266 INTERNAL SECRETIONS 



of the endocrine cells. And it must be remembered that 

 probably different sorts of endocrine cells come into play, and 

 that the cells of the theca interna of atretic folhcles, the cells 

 of the granulosa of ripening follicles, and lutein cells of the 

 corpus luteum may all participate. It follows that it is 

 absolutely necessary to examine the whole follicular apparatus 

 together with the stroma, regarding them as a unity, if we wish 

 to investigate the question as to the dependence of menstrua- 

 tion, heat, and the changes of pregnancy upon the ovary. 



Marshall and Wood (1923) hold that the interstitial cells, the 

 ripening follicles and the corpus luteum produce qualitatively 

 different hormones ; the secretion of the interstitial cells may be 

 responsible for maintaining the normal nutrition of the uterus, 

 the secretion of the ripening folhcles may account for the 

 phenomena of heat, and the secretion of the corpus luteum may 

 cause the uterine and the mammary hypertrophy during 

 pregnancy. I do not think that there is as yet sufficient experi- 

 mental evidence for such a definite delimitation between the 

 different endocrine elements of the ovary. 



The objections Aschner made as a result of chnical observa- 

 tions to the view that menstruation is caused by the corpus 

 luteum are without foundation. Menstrual bleeding is evidently 

 caused by the fact that the premenstrual uterine changes 

 suddenly cease instead of continuing till pregnancy; this, we 

 assume, is due to the corpus luteum entering upon regression. 

 Now we can understand how it is that a corpus luteum which 

 persists longer than usually can retard menstrual bleeding; a 

 persisting corpus luteum is evidently correlated with a persist- 

 ing premenstrual stage, and that means that menstrual bleeding 

 will be retarded. Menstrual bleeding is nothing else than a 

 pregnancy which has failed to come about, or a very early 

 abortion. As Labhardt (1920) has rightly pointed out, it is 

 gravidity, not menstruation, which is monthly prepared for 

 in the uterus. The amenorrhoea observed in cases of unilateral 

 cysts of the corpus luteum can be explained as a prolonged 

 premenstrual stage, or a prolonged persistence of pregravid 

 uterine changes. To decide this question it would be necessary 

 to examine the uterine mucosa in such clinical cases. Aschner 

 says that the menstrual bleeding is "inhibited" by the 

 corpus luteum, this "inhibition" being one of the functions 

 of the corpus luteum. This view to my mind is absolutely 



