570 EXPERIMENT STATIOlSr EECOED. 



shape of eggs and also in respect to tlie weight of albumin and shell than weight 

 of yolk. There is a tendency for the several egg characters to be related to 

 each other in such a way that when the eggs of an individual are large they 

 are both long and broad and each of the parts is large ; but the hens which lay 

 large eggs lay eggs with a smaller proportion of yolk than hens which lay small 

 eggs. Also individuals may show a decided tendency to vary from the flock 

 type in quite different degrees in different characters. 



" The eggs of an individual tend to be either uniform or variable in all the 

 egg characters, but certain individuals may be variable in certain egg characters 

 and uniform in others. An individual is in general less variable than the race 

 in respect to egg characters; but certain individuals may show a variation in 

 an egg character which is relatively as great as the variation in the race. 

 Also certain egg characters (particularly yolk weight) show a decided tendency 

 to approach the race variation in several individuals. The factors which bring 

 about the individuality in respect to egg characters are too complex for 

 analysis from the data at hand." 



With regard to the correlation of egg character it was determined that " each 

 egg character is related to every other egg character, but different pairs of 

 characters show a decidedly different degree of correlation. There is a general 

 tendency for a given pair of characters to be similarly related in the eggs of 

 the several individuals, but different individuals may show significantly differ- 

 ent degrees of correlation in any pair of characters. Length and breadth are 

 significantly but not highly correlated. Both length and breadth are signifi- 

 cantly correlated with the weight of the whole egg and of each of the egg 

 parts. Breadth is as a rule more highly correlated with these weight charac- 

 ters than is length. The shape of the egg as measured by the length-breadth 

 index is negatively correlated with the weight of the egg and with the weight 

 of each of the egg parts. The weight of each part of the egg is positively corre- 

 lated with the weight of both the other parts." 



It was noted that with respect to intraindividual variation " the variation 

 among the eggs of the same bird is shown to be related to certain other changes 

 in the bird. The egg weight and the weight of the egg parts, especially the 

 weight of the yolk, increases as the bird matures. The rate of this gain in 

 weight decreases with the successive months. Each part of the egg shows a 

 seasonal fluctuation in weight which is apparently related to the general sea- 

 sonal fluctuation in the physiological activities of the bird, expressed also in 

 the curves for food consumption and egg production. The state of health also 

 may affect the size of the egg. The size of the egg is related to the rate of 

 production as it expresses itself in the laying of litters. As a rule the first 

 and last eggs of a litter are smaller than the intermediate ones. When eggs 

 are produced on successive days they tend to decrease in weight, while the egg 

 laid on a day after one on which no egg is produced is larger than the last 

 egg of the preceding series." 



A biometrical study of egg production in the domestic fowl. — IV, Factors 

 influencing' the size, shape, and physical constitution of egg's, ISIaynie R. 

 Curtis (Arch. Euticwkl. Mech. Organ., 39 (1914), pt- 2-3, pp. 217-327, figs. IS).— 

 This paper reports in more extended and detailed form the data noted above. 



A bacteriological and chemical study of commercial eggs in the pro- 

 ducing districts of the Central West, Mary E. Pennington et al. (U. S. 

 Dept. Agr. Bui. 51 (1914), pp. 77, pis. 8, figs. 2).— This bulletin deals with the 

 subject of the quality of eggs which go to the egg-breaking establishments of 

 the egg-producing sections of the Central West. 



It has been found that when the egg is laid it is of a fairly constant chemical 

 composition and contains but few bacteria or molds. However, in the process 



