Gangrene (Gr.Gangrene 700257 ), the loss of life in any of the soft parts of the body, without extinction of the vital powers in the rest of the organism. The term sphacelus has been applied to the condition in which gangrene may terminate, the utter and irrecoverable death of a part, while in some stages of gangrene the circulation may not be completely arrested, the sensibility of the nerves not entirely gone, and recovery of the local loss of action not impossible. The death of the bony tissue is called necrosis. When gangrene is the consequence of violent inflammation or of the obstructed return of venous blood, the affected parts are gorged with fluid, constituting humid gangrene; while dry gangrene generally arises from a deficient supply of arterial blood or from constitutional causes, accompanied by very slight or by no inflammation, the mortified part becoming dry and hard; the gangrenous portion in the former case is called a slough, in the latter an eschar. The local predisposing causes are congestion and deficient circulation; the constitutional are weakness from disease, old age, or privation.

The exciting causes are mechanical and chemical injuries, especially gun-shot, lacerated, and poisoned wounds; insufficient supply of arterial or obstructed return of venous blood, as in the gangrene from ossified arteries in the first case and that from heart disease and varicose veins in the second; and injury or division of nerves. The areolar tissue is most subject to gangrene; after this come tendons and ligaments, denuded bone, the skin, and the muscles, in the order of enumeration. Gangrene spreads slowly or rapidly, according to the accompanying inflammation or the energy of the vital processes. When inflammation is about to end in gangrene, the redness becomes livid, with diminution of pain and sensibility, though the swelling may be increased; the parts become soft and cold, and emit an odor of decomposition; the livid color, when the disease is spreading, is gradually lost in the surrounding skin, but when the dead portion is to be cast off, a bright red line separates the healthy from the gangrenous tissue, called the "line of demarcation;" in a healthy person there may be high accompanying fever, but in a debilitated constitution the symptoms will be those of prostration and typhoid.

The indications of treatment are to diminish the inflammation by general and local means; to support the strength by tonics and stimulants, when the gangrene is extensive or the system debilitated; to quiet restlessness and nervous irritability by opium; and to facilitate the separation of the dead parts by warm and stimulating applications, and by incisions to permit the free escape of fluids whose absorption might propagate the disease to internal vital organs. Amputation of a limb is sometimes the only way of arresting the spread of gangrene. Surgery often has occasion to produce gangrene as a remedial measure, in the removal of tumors and diseased growths; haemor-rhoidal swellings, nasal and uterine polypi, erectile tumors, cancerous growths, etc, are eflec-tually and safely removed by cutting off their supply of blood by ligature of the principal vessels. Gangrene is always a dangerous symptom, especially in very young or very old persons, and in weakened constitutions; and when terminating favorably, it may leave behind it tedious suppurations, fistulous ulcers, and various deformities.

Hospital gangrene, or sloughing phagedoena, a putrid disease caused by crowding sick and wounded men into ill-ventilated and dirty rooms, is one of the most terrible accompaniments of war, often destroying more than the bullet and the sword; and the army surgeon generally finds his best directed efforts set at defiance by the force of surrounding and insurmountable obstacles. The principles of treatment are the same as in ordinary gangrene.