The effect on male rats of the simultaneous administration of male and female sexual hormones and the relation to the assay of the hormones

THE experiments on rats, of Moore and Price [1932] and of Freud [1933], relating to this question have already been referred to by us [1934, 2].Schoeller and Gehrke [1933] also performed some interesting experiments on birds.In hens, injected with 10 c.u. of testicular hormone daily for 4 weeks, the comb-growth increased 23 %, while in those injected with 4000 M.U. of oestrin per week for 6 weeks the size of the comb decreased by 11 %.When capons were injected for 2 days, with testicular hormone (2 c.u.) and oestrin (5000 M.U.)