THE SEXUAL ORGANS. 645 



same time, its tissue to become more organized and more compact ; this 

 change taking place by the transformation, on the one side, of the in- 

 ternal substance into fibrous tissue, and on the other by the more 

 intimate fusion of the yellow cortex with it, and the more abundant 

 development of immature connective tissue in the former. In the fourth 

 and fifth months the atrophy of the corpus luteum commences, and is 

 slowly continued to the end of pregnancy ; so that in persons dead in 

 childbed, it still measures 4 lines on the average, but afterwards more 

 rapidly, until ultimately, after some months, the metamorphosed Graa- 

 fian follicle has entirely disappeared, or become reduced to a diminutive, 

 variously colored corpuscle, which undoubtedly may still exist for a long 

 time, and, perhaps, is not removed altogether for some years. Such 

 arrested corpora lutea (corpora albicantia and nigra, of authors) at first 

 retain a distinct limitation, a dentate nucleus, containing a minute 

 cavity of a grayish white, or red-brown, even black color depending upon 

 altered hematin, and a cortical substance presenting various tints of 

 yellow or yellowish-white, or even quite white, and often still distinctly 

 plicated, but subsequently they become mere amorphous spots, coales- 

 cent with the stroma of the ovary. Their elements are fibres, more of 

 an embryonic character, such as also form the ovarian stroma, together 

 with various pigmentary molecules and colored crystals (hsematoidin), 

 and a whitish-yellow fat, which latter at first occurs in the cortical sub- 

 stance still contained in larger, round, elongated, or fusiform cells, but 

 is ultimately liberated by their rupture, and at last subjected to a more 

 or less complete absorption. 



In the corpora lutea, which are not formed at the time of a preg- 

 nancy, the same processes, in general, take place as in the others, but 

 with much greater rapidity ; so that these bodies have usually entirely 

 disappeared in the space of one or two months, or left only the merest 

 trace, whence they never possess the peculiar conformation of the 

 others, which have been termed the true corpora lutea.* 



The place of the numerous follicles which disappear from the ovaries 

 during the whole of the vigorous periods of life, is supplied by the 

 constant production, even in the adult, of new ovisacs, which are 

 developed into Graafian follicles. In animals, these new formations 

 which take place at the time of heat, and were first noticed by Barry, 

 Bischoff, and Steinlin, are very abundant, and very easily observed, 



* [Besides the difference in size and the rapidity of their metamorphoses, the true corpora 

 lutea are distinguishable from the corpora lutea formed in the non-pregnant state by the 

 thickness of the wall, and by their different color. The convoluted wall of the true corpus 

 luteum is almost always twice as thick, whilst its color and that of the central coagulum, 

 is never of so decided a yellow, but has generally more of a dusky and indefinite hue ; a 

 difference which is probably owing to a less number of yellow oil-globules. (Vide Dalton's 

 Prize Essay, " On the Corpus Luteum of Menstruation and Pregnancy," Transactions of the 

 American Medical Association for 1851.) DaC.] 



