melanism

[Fr. mélanisme.] 1. Physiology: (1) Human : A term introduced by St. Hilaire to denote the change of coloration of the skin in which the pigment is of a deeper hue, and in greater quantity than natural. (2) Animal : The term has been applied as the converse of albinism, occurring in the lower animals. "Throughout intertropical America, both melanism and albinism make their appearance very frequently in warm-blooded animals." -Pritchard: Nat. Hist. of Man , p. 39. 2. Bot .: A disease producing blackne in plants. mel-an-ite, s. [Gr. melas (gen it. melanos ) = black; suff. -ite ( Min .).] Min.: A black variety of garnet (q. v.); a limeiron garnet in which the protoxides are almost wholly lime. Dana includes most of the black garnet in his group andradite (q. v.), but excludes that from Arendal, Norway, referring it to the magnesia-alumina garnet group, for which he adopts the name of pyrope.