Gunshot wounds of the chest may conveniently be divided for study into two classes, viz., _non–penetrating_ and _penetrating_. NON–PENETRATING wounds become subdivided into simple contused wounds of the soft parietes; contused and lacerated wounds; the same accompanied with injury to bones or cartilage; and, lastly, those complicated with lesion of some of the contents of the chest, the pleura remaining unopened, or, if opened, without a superficial wound. PENETRATING wounds may exist without wound, or with wounds of one or more of the viscera of this cavity. Among the more serious complications with which the latter may be accompanied is the lodgment of the projectile or other foreign bodies, as of fragments of bone, within the chest. As wounds of the heart and great vessels are almost invariably at once fatal, and as the organs of respiration occupy the greater part of the cavity of this region, it is in reference to the latter that the treatment of chest wounds is chiefly concerned. =Non–penetrating wounds.=—Of the simpler wounds in which the soft parietes only are involved little need be observed, excepting that the healing process is often prolonged by the natural movements of the ribs to which the wounded structures are attached, especially when the ball has taken a circuitous course beneath the skin, and that the surgeon must be on his guard to watch for pleuritis arising as an occasional consequence of these injuries. In two deaths recorded in the Director–General’s History of the Crimean War, under simple flesh wounds, without fracture or pleural opening, from bullets, the fatal termination arose from pleuro–pneumonia. When the force has been great, as when fragments of shell or rifle–balls strike at full speed against a man’s breast–plate, not only may troublesome superficial abscesses and sinuses follow, but the lungs may have been compressed and ecchymosed at the time of the injury, and hemoptysis be one of the symptoms presented. When the projectile has been of large size, although no opening of the parietes or fracture exists, death sometimes ensues by suffocation as the direct result of pulmonary engorgement. The danger of pleuritis or pneumonia will be greater when the injury has been so severe as to cause division of bone or cartilage, and the subsequent suppuration and process of exfoliation will not unfrequently prove very tedious and troublesome. Although the pleura has not been opened, the lung may be lacerated either by the force of contusion or, as in a case recorded by Dr. Macleod, by the edges of the fractured ribs, which may afterward return to their normal relative positions, so as to leave no indication during life of the means by which the lung had been wounded. Such an injury would be rendered much more probable by the existence of old adhesions, connecting the pulmonary and costal pleuræ opposite to the site of injury.