INTERNAL SECRETION OF OVARY 269 



lutea graviditatis are to be understood as parts of the female 

 endocrine sex gland, originating together with all the other 

 endocrine cells from the follicular apparatus from soon after 

 birth till sexual maturity. 



All the various endocrine cells which are to be found in the 

 ovary represent an essential unity, the endocrine gland of the 

 ovary. The manifold changes and rhythms undergone by the 

 female, both somatically and psychically, in sexual life may he 

 regarded as phases of puberty in a broader sense of the word, 

 caused by developmental changes in the endocrine gland of 

 the ovary. These quantitative changes evidently play in the 

 female a much greater role than in the male. 



We have supposed that there are for man two great phases 

 of puberty corresponding to two climaxes in the develop- 

 ment of the sexual gland. In a similar way we may suppose 

 that there are two great phases of puberty for woman. 

 The second great phase is the time when the first corpus 

 luteum menstruationis develops, and this leads to the climax 

 of puberty in woman, that is to say, to pregnancy. 

 As to the hypothetical first great phase, we have at 

 present little knowledge concerning the endocrine gland or, 

 in other words, concerning the ovarian changes during em- 

 bryonic life. Unanimity does not yet exist as to follicular 

 atresia during extrauterine life, and there is still less know- 

 ledge of the follicular apparatus during embryonic hfe. Ac- 

 cording to some authors (see Aschner, 1914b, p. 479) follicular 

 atresia already occurs^ in the fifth month of embryonic de- 

 velopment. Would it be possible to attribute to this follicular 

 atresia the production of endocrine cells and hormones 

 necessary for the development of the somatic sexual aharacters ? 

 It is conceivable also that the endocrine cells originate during 

 embryonic life from other parts of the ovary. Lacassagne 

 (1913, p. 201) is of the opinion that in the rabbit the epithelioid 

 cells of the interstitial tissue may originate from ordinary 

 stroma cells. According to Athias (1919) interstitial tissue is 

 considerably developed in the bat during foetal life, the cells 

 originating from the ovarian stroma. Evidently in the early 

 embryonic development epithelioid endocrine cells arising 

 from stroma cells predominate, the follicle becoming later the 

 most important or even the sole seat of origin for these cells. 

 But, as Athias states, the interstitial cells also of the young 



