488 



THE EEPEODUCTIVE SYSTEM 



chondria) arid fatty granules. The nature of the lipoid granules is dis- 

 cussed by Whitehead (Amer. Jour. Anat., 14, 1, 1912). These cells 

 increase in number during senile atrophy of the testis, but later entirely 



disappear. They are rela- 

 tively larger and more abun- 

 dant also in the testes of 

 tuberculous patients where 

 /there is considerable degen- 

 eration and a general in- 

 fantile condition of the 

 seminal epithelium. Vari- 

 ous functions have been 

 ascribed to them that is, 

 those obviously dependent 

 upon the internal secretion 

 of the testes prominently, 

 origin and maintenance of 

 secondary sexual characters, 

 and basis of sexual in- 

 stinct. Obviously other cells 

 of the testis might conceiv- 

 ably subserve these func- 

 tions, namely, the susten- 

 tacular cells and the sex- 

 cells. However, observa- 

 tions on testes of mules (in- 

 fertile) and cryptorchid 

 horses, and the findings of 

 Whitehead (Anat. Eec., 2, 

 5, 1908) in a third abdom- 



FIQ. 433. A GROUP OF INTERSTITIAL CELLS 



FROM THE TESTIS OF A THIRTY-FIVE YEAR 



OLD NEGRO. 



The outlines of three adjacent seminiferous 

 tubules are shown. Among the interstitial cells 

 are three nuclei of ordinary connective tissue. 

 The interstitial cells are filled with lipoid spher- 

 ules and granules. Formalin fixation, iron- 



hematoxylin stain. X 1500. 



inal testicle of a horse 

 where only interstitial cells 

 in great abundance persisted in normal condition, would seem to rele- 

 gate these functions to the interstitial cells. 



Kingsbury's careful studies (Amer. Jour. Anat., 16, 1914) of the inter- 

 stitial cells of the ovary of the cat (elements presumably homologous with 

 the interstitial cells of the testis) strongly support the interpretation of 

 these cells in terms of absorbers of degenerating and disintegrating ma- 

 terials. In the ovary all of the earliest and many of the later primary 

 oocytes disintegrate. In the vicinity of such atretic follicles interstitial 



