382 Dr, Prout’s experiments on the changes which take place 
nal weight of the egg be 1000 grains, weighs, when dried in 
vacuo at 212°, about 2.35 grains ; and on being burnt, yields 
traces of phosphate of lime. 
It may be observed here, that the great differences in the 
quantities of the earthy matter existing in the shells of different 
eggs, have rendered the average totally inapplicable in these 
experiments, as will be shown hereafter ; hence, a more 
detailed analysis of this part of the egg was deemed un- 
necessary. 
Saline contents of the recent egg. 
As my attention at present is chiefly confined to the fixed 
principles of the egg, I shall not here enter on a description 
of its immediate principles, which will be found sufficiently 
detailed in all the modern chemical treatises. The saline 
principles, however, particularly of the yelk, have been less 
minutely examined ; hence, it becomes necessary to relate 
the manner in which the following analyses were conducted ; 
and here it may be premised generally, that all the results were 
obtained by combustion ; and that the following observations 
are to be understood as applicable to the whole of the experi- 
ments subsequently related in this inquiry. 
The albumen burns with difficulty, unless care be taken to 
remove the saline matter by frequent washings ; but if this 
point be attended to, the whole of the carbonaceous matter may 
be burnt off' even in a covered crucible. In the subsequent 
experiments, the saline and earthy matters were removed from 
the crucible after combustion by distilled water ; a little am- 
monia was then added, and the whole permitted to remain at 
rest for twenty-four hours ; the clear solution containing the 
alkaline salts was now carefully poured off, and the insoluble 
residuum, consisting of the phosphate of lime and triple phos- 
