Gun-Shot Wounds , injuries caused by the discharge or bursting of firearms. They are of two classes, according as the explosion of the powder does or does not carry solid projectiles. Slight wounds from powder alone are properly burns; but if the quantity of powder be large or in a confined space, serious contusions and lacerations may ensue. Not only the expansion of the liberated gases, but the unburned portions of powder, and the contact of surrounding bodies put in motion by the explosion, are to be considered in these complicated wounds, though their treatment is ordinarily the same as for burns, lacerations, and contusions from other causes. These wounds are purely mechanical, and are more dangerous in proportion to the contiguity to vital organs; an explosion from a pistol introduced into the mouth or near the thoracic or abdominal cavity might prove fatal, while the same on the back or limbs would be trifling. A wound from a musket ball in a fleshy part presents an opening of entrance smaller than the ball in most cases, and with livid and inverted edges, and the opening of exit, if there be such, larger, more ragged, and with everted edges; if the ball was fired very near, the entrance is larger than the exit.

These facts often enable an expert to tell the direction and the distance from which a wound was received. The diminished velocity of the ball, its more rapid rotation on its axis, and its consequent more lacerating progress, explain the larger and more irregular opening of its exit. A slight obstacle is sufficient to divert a ball from its original direction, causing singular eccentricities in its course; a trifling obliquity of surface, or difference of density in the parts struck, may produce the most circuitous passage. A ball may enter on one side of the head, neck, chest, abdomen, or limb, and pass out on the other, having apparently passed directly through, whereas it has really passed entirely round. Spent balls cause injuries of great violence and with little apparent external wound. These cases were formerly attributed to the wind of the ball, from compression or displacement of air in its course; but it is now known that a ball after a certain period of its course acquires a rotary motion on its axis, the more rapid as its progress is nearly ended.

If a ball with such a motion strike a part of the body, it does not pierce or carry it away, but simply rolls over it like a wheel, crushing the unyielding and resisting tissues, without necessarily lacerating the skin; contusing the viscera, for instance, without opening the abdominal cavity. A ball in its course may meet and force into the body pieces of clothing, bone, or other foreign bodies, more mischievous than the original projectile. The pain of a gun-shot wound is dull and heavy, though in the excitement of battle it would be less noticed than a sabre or bayonet wound. The bleeding is generally less externally than would be supposed, unless a large artery be severed. The constitutional disturbance is great and peculiar. Paleness and coldness of surface, trembling and weakness of limbs, faint-ness, alarm, and confusion of mind, are more marked than in other kinds of wounds of equal severity. In common cases, inflammation comes on in the course of 24 hours, with swelling and stiffness, and pain; pus forms on the third or fourth day, and in the course of the next five days more or less of the parts torn by the ball slough away; this over, granulations form, the wound contracts, and heals in six or eight weeks, the lower opening closing first.

In healthy persons the constitutional disturbance is neither great nor of long duration. In unhealthy constitutions inflammation runs high, the suppuration is profuse and obstinate, and the patient recovers with a disabled limb or an enfeebled body. If the ball or a foreign body carried with it enters a sensitive or vital part, there will be no safety until it comes away; but if it enters parts without much sensibility and presses upon no nerve, it may remain for years without inconvenience. Mortification of a limb after a gun-shot wound may arise from the severity of the wound, the excess of inflammation, or division of the large blood vessels. Another dangerous complication of these wounds is secondary haemorrhage from excess of arterial action, separation of sloughs from arteries, ulceration of their coats, or general inflammatory exudation; this is most likely to occur in persons of sanguine temperament, when exposed to the depressing influences of hospital life. The prognosis in these wounds should be given with much reserve, as it is impossible in most cases to predict the exact result.

If the thoracic and abdominal cavities or the joints are penetrated, or any important organ is wounded, with injury of large vessels or nerves, or comminuted fracture of bones, the danger of a fatal termination is great. But, apart from the battle field, there are instances of survival after great injuries of vital organs. Perhaps the most notable case is that of Alexis St. Martin, recorded by Dr. Beaumont. (See Beaumont, William.) Among other cases are those of William Poole, a New York rough, who lived for some time with a ball lodged in the substance of the heart, and of Virginia Stewart, a woman of the town in the same city, who lingered for several days after a pistol bullet had passed through her brain. The wounds made by conical rifle balls are attended with much laceration of soft parts and splintering of the bones. - The treatment of simple gun-shot wounds does not materially differ from that of lacerations and deep punctures. Cleansing of the openings, the arrest of haemorrhage, stimulants and opiates, antiphlogistic and soothing applications, free exit of pus, and rest of the part, are the principal points to be attended to; if there is but one opening, search should be made, by dilatation if necessary, for the ball or other foreign body, which should be extracted if it is likely to prove inconvenient or dangerous; secondary haemorrhage will require compression, cold, caustic, or the ligature, according to circumstances.

In cases of severe laceration with splintering of bones, the question of primary or secondary amputation becomes one of the most difficult the surgeon has to decide. - In the "Medical and Surgical History of the War of the Rebellion," published by the United States government in 1870, will be found the best collection of cases and illustrations of gun-shot wounds in any language.