128 MAINE AGRICULTURAL EXPERIMENT STATION. I914. 
The egg then represents not a normal organic part of the 
individual but a discrete unit of production of certain corre- 
lated organs. The size and form of such units are to a cer- 
tain extent dependent upon the size and form of these organs. 
But the size, form and frequency are necessarily also dependent 
upon the physiological tone of the organs and of the entire 
organism. 
It is not strange that the same individual at different 
seasons and different individuals throughout the year may 
show variations in egg size and in the number of eggs produced 
which are out of proportion to the variation in body size. It 
is quite possible that egg production like milk production * is 
related to the amount of food consumed above maintenance. 
That is the bird which lays large eggs and many of them is 
one which in addition to the organic potentiality to lay eggs 
of this size possesses also both the physiological capabilities of 
digesting a large amount of food above the amount required 
for the maintenance of the body and of using this absorbed 
food for the production of yolk, albumen, etc. The fact that 
the same individual lays larger eggs and more of them at cer- 
tain seasons than at others may be due to the fact that she is 
capable of digesting and utilizing for egg production more 
food at those seasons. It has in fact been shown by Rice ** 
that the number of eggs produced by a flock is positively cor- 
related with the amount of food consumed, and the fluctuations 
which he found characteristic for the amount of food consumed 
are very similar to the seasonal fluctuation in egg weight. The 
work of Riddle t on yolk formation also supports this view. 
In general the conditions which favor the production of a 
large number of eggs also favor the production of large eggs 
(i. e., large for the particular individual). Yet there are 
* Eckles, C. H., and Reed, O. E. A Study of the Cause of Wide 
Variation in Milk Production in Dairy Cows. Mo. Agr. Expt. Sta. ’Re- 
search Bui. No. 2, 1910, ipp. 107-147. 
** Rice, J. E. The Moulting of Fowls. Cornell Univ. Exp. Sta. Bui. 
258, 1908, pp. 211-68. 
f Riddle, Oscar. On the Formation Significance and Chemistry of 
White and Yellow Yolk of Ova. Journal of Morphology, Vol. 22, 1911, 
pp. 456-484. 
