124 



INTERNAL SECRETIONS 



months after birth the interstitial cells become fully developed 

 We have in the guinea pig and the rabbit a close correspondence 

 between the state of the interstitial cells and the development 

 of the sexual characters. Are the latter caused by the former ? 





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Fig. 59. — Section through testicle of rabbit, 2 months 

 old (Prot. Nr. 46). x 280. Seminal tubules with 

 mostl}'' one stratum of cells; spermatogonia are 

 present. Small spherical nucleus. At many places 

 cells with spindle-shaped nucleus prevail. — Prepar. 

 of Wagner; photo of Kull. 



And is there also a close correspondence between the state of 

 the seminiferous tubules and the development of the sexual 

 characters ? For deciding this question it would be necessary 

 to study the time relations concerned in a more detailed manner 

 than we have done hitherto. 



