450 LIQUID PARTS OF ANIMALS. 



1-090. When kept, eggs rapidly lose weight and become spe- 

 cifically lighter than water. This is owing to the diminution of 

 bulk in the contents of the egg ; the consequence of which is that 

 a portion of the inside of the egg comes to be filled with air. Dr 

 Prout kept an egg two years, and found that it lost weight daily 

 at the average rate of 0-744 grains. The original weight was 

 907*5 grains, and after two years exposure to the atmosphere it 

 weighed only 363-2 grains. The total loss amounted to 544-3 

 grains, or considerably more than half the original weight. The 

 loss in summer was somewhat greater than in winter, owing, no 

 doubt, to the difference of temperature. Had the original weight 

 of the egg been 1000, then after two years exposure to the at- 

 mosphere it would be reduced to 400. 



The relative weights of the shell and lining membrane, albu- 

 men, and yolk are very different. Supposing the original weight 

 of the egg to have been 1000, Dr Prout found the relative pro- 

 portions in ten different eggs as follows : 



Yolk. 



106-9 604*2 288-9 average. 



When an egg is boiled in water it loses weight, particularly 

 if it be removed from the water when boiling, and be permitted 

 to cool in the open air. The water will be found to contain a 

 portion of the saline constituents of the egg. The loss of weight 

 from boiling is not constant, varying from twenty to thirty grains, 

 supposing the original weight of the egg to have been 1000 grains. 

 The quantity of saline matter obtained by evaporating the dis- 

 tilled water in which an egg was boiled, amounts at an average 

 to 0'32 grains. It is strongly alkaline, and yields traces of ani- 



