INTERNAL SECRETION OF TESTICLE 



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quantity of fat in the interstitial cells is very inconstant, 

 and that fat may even be absent. On the other hand, the inter- 

 stitial cells are sometimes completely filled up with fatty 

 inclusions; a " Sudan" preparation from the testicle of an adult 

 cat shows this in a very striking manner {Fig. 55). It seems 



Fig. 54a. — Section through testicle of hitman embryo of 

 fifth month. Same augmentation as 54. The greater 

 part of the testicle consists of interstitial cells. 

 Note the great quantity of capillaries in the 

 interst. tissue. — From a preparation kindly lent 

 by Aunap; design, Lehbert. 



to us improbable that the fatty inclusions are to be considered 

 as the characteristic feature of the interstitial cells, and it is 

 not possible to deduce therefrom conclusions as to the function 

 of these cells. This is clear if we take into consideration the 

 fact that numerous other inclusions are detected in the inter- 

 stitial cells by other differential stains. I mention only the 

 crystaloids detected by Reinke in the testicle of man, and the 



