Bernhard Zondek 58 1 



the aspirated fluid it was possible to make sure that the ovum had actually been 

 entirely removed. After intravenous injection of prolan this follicle, which 

 contained no ovum, developed into a typical corpus luteum. When, after 

 aspiration of the ovum, the topmost portion of the follicle was also cut off 

 with scissors, even this torso grew into a corpus luteum. These experiments 

 give very clear evidence that a follicle which certainly contains no ovum may 

 be transformed into a corpus luteum in precisely the same manner as is 

 normally the case. From the foregoing evidence the ovum may thus be as- 

 sumed to have no importance for corpus luteum formation. 



4. What happens if the gonadotrophic function is inhibited? By giving 

 thallium" to sexually mature mice the cycle is interrupted. In contradistinction 

 to functional interruption, the ovary shows in this case no morphological 

 changes. Large follicles are to be found containing the cumulus oophorus and 

 ova in mitosis. Thallium, no doubt, effects partial inhibition of the gonado- 

 trophic secretion of the anterior pituitary lobe so that, although sufficient 

 amounts of hormone are elaborated to maintain the intactness of the ripening 

 follicle anatomically, the hormone production does not suffice to initiate the 

 elaboration of estrogenic hormone in the theca cells. If now gonadotrophic 

 hormone is injected into the thallium-treated animals they instantly go into 

 estrus. It is, therefore, apparent that, although the cycle has been discon- 

 tinued and the production of gonadotrophic hormone to some extent in- 

 hibited, the ovary nevertheless contains ripe follicles with fully developed ova. 



That even the complete elimination of hypophysial function has no bearing 

 on the ripening of the ovum is shown by experiments on hypophysectomized 

 animals. H. M. Evans and O. Swezy^^ found, in hypophysectomized but sexually 

 mature rats, the new formation of germinative cells, increased oogenesis, and, 

 in the atresic follicles, the nuclei in the stage of mitotic division with polar 

 bodies. We have examined the ovaries of infantile rats in which the hypophy- 

 sis had been removed on the twenty-seventh day of their life and which had 

 then been sacrificed twenty days later. In these ovaries, too, ripening ova with 

 mitoses were found to be present. There can, therefore, be no doubt that the 

 process of maturation may take place in ova which, for a considerable length 

 of time, have not been under the influence of the gonadotrophic hormone of 

 the anterior pituitary. 



Summarizing, it may thus be said that the ovum does not stimidate the pro- 

 duction of estrogenic hormone, that estrogenic hormone has no influence 

 whatsoever on follicular maturation or on the growth of the ovtmi itself. The 

 ovum has no influence on corpus luteum formation or the production of its 

 hormone. Neither is there a dependency of the ovum on the anterior pituitary 

 and its gonadotrophic hormones. It thus appears that the ovum leads its own 

 life, its development does not depend in any way on either the follicle Avith 

 its hormone or the anterior pituitary lobe. The ovary is the host of the ovum 

 but at the same time its servant, since with its hormones it assists in preparing 

 the uterine mucous membrane anatomically and functionally for the rcceji- 



