All the physical appearances and clinical symptoms associated with dry gangrene supervene, and the dead portion is delimited by a line of demarcation. If this forms slowly and irregularly it indicates a very unsatisfactory condition of the circulation; while, if it forms quickly and decidedly, the presumption is that the circulation in the parts above is fairly good. The separation of the dead part is always attended with the risk of infection taking place, and should this occur, the temperature rises and other evidences of toxæmia appear. _Prophylaxis._--The toes and feet of old people, the condition of whose circulation predisposes them to gangrene, should be protected from slight injuries such as may be received while paring nails, cutting corns, or wearing ill-fitting boots. The patient should also be warned of the risk of exposure to cold, the use of hot-bottles, and of placing the feet near a fire. Attempts have been made to improve the peripheral circulation by establishing an anastomosis between the main artery of a limb and its companion vein, so that arterial blood may reach the peripheral capillaries--reversal of the circulation--but the clinical results have proved disappointing. (See _Op. Surg._, p. 29.) _Treatment._--When there is evidence that gangrene has occurred, the first indication is to prevent infection by purifying the part, and after careful drying to wrap it in a thick layer of absorbent and antiseptic wool, retained in place by a loosely applied bandage. A slight degree of elevation of the limb is an advantage, but it must not be sufficient to diminish the amount of blood entering the part. Hot-bottles are to be used with the utmost caution. As absolute dryness is essential, ointments or other greasy dressings are to be avoided, as they tend to prevent evaporation from the skin. Opium should be given freely to alleviate pain. Stimulation is to be avoided, and the patient should be carefully dieted. When the gangrene is limited to the toes in old and feeble patients, some surgeons advocate the expectant method of treatment, waiting for a line of demarcation to form and allowing the dead part to be separated. This takes place so slowly, however, that it necessitates the patient being laid up for many weeks, or even months; and we agree with the majority in advising early amputation.