THE E EM ALE G EXE NATIVE APT A RATES. 



175 



The normal ovarium contains besides a small number of 

 ripest gland capsules (12 to 20). These are the Graafian fol- 

 licles (Fig. 157), discovered long ago by De Graaf. Their size 

 is determined, in a measure, by the dimensions of the mam- 

 malial ovum. In women they finally attain to 6 to 9 mm. 





Fig. 157. — Mature follicle ; a, ovum : epithelial stratum covering the same, i, and lining the 

 cavity, c ; d, connective-tissue wall ; t», outer surface of the follicle. 



The parietes consist of a double layer, an inner one with a 

 close capillary net-work, and an outer one with the ramifica- 

 tion of the larger blood-vessels. The wall itself (e, d) is unde- 

 veloped connective tissue. We here again meet with the 

 granular connective-tissue cells mentioned at page 54. They 

 may surround the vessel like a mantle. The small epithelial 

 cells of the follicles measure 0.0074 to 0.OT13 mm. (c). 



At one point, mostly at the bottom of the follicle (Schro'n, 

 His), but occasionally also at the surface that is turned to- 

 wards the germinal epithelium (Waldeyer), we meet with the 

 mature ovum (a) surrounded by a thicker epithelial stratifica- 

 tion (8). 



In the mammalial animal it remains uncommonly small, 0.2 

 to 0.3 mm. in diameter. This explains why its discovery was 



