Frost-bite. The circulation of the blood in the more exposed parts of the body may be so obstructed by subjection to the influence of extreme cold, and the vitality of the tissues of the affected parts may become so depressed, that a localised mortification or gangrene (q.v.) results. The mortification may be the immediate effect of the exposure to cold, or may be consecutive to the inflammatory reaction which is set up in the benumbed tissues. The symptoms do not essentially differ from those of gangrene arising from other causes: if the injury to the parts be considerable, there is an nctueil ' slough"' formed, a "line of demarcation" being set up between the living tissues and those which have perished. Frost-bite is rare in Britain, though it may occur in poorly-fed and badly-clothed persons, who are exposed to extreme cold; it has teen known on the Continent, however, to work great havoc in the case of an army undergoing a winter campaign. In cases of threatened frost-bite it is important not to apply warmth too suddenly to the injured part. Rubbing with snow has been found useful; and, as soon as practicable, the application of cotton wool or flannel should be resorted to, and absolute rest enforced, while the gradual re-establishment of the circulation is encouraged. If heat is applied at once, inflammatory reaction is apt to occur, and gangrene may result.