I06 MAINE AGRICULTURAL EXPERIMENT STATION. I914. 



2. The eggs of an individual are more like each other than 

 they are like the eggs of other individuals of the same strain. 



3. In spite of this resemlblance between the eggs of the 

 individual they nevertheless show a certain degree of variation 

 in all their characters. 



4. The first eggs laid by the pullets are smaller than those 

 laid by the same birds later. 



An analysis of the factors underlying this individuality ana 

 variation in the quantitative characters of the <:gg offers a new 

 point of attack in the study of the physiology of egg produc- 

 tion. A statistical study was made of the quantitative charac- 

 ters of all of the eggs laid by twenty-two Barred Plymouth 

 Rock birds during their first two laying years. These birds 

 were all from the Maine Agricultural Experiment Station 

 strain, the purity of which has been amply proven by breeding 

 experiments. ■* 



This paper presents briefly the results of this investigation 

 of the shape and size, both absolute and .relative, and the pro 

 portion of parts of the successive eggs of each of these birds. 

 It includes (a) a study of the individuality of the eggs of each 

 bird and the variation among them; (b) a study of the relation 

 of the individuality of the eggs to other facts known ab)Out the 

 bird, such as body weight, relative size of the several viscera^ 

 organs, age, number of eggs laid, and tendency to broodiness ; 

 (c) the variation in egg characters in relation to the age of the 

 bird, the seasonal reproductive cycles and the intensity of the 

 reproductive activity, including the grouping of the successive 

 eggs into clutches and litters, the size of these groups and the 

 position of the eggs within them. 



The Individuality of the Eggs oe Each Bird in Regard to 



Shape, Size, and Size and Proportion of Parts. 



It was not necessary to resort to mathematical calculation 

 to demonstrate the fact that the eggs of the different individual 

 "birds used in this investigation varied considerably in respect 

 to size and shape. This inter-individual variation was easily 

 seen by comparing the eggs of the different individuals. The 

 eggs of one bird were from one-fourth to one-third larger than 



