GANGRENE, gan'gren, the term applied to death of soft tissue in masses large enough to he seen. There are two forms, differing in causation, appearance and progress. Dry or senile gangrene results from the gradual occlu sion of arteries, the venous return being unim paired. For weeks or months the toes and feet, the parts most frequently affected, may feel cold or numb, or be actually painful, then gradually the skin becomes dry, then purple and black. The spread is usually very slow. It is particularly a disease of old age, due to the tendency at that period of life toward thickening and stiffening of the arterial walls. Moist gangrene results from sudden stoppage of the arteries, obstruction of veins, mechanical destruction of the issues or from specific in fection by germs. It is generally due to an in jury which destroys a part of the living flesh, as in wounds, frostbite, burns by fire or cor rosion by acids, etc. It also follows carbuncles and bedsores in some cases, and has occurred as the result of a tourniquet too vigorously ap plied or left on too long. This form shows a soft, boggy, bluish mass covered with blisters and emitting the odor of putrefaction. In both
forms of gangrene there may be a zone of in flammation between the dead and the living tis sue, called the line of demarcation. The dead flesh may separate naturally leaving a scar on the healthy tissue, or the separation may have to be made by amputation of the diseased part.
Hospital gangrene was formerly very preva lent in military hospitals; a wound becoming infected would quickly change to a gray slough, which in a few hours might involve the entire limb unless prompt removal of the tissue was undertaken. Aseptic surgery has made this fatal disease a thing of the past. Spreading gangrene is due to infection by a specific germ, the bacillus of malignant cedema, so called from the fact that it generates a gas that puffs up the tissue affected. The spread is rapid, and life is sometimes saved by amputation far above the wound. The treatment of gangrene is usually a matter of amputation, well beyond the affected part. Careful aseptic dressing is imperative, particularly where the condition of the patient is apt to contra-indicate radical cure,