ON SOMATIC SEX-CHARACTERS 93 



sex-characters. They conclude that the interstitial 

 cells supply a nutritive material (hormone ?), wliich 

 has an effect on the sexual orientation of tlie primitive 

 generative cells. In addition to this function, the 

 interstitial cells by their hormone also give tiie 

 sexual character to the soma. When castration is 

 carried out at birth the male somatic characters do 

 not entirely disappear, because the hormone of the 

 interstitial cells has acted during intrauterine life. 

 The functional independence between the interstitial 

 cells and the seminal tubules is shown by the fact 

 that if the vasa deferentia are closed the seminal 

 gland (^.e. tubules) degenerates while the interstitial 

 cells do not. In the embryo the interstitial gland is 

 large, in the adult proportionately small. 



There is complete disagreement between the 

 results of Ancel and Bouin on the one hand, and 

 those of Shattock and Seligmann on the other, with 

 regard to the effects of ligature of the vasa deferentia. 

 The latter authors, as mentioned above, found that 

 after ligature not only the somatic characters but 

 the testis itself developed normally. The experi- 

 ments were performed on Herdwick sheep and 

 domestic fowls. They state that on examination 

 the testes were found to be normally developed, and 

 spermatogenesis was in progress. The experiments 

 of Ancel and Bouin were carried out on rabbits 

 seven to eight weeks old, and consisted in removing 

 one testis, and ligaturing the vas deferens of the 

 other. About six months after the operation the 

 testis left in situ was smaller, the seminal tubules 

 contained few spermatogonia, though Sertoli's cells 

 (cells on the walls of the tubules to which the true 

 spermatic cells are attached) were unchanged ; 



