The sex organs of the male are more resistant to dietary deficiencies, the animals showing only retrogression along with a significant loss in weight. Testosterone and gonadotropic hormone (of pregnant mare serum) produce a small but definite restorative effect. Oral administration of estrin to females depresses the food intake, while testosterone, and less so the gonadotropic hormone in males produces the opposite effect. This effect can be regarded as evidence of the dietary significance of these two hormones. The expenses of the present investigation were defrayed by the U. S. Vitamin Corporation, of New York City.