258 INTERNAL SECRETIONS 



a highly developed typical interstitial tissue. Since ovulation 

 in the normal ovary was inhibited without corpora lutea being 

 present in the graft, one must assume that the atretic folhcles 

 or the interstitial tissue produced hormones similar to those of 

 the corpus luteum, and thus suppressed ovulation. 



We have hitherto compared the interstitial tissue with the 

 corpus luteum of pregnancy only. But the experiments of 

 Fraenkel show that menstruation also depends upon the corpus 

 luteum. Is there a similar functional relationship between 

 the interstitial cells and the corpus luteum menstruationis ? 

 As already mentioned, the number of atretic follicles which 

 constitute, in the human ovary, an organ homologous with the 

 interstitial tissue of other animals, according to Aschner 

 decreases in man gradually until puberty, when the first corpus 

 luteum menstruationis appears. So one might suppose that 

 the first corpus luteum menstruationis takes over the function 

 of the atretic follicles in the same manner as the latter take 

 over the functions of the degenerating corpus luteum gravidi- 

 tatis in the second half of pregnancy. But the statements of 

 the different observers as to the quantity of interstitial cells, 

 in the broader sense of the term, in the human ovary at 

 different times are very conflicting. Aschner thinks that just 

 as the corpus luteum menstruationis replaces functionally the 

 interstitial tissue of the human ovary, so the corpus luteum 

 appearing at the time of heat in the ovary of the lower mammals 

 also replaces interstitial cells to a certain degree in respect of 

 hormonic function. 



Bouin and Ancel (1909) have discussed fully the question of 

 functional relationship between the interstitial tissue and the 

 corpus luteum menstruationis, or, to be more accurate, the 

 periodic corpora lutea. They assumed that in those species 

 where there is a spontaneous ovulation, as in man, monkeys, 

 dog, horse, pig and cow, and where there is no interstitial tissue, 

 in the sense of a parenchyma of epithelioid cells, but only nests 

 of epithelioid cells in the form of atretic follicles, the periodic 

 corpora lutea represent a physiological equivalent of the 

 interstitial tissue. On the contrary, the interstitial tissue is 

 well developed in those species where, according to Bouin and 

 Ancel, no spontaneous ovulation occurs, as in the rabbit, 

 guinea pig and cat. Here no periodical formation of new 

 epithelioid cells takes place, and here the function of the latter 



