INTERSTITIAL CELLS OF MAMMALIAN OVARY 81 



in the ovary from a 95-mm. fetus to extreme old age, and Sai- 

 mont has described them in younger fetuses, stages that I lacked. 

 They are markedly abundant before the time of sexual matu- 

 rity, and are likewise abundantly present during adult life. The 

 number of series is too limited to determine whether they are 

 more abundant during pregnancy, but have given no indication 

 that such is the case. The large numbers of interstitial cells 

 in the ovary of the maturing kitten might be suggestive, were 

 it not for their presence in both ovaries of a 17-year-old cat. 

 One ovary was atrophic, oocytes had completely disappeared, 

 but interstitial cells were relatively abundant as were cords and 

 groups of the indifferent or follicle cells. The other ovary was 

 hypertophied, due to the large increase in the indifferent cells 

 giving a superficial resemblance to a cryptorchid testis. Inter- 

 stitial cells were present in relative abundance. Hence the dis- 

 tribution throughout the different periods of the life cycle gives 

 no support to their secretory nature. 



The stromal cell might with more likelihood be seized upon as 

 the former of ovarian 'hormones' than the interstitial cell which 

 is but a transitory development out of it of variable occurrence. 

 Still more likely, from the writer's point of view, if he may be 

 pardoned for intruding it, is the suggestion that end-products 

 of the metabolism of the parenchyma itself may be a source of 

 'hormones' upon which depends the effect of the ovary upon the 

 bodily metabolism. These possibly are set free in the degener- 

 ation of ovum and follicle.*' Certain it is that one of the most 

 striking features of ovarian morphogenesis is the constant de- 

 generation of egg cells and follicle cells throughout fetal and 

 postnatal development until the onset of sexual senility. Before 

 the onset of sexual maturity the degeneration is most pronounced 

 (cat, man). The assumption that the end-products of me- 

 tabolism may stimulate growth, is not I believe opposed to the 

 facts of general physiology but rather the reverse. Whatever 

 may be the outcome of future investigations as to the source 

 and nature of the substances through which the ovary affects 



•^ Coini)arc Loiscl, 1905, p. 89. 



THE AMERICAN JOURNAL OF ANATOMY, VOL. 1(1, NO. 1 



