LOCATION OF THE LIFE GERM 397 



lay because there is not sufficient fat to develop the yolk. There- 

 fore, it will be found that the best layers are neither too thin nor 

 over-fat; rather those which are active and in good spirits from 

 dawn to dark. 



Germ. — ^Although invisible to the naked eye, the yolk is 



(Courtesy U. S. Dep't Agriculture) 

 Fig. 259. — Yellow yolk of fresh egg. Magnified 250 times. 



covered by a delicate membrane, called the vitelline membrane, 

 so named, perhaps, because clinging to this membrane is found 

 the life germ, the really vital part of the egg. The contents of 

 the yolk is called the vitellus, upon which the life germ draws 

 for its sustejnance. When a hen's vitality becomes weakened it 

 is generally manifested in the composition of the vitelline mem- 



