally due to injury of main vessels, and may end fatally unless first help be instantly rendered. Since the introduction into the army of a trained hospital corps, and a widespread diffusion of a knowledge of “first-aid dressings,” this is much less likely to occur than in the days previous to the use of the emergency packet. Recent military experiences have been that hemorrhages from limb vessels are much more likely to subside spontaneously than those of the viscera.