Statistics show that human diabetes does not appear with the same frequency in both sexes, particularly after the age of forty years (Joslin, 1946; Marks, 1947; Dahlberg, 1947; Penrose and Watson, 1945; Vartianen and Vartianen, 1944, etc.) No sexual differences have been reported in experimental diabetes except by Foglia (1945) in the rat. Probably experimental diabetes is produced too suddenly and with a too great intensity, so that sexual influences have no time to act. Shapiro and Pincus (1936) technique for extirpation of 95% of the pancreas in the rat has made it possible to produce an experimental diabetes in this species. The diabetes observed in the rat has many advantages from the experimental point of view over that provoked in the dog: a) it is possible to work with a standard animal, because uniform genetic strains can be obtained by inbreeding; b)