INTERNAL SECRETION OF TESTICLE 



113 



The 



being small; two or three nucleoli are generally present, 

 protoplasm surrounding the nucleus is very large. The dimen- 

 sions of these cells are very variable, but by their characteristic 

 appearance they are as a rule easy to distinguish from common 

 connective tissue cells which are present in the testicle of an 

 adult rabbit or guinea pig only in small quantity. In the 

 testicle of the mouse the number of the interstitial cells is less, 



Fig. 53. — Group of interstitial cells in testicle of 

 adult cat (Prot. Nr. 277, weight 3-2 kgr.). 

 Weight of testicle, 1-2 gr. The big inter- 

 stitial cells with spherical nucleus and 

 vacuolated protoplasm can easily be dis- 

 tinguished from connective tissue cells. — 

 Prepar. Wagner; design, Lehbert. 



whereas, as stated by different authors, it may be enormous in 

 other species as, for instance, in the wild boar. In the cat 

 {Fig. 53) the interstitial cells are also very well developed. In 

 man the interstitial cells are embedded in connective tissue con- 

 sisting of fine filaments {Fig. 54). Very often one finds between 

 the tubules and the interstitial cells empty spaces about which 

 there has been much discussion {Figs. 51, 52); some authors 

 consider these spaces to be artificial, whereas others regard 

 them as something in the nature of l37mphatic spaces. Lately 



