INTERNAL SECRETION OF TESTICLE 123 



well-developed interstitial cells soon after birth. The puberal 

 development of the sexual characters begins in the guinea 

 pig a few weeks after birth. In the rabbit puberty does not 











^^ 





Fig. 58. — Section through testicle of guinea pig, 2 to s 

 weeks ^ old (Prot. Nr. 32). x 280. Interstitial cells 

 rich in protoplasm with big spherical nucleus. 

 Above the * the granular mass is visible. — 

 Prepar. of Wagner; photo of KuU. 



begin until about three or four months after birth, and until 

 this time we find the whole testicle in an infantile condition. 

 Each interstitial cell is very small— a narrow band of protoplasm 

 surrounding a small spherical nucleus [Fig. 59). The protoplasm 

 does not stain well with eosin. At about three and a half 



