ii8 INTERNAL SECRETIONS 



As to the origin of the interstitial cells there are two different 

 opinions. According to Bouin and Ancel (1903 c), who made 

 observations on the embryo of the pig, the interstitial cells 

 belonged to the mesenchyme, but grew into the primitive 

 generative epithelium, separating the latter into solid cords. 

 On the other hand, Rubaschkin (1912), who published very 





Fig. 5 7 a. — Development of interstitial tissue in guinea pig. 

 Abortus, not very far from normal birth (Prot. Nr. 

 loi). 



detailed observations on the guinea pig, showed that it is 

 probable that the interstitial cells originate from mesodermal 

 epithelium, i.e., from the generative cords; it maybe mentioned 

 that from the mesoderm arise also some other glandular cells, 

 for instance, those of the renal tubules. 



It seems to me that the views are not so contradictory as one 

 might at first think. The observations of a number of workers 

 whom Wagner has confirmed {Figs. 57A, B, c, d), for guinea pigs, 

 before and after birth, leave no doubt that real interstitial cells 



