Estrogenic substances are now administered by physicians in a wide variety of physiologic and pathologic states. They are given to relieve menopausal symptoms, to suppress lactation, for gonorrheal vaginitis in children and for senile vaginitis and pruritus vulvae. They have been advocated for amenorrhea, abnormal uterine bleeding, dysmenorrhea, sterility, habitual abortion, chronic mastitis, painful breasts, hypertension, involutional melancholia, epilepsy, eclampsia, vomiting of pregnancy, menopausal arthritis, migraine, hemophilia, senile deafness, atrophic rhinitis and acne. New and more potent preparations of the estrogens are being made available to the medical profession for these therapeutic uses. In addition, the public has been purchasing in drug stores and beauty shops a face cream which contains estradiol. Moore1has shown that this hormone is absorbed through the skin. This widespread use of the estrogenic substances is, in the light of our knowledge of their possible carcinogenic effect, a matter for serious consideration. It is