130 INTERNAL SECRETIONS 



sac of the guinea pig degenerated and regenerated some months 

 later. Unfortunately in this case we did not find the testicular 

 fragment, and therefore we cannot say whether there was 

 really a regeneration in the seminiferous tubules. Finally, 

 Ancel and Bouin (1923) kept vasectomized rabbits iovfour years 

 after the operation, the sex characters remaining normal. 



Although there is no proof that the seminiferous tubules are 

 involved in the internal secretion of the testicle, one must, 

 indeed, recognise, that this question is not decided negatively 

 by the experiments of Bouin and Ancel in a definite manner. 

 Even when regeneration of the tubules does not take place, 

 cells of SertoU, and possibly also spermatogonia, are present 

 in the tubules. As regards spermatozoa and cells in late stages 

 of spermatogenesis, we shall see below that there can be no 

 doubt that they are not directly involved in the endocrine 

 function of the testicle. As regards cells of Sertoli and sper- 

 matogonia, Bouin and Ancel (1903 b, 1904 c) tried to show by 

 the following experiments that they have nothing to do "with 

 the internal secretion of the testicle. They performed a uni- 

 lateral castration on rabbits and ligatured on the other side the 

 vas deferens so as to evoke a compensatory hypertrophy of 

 those elements which perform the internal secretory function. 

 The result was that only the interstitial cells proliferated, 

 whereas the cells of Sertoli remained unaltered. The interstitial 

 cells in these cases, according to Bouin and Ancel, show signs of 

 great secretory activity. They are obviously situated around 

 the blood vessels in thick layers. Sand (1918) has repeated 

 this experiment of Bouin and Ancel on rabbits, rats and guinea 

 pigs. He also claims to have shown that unilateral castration 

 was followed by an enormous hypertrophy of the cells of Le^^dig 

 in the remaining testicle, the vas deferens of which was 

 ligatured, whereas the spermatozoa disappeared and the cells 

 of Sertoli became partly degenerate. But a considerable 

 hjrpertrophy of the interstitial tissue occurred only in two out 

 of six experiments of Sand (1921 b). The sexual characters 

 were normally developed. 



In section 6 of this chapter we shall return to the question 

 of compensatory hypertrophy of the interstitial cells, and shall 

 show that it is very improbable that they undergo a com- 

 pensatory hypertrophy for endocrine purposes. The same is 

 true also for the generative part of the testicle. 



