INTERNAL SECRETION OF TESTICLE 



151 



castration. But after a short time further changes take place 

 in the graft. There is an increase of connective tissue. Although 

 the interstitial cells surrounded by connective tissue persist for 

 months, they, nevertheless, finally undergo degeneration. 



Fig. 78. — Section through testicle of 

 normal adult guinea pig (Prot. Nr. 

 228, 600 gr.). X 70. Full sperma- 

 togenesis. Normal quantity of 

 interstitial cells; the latter often 

 surrounded by granulated mass 

 (especially at the *). To be com- 

 pared with Fig. 79, — Prepar. of 

 Wagner ; design of Lehbert. 



'•r 



/ 



4 



■-- 



' s. 



Fig. 79. — Upper testicular fragment 

 of a partial *' castrate " (guinea pig. 

 Prot. Nr. 30). X 70. Operation at 

 age of 10 days; fragment removed 

 at age of ^^ months. Fragment 

 represents about i per cent, of total 

 normal testicular mass. Seminal 

 tubules with one stratum only; 

 diameter of some tubules remains 

 normal. Number of interstitial 

 cells in general increased; besides 

 this, very pronounced local increase. 

 Sex characters normal. — Prepar. of 

 Wagner; design of Lehbert. 



We have already mentioned that the number of interstitial 

 cells in the graft can be sometimes greatly increased. Steinach 

 argues that if the interstitial cells are the endocrine apparatus 

 of the testicle, one might expect that where there is an increased 

 number of interstitial cells there would also be signs of an 



