80 B. F. KINGSBURY 



together with a hpochrome (lutein).^ The suggestion is close 

 therefore that the lipoids' are either closel,y concerned with the 

 ovarian effect upon other parts of the body, or otherwise im- 

 portant. We have thus the interpretation of Regaud and Du- 

 breuil that the secretion is hpoid in nature; and that of Loisel 

 that the hpoid is associated with an activity in the neutrahza- 

 tion .of poisons formed in the bodily metabolism. He there- 

 *fore looks with favor on the comparison of the interstitial cells 

 and the cells of the suprarenal cortex made by Mihalkovics and 

 others. As a source of 'internal secretion' he considers the de- 

 generation of egg and follicle cells as well as the interstitial cells, 

 and if I interpret him rightly, the undegenerating follicle and 

 egg cells as well. Mulon ('10) holds similar views of the anti- 

 toxic action and of the comparison with the suprarenal cortex. 



However attractive the view that the interstitial cells are the 

 formers of specific substances that are correlated with the ap- 

 pearance of the secondary sexual characters, it should be borne 

 in mind that there is no direct evidence in favor of the view, nor 

 does it seem possible from the character of their morphological 

 position and relations that such evidence could be obtained. 

 The circumstantial or indirect evidence seems to the writer, far 

 from conclusive on this point. The following comments are 

 offered from a purely morphological point of view. First, the 

 same argument holds against the acceptance of these cells as 

 constituting an internal secretory gland in the physiological sense 

 as against their recognition as a morphological gland, namely, 

 the variability in the amount and in the time of appearance, 

 mentioned and briefly discussed above and in the introductory 

 paragraphs of the paper. In many forms, after birth at least, 

 the interstitial cells appear to be lacking; in others lacking 

 before a certain age (e.g., rabbit). It should of course be 

 borne in mind that a full history of the development of the ovary 

 in most of these forms has not been worked out. In the cat, 

 from my series, interstitial cells appear to be continuously present 



5 Cf. Regaud et Dubreuil; Pargon, Dumitresca and Xissipesco, Wallart; Holin 

 and Staedeler; Mulon. 



