222 ON THE VARIETIES OF VEGETABLE FOOD. 
in water, but coagulable by tbe heat of boiling water, it is called 
albumen, as, for instance, the white of an egg. When soluble 
in water, not coagulated by heat, but separable on the addition 
of an acid, it is called casein ; as, for example, the cheesy mat¬ 
ter of milk, separable as curds on the addition of rennet. These 
several varieties exist in many vegetables. If turnips or man- 
gold-wurtzel be subject to pressure, the albumen and casein will 
be found in the j .ice, and the fibrine or gluten will lemain in 
the solid mass along with the more nitrogenous portions of the 
turnip. If the strained juice be boiled, the albumen will coa¬ 
gulate and float on the top. On removing the albumen, the 
casein will be liberated on the addition of any acid. The fol¬ 
lowing table will shew how nearly these substances agree in 
composition. The first (the gluten) shews less nitrogen than 
the others ; but it is always difficult to wash away the whole of 
the starch, and no doubt the sample was not pure :— 
Gluten 
Casein 
Albumen 
from Flour. 
from 
from 
Ox-blood. 
Ox-flesh. 
Bonssin- 
gault. 
Peas. 
Scherer. 
Eggs. 
Jones. 
Playfair. 
Playfair. 
Carbon 
54.2 
54.138 
55.000 
54.35 
54.12 
Hydrogen . 
7.5 
7.156 
7.073 
7.50 
7.89 
Nitrogen 
13.9 
15 672 
15.920 
15.76 
15 67 
Oxygen . 
24.4 
23.034 
22.007 
22.39 
22.32 
100.0 
100.000 
100.000 
100.00 
100.00 
The variations in the decimals are not greater than those 
which we always find in analyzing the same substance half-a- 
dozen times. Now, gentlemen, we have got hold of a very 
wonderful fact; namely, that the flesh of animals is prepared by 
vegetables; that instead of animals preparing flesh for them¬ 
selves, flesh is absolutely prepared for them. This portion of 
vegetable food is taken into the system ; it is there dissolved; 
the body merely changes its mechanical form and condition, its 
chemical composition remaining the same. It is wonderful to 
think that it should be thus operated upon by the principle of 
vitality; that it should be resolved, by the action of the vital 
principle, into the various forms of nails, hair, flesh, skin, and so 
on. But, gentlemen, if you examine this question carefully, 
you will find that such is absolutely the fact in another case, 
which is very familiar to you all. Let us take a common egg. 
In this you have a little oily matter, and the rest is made up 
chiefly of albumen. You subject the albuminous matter to a 
certain temperature lor about three weeks, and what then be- 
