BULLET WOUNDS.—Recent researches are tending to clear up the mystery sur rounding the contradictory reports on the effect of modern projectiles. A slowly-moving bullet, one almost spent, if it strike a bone will bore through it more or less completely and splinter it more or less widely in a manner that can be explained by the velocity, the angle of impact, and the quality of the bone; but with a swiftly-moving, small-calibre bullet, another force has to be considered. —that of vibration. If the vibration imparted to the bone by the projectile is such that the point of impact of the projectile coincides with a nodal point, the bullet will simply pierce the bone and no shattering will result. But if the point of impact does not coincide there will be more or less shattering at the point and at the extremities of the bone, the amount of shattering being depend ent on the amount of vibration imparted to the bone. Now, the qualities in the
bullet that tend to produce vibration are its momentum (weight and speed), which is imparted more or less to the bone as the bullet is larger or smaller and at its point is harder or softer. Consequently the shattering power of a bullet increases with its velocity, its weight, its size, and its capacity to flatten out when it strikes a hard object.
In bullet wound of the cranial cavity, and to a less degree of the thoracic and pelvic cavities, the amount of damage is again, often dependent on the vibrations produced, the waves set up by the pas sage of a solid object through a semifluid medium, more or less hermetically sealed within an unyielding envelope. Whereas the even passage of the bullet does com paratively little damage, the waves of motion it produces may suffice to liter ally blow the top of a man's head off.