584 
PHYSIOLOGY: L, S. PALMER 
from these eggs. The young chicks appeared normal in every way 
except for the complete absence of yellow pigmentation from the 
shanks, beaks, and other skin parts. 
The newly hatched chicks were immediately placed on a carotinoid- 
free ration and were cared for as nearly as possible in the same manner 
as the young chicks of the preceding generation. By the end of three 
months, however, all had died. Although it is probable that this 
unfortunate result may be explained on the ground that the chicks were 
hatched very late in the season and therefore had to combat a period 
of extreme heat, as well as a very restricted diet during the most pre- 
carious period of their growth, nevertheless the question remains open 
as to whether it is possible to continue the carotinoid-free condition 
into more than one generation. 
Physiological relation of pigmentation to egg laying. — Practical poultry 
men have recognized for several years that a relation exists between 
the amount of yellow pigment visible in the shanks, ear lobes, beak 
and vent of hens of the Leghorn, Plymouth Rock, Wyandotte and 
Rhode Island Red breeds and their previous egg laying activity. Ex- 
tensive biometric analyses have been made by Blakeslee and Warner^ 
and by these authors with Harris and Kirkpatrick^ of data collected 
at the Storrs Agricultural Experiment Station egg laying competitions 
in order to establish the character of this relation. The results show a 
positive correlation between pale colored shanks, ear lobes, beak, etc., 
and a recent more or less heavy egg production. 
The hypothesis which has been adopted by these investigators to 
explain the physiological relationship which has been observed between 
fecundity and pigmentation is that the growth of the egg abstracts the 
pigment from the body tissues. The idea that the relationship could 
be explained also on the basis that the egg yolk abstracts fat-soluble 
pigment from the food, thus precluding its locaKzation in the body 
tissues, was advanced by Harris, Blakeslee and Warner^ in an earlier 
paper, but was apparently abandoned. The high percentage of fat in 
the blood of laying hens, as compared with non-laying hens, as shown 
by Warner and Edmonds,^^ and by Riddle and Harris,^^ is believed by 
the former authors to support the hypothesis that the tissue fat is being 
transferred to the egg yolk during laying with a consequent subtraction 
of pigment. 
The success attained in raising a flock of White Leghorn fowls entirely 
lacking in pigmentation in both adipose tissue and visible skin parts 
presented the opportunity for ascertaining the true physiological relation 
