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HANDBOOK OF PHYSIOLOGY. 



ate processes pass as septa between the several lobules. Very often, in 

 the cow and sheep, there is no white substance in the centre; and the 

 lobules projecting from the opposite walls of the Graafian vesicle appear 

 in a section to be separated by the thinnest possible lamina of semi, 

 transparent tissue. 



When a Graafian vesicle is about to burst and expel the ovum, it be- 

 comes highly vascular and opaque; and, immediately before the rupture 

 takes place, its walls appear thickened on the interior by a reddish glu- 

 tinous or fleshy-looking substance. Immediately after the rupture, the 

 inner layer of the wall of the vesicle appears pulpy and flocculent. It is 

 thrown into wrinkles by the contraction of the outer layer, and, soon, 

 red fleshy mammillary processes grow from it, and gradually enlarge till 

 they nearly fill the vesicle, and even protrude from the orifice in the ex- 

 ternal covering of the ovary. Subsequently this orifice closes, but the 

 fleshy growth within still increases during the earlier period of preg- 



FIG. 439. Corpora lutea of different periods. B, Corpus luteum of about the sixth week after 

 impregnation, showing its plicated form at that period. 1, substance of the ovary; 2, substance of 

 the corpus luteum ; 3, a grayish coagulum in its cavity . (Paterson.) A, corpus luteum two days 

 .after delivery; D, in the twelfth week after delivery. (Montgomery.) 



nancy, the color of the substance gradually changing from red to yellow, 

 and its consistence becoming firmer. 



The corpus luteum of the human female (Fig. 439) differs from that 

 of the domestic quadruped in being of a firmer texture, and having more 

 frequently a persistent cavity at its centre, and in the stelliform cicatrix, 

 which remains in the cases where the cavity is obliterated, being pro- 

 portionately of much larger bulk. The quantity of yellow substance 

 formed is also much less: and although the deposit increases after the 

 vesicle has burst, yet it does not usually form mammillary growths pro- 

 jecting into the cavity of the vesicle, and never protrudes from the ori- 

 fice, as is the case in other Mammalia. It maintains the character of a 

 uniform, or nearly uniform, layer, which is thrown into wrinkles, in 



