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HANDBOOK OF PHYSIOLOGY. 



liclc jit the time of its rupture, especially in the human subject, but it 

 has no share in forming the yellow body; it gradually loses its coloring 

 matter. The serum of the blood sometimes remains included within a 

 cavity in the centre of the coagulum, and then the decolorized fibrin 

 forms a membraniform sac, lining theoorpus luteum. At other times 

 the serum is removed, and the fibrin constitutes a solid stelliform mass. 



The yellow substance of which the corpus luteum consists, both in 

 the human subject and in the domestic animals, is a growth from the 

 inner surface of the ruptured follicle, the result of an increased devel- 

 opment of the membrana granulosa. 



The first changes of the internal coat of the Graafian vesicle in the 

 process of formation of a corpus luteum seem to occur in every case in 

 which an ovum escapes; as well in the human subject as in the domestic 

 quadrupeds. If the ovum is impregnated, the growth of the yellow sub- 

 stance continues during nearly the whole period of gestation and forms 

 the large corpus luteum commonly described as a characteristic mark of 

 impregnation. If the ovum is not impregnated, the growth of yellow 

 substance on the internal surface of the vesicle proceeds, in the human 

 ovary, no further than the formation of a thin layer, which shortly dis- 

 appears; but in the domestic animals it continues for some time after 

 the ovum has perished, and forms a corpus luteum of considerable size. 

 The fact that a structure, in its essential characters similar to, though 

 smaller than, a corpus luteum observed during pregnancy, is formed in 

 the human subject, independent of impregnation or of sexual union, 

 coupled with the varieties in size of corpora lutea formed during preg- 

 nancy, necessarily renders unsafe all evidence of previous impregnation 

 founded on the existence of a corpus luteum in the ovary. 



The following table by Dalton, expresses well the differences between the 

 corpus luteum of the pregnant and unimpregnated condition respectively : 



Corpus Luteum of Menstru- 

 ation. 



Corpus Luteum of Pregnancy. 



At the end of 



three weeks 



One month . 



Two months 



Six months . 

 Nine months 



Three-quarters of an inch in diameter ; central clot reddish ; con 

 voluted wall pale. 



Smaller ; convoluted wall 



bright yellow ; clot still 



reddish. 

 Reduced to the condition 



of an insignificant cica- 



trix. 



Absent. 



Absent. 



Larger ; convoluted wall bright yel- 

 low ; clot still reddish. 



Seven-eighths of an inch in dia- 

 meter ; convoluted wall bright 

 yellow ; clot perfectly decolor- 

 ized. 



Still as large as at end of second 

 month ; clot fibrinous ; convoluted 

 wall paler. 



One-half an inch in diameter; cen- 

 tral clot converted into a radi- 

 ating cicatrix ; the external wall 

 tolerably thick and convoluted, 

 but without any bright yellow 

 color. 



