It is a substance of very complicated composition, and chemists are not
agreed as to the formula by which its constitution is to be expressed, a
difficulty which occurs also with most of the other nitrogenous
compounds. The results of the analyses of albumen from different sources
are however quite identical, as may be seen from those subjoined--

From From From From
Wheat. Potatoes. Blood. White of Egg.
Carbon 53.7 53.1 53.4 53.0
Hydrogen 7.1 7.2 7.0 7.1
Nitrogen 15.6 ... 15.5 15.6
Oxygen } { ... 22.1 22.9
Sulphur } 23.6 { 0.97 1.6 1.1
Phosphorus } { ... 0.4 0.3
----- ----- -----
100.0 100.0 100.0

Closely allied to vegetable albumen is the substance known by the name
of _glutin_, which is obtained by boiling the gluten of wheat with
alcohol. It appears to be a sort of coagulated albumen, with which its
composition completely agrees.

_Vegetable Fibrine._--If a quantity of wheat flour be tied up in a piece
of cloth, and kneaded for some time under water, the starch it contains
is gradually washed out, and there remains a quantity of a glutinous
substance called gluten. When this is boiled with alcohol, the _glutin_
above referred to is extracted, and vegetable fibrine is left. It
dissolves in dilute potash, and on the addition of acetic acid is
deposited in a pure state. Treated with hydrochloric acid, diluted with
ten times its weight of water, it swells up into a jelly-like mass.
When boiled or preserved for a long time under water, it cannot be
distinguished from coagulated albumen.

_Animal Fibrine_ exists in the blood and the muscles, and agrees in all
its characters and composition with vegetable fibrine, as is shown by
the subjoined analyses--

Wheat Flour. Blood. Flesh.
Carbon 53.1 52.5 53.3
Hydrogen 7.0 6.9 7.1
Nitrogen 15.6 15.5 15.3
Oxygen 23.2 24.0 23.1
Sulphur 1.1 1.1 1.2
----- ----- -----
100.0 100.0 100.0

_Caseine._--Vegetable caseine exists abundantly in most plants,
especially in the seeds, and remains in the juice after albumen has been
precipitated by heat, fro