THE SEXUAL ORGANS. 641 



of the size, position, and number of the Graafian follicles. The latter 

 amounts to 30-50-100 in each ovary, and in many cases may reach 

 200 ; whilst in arrested or degenerated ovaries, such as are frequent 

 especially in old women, not more than 2 to 10, or even none at all, 

 are often met with. 



Each follicle, in the fully formed condition, consists of a membrane 

 and contents. The former may be most aptly compared with a mucous 

 membrane and presents : 1, a highly vascular fibrous layer, tliecafolli- 

 culi v. Baer, s. tunica iibrosa, of a proportionately not inconsiderable 

 thickness, which is united to the stroma of the ovary by a rather loose 

 connective tissue, and consequently can be readily stripped off in its 

 totality. Its external, somewhat firmer, reddish-white layer (Fig. 264 

 a), has been distinguished by v. Baer from the internal, thicker, softer, 

 and redder portion (Fig. 264 b) ; but at the same 

 time it should be remarked, that the inner layer 

 also may be again divided, and that both lamince 

 are composed of the same undeveloped, nucleated 

 connective tissue, intermixed with numerous, 

 mostly fusiform, formative cells. In young folli- 

 cles a delicate, structureless, membrana propria, 

 bounds the fibrous coat on the inner aspect and 

 may, by the use of alkalies, even at a later 

 period, frequently be demonstrated as a distinct membrane. 2, an 

 epithelium (granular layer, membrana granulosa of authors), (Fig. 264 

 b, c). This membrane, 0-008-0-012 of a line or more, in thickness, 

 lines the entire follicle, and on the side looking towards the surface 

 of the ovary, where the ovum is situated, presents a wart-like thicken- 

 ing, projecting towards the interior and enveloping the ovum the ger- 

 minal eminence, cumulus proligerus, J of a line broad (Fig. 264 e). 

 Its roundish, polygonal cells, 0-003-0-004 of a line in size, with pro- 

 portionately large nuclei, and, frequently, some yellowish fatty granules 

 disposed in several layers, are extremely delicate, and after death soon, 

 become indistinct, in consequence of which the whole epithelium pre- 

 sents the appearance of a fine granular membrane with numerous 

 nuclei. The interior of the follicles is occupied by a clear, light-yel- 

 lowish fluid liquor folliculi of the density of the serum of the blood, 

 containing, almost always, isolated granules, nuclei, and cells, which are 

 scarcely anything more than detached portions of the membrana granu- 

 losa, and do not originate in the fluid. 



In the germinal eminence, close upon the fibrous membrane of the 

 follicle, and therefore in the most prominent part of it, is placed the 



FIG. 204. Graafian follicle of the Sow, magnified about 10 diameters: a, external ; 6, 

 internal, layer of the fibrous membrane of the follicle: c, membrana granulosa; d, liquor 

 folliculi e, germinal eminence, a projection of the membrana granulosa ;/, ovum with a zona 

 pellucida, vitellus, and germinal vesicle. 



41 



