644 SPECIAL HISTOLOGY. 



conception and pregnancy ensue upon the detachment of the ovum, and, 

 when in perfection, appear as roundish or oval, firm bodies, mostly 

 rather larger than the former follicles, and are usually visible even on the 

 exterior as projections, exhibiting on the summit a stellate cicatrix, 

 arising from the rupture of the Graafian follicle. Exteriorly, these 

 bodies are bounded, towards the stroma of the ovary, by a thin whitish 

 fibrous membrane (Fig. 266, 2 /), succeeded by a yellowish vascular 

 lamella, which is much plicated, and consequently appears thicker (Fig. 

 266 c); and in the interior is a larger or'smaller cavity filled, either with 

 coagulated blood (blood-clot), or with a somewhat gelatinous fluid tinged 

 with blood (Fig. 266 d e). With respect to the origin of these bodies, 

 it is easily perceptible, that their "nucleus" or contents consist of the 

 blood poured out upon the rupture of the follicle, frequently mixed with 

 some remains of the liquor folliculi, and that the outer fibrous mem- 

 brane is the external layer of the original fibrous coat of the follicle ; 

 and as regards the yellow plicated cortical layer, this is referable for 



the most part to the internal layer of the 

 fibrous membrane of the original follicle, 

 which, even before the expulsion of the 

 ovum, becomes loosened in texture, and 

 afterwards rapidly expanded to the thick- 

 ness of J-J a line and more. The remains 

 of the epithelium, or membrana granulosa, 

 which were not expelled with the ovum from 

 the follicle, also seem to contribute to this 

 thickening, though in a subordinate degree, 

 and by no means in the same proportion as 

 the layer in question ; the increased thick- 

 ness of which is accompanied by the deve- 

 lopment of a vast number of smaller and 

 larger cells, which are, in part, transformed 

 into immature connective tissue and vessels, in part remain in the con- 

 dition of cells, characterized by their size, which reaches as much as 

 01-0'2 of a line, their well-marked, vesicular nuclei with nucleoli, and 

 a greater or less number of yellow oil-drops in the interior. The corpus 

 luteum, thus constituted, retains its original size for some time, up to 

 the second or third month of pregnancy ; because, whilst the contents 

 (whether these are a blood-clot, or a reddish gelatinous substance with 

 a small cavity in the interior) gradually diminish and lose their color, 

 the yellow cortical layer continues to increase in thickness, and, at the 



FIG. 266. Two corpora lutea, of the natural size, in a transverse section. 1, quite recent, 

 eight days after conception; 2, at the fifth month of pregnancy: a, t,albuginea; b, stroma 

 ovariij-c, thickened and plicated fibrous membrane of the follicle (inner layer); rf, blood-clot 

 within it ; e, discolored blood-clot ; /, fibrous coat bounding the corpus luteum. 



