m which it may be separated in flocks by the
addition of an acid. It has been obtained for chemical examination,
principally from peas and beans, and from the almond and oats. When
prepared from the pea it has been called _legumine,_ from almonds
_emulsine_, and from oats _avenine_; but they are all three identical in
their properties, although formerly believed to be different, and
distinguished by these names. Vegetable caseine is best obtained by
treating peas or beans with hot water, and straining the fluid. On
standing, the starch held in suspension is deposited, and the caseine is
retained in solution in the alkaline fluid; by the addition of an acid
it is precipitated as a thick curd. Caseine is insoluble in water, but
dissolves readily in alkalies; its solution is not coagulated by heat,
but, on evaporation, becomes covered with a thin pellicle, which is
renewed as often as it is removed.

_Animal Caseine_ is the principal constituent of milk, and is obtained
by the cautious addition of an acid to skimmed milk, by which it is
precipitated as a thick white curd. It is also obtained by the use of
rennet, and the process of curding milk is simply the coagulation of its
caseine. It is soluble in alkalies, and precipitated from its solution
by acids, and in all other respects agrees with vegetable caseine.

The composition of animal caseine has been well ascertained, but
considerable doubt still exists as to that of vegetable caseine, owing
to the difficulty of obtaining it absolutely pure. The analyses of
different chemists give rather discordant results, but we have given
those which appear most trustworthy--

From Peas.
Carbon 50.6 50.7
Hydrogen 6.8 6.6
Nitrogen 16.5 15.8
Oxygen 25.6 23.8
Sulphur 0.5 0.8
Phosphorus ... 2.3
----- -----
100.0 100.0

Other results differ considerably from these, and some observers have
even obtained as much as eighteen per cent of nitrogen and fifty-three
of carbon.

The composition of animal caseine differs from this principally in the
amount of carbon. Its composition is--

Carbon 53.6
Hydrogen 7.1
Nitrogen 15.8
Oxygen 22.5
Sulphur 1.0
-----
100.0

The most cursory examination of these analytical numbers is sufficient