572 



GENERATION AND DEVELOPMENT. 



brana granulosa, which naturally Hues the internal tunic of 

 the vesicle. 



The first changes of the internal coat of the Graafian vesicle 

 in the process of formation of a corpus luteura, 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 im- 

 pregnated, the growth of the yellow substance grows on during 

 nearly the whole period of gestation, and forms the large cor- 

 pus 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 disappears ; 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 pregnancy, necessarily renders unsafe all evidence of 

 previous impregnation founded on the existence of a corpus 

 luteum in the ovary. 



The following table by Daltou, expresses well the differences 

 between the corpus luteum of the pregnant and uuimpregnated 

 condition respectively. 



At the end of 

 three weeks, 

 Gne month, 



Two months, 

 Six months, 

 Nine months, 



CORPUS LUTEUM OF MEN- 

 STRUATION. 



Three-quarters of an inch 



reddish ; convoluted wall 

 Smaller; convoluted wall 



bright yellow; clot still 



reddish. 

 Reduced to the condition 



of an insignificant cica- 



trix. 



Absent. 



Absent. 



CORPUS LUTEUM OP PREG- 

 NANCY. 



in diameter; central clot 



pale. 



Larger; convoluted wall 

 bright yollow ; clot still 

 reddish. 



Seven-eighths of an inch 

 in diameter; convoluted 

 wall bright yellow ; clot 

 perfectly decolorized. 



Still as large as at end of 

 second mouth ; clot fib- 

 rinous; convoluted wall 

 paler. 



One-half an inch in diam- 

 eter ; central clot con- 

 verted into a radiating 

 cicatrix ; the external 

 wall tolerably thick and 

 convoluted, but without 

 anj 7 bright yellow color. 



