THE STORY OF AN EGG. 



W. R. Graham, B.S.A. 



Everyone is familiar with the size and shppe of an egg; but very few 

 of us stop to think how wonderfully it is made. We all know that the 

 contents of the egg- are enclosed in a shell. This shell appears to be 

 hard and solid, but this is not the case. True, it has much strength ; 

 but we find upon examination, that it is full of little holes. These small 

 holes allow the air next to the shell to get into the egg. Thus it will be 

 seen that we should keep the egg in a clean place, away from dirty straw, 

 such as we often see in the nest ; also away from strong-smelling sub- 

 stances, such as onions ; otherwise, these strong odors, passing through 

 the shell, will affect the taste of the egg more or less. 



Next to the shell is a 

 thin tissue. This tissue 

 is made of two layers all 

 over the egg, except at the 

 larg-e end, where they 

 separate, forming a small 

 open space, called the air- 

 space. This air-space 

 increases in size as the 

 ^§'8' evaporates or dries. 

 The longer the egg is 

 allowed to remain in the 

 air, the more air will pass 

 through the shell; and each 

 little particle of air carries 

 away with it some of the 

 moisture of the egg, and 

 thus the contents dr}' up 

 and the air-space increases 

 in size. Sometimes eggs 

 that have been left exposed 

 to the air in a nice clean 



Fiaf. 86. Diasrauimatie seotion of an unincubated fowl's egg : 

 III y:eriii-sp()t ; ici/, white yolk, consisting: of a central flask-shaped 

 mass, and a number of layers concentrically arranged around it, 

 the outer layer of white yolk lying: immediately beneath the 

 vitelline membrane, and connected with the central mass beneath 

 the blastoderm ; (/.'/. yellow yolk ; i\ vitelline membrane ; /', layer 

 of more fluid albumen surrounding' the yolk ; (•/(, chalaze ; a, air 

 chamber between the two layers of the shell membrane ; in, shell 

 membranes, where they lie in contact over the t;reater portion of 

 the egg ; .y, shell : </, denser albumen, which extends around the 

 place for a year, are found yolk, outside of the internal layer of more fluid albumen ; c, 

 r , ' i-,,i j_ ^ boimdarv between the outer and middle iiortion of the albumen. 



to have very little content ; 



and that which is left is dry and almost hard. These tissues may be pulled 



off the shell, especially in the case of a hard boiled egg. 



Now we come to the white of the eggs, or what is called the 



albumen. This is said by doctors to be a very good food ; but we are 



particularly interested in its appearance. So let us break an egg in a 



saucer. Notice that the white on the outside is thin and watery ; in a 



iltle farther, we see a grey or whitish streak that extends all the way 



around the yolk, or yellow portion, but does not touch it. You will 



also notice that at each end of the yolk and extending from this whitish 



portion is a knotted portion, like a little piece of white string. We 



wonder what these are lor, and observe that they are simply an extended 



