Regenerative Capacity of Ovarian Tissue 37 



different views about oogenesis — Lane-Claypon that oocytes 

 were formed from interstitial cells, and Pincus and Enzmann 

 that not only was this not the case, but that few mitoses 

 occurred in the germinal epithelium, and that no primordial 

 oocytes migrated from this epithelium. In themselves, these 

 differences of view merely indicate that the so-called histo- 

 logical evidence of oogenesis is anything but clear-cut. But 

 the fact that they exist makes it reasonable to expect some 

 justification for giving greater weight to one rather than 

 another interpretation of the histological data. This Aron et 

 al. do not do. 



Matthews' and Harrison's (1949) observations on the seal 

 are also cited as cast-iron evidence that invaginations of the 

 mature germinal epithelium give rise to oocytes. But on this 

 point, these two authors are completely non-committal. All 

 they say is that "in many instances the smaller crypts, and 

 diverticula of the larger ones, are found to terminate as 

 primary follicles, the epithelium surrounding the oogonia 

 being directly continuous with the germinal epithelium lining 

 the lumina of the crypts. ... It is not yet clear whether the 

 oogonia arise directly from the epithelium of the crypts or 

 whether they have reached their position previously from 

 some other source." 



Other authors, again, are quoted as stating that oocytes 

 may be present between the cells of the germinal epithelium 

 of the mature ovary, the implication being that they are 

 formed there. The observation is one which must be familiar 

 to all who have studied the ovary. It is, however, another 

 and purely arbitrary matter to infer that the presence of 

 oocytes in this situation indicates that they are derived from 

 germinal epithelium. Furthermore, it is not at all clear that 

 many of the authors cited by Aron et al. themselves regarded, 

 or would now be prepared to regard, their observations as 

 indicative of this particular conclusion. For example, all that 

 Deane (1952), one of the workers referred to, states is that 

 "small ova are occasionally seen within the germinal epithe- 

 lium — more frequently they occur just below it, accompanied 



