During the Russo-Japanese war, in which nearly all previous records were broken, the deaths from gunshot wounds constituted but a small proportion of the entire loss in camp and warfare, a larger number of soldiers dying from disease and exposure. Statistics also show that out of every 100 cases of gunshot wounds 12 per cent. have been produced by bullets, the remaining portion being caused by shell, etc. De Nancrède has epitomized some interesting figures which may be here quoted: In the United States army during the Spanish war 4750 casualties were accurately studied; of these wounds of the lower extremities constituted nearly 33 per cent., those of the upper extremities nearly 30 per cent., those of the trunk a little over 22 per cent., and those of the head and neck a little over 15 per cent. During the South African campaign the mortality among the wounded was 5.7 per cent., essentially the same as that during our Cuban and Filipino campaigns, and in marked contrast to the 14 per cent. mortality of the Civil War. Considering that with our Mauser weapons the trajectory is practically flat up to 500 yards, and they may kill up to a distance of two miles, it will be seen that this difference in figures is important. The British discovered in their campaign against the Afghans, who were using antiquated weapons, that their own Lee-Metford bullets would pass through their enemies without disabling them, while the British soldiers who were once struck by the large, soft-lead bullets of their antagonists were far more seriously injured or absolutely disabled.
As one explanation of the injury inflicted by modern projectiles there has been advanced the theory that a bullet with a high-muzzle velocity, striking an object while it still retains most of its original speed, compresses and forces ahead of it into the wounded tissues a small column of air, which, exercising an expansive force, produces more or less explosive effect, that may be seen along the bullet track or at the point of exit. These explosive effects are proportionate to the size of the bullet, its bluntness, and its velocity. This theory was more tenable in the days of large and blunt projectiles than today, for in time past experiments have shown that when a bullet is dropped into water from a height there is forced into the water along with it a certain amount of air, estimated by Longmore at twenty times the actual volume of the bullet itself. It may be doubted, however, whether the rifle projectiles of today can produce sufficient air pressure to cause the destructive effects thus attributed to it.
Fig. 47
a, completely shattered after perforating a horse’s thigh-bone at 220 yards; steel mantle stripped; b, ball with mantle torn off and rolled up, core deformed, after shattering human tibia at 60 yards; c, wholly disorganized ball, which destroyed middle metatarsal bone of horse at 660 yards, steel-mantled; d, ball which shattered a human femur at about 750 yards, steel-mantled; e, remains of steel mantle and part of core lodged in human femur, wound inflicted at about 1100 yards; f, g, fragments of mantle found near the orifice of the wound of exit at about 1100 yards’ range, steel-mantled; h, piece of steel mantle split off by striking a dried horse’s metatarsal at over 1300 yards; i, steel-mantled ball which perforated the internal femoral condyle and lodged beneath the skin at nearly 2200 yards. (Recent foreign report.) (De Nancrède.)
Another method of accounting for shattering effects noted in many of these wounds is hydrodynamic pressure, depending upon the incompressibility of fluid and of tissue containing it, and the narrowing of the space occupied by fluid as a result of the transfer of pressure in all directions. Other things being equal, the most marked effects would be manifest in organs containing the most fluid, the effect increasing with the amount of fluid, the speed of the bullet, its size, and any alteration of shape which it has undergone in transit. It has been shown that the hydrodynamic pressure of steel-jacketed modern bullets varies from six to eight atmospheres. This theory accounts for the peculiar destructive effects seen in the brain, the heart, the stomach, and intestines when struck at short range.
Another method of accounting for the results of a bullet wound takes account of the peculiar effect due to the rapid rotation of the bullet, the movement given it by the rifling of the barrel from which it is fired. It appears that a bullet travelling at the rate of 620 meters per second will average about four rotations per meter. Even in passing through a human body this would scarcely give it but two rotations in transit, while in passing through any given bone the force would be too slight to be appreciable.
While the theories mentioned above, the hydraulic and hydrodynamic, are attractive, yet they are unsatisfactory; we can do little more than sum up the damage done by a rifle ball as due to arrest and divergence of its energy, penetration depending upon its remaining velocity, its preservation of its original shape, and the resistance offered by the part injured. If the latter be great, and its shape be but slightly changed, there are pronounced explosive effects. Moreover, one end of the bullet is a little heavier than the other, and this will tend to produce a certain amount of tilting, by which a key-hole wound may be also produced. [Fig. 47], from De Nancrède, shows the many alterations in shape which may be produced under various circumstances. Again, hard-metal jackets or mantles may be stripped off bullets before the latter reach the body, or in passing through it, as has been shown.
Bruns has shown that with the ordinary small arms the size of the wounds of entrance and exit diminishes with the decrease in velocity or increase of the distance, although allowance should be made for the manner and angle at which the bullet strikes the surface, the wound being circular or oval according to these conditions. The wound of exit will depend upon the direction of the axis of the bullet at the instant it leaves it; thus it may be oval or irregular. When the bullet in transit shatters or comminutes a bone the wound of exit may be made much larger and more ragged than otherwise. In a general way Bruns makes the statement that, other things being equal, the damage inflicted by the escape of a projectile from the body varies according to distance from the weapon. Thus up to fifty meters a considerable amount of destruction of muscle, etc., may be produced. The area is small and the track of the bullet is smooth and little larger than the caliber of the projectile. Between 100 and 300 meters there is little destruction of muscle, and the wound of exit is smooth and may contain some bone debris. Thus Bruns would make it appear that the distinguishable characteristics of near and distant shots appear in the variations to be noted between the wounds of entrance and exit.
After a careful study of the alterations in the shape of the bullets themselves, Coler and Schjerning reported at the Twelfth International Medical Congress that only in 4.5 per cent. of all hits does deforming of the bullet occur; if hits in the bones only are considered, the percentage would be much greater. In wounds of the other parts alone there is rarely any deforming effect upon the projectile. They also show that careful distinction must be made between the deformity of the bullet caused by the body and that resulting from impact upon some object before reaching the body. Thus if a bullet have first struck a branch of a tree, or some object upon the ground, it may have become so altered in shape as to correspond almost to a Dumdum bullet. The harm done by such a ricochet shot depends upon its unexpended energy and its altered shape, but will always be greater than if it had struck in the direction of its long axis.