BY C. A. ROGERS 



79 



day, depending apparently, upon the state of development of the egg when 

 the dye is fed. 



After two days of incubation the fertile eggs colored with Sudan III 

 undergo a change. The outer bands of color break up and intermingle with 

 the yellow bands of the yolk. By the fifth day of incubation, the yolk is 

 quite well mixed so that only a faint resemblance of the banded condition 

 remains. By this time, also, the albumen near the developing embryo 

 has turned pink. The bulk of the albumen, however, is still white. (Plate 

 I, D) . Upon boiling the egg, which is necessary in order to make this study 

 the white albumen becomes quite like rubber, while the pink albumen 

 remains very soft; in fact, on the third and fourth, and often on the fifth 

 day of incubation it is impossible to coagulate the pink albumen by 

 boiling. The amount of pink albumen upon which, to all appearances, 

 the embryo directly feeds, remains quite constant. The white albumen 

 gradually decreases until entirely softened and consumed. 



The presence of color in the albumen leads one to suspect fat, since 

 Sudan III colors fat only. Analysis does show its presence in a large 

 percentage. 



ANALYSES OF THE YOLK AND ALBUMEN OF FRESH AND INCUBATED EGGS 



4 (NOTE The analytical work was done by Mr. L. J. Cross of the Department of Agricultural Chemis- 

 try at Cornell University. 



We have already seen in the concentric layers of Sudan III colored 

 yolk, that Sudan III does not stain previous deposits into which there 

 is no circulation or communication. Now, since this albumen is 

 white before being influenced by incubation, how can its fat be colored 

 unless circulation between it and the yolk is begun when the egg is incu- 

 bated? Also the facts that there still remains after twelve days of incuba- 

 tion practically as much fat as in the fresh yolk and that the yolk still has 

 the same approximate size and moisture content, tend to indicate that 

 the fat in the albumen does not come wholly or even in small part from the 

 yolk itself. The natural explanation of this unexpected condition is that 



