GRAVITY OF THE EGG. 73 



CHAPTER V. 



The Egg. Its Composition. Anatomy. Monstrous Deviations 

 in Form, Size, and Weight Pistinction of the future Germe. 

 Quantity. Season of Laying. Uses and Value of Eggs. 

 Mode of Preservation. Unimpregnated Eggs best for that 

 Purpose. 



THE specific gravity of a new-laid egg at 

 first rather exceeds that of water, or, in oth- 

 er words, sinks in water ; but, by the evap- 

 oration from it through the shell, it soon be- 

 comes lighter. The mean weight of a hen's 

 egg is 875 grains ; of which, 



The shell and inner membrane weigh 93.7 



The white 529.8 



The yolk - 251.5 



The shell and the membrane are composed 

 almost entirely of lime, with a little magne- 

 sia and animal matter. More accurately, 

 it is composed, in a hundred parts f 



Of carbonate of lime .... 89.0 



" of magnesia - - - 00.6 



Phosphate of lime - - - - 4.8 



" of magnesia - - - - 0.9 



Animal matter 4.7 



