380 THE CORPUS LUTEUM OF DASYi'liCS, 



between them with corpus luteum cells. Whether they are 

 formed by the connective tissue previously in the interior of the 

 follicle, or by the sprouting of the blood vessels of the theca, is 

 uncertain (see tigs. 12, 13 and 14). These blood vessels are of 

 the nature of venous sinuses, and no structures comparable to 

 .small arteries are found in the corpus luteum at any time. 



Whilst the vessels are forming, the cells of the membrana 

 granulosa undergo a peculiar change. This has been seen in its 

 initial stages previously, but now becomes more marked. The 

 ceil cytoplasm swells, becomes filled with granules (even drops of 

 •secretion are described in some animals), the cell boundaries 

 become distinct and the nuclei become oval with their long axis 

 radial, whilst man}" of them have two distinct nucleoli. The 

 nuclear chromatin becomes aggregated round the peripherj^ of 

 the nucleus, but karj^okinetic figures are uniformly absent, though 

 they have been searched for with great care. Some of the cells 

 have two or even three nuclei, and the multiplication of the cells, 

 if it takes place, is direct. Taken on the whole, the change in 

 the membrana granulosa cell is probably a process of simple 

 hypertrophy. The hypertrophying cells push inwards the other 

 cells into the spaces between the blood vessels previous^ described, 

 so that the cavity is encroached on and filled up. In most cases 

 this filling up is completed at the Stage H, but a cavity filled 

 with blood vessels and connective tissue ma}' persist for a long 

 time (see tigs. 15 and 16). 



The membrana propria loses its former distinctness. It is 

 encroached upon by the cells of the theca nearest to it. The 

 nuclei of the cells nearest the membrana propria increase in size, 

 the membrana propria is dissolved, and the connective tissue 

 cells invade the cells of the corpus luteum. 



By the processes described it comes to pass that the emptied 

 follicle is transformed into the corpus luteum. Briefly, these 

 processes are the irruption of connective tissue into the cavit}' of 

 the follicle and its subsequent vascularisation, accompanied by 

 hypertrophy of the cells of the membrana granulosa. The corpus 

 luteum forms (Quickly (within three days) and persists during the 



