THE EGG OF THE DOMESTIC CAT 151 



O. Van der Stricht ('08) agrees with Bischoff ('45) that in the 

 ovary of the dog the development of the corpus hiteum is begun 

 before the rupture of the follicle. He finds that certain 'hin- 

 einspringende Zottchen und Faltchen' seen by the earlier inves- 

 tigator in the mature follicles of the dog before ovulation are 

 caused by a movement of the connective tissue elements of the 

 theca interna, as a result of which the membrana propria does 

 not retain its usual position, but is thrown up into folds, on which 

 in some cases a series of secondary folds is superimposed. The 

 effect of the folding of the basal membrane is to loosen the gran- 

 ulosa cells effectually^ and cause them to rise irregularly, giving 

 the interior of the follicle the tufted appearance noted by Bischoff. 

 With ovulation the change in the follicle is apparently one in 

 degree only, and not one in kind. 



In only one case in the cat was anything noted comparable to 

 the above. In a single follicle which had already ruptured its 

 granulosa layer, and put the bounding layer of the tunica albugi- 

 nea under extra tension, the membrana propria of the deeper 

 wall was thrown into the characteristic wrinkled form. Since 

 the most that patient search has ever revealed in any other unrup- 

 tured follicle is an occasional slight irregularity in the membrana, 

 and since a follicle just ruptured (fig. 7), and with the egg still 

 retained in the clotted fluid near the opening showed a consider- 

 able upheaval of the granulosa cells, we must conclude that in the 

 cat the first step in the formation of the corpus luteum is contem- 

 poraneous with the rupture of the follicle. 



In general, ovulation occurs only after the first polar body 

 has been extruded, but there are occasional exceptions to this 

 rule, two of which have come to the writer's notice. The first 

 was manifestly a case in which an egg was escaping through a 

 rupture in the cortex of the ovary caused primarily by the burst- 

 ing of a follicle other than its own. It is of especial interest in 

 this respect, that the egg whose discharge is the secondary phe- 

 nomenon, is being passed out surrounded by its entire follicle, 

 with the thecae intact. Incidentally, it might be observed that 

 there are leucocytes present in its antrum, and that its follicular 

 fluid has the appearance of a homogeneous coagulum. These 



