GUNSHOT WOUND. The chief causes of wounds in modern warfare are small-arms bullets, shrapnel balls, fragments of shell, and grenades. Rifle bullets are of a roughly conical shape, and are generally made with a lead core and a German silver or steel jacket. They have, besides their motion of progress, a very rapid motion of rotation, due to the fact that they are fired from a rifled barrel, and a move ment of oscillation, which is especially well de veloped in the sharply pointed bullets used by the United States, France, Germany and Tur key. The oscillatory movement is strongest at the beginning of the course of the bullet, so that up to about 550 yards the bullet has a quasi-explosive action, lacerating and com minuting all tissues in its path. It breaks into pieces, and the jacket and core become separated. Beyond 550 yards the bullet will normally make a clean hole where it hits, and a clean, but larger hole of exit. However, if it hits a bone, it still tends to shatter and splinter it. At extreme ranges, the bullet has rather a bruising than a perforating action. A bullet which hits the ground and ricochets will probably be deformed and will almost cer tainly hit side on, or even rear on. It further more often sends a shower of sand and gravel as secondary projectiles. The result is a large lacerated wound which will in all probability be infected by fragments of clothing carried in ahead of the projectile. On the other hand a bullet striking point on will generally cause a wound either entirely aseptic or so slightly septic that the tissues can take care of the germs introduced without any aid. Further more, while the wound of a bullet striking point on will often be confined to the destruction of tissue in the path of the bullet, a ricochet wound will contain a large amount of dis organized tissue forming an excellent nidus for pyogenic and pathogenic infection. Shrapnel consists of a casing containing closely packed lead balls and a small explosive charge set off by a time fuse. The velocity of these balls is low compared to that of a rifle bullet, and their size is considerably greater. Accordingly the wound which they make is less clean cut than that of a rifle bullet, and the surrounding tissues are bruised and crushed. Infection by clothing is also highly probable. The modern high explosive shell is a case of steel which is completely disrupted by the explosion of the contained charge of high explosive. The vio lence of this disruption may cause severe in jury or even death without any externally visible lesion. The proximate cause of the injury in such cases is the sudden disturbance of the pressure within the tissues, which often engenders internal hemmorrhages in the vital organs. Wounds from shell fragments bear a general similarity to those from deformed rifle bullets in the lacerating character of the injury and the almost invariable presence of infection. They gain an added seriousness from the fact that the shell fragments are often much larger than a bullet and that a large number of frag ments are likely to cause wounds at the same time. Wounds caused by hand and rifle grenades, trenchmortar and airplane bombs, etc., bear a general similarity to shell wounds. The infection of war wounds is of two sorts pyogenic and pathogenic. The pyogenic bac teria are those familiar in civil practice. The two chief pathogenic bacteria are Bacillus tetani and B. perfringens. Both are anzrobic, and their frequent occurrence in the wounds of the Great War is due to richly manured nature of the Flanders soil. B. tetani is
the germ of lockjaw, while B. per fringens causes the so-called gas gangrene. As has been said, it is anwrohic, and it is char acteriz,.(1 i preference it shows for dead and dying tissue. For this rea son it is most frequently and virulently found in wounds where there has been extensive dis organization of tissue. In these wounds it causes .tangrene, putrefaction, intense fetor, and the su cutaneous generation of an inflammable gas. It frequently runs a frightfully rapid course, often causing death in a day or two by its rapid progress and by the poisons which it pours into the blood. In such cases an im mediate high amputation, leaving the end of the stump freely exposed to the air, offers the only hope. In less rapid cases, where the blood supply of the injured limb is still fairly good, more local measures offer promise. These methods consist in the removal of diseased tis sue, the free aeration of the wound, and its subsequent irrigation with a solution of chloride of lime, or with a hypersonic or isotonic salt solution. These latter methods are also effec tive against pyogenic bacteria. Tetanus is treated by preventive doses of antitoxin. The great injury caused to bones in war wounds has caused especial attention to be devoted to the facilitation of their repair. The extensive comminution commonly found is likely to cause great deformity in healing. It also renders effective immobilization by any kind of splint exceedingly difficult. For these reasons great use is made of various appliances which depend on the extension of the limb by weights and springs rather than on rigid supports. The use of plates attached to the bones is generally discountenanced on account of the additional injury thereby caused to the bone circulation. Bone fragments are conserved as far as pos sible as nuclei for callus formation. In cases where an irreplaceable loss of bone has occurred, grafting is frequently employed. Wounds of the viscera are fatal in an enormously smaller percentage of cases nowadays than in former times, when a perforation of the intestines was practically equivalent to a death-warrant. The antiseptic and aseptic methods of modern sur gery are very often successful. Head wounds, which are especially frequent in trench warfare, are often much more serious than they appear on the surface. What seems to be a mere graze of the scalp and skull may involve the fracture and depression of the lower table. The blood vessels and nerves are frequently in volved in gunshot wounds. The high velocity of modern projectiles, together with their small size, has made especially frequent the forma tion of false aneurisms of various types from wounds of arteries and veins. These
erally treated by ligation, provided there is an adequate collateral circulation. Nerve wounds are very slow in healing, for they only heal by the growth of new axis-cylinders into the distal part of the cut nerve. However, surgical methods make this regeneration possible even where a considerable part of the nerve is lost. Electrical method is often used later. The ques tion whether a projectile should be left in a wound or not depends on whether the wound is infected, and on whether the projectile causes pain and irritation or not. Often the removal of a tolerated foreign body in a healed wound will waken a latent infection into renewed activity, and cause serious results. Consult Groves, E. W. H.,