INTERNAL SECRETION OF TESTICLE 147 



testicles and recorded here supply evidence that the sperma- 

 tozoa or other cells in late stages of spermatogenesis are not 

 necessarily involved in the internal secretion of the testicle. 

 But they do not afford conclusive evidence for the suggestion 

 that the interstitial cells only represent the endocrine apparatus 



Fig. 75. — Retained testicle of pig with unilateral cryptorchism ; 

 the normal testicle has been removed, x 200. Increased 

 number of interstitial cells; no change of number of 

 cells of Sertoli. — From Bouin and Ancel. 



in the testicle. The observations of Bouin and Ancel alone, 

 where the sexual characters were normally developed, although 

 there was a complete disappearance of cellular elements of the 

 tubules, can be regarded as a proof of the theory that the 

 interstitial cells are the only testicular internal secretory organs. 

 But here, also, we are confronted by an objection. It takes 

 some time for the effects of castration to become visible after 

 the disappearance of the endocrine testicular elements. It is 



