250 



HELEN DEAN KING. 



itself. Possibly there is a slight increase in the size of the egg 

 at this time which produces sufficient pressure on the surround- 

 ing membranes to cause a break at the weakest point. This 

 would seem to be where the egg is attached, because here there 

 are only two membranes over the egg instead of three (Fig. i). 

 This suggestion, however, fails to account for the rare cases 

 where the egg breaks through its membranes and falls into the 

 cavity of the ovary. Such eggs never leave the ovary ; sooner 

 or later they undergo degenerative processes and are gradually 

 absorbed, as are also the few eggs that do not leave the mem- 



FlG. 4. Part of the follicle sac shown in Fig. 3 more highly magnified. Zeiss 

 apoc. 2 mm. Oc. 8. 



branes at all but remain attached to the ovarian wall. In the 

 latter case the eggs are almost invariably smaller than those taken 

 from the body cavity, and, therefore, retarded development may 

 explain their failure to undergo normal processes. 



On spreading out a piece of the collapsed ovary after the eggs 

 have passed into the body cavity, one can plainly see the numer- 

 ous follicle sacs without the aid of a microscope. These sacs 

 vary in length from 0.36 mm. to 0.54 mm., and their walls are 

 very much wrinkled and folded. Although from 0.60 to 0.70 of 



