24 



THE TESTIS AND ITS RELATION TO REPRODUCTION 





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Fig. 12. Sections of the testis of the deer, Odocoileus virginianus borealis. (After 

 Wislocki.) (A) Seminiferous tubules of deer in June. Observe repressed state of tubules 

 and absence of sperm. (B) Epididymal duct of same deer. Observe absence of sperm 

 and smaller diameter of duct compared with (D). (C) Seminiferous tubules of October 

 deer; spermatogenic activity is marked. (D) Epididymal duct, showing well-developed 

 epididymal tube and presence of many sperm. 



stitial tissue remains. The sex hormone, under these circumstances, continues 

 to be produced. Again, males having cryptorchid testis (i.e., testes which have 

 failed in their passage to the scrotum) possess the secondary sex character- 

 istics of normal males but fail to produce sperm cells. Also, it has been demon- 

 strated that the mammalian fetal testis contains the male sex hormone. How- 

 ever, in this fetal condition, the seminiferous tubules are present only in an 

 undeveloped state, whereas interstitial tissue is well differentiated. It is probable 

 in this case that the interstitial tissue of the fetal testis responds to the 

 luteinizing hormone in the maternal blood. 



In hypophysectomized male rats injected with dosages of pure follicle- 

 stimulating hormone (FSH) or with small doses of pure luteinizing hormone 



