Few studies have been made of the effects of gonadotrophic stimulation of the ovary of the goat during the anoestrous season (roughly March to September). Such reports as have appeared [Stevenson, 1938; Sandburg, 1942; Phillips, Simmons & Schott, 1943; Hammond Jnr., 1943; Frank, Schott & Simmons, 1945], are concerned mainly with attempts to cause anoestrous goats, by treatment with pregnant mares' serum gonadotrophin (p.m.s.), to kid down in the autumn, thus ensuring a good yield of milk in the winter. The present paper reports quantitative data on follicular growth and ovulation in the anoestrous goat ovary in response to p.m.s., similar to those obtained for the heifer by Folley & Malpress [1944]. It also describes experiments in which goats were given p.m.s. and made to breed during the anoestrous season. This method of inducing ovulation during anoestrus would appear to provide the greatest promise of consistent results, both from the