CHAPTER XXVI 

 EGGS AND INCUBATION 



The egg is an object of much interest, for not only is it 

 the source of the chicken itself, but it is also a most important 

 source of income to the poultryman. If one is to handle the 

 egg intelligently, he must know something of its composition, 

 of how the chick is developed within the shell, and of com- 

 mercial differences and values. 



The parts of the egg of special interest are five. These 

 are the following: 



a. The shell, composed mostly of lime, and hard enough 

 to enclose and protect the softer interior. 



b. Two tough membranes lying next within the shell. 

 These separate at the large end, forming a small air sac, 

 which is easily seen in hard-boiled eggs. 



c. The albumen, or as it is commonly called, the white of 

 the egg. This forms about 57 per cent of the egg and con- 

 sists of much nitrogenous matter of a liquid, sticky, trans- 

 parent character. Boiling hardens or coagulates the white 

 into a firm, white structure. 



d. The yolk, comprising about 33 per cent of the egg, is 

 a round yellow sac, surrounded by the white. This is used 

 for nourishing the young chick just before and after leaving 

 the shell. The yolk is suspended midway in the white and 

 kept in proper position by two albuminous cords. 



e. The germ, in the fresh-laid egg is seen as a white speck 

 about one-eighth of an inch in diameter on the upper side 

 of the yolk. The germ is the true egg and source of the chick 

 in incubation. 



