So far as the authors are aware, turkey pituitaries have not been used previously as a source of the gonad-stimulating hormone. The present study was designed to give a crude measure of the gonad stimulating potency of the turkey pituitary taken from heads of turkey prepared for the market in the usual way.Domm (1932) reported that males crowed at nine days of age and treaded at thirteen, after receiving daily injections of hebin from the time they were three days old. Day old or younger chicks were used as experimental animals in the present study because it was hoped such chicks would yield a definite response before feed and water were required. It was considered likely that the day-old chick would be relatively less variable than older chicks. Jaap (1934) reported great variability in testis weight among chicks eleven days old.The turkeys used as a source of material .