294 ANIMAL LIFE 



stored up as food for the young. Within the shell of a hen's 

 egg is sufficient food to nourish the growing chick, called 

 the embryo, until it is able to run about. If a fresh egg be 

 placed in water and a circular piece of shell removed with 

 the scissors, a white spot a quarter of an inch in diameter 

 lying on the yolk is seen. This is a young chick composed 



PIG. 329. At the left a fresh hen's egg showing the young chick at the center. 

 At the right an English sparrow one day old. Photograph. 



of several hundred cells which have developed during 

 twenty-four hours from the one cell formerly occupying 

 this place. Some birds are in a helpless condition when 

 hatched, and must be fed by the parents several days before 

 they can fly or walk. The eggs of frogs and toads contain- 

 ing but little food material for the young are small, and in 

 growing the whole egg may be seen with the naked eye 

 to divide into two cells within two or three hours after 



