THE SYMPATHETIC SYSTEM 209 



THE INTERSTITIAL GLAND OF THE TESTICLE HAS A 

 DOUBLE FUNCTION. 



1. It maintains the nutrition of the seminiferous 

 tubules and protects the spermatic cells by fixing or 

 neutralizing the toxins which are liable to affect them. 

 This action is more or less hypothetical and the mechan- 

 ism has not been sufficiently demonstrated. 



2. It controls the whole of the sexual characteristics. 

 This is its most important action and has been demon- 

 strated by physiology, histology and experimentation. 



We must remember that the sexual characteristics in 

 the young, as well as in the old, consist of : 



a. The primary characteristics, namely, the sex itself. 



6. The secondary sexual characteristics: the growth 

 of the genital tract and its adnexa. 



c. The tertiary characteristics: the development of 

 the skeleton and the sexual instinct. 



The decrease, then the disappearance of the sexual 

 instinct in old men, as well as in old animals, corresponds 

 to a physiological evolution of the interstitial gland; 

 the cells lose their fatty granulations, their crystals, 

 and atrophy. 



The study of the cryptorchidism in animals shows 

 clearly the action of this gland. Certain animals with 

 cryptorchidism have well developed external genitalia, 

 and have all the characteristics of a stallion except that 

 they cannot reproduce, while others resemble castrated 

 animals. In the first type of case, the interstitial gland 

 is preserved while it is missing in the other. The ligation 

 of the vas deferens when performed on young animals does 

 not modify their development and does not prevent the 

 appearance of the sexual characteristics. Richon and 

 Jeandelize, Tournade, Bouin and Ancel have noticed that 



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