jji the fixed principles of the egg during incubation. 381 
the supposition, that the original weights of the eggs em- 
ployed were 1000 grains. On the same supposition, also, it 
has been found, that the quantity of saline matter obtained by 
evaporating to dryness the distilled water in which an egg 
has been boiled, amounts, at an average, to about .32 grain. 
This saline residuum is strongly alkaline, and yields traces of 
animal matter, sulphuric acid, phosphoric acid, chlorine, an 
alkali, lime and magnesia, and carbonates of lime and mag- 
nesia ; in short, of almost every principle existing in the egg. 
The carbonate of lime, however, is generally most abundant, 
and is obtained by evaporation in the form of a fine powder. 
The shells of eggs have been analyzed by Vauquelin* and 
Merat Guillot but these chemists seem to have over-rated 
the quantity of animal matter, and of phosphate of lime con- 
tained in them. When shells which had been dried in vacuo 
at 212 0 , were dissolved in dilute muriatic acid, the quantity of 
animal matter obtained was only about 2 per cent, while 
the quantity of phosphates of lime and of magnesia never 
amounted to quite 1 per cent. ; the rest was carbonate of lime 
mixed with a little carbonate of magnesia. When burnt, egg- 
shells, as Vauquelin has observed, yield traces of sulphur 
and iron. 
The membrana putaminis, on the supposition that the origi- 
* Annales de Chimie, tom. 29 et 8 1 . 
f Ibid. tom. 34. It is probable that the different results obtained by these 
chemists depended, in a great degree, on the different mode in which the experi- 
ments were made. The phosphate of lime present in egg-shells is apparently con- 
nected with the animal matter, and when the latter is destroyed by combustion, 
the whole quantity present will of course be obtained. The quantity of animal 
matter present also, being in this mode of analysis necessarily estimated from the 
loss of weight occurring during the process, must appear greater than it ought to 
do, because part of this loss will obviously depend on the escape of water. 
