92 MAINE AGRICULTURAL EXPERIMENT STATION. I9OI. 



PREPARATION OE EGGS EOR ANALYSIS. 



The analyses were made in the usual way by the official 

 methods. The samples were prepared for analysis as follows : 



The eggs as received were weighed individually and then 

 "hard-boiled." Upon cooling each egg was weighed. The 

 shells, whites, and yolks of each egg were carefully separated 

 and weighed. The shells were then rejected. The whites as 

 well as yolks were chopped with a chopping knife and tray till 

 the pieces were about the size of kernels of wheat. The samples 

 were then weighed and partially dried at a temperature of 45 C. 

 After partially drying the samples were weighed and ground in 

 a mortar. No attempt was made .to determine the lecithins 

 which were largely included in the fats. 



The detailed weights and the results of the analyses are given 

 in the preceding tables. 



There is a great similarity in the proportion of shell, white 

 and yolk in the eggs of the different domesticated fowl. 

 Roughly speaking, the shell makes up about one-ninth, the yolk 

 one-third, and the white about five-ninths of the whole eggs. 

 The white of the egg is nearly seven-eighths water. The solids 

 of the white are practically all nitrogenous matters and are some- 

 times said to be pure albumen. The Connecticut State Experi- 

 ment Station has made an extended investigation of the white 

 of hens' eggs and finds that it consists of four different though 

 quite closely allied albuminoids. The usual factor for protein 

 (nitrogen multiplied by 6.25) is apparently too small, and the 

 protein "by difference" is probably the more accurate. It will be 

 noted that the white of the different kinds of eggs are practically 

 alike in composition and fuel values. 



While the yolks of different kinds of eggs differ rather more 

 in composition than the whites they are still remarkably alike. 

 The yolk is rather less than half water. The solids are more 

 than three-fifths soluble in ether. This ether extract consists of 

 the ordinary fats (palmitin, stearin, and olein) and a small 

 amount of other materials. The yolk is very complex in com- 

 position and the classes of. nutrients are only approximately? 

 separated in the usual food analysis. It will be noted the pro- 

 tein "by difference" and "by factor" are practically the same and 

 that the fuel value. varies with the fat content from 1,800 calo- 



