148 W. H. LONGLEY 



Sobotta ('9G) observes that in the mouse bleeding occurs 

 ordinarily neither at nor after the rupture of the follicle. Clark 

 ('90) working upon pig's ovaries, reports upon the contrary 

 that more or less blood is found in all the recently ruptured fol- 

 licles, and with his observations those made upon the cat b^' the 

 writer more closely agree. Some follicles were nearly choked 

 with blood, but there is a great variation in the amount present. 

 The impression given is not that the rupture of the blood vessels 

 of the theca interna causes the rupture of the follicle, but rather 

 that it is dependent upon it. Since the rupture of the follicle 

 and the loss of follicular fluid diminishes the pressure in the an- 

 trum, the blood pressure in the small vessels is an unbalanced 

 force, which, in some cases more than in others, causes the blood 

 to burst from its confines. In extreme cases it seems to gain 

 direct access to the antrum of the follicle, but usuallj^ the blood 

 spaces lie in elevated portions of the theca interna or are bounded 

 by the membrana propria. 



The usual process followed in ovulation is that an accumulation 

 of fluid causes the distension of the follicle, which consequently 

 bulges beyond the general surface of the ovarj^ The external 

 follicular wall becomes very thin and finally its granulosa layer 

 divides at the point nearest the periphery. The rupture of the 

 tunica albuginea follows. With the yielding of the layer last 

 mentioned either the elasticity of the theca, or its active muscular 

 contraction or the pressure from the surrounding stroma de- 

 creases the size of the antrum. As a consequence part of the 

 follicular fluid containing the egg, which at this period lies prac- 

 tically free surrounded only by its zona and corona (fig. 3) 

 is forced from the follicle. 



The membrana propria is not sufficiently elastic to adjust 

 itself to the new dimensions of the follicle and is thrown up into 

 folds, beneath which the connective tissue fibres and lutein cells 

 follow more or less closely and form a supporting axis. The 

 granulosa cells are thrown into a corresponding series of elevations. 

 Upon preliminary examination they seem to be a very thick, 

 loose layer, but they really are only a thin one, sometimes only 

 two or three cells thick, and their apparent depth is only the 



