INTERSTITIAL CELLS OF MAMMALIAN OVARY 85 



existing by themselves— in the absence of seminal tubules, al- 

 though tubule and interstitial cells seem to be often in reciprocal 

 relation — atrophic changes in the tubule being accompanied by 

 increase in the number of interstitial cells (Ancel and Bouin, 

 Voinov; Biedl, p. 3G5). There is no evidence, therefore, that 

 the factors that determine the transformation are intrinsic, that 

 is, in the cells themselves. From the condition in the fetal tes- 

 tis, cryptorchid testis, the experimental results of vaso-ligation, 

 and action of Roentgen rays (Biedl), it is clearly evident their 

 presence is not directly correlated with the spermatogenetic 

 process as such, l)ut with the indifferent cells alone. 



In fact, the absence of the reproductive cells — ^or the altera- 

 tion in the processes in the indifferent cells correlated therewith, 

 possibly of a distinctly 'degenerative' character — ^seems to par- 

 ticularly determine the appearance of these cells (fetal testis, 

 cryptorchid testis, diseased condition). 



Plato, in an excellent paper, attempted to correlate the pres- 

 ence of the interstitial cells in the reproductively active testis 

 with the Sertoli cell and concluded that they fulfilled an essen- 

 tially 'trophic function.' It may be mentioned, however, that 

 during spermatogenesis the indifferent cells are continuously and 

 alternately undergoing regressive as well as progressive changes, 

 and that the largest part of the cytoplasm of the spermatids un- 

 dergoes degeneration. Hence, it is rather difficult to determine 

 with which phase of the cyclic activity of the Sertoli cells the 

 correlation might be — the entire evidence seems to me to point 

 to the regressive rather than the progressive. In the testis as 

 in the ovary, therefore, it seems to me that the evidence of others 

 indicates that the interstitial cell formation is related to processes 

 that take place within the indifferent cells of the tubule, not 

 directly correlated with spermatogenetic cells and in their ab- 

 sence, and of a fundamentally regressive character. With full 

 cessation of activity within the tubule the interstitial cells would 

 accordingly more or less completely disappear; as, it may be 

 suggested, in extreme atrophy (Cushing's case xxxii, p. 277), 

 and in hibernation (Tandler). 



