aaa mn aaa Te Serer 
‘ —_ 
a, eT 
Bee eee se ae 
Composition of Eggs. Al 
When endeavoring to follow in another paper certain of the modi- 
fications which are produced in the egg during incubation, we 
shall then return to the peculiarities which relate to the constitu- 
tion of albumen, and we shall examine, while supported by the 
labors of M. Chevreul, whether soluble albumen is to be taken as 
a pure proximate principle or not. 
The yellow of a bird’s egg is formed of a viscous liquid, holding 
suspended in it a fatty phosphuretted matter which shows some 
analogy to the cerebral fat. The viscidity of this liquid is due 
to the presence of an albuminous substance which has been care- 
fully studied by Dumas and Cahours, and which chemists call 
vitellin. Vitellin is always found in the yellow of a bird’s egg, 
associated with a certain quantity of albumen. The presence of 
albumen in the yolk of birds led us to modify the process which 
up to this time has been used in preparing vitellin. This mate- 
tial was obtained by drying with ether the yolk of a hen’s. egg 
previously cooked. To prepare vitellin, we treat the yolk of a 
water, while the vitellin is precipitated. The latter, washed 
with water, alcohol and ether, is nearly pure vitellin. While 
this substance thus obtained shows all the characteristics which 
catises the precipitation of the vitellin; this solidification is first 
observed on the surfaces of the liquid which are in contact with 
the air. While examining the properties of the albuminous 
body which characterises the yolk of bird’s eggs, and which has 
received the name of vitellin, we must first point out the resem- 
blance between it and fibrine. ‘The elementary analyses of these 
two substances give the following results: 
Fibrin. ‘ Vitellin. ‘i, 
Carbon, - ‘ i i - 525 \ 52-26 51°60 
Hydro; “i a x - 70 724 3 
Oo gi f : 3 - 165 1508 1502 
Oxygen and Sulphur, f § 240 25:42 26:16 
1000 10000 100-00 
Vitellin and fibrin may be said to have the same composition ; 
t with two bodies of this kind, uncrystalline, insoluble in water, 
and which consequently are purified with difficulty, what chemist 
can answer, in an organic analysis, for the one-hundredth part of 
azote? As to the chemical properties of these two bodies, it 
Szcoxp Series, Vol, XIX, No. 55,—Jan,, 1855. 6° 
