EFFECTS of various types of dietary restriction upon the reproductive system have been investigated. These studies include chronic and acute starvation, caloric restriction, and vitamin and mineral deficiencies (Ershoff, 1952). Of equal importance in reproductive physiology is the availability of more specific food elements such as proteins. Results obtained by Evans and Nelson (1952) and Nelson and Evans (1953) illustrate the deleterious effect of protein depletion during the embryonic period. These same authors (Nelson and Evans, 1954) have shown, however, that pregnancy can be maintained hormonally in the the absence of dietary protein. Protein depletion during the last trimester of pregnancy apparently has little effect on the newborn (Campbell, Innes and Kosterlitz, 1953). Weight losses of accessory sex organs (Samuels, 1950; Aschkenasy, 1954) and an obvious resistance to loss of testis weight (Leathern and Glasser, 1953) have been noted in adult rats fed protein-free diets.