359 



investigators. Practically all the authors who have studied complete 

 series of corpora lutea in the various stages of development in the 

 Avay first adopted by Sobotta in his researches on the mouse (21) 

 and the Rabbit (22) have supported the hypothesis put forward by 

 BiscHOFF (5). This author regarded the luteal cells as derived from 

 the follicular cells as against von Baer (2) who maintained that such 

 cells were entirely of connective tissue origin. Although recent 

 writers such as Jankowski (10) und Williams (28) have upheld von 

 Eaer's hypothesis the weight of evidence seems against it and it is 

 certainly incorrect in the case of D. viverrinus. Both in the pregnant 

 and non-pregnant female the luteal cells are greatly hypertrophied 

 follicular cells ^ and only the connective tissue network of the corpus 

 luteum is derived from thecal ingrowths. 



Various authors have recorded the occurrence of mitotic divisions 

 in the cells of the membrana granulosa during the formation of the 

 corpus luteum. Thus it has been noted in the sheep by Marshall 

 (12) in several bats by van der Stricht (25), in the rat and Guinea- 

 pig by Belloy (3) and also by Bouin (6) in the Guinea-pig by Loeb 

 (11), in Tupaja, Sorex and Tarsius by Stratz (24) and by Regaud 

 and Dubreuil in the rabbit (17). But in the last case at any rate 

 this does not occur until the last week of pregnancy. 



On the other hand Sobotta in the mouse (21) and the rabbit 

 (22) and Honore in the rabbit (9) state that there is no division of 

 the follicular cells. As has already been pointed out careful searching 

 has failed to reveal any signs of direct or indirect division of these 

 cells in D. viverrinus after the closure of the ruptured follicle. 

 ' Two different accounts have also been given of the origin of 

 the connective tissue of the corpus luteum. On the one hand it 



1 In some cases this is particularly obvious as the cells of the mem- 

 brana granulosa have increased considerably in size before the irruption of 

 the theca commences and have become partially transformed into luteal cells. 

 The condition in No. 15 is also interesting in this respect. It seems that the 

 ovary on one side has ovulated in quite a usual manner and possesses normal 

 corpora lutea. The other ovary however, has not ovulated, but the cells of 

 the membrana granulosa have swollen up so as to almost completely fill the 

 cavity of the follicle in the centre of which is the ovum undergoing de- 

 generation (fig. 5). Although the follicular cells have enlarged to such an 

 extent and closely resemble lutein cells the theca folliculi has not broken 

 through the membrana propria. The reason for the abnormal behaviour of 

 this ovary is not apparent. 



