INTERNAL SECRETION OF TESTICLE 183 



erotization. Moreover, as has been shown, especially by Kasai, 

 there is sometimes a degeneration of the whole testicle, as, 

 for instance, in tuberculosis; the interstitial cells are often 

 of the so-called quiescent type, with a little protoplasm and 

 with an elliptic nucleus. 



Bouin and Ancel suggested that the hypertrophy of the 

 interstitial cells in diseases represents a means of defence for 

 the organism. As a result of various experiments, Voinov 

 (1905) put forward the theory that the interstitial cells produce 

 certain chemical substances for the protection of the generative 

 part of the testicle. A similar view is held b}^ Kit ah ar a 

 (1923J, being based upon embryological evidence. Kitahara 

 and Cejka (1923) consider it possible that the interstitial cells 

 act also as a kind of chemical transformer of substances 

 produced in the generative part. Although it cannot be denied 

 that there is, perhaps, some truth in all these hypotheses, they 

 are none of them based on sufficient evidence. The papers of 

 Goette (1921), Jaffe (1922), and Berherich and Jaffe {ig22),who 

 deal with a great number of pathological observations, and of 

 Brack (1922), may also be referred to here. 



In any case there can be no justification for urging the dis- 

 proportion between the number of the interstitial cells and the 

 very low level of erotization in certain diseases as evidence 

 against the theory that the interstitial cells elaborate an 

 internal secretion. 



According to Stcinach and Kammerer (1920) the quantity of 

 interstitial cells is increased when animals are kept for a long 

 time under a higher temperature. They claim that there was 

 in these animals an hypertrophy of sex characters such as the 

 seminal vesicles and the prostate. 



As was shown recently by Tsuji (1920) a degeneration of the 

 seminiferous tubules may occur when rats are fed on a diet 

 poor in vitamines, such as a mixture of casein, starch, cane 

 sugar, lard and salts; the degeneration of the tubules can be 

 prevented when small quantities of milk are added to the 

 standard diet. No changes were found in the interstitial cells 

 surrounding the degenerated tubules. As Tsuji points out, 

 the changes in the testicle are evidently due to a diminished 

 activity on the part of the thyroid gland, which showed con- 

 siderable changes in the experimental animals, the weight of 

 the thyroid per 100 gr. body weight not reaching even half of 



