28 THE SEX-COMPLEX 



The inter- the origin of these cells. Are they always derived from 

 corpus lutea or from the stroma-cells of the ovary ; or 

 is there one mode of origin in some species of animals 

 and another in others ? I incline to the view that the 

 interstitial cells, as they are known to us, have this dual 

 origin. Whether, on the other hand, we are entitled to 

 call the cells interstitial when they arise from the 

 corpora lutea is another question, for such a standpoint 

 seems to me to complicate a clear understanding of their 

 function. 



In the following remarks it will be apparent how 

 confused the subject becomes if we admit derivatives of 

 the corpora lutea into the discussion, as necessarily we 

 must in the present state of our knowledge and of our 

 terminology. 



Ancel and Bouin 1 , and, with certain restrictions, 

 Loeb 2 advance the hypothesis that the interstitial cells 

 inhibit ovulation in animals, such as the rabbit, that do 

 not ovulate spontaneously, in which species these cells 

 are plentiful (fig. 11); and it is in these very animals 

 that the evidence points to the origin of the interstitial 

 cells from the corpora lutea. It may be said, therefore, 

 that the interstitial cells in the animals just mentioned 

 play the same part already described (p. 24) as that 

 fulfilled by the cells of the corpora lutea in those animals 

 in which ovulation occurs spontaneously, and in which, 

 therefore, periodic corpora lutea are formed. 



If we examine the ovary of a carnivore, such as the 

 cat (fig. 13), we see the interstitial cells may truly be 

 described as such, and in no way can they be considered 

 derivatives of the corpora lutea. 



I have found experimentally that in the rabbit the 

 so-called interstitial cells when grafted are capable of 

 keeping the uterus active (see p. 47). 



Again, it is commonly supposed that the interstitial 

 cells of the testes and ovaries are responsible for the 



1 Ancel, P., et P. Benin, Compt. Rend. Soc. de BioL, 1909, vol. 

 Ixvi, p. 497. 



2 Loeb, L., Trans. Amer. Oynecol. Soc., 1917, vol. xlii, p. 172. 



