uncombined state in the white of an egg, which is almost wholly composed
of albumen. It exists, combined with other food elements, in many other
foods, both animal and vegetable. It is found abundant in oatmeal, and
to some extent in the other grains, and in the juices of vegetables. All
natural foods contain elements which in many respects resemble
_albumen_, and are so closely allied to it that for convenience they are
usually classified under the general name of "albumen." The chief of
these is _gluten_, which is found in wheat, rye, and barley. _Casein_,
found in peas, beans, and milk, and the _fibrin_ of flesh, are elements
of this class.

_Fats_ are found in both animal and vegetable foods. Of animal fats,
butter and suet are common examples. In vegetable form, fat is abundant
in nuts, peas, beans, in various of the grains, and in a few fruits, as
the olive. As furnished by nature in nuts, legumes, grains, fruits, and
milk, this element is always found in a state of fine subdivision, which
condition is the one best adapted to its digestion. As most commonly
used, in the form of free fats, as butter, lard, etc., it is not only
difficult of digestion itself, but often interferes with the digestion
of the other food elements which are mixed with it. It was doubtless
never intended that fats should be so modified from their natural
condition and separated from other food elements as to be used as a
separate article of food. The same may be said of the other carbonaceous
elements, sugar and starch, neither of which, when used alone, is
capable of sustaining life, although when combined in a proper and
natural manner with other food elements, they perform a most important
part in the nutrition of the body. Most foods contain a percentage of
the _mineral_ elements. Grains and milk furnish these elements in
abundance. The cellulose, or woody tissue, of vegetables, and the bran
of wheat, are examples of _indigestible_ elements, which although they