The discovery by Dodds, Golberg, Lawson, and Robinson [1938] of a new synthetic oestrogenic substance, diethylstilboestrol, with an oestrogenic potency resembling that of oestrone [Dodds, Lawson, and Noble, 1938; has stimulated investigations dealing with the further biological properties of this compound. The action of diethylstilboestrol proves to be similar in many respects to that of oestrone. This applies to its effect on the uterine mucosa [de Fremery and Geerling, 1939], the hypophysis [Noble, 1938], the male genital system [Gaarenstroom, 1939 b], the feathering of cocks and the comb of the capon M\l=u"\hlbock,1939], the sex of the chick embryo [Gaarenstroom, 1939 a], &c.The synthesis of diethylstilboestrol is comparatively cheap and therefore this compound arouses clinical interest. With regard to its clinical application it was necessary to have exact information about a possible toxic action, since Loeser [1939] and Cobet, Ratschow, and Stehner [1939] recently reported toxic effects following its use in several species of animals, which were not produced by corresponding amounts of oestrone. These effects consisted of vaginal and intestinal bleedings, degenerative changes in liver and kidneys, a disturbance of the general condition, &c. Further, the carcinogenic effect of diethylstilboestrol is claimed to be much greater than that of oestrone [Lacassagne, 1938]. notable disturbances arising from its clinical administration. There is some evidence, therefore, to show that diethylstilboestrol possesses a greater activity than oestrone in the production of certain toxic effects. In view of this fact we investigated the extent to which a well-known undesirable effect of oestrone, the growth inhibition following its admini¬ stration in large doses, is produced by diethylstilboestrol.
