Slough (pronounced ‘sluff’) is dead tissue separated by natural processes from the living body. The term is applied to hard, external parts which the lower animals cast off naturally in the course of growth, like the skin of snakes or the shell of crabs. In humans, however, the process is generally associated with disease, and is then known as GANGRENE. Sloughs may be of very small size, as in the case of the core of a boil, or they may include a whole limb; but in general a slough involves a limited area of skin or of the underlying tissues. The process of separation of a slough is described under gangrene.