Xanthophyll, the Principal Natural Yellow Pigment of the Egg Yolk, Body Fat, and Blood Serum of the Hen. the Physiolog- Ical Relation of the Pigment to the Xan- Thophyll of Plants.*

The pigmentation of the yolk of the egg and of the flesh (body fat) of poultry is a subject of much practical importance in the egg and poultry industry of this country. The consumer demands highly colored yolks in (‘fancy” eggs throughout the year, and the eggs with pale colored yolks, so frequently found on the market during the winter months, are the object of much complaint, particularIy in cities. Similarly, in some sections of the country the poultry trade demands a highly colored flesh. For the fancy trade, however, the demand is for a flesh with the least color possible. The yellow pigment characterizing the skin of hens is becoming of considerable importance in judging their egg laying activity. Thus, Woods3 has recently stated that heavy laying invariably produces a marked reduction in the yellow color of the shank, and that, “it is possible to say positively that no bird which has been a high producer will have bright yellow legs at the end of the lay-