^i|^ PHIMAliy ANIMAL FLltlBS. 



Mod convenl- In order (o obtain it in a ftate of purity, I had recourfe to 



ently obtained ^he white of the egpr, a fubftance to which the name of albu- 



from wnitc oi oo' 



egg. ' men was originally applied, and which is ftill confidered by 



the moft eminent chemifts * as compofed entirely of this fub- 



flance. In order to afcertain how far this opinion was correct, 



I kept a quantity of the white of the egg in a temperature of 



212®, until it was firmly coagulated. It was then cut into 



fmall pieces and placed in the upper part of a narrow-necked 



^ funnel, when a few irops of a brownifh vifcid fluid were fe- 



paratcd from it. Other pieces of the fame coagulura were 

 kept for fome time in boiling water, the fluid being then paflTed 

 through a filtre, had acquired a light brownifti colour, and a 

 faint odour; when agitated it was flightiy mucilaginous. By 



"White of egg is flow evaporation, a fmall quantity of a brittle, femi-tranfparent 



not pure albu- f^j^ftance was obiamed. It appeared therefore evident, that 



men ; it contains r 



a little of matter the white of the egg contains a fmall quantity of a fubftance 



not coagulable. incapable of coagulation, and therefore eflentially different 

 from albumen. I ftill, however, continued to employ it for 

 the purpofe of afcertaining the properties of albumen, as it 

 affords this fubflance in a ftate of greater purity than it can be 

 obtained from any other fource. 

 White of egg I*^ was an objedt of fome importance to afcertain the pro« 

 contains 80 parts portion which this foreign ingredient bore to the albumen it- 

 JoHdVibumen ^^'^» *^^ grains of firmly coagulated albumen were kept for 

 and 4,5 unco fome time in boiling water, and this being poured off, a frefli 

 aguiat>le matter, qyj^j^tity was added, and this procefs repeated until the water 

 appeared to contain no farther impregnation. The whole of 

 the fluid was then evaporated, and a reliduum was left which 

 amounted to 4j grains. Befides the admixture of this peculiar 

 fubftance, the white of the egg contains a confiderable quan- 

 tity of water, not only in its liquid ftate, but after it is coagu- 

 lated. By a gentle heat the water may be evaporated, and the 

 folid matter is left behind in the form of a hard, brittle, tranf^ 

 parent fubftance; I have lound that upon an average, | of 

 recently coagulated albumen may be confidered as confifting 

 of water. Hence it will appear, that 100 grains of the white 

 of egg confift of 80 grains water, 4.5 grains of uncoagulable 

 matter, and 15.5 grains only of pure albumen. 





*H«chett, Phil. Tranf. 1800, p. 375. 

 Thomfon's Chemiflry, IV. p. 484. 



The 



