THE GESTRUS-PRODUCING HORMONE 107 



interna cells, especially in atretic follicles, and absent in the 

 follicular granulosa, the ovarian stroma, and the germinal 

 epithelium. The hormone has, however, been shown to occur 

 in residual ovarian tissue, after removal of large follicles and 

 corpora lutea, in much larger amounts than could be accounted 

 for by the remaining follicles (158, 503). Various workers have 

 noted oestrin in ovarian cysts (24, 488). Much controversy has 

 raged around the alleged presence of oestrin in the corpus 

 luteum. Early workers were almost unanimous in supposing 

 that oestrin could be obtained from the corpus luteum. 

 Thus, Iscovesco (313), Seitz, Wintz and Fingerhut (558), 

 Fellner (192), and Herrmann (292) all obtained active extracts 

 from this source. Some of these workers used growth of the 

 rabbit uterus as a test-object, so that the possibility of other 

 than oestrus-producing substances giving the reaction is not 

 excluded. Their illustrations, however, give no suggestion of 

 any reaction except the oestrous condition. Okinschitz (481) 

 failed to obtain positive results from corpus luteum. More 

 recently, positive results have been obtained by Frank and 

 Gustavson (229), Fraenkel and Fonda (218), by Glimm and 

 Wadehn (245), and Zondek and Aschheim (654). Allen and 

 Doisy failed to obtain positive results with corpora lutea from 

 the cow and pig, except in one case of tertiary liquor folliculi, 

 while Johnston and Gould (316) failed with pig corpora lutea. 

 Brouha and Simonnet (93) also obtained negative results from 

 cow corpora lutea. Allen and Doisy did, however, find a slight 

 activity in the hollow human corpora lutea during the early 

 stages of development. The discrepancy in these observa- 

 tions is probably due to the fact that, in the cow particularly, 

 many corpora lutea contain a fluid centre derived from the 

 remains of the liquor folliculi. This fluid might reasonably be 

 supposed to contain oestrin. It is unlikely that the corpus 

 luteum itself, an organ whose development is always asso- 

 ciated with the absence of oestrus, would produce the 

 oestrous hormone. Parkes and Bellerby (507) found that in 

 the cow's corpus luteum the fluid enclosed in the centre of 

 hollow specimens contained oestrin, but that the tissue of 

 solid corpora lutea possessed no activity whatever. If, as this 

 work suggests, the oestrin content of the corpus luteum is 



