122 GEORGE W. CORNER 



that in the fully formed corpus luteum most of the lutein cells 

 are of granulosa origin; a few of them, however, are from the 

 theca interna. 



A nearly identical theory is that proposed by Rabl ('98), who 

 studied human corpora lutea (the youngest estimated at ten 

 days), and found in them about the periphery a layer of cells 

 differing from the rest of the lutein tissue; this, he suggested, 

 might be the theca interna, which he supposed to persist in its 

 original position until its cells were lost to view, some by becoming 

 converted into lutein cells, others by degenerating. 



During these five years from 1896 to 1901 there was no lack 

 of publications restating the total loss of the granulosa before 

 rupture, in opposition to the descriptions of Stratz, Sobotta, and 

 Van der Stricht. A few of these investigations were carried out 

 upon the ovaries of swine, and will therefore be discussed more 

 fully later in this paper. As Sobotta pointed out in his resume 

 of 1902, not one writer among those who taught the non-partici- 

 pation of the granulosa in corpus luteum formation had been 

 able to prove that his specimens were normal mature follicles 

 and corpora lutea by presenting the ova which had proceeded 

 therefrom. 



RECENT INVESTIGATIONS 



From 1901 to 1917 there have been about thirty-five more 

 publications upon the question, of which some twenty-five rep- 

 resent actual original investigations. As the subject has not been 

 brought up to date in any publication in English, it may be as 

 well to take up in some detail the work of the past sixteen years, 

 especially as the old differences of opinion still persist. 



Jankowski ('04) reports studies upon a series of ovaries of sows 

 and guinea-pigs, collected without an attempt to learn the repro- 

 ductive cycle of the animals or to test the normal conditions of 

 the specimens according to the postulates of Sobotta (which he 

 says he had found impracticable to apply and whose value he 

 questions). He believes the granulosa to be intact until the 

 rupture of the follicle and even afterward, but to degenerate 

 before the ingrowth of the theca interna, to which he ascribes the 



