CHAPTER XVIII 



THE INTERNAL SECRETIONS OF THE GENERATIVE 

 GLANDS IN THE MALE 1 



The Interstitial Cells of the Testicle 



It was noticed by Leydig in 1850 that the intertubular connective tissue 

 of the testicle is characterised by the presence of strands of epithelium-like 

 cells; these have been termed the cells of Leydig, and, collectively, the 



Fig. 90. —Section of testicle, human, showing groups of interstitial cells between the 

 tubules. Magnified 50 diameters. 



interstitial gland of the testis. They vary in development in different 

 species of animals, being very well marked in the cat (fig. 92), less so in 

 the dog and mouse, and still less in the rat and rabbit : in man they may 

 be quite conspicuous (figs. 90, 91). The cells are always present to some 

 extent, and Tandler and Grosz have shown that in animals which undergo 

 seasonal changes in sexual activity the interstitial cells may be even better 

 developed when the seminiferous tubules are inactive than during the time 



1 For a fuller discussion of the subject of internal secretion in connexion with the sexual 

 organs, F. H. A. Marshall's Physiology of Reproduction may be consulted. 



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