Clinical recognition of the importance of ovarian function in thyroid disease led us to try the effect of pregnancy urine extract containing sex gland-stimulating hormone on the course of hyperthyroidism. The preparation used was Antuitrin-S, generously furnished by Dr. E. A. Sharp of Parke, Davis & Company. This corresponds to the Prolan solution of Zondek (1) and has a strong luteinization effect on the ovaries of small animals when large doses are given, but is reported to have a follicle-ripening effect in such experiments when given in high dilutions. Its chief clinical use at present is in the control of menstrual disorders (2). Geist (3) reports that he found at operation no ovarian change in 22 patients who had been treated for two weeks with anterior luteinizing hormone. Recently Mandelstamm (4) found at operation, along with other effects, cystic follicles in the ovaries of patients treated with. Prolan but no evidence of luteinization. The solution used by us contains no thyreotropic anterior p...