A total disappearance of the ability to perspire is rarely seen. The sporadic and familial cases of general anhidrosis that have been reported in the past (Quilford,1Loewy and Wechselmann, Richardson,2Tannhauser3and others) resulted from a congenital and general developmental anomaly of the dermic organ; i. e., an ectodermal dysplasia. Nowhere in the medical literature, however, have I been able to find a description of a case such as the one cited here; i. e., in which cessation of the function of sweating occurred in a person who had previously been perfectly normal in this respect. A case of this sort gives rise not only to diagnostic observations and examinations but also to a number of pathophysiologic ones, which, among other things, serve to throw light on the normal function of perspiration. REPORT OF CASE History.— A man, aged 25, a patient in the Rigs Hospital,