248 SPECIAL HISTOLOGY. 



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 com- 

 pared with a mucous membrane and presents : 1. a highly 

 vascular fibrous layer, theca folliculi v. Baer, s. tunica fibrosa, 

 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 in- 

 Fi 264 tenia], thicker, softer, and redder portion 



(fig. 264 b) j 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 fusi- 

 form, formative cells. In young fol- 

 licles 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, mem- 

 brana granulosa of authors) (fig. 264 b. c). This membrane, 

 0*008 — Q'012'" 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 thickening, project- 

 ing towards the interior and enveloping the ovum — the ger- 

 minal eminence^ cumulus proligerus, J'" broad (fig. 264 e). Its 

 roundish, polygonal cells, 0003 — 0004'" in size, with propor- 

 tionately 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 presents the appearance of a fine 

 granular membrane with numerous nuclei. The interior of 

 the follicles is occupied by a clear, light-yellowish fluid — 



Fig. 264. Graafian follicle of the Sow, x about 10 diaro.: a, external; b, 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. 



