THE GENERATIVE GLANDS 405 



to the seventh day, the blastula are formed in the uterus, and 

 upon the seventh day they become intimately connected with the 

 uterine mucosa. 



Frankel discovered that pregnancy is prevented by bilateral 

 castration carried out between the first and sixth days, but that 

 the presence of one ovary is sufficient to ensure the development 

 of the ova. Destruction by galvano-cautery of all the corpora 

 lutea produced the same effect as bilateral castration, while 

 cauterization of other parts of the ovary had no influence whatever 

 upon pregnancy. It is evident then, that suppression of the 

 corpora lutea prevents the occurrence of pregnancy. But the 

 function of the corpora lutea is also to secure the development 

 of the already established ovum, for both bilateral castration and 

 the cauterization of all corpora lutea between the eighth and 

 twentieth days, are followed by involution of the embedded ova. 

 Further experiments showed that one corpus luteum is able to 

 perform the function of at least two or three; and further that 

 this trophic function is conveyed to the uterus by way of the 

 blood stream, in other words, through the agency of the internal 

 secretion of the corpus luteum. Frankel finds support for his 

 hypothesis in the hydatid moles and abortions which are by no 

 means infrequent accompaniments of ovarian tumour, and in the 

 corpus luteum cysts sometimes observed in tubular pregnancy. 



In a further development of this hypothesis, Frankel adopted 

 the view that the corpus luteum menstruationis, which is formed 

 in women in every fourth week and in animals at varying inter- 

 vals, also possesses an internal secretion, and that it is the 

 function of this secretion in man to supply a nutritional impulse 

 of a cyclic nature to the uterus, and that this impulse prevents 

 the uterus from reverting to the infantile, or anticipating the senile, 

 stage. The mucous membranes are made ready for the reception 

 of the fertilized ovum ; if fertilization does not take place the 

 hyperasmia leads to the phenomena of menstruation and the 

 corpus luteum undergoes involution. As evidence of the part 

 played by the corpus luteum in the production of menstruation, 

 Frankel cites the fact that, in operative surgery, cauterization of 

 the recent corpus luteum prevents the occurrence of the next 

 menstrual period in six cases out of seven. 



According to Frankel, the corpus luteum is an ovarian gland 

 which undergoes periodic regeneration, and which, from the time 

 of puberty until the menopause, regulates the nutrition of the 

 uterus. 



The practical outcome of Frankel 's theory was the therapeutic 

 employment of lutein tabloids, prepared by him from the corpus 

 luteum of the cow, in the treatment of the clinical symptoms result- 

 ing from ovarian insufficiency. Frankel obtained better results 

 by this method than by the exhibition of ovarian tabloids. 



The corpus luteum hypothesis, as propounded by Born and 



