210 THE LIFE OF A BIRD. 



specific gravity of the white and yolk is thereby 

 increased. An egg is continually losing weight 

 after it is laid. An egg which weighed on a cer- 

 tain day in May, 907 grains, two years afterwards 

 on the same day only weighed 363 grains, having 

 lost in that time by evaporation 544 grains. 

 When this egg was broken, its whole contents 

 were found collected at the small end in a solid 

 state, and on being put into water they absorbed 

 a large portion of that fluid, and assumed an 

 appearance not much unlike that of a fresh egg. 

 The most curious fact, however, was that the egg 

 was still fresh. When an egg is boiled in water 

 it always loses weight, particularly if it be re- 

 moved from the water while boiling, and cooled 

 in the open air. The water in which it has been 

 boiled will be found to contain a portion of the 

 saline contents of the egg. The loss of weight 

 from boiling varies, according to Dr. Prout, from 

 20 to 30 grains, supposing the original weight of 

 the egg to have been 1,000 grains. This loss, 

 however, is not due to the amount of saline matter 

 dissolved by the water, which is very trifling. 



A very interesting though little understood 

 part of our present subject is that which refers to 



