BBCT. 204.] CORPORA LUTE A. 455 



licles. As a rule, they arc visible externally as prominences, and 

 exhibit, on the summit, a stellate cicatrix, arising from the opening 

 of the Graafian follicle. Their outermost limit from the stroma 

 of the ovary is formed by a thin, whitish, fibrous coat (fig. 186, if), 

 then follows a yellowish vascular layer, much plicated, and hence 

 having the appearance of considerable thickness (fig. 186, c) ; and 

 in the interior we find a cavity of various size (fig. 186, d e), filled 

 either with coagulated blood, or else with a somewhat gelatinous 

 fluid tinged with blood. With regard to the origin of these 

 bodies, it is easy to see that the central part of them consists of 

 the blood which has been effused during the rupture of the follicle, 

 with or without an admixture with the remains of the liquor fol- 

 liculi ; and that the outer fibrous coat is the outer lamina of the 

 original fibrous coat of the follicle. With respect to the yellow, 

 plicated cortical layer, it belongs, for the most part, to the inner 

 lamina of the fibrous coat of the original follicle, which, before the 

 escape of an ovulum, becomes loose and spongy, and afterwards 

 becomes rapidly thickened, measuring as much as X" to \'", or 

 even more. This growth is accompanied by the formation of a 

 huge number of various-sized cells, which partly become trans- 

 formed into an imperfect connective tissue and into vessels ; while 

 another part of them continues in the state of cells, which are 

 then characterised by their beautiful vesicular nuclei, measuring 

 up to 0"Oi'" to 0"02"' in size, with nucleoli and a variable number 

 of yellow fat-globules in the interior. The yellow body, having 

 the structure here described, continues of its original size for some 

 time, until the second or third month of pregnancy; but during 

 this period, its central part or nucleus (no matter whether it be a 

 blood-coagulum, or a reddish gelatine with a small cavity) gra- 

 dually decreases in size, and becomes decolorised, while the yellow 

 cortical layer becomes thicker and thicker. At the same time, the 

 tissue of the corpus luteum becomes more compact and further 

 organised, by the conversion of its inner substance into fibrous 

 tissue, and by the coalescence therewith of the yellow cortical 

 part, in which, meanwhile, more and more young connective tissue 

 is being formed. The atrophy of the yellow body commences in 

 the fourth and fifth months of pregnancy, and advances slowly till 

 the period of gestation, so that in those who have died in child- 

 bed it measures 4 lines on an average; afterwards it diminishes 

 more rapidly, until, after some months, the metamorphosed 

 Graafian follicle has entirely disappeared, or has become a 

 minute, variously coloured corpuscle, which may persist for a 

 long period, and, perhaps, disappear completely, only after a series 



