CHANGES IN THE OVARY 



147 



the changes exhibited by discharged follicles and retrogressive 

 undischarged follicles are identical in character. It is to be 

 noted further that in the investigations of all those writers who 

 have upheld the connective tissue hypothesis, the ages of the 

 developing corpora lutea were unknown, the material having 

 been collected in no case by Sobotta's method of killing the 

 animals at successive intervals after coition. 



In 1901, after the publication of the papers referred to above. 



Fio. 36. — Corpus luteum of mouse fully formed. (From Sobotta.) The luteal 

 tissue is vascularised and the central cavity filled in with connective 

 tissue. 



the present writer issued a preliminary account ^ of an experi- 

 mental inquiry upon the formation of the corpus luteum in the 

 sheep. In this inquiry the animals were killed at successive 

 intervals after coition, or (in cases where coition did not or was 

 not known to occur) after oestrus was observed. The result of 

 this investigation was to confirm BischofE's hypothesis in all 



1 Marshall, "Preliminary Communication on the (Estrous Cycle and the 

 Formation of the Corpus Luteum in the Sheep," Proc. Roy. Soc, vol. Ixviii., 

 1901. The full paper wras afterwards published in the Phil. Trans., B., 

 vol. cxcvi., 1903. 



