CORPUS LUTEUM IN OVARY OF THE CHICKEN 9 



orange (1. The cell masses finally become nearly filled with this 

 yellow material, some of it collecting in clumps several times 

 larger than the degenerated nuclei. 



Further tests of the character of the cell contents in these cell 

 masses were made with Sudan III. Hand sections were made 

 of material in McClendon's fluid. Although these could not 

 be cut very thin, they showed that the inner lining of the early 

 discharged follicles contains fatty material. In an old follicle 

 with central yellow mass the cells of the yellow mass take the 

 red of the Sudan III, but the yellow amorphous particles show 

 in the mid^t of the red. They can be squeezed out of broken 

 cells and isolated from the red fatty background, showing they 

 are still yellow, unaffected by the Sudan III, and therefore not 

 of a fatty nature. The fatty substance indicated by the Sudan 

 III reaction in both young and old folhcles is probably con- 

 tained in the vacuoles so conspicuous in paraffin sections. The 

 xylol would have dissolved out all the fat lea\dng the vacuoles 

 in which it had been contained. 



IV. DEGENERATION OF CORPUS LUTEUM IN COW OVARY 



In order to show the significance of the yellow mass formed 

 in the center of discharged follicles in the hen ovary, we have 

 made a brief study of the degeneration of the corpus luteum in 

 the cow ovary for comparison. There is an extensive literature 

 on mammalian corpus luteum, but this deals chiefly ^vith the de- 

 velopment and early involution. Now the bird quite evidently 

 has no structure similar to the large corpus luteum which fills 

 up half the ovary of a cow at its full development. The small 

 yellow spot on the bird ovary resembles the small yellow spots 

 on the cow ovary which mark the old remains of former corpora 

 lutea. Ovulation in the cow alternates between the two ovaries. 

 So by studying the two largest corpora lutea on both ovaries 

 we can arrange a series of four involution stages. Beyond that, 

 they all seem equally shrunken and therefore can not be ar- 

 ranged in a further series. Such a series of four involution 

 stages has been studied for two cows, and in addition several older 

 corpus luteum remains. 



