all oils,
while it would appear that the drying and non-drying oils actually
contain substances of different composition. The acid extracted from
olive oil appears to have the formula C_{36}H_{34}O_{4}, while that from
linseed oil is C_{46}H_{38}O_{6}, but this is still doubtful.

Other fatty acids have been detected in palm oil, cocoa-nut oil, &c.
&c., which so closely resemble margaric and stearic acids as to be
easily confounded with them. Though presenting many points of interest,
it is unnecessary to describe them in detail here.

_Wax_ is a substance closely allied to the oils. It consists of two
substances, cerine and myricine, which are separated from one another by
boiling alcohol, in which the former is more soluble. They are extremely
complex in composition, the former consisting principally of an acid
similar to the fatty acids, called cerotic acid, and containing
C_{54}H_{54}O_{4}. The latter has the formula C_{92}H_{92}O_{4}. The wax
found in the leaves of the lilac and other plants appears to consist of
myricine, while that extracted from the sugar-cane is said to be
different, and to have the formula C_{48}H_{50}O_{2}. It is probable
that other plants contain different sorts of wax, but their
investigation is still so incomplete, that nothing definite can be said
regarding them. Wax and fats appear to be produced in the plant from
starch and sugar; at least it is unquestionable that the bee is capable
of producing the former from sugar, and we shall afterwards see that a
similar change is most probably produced in the plant. The fatty matters
contained in animals are identical with those of plants.

_3d. Nitrogenous or Albuminous Constituents of Plants and Animals._--The
nitrogenous constituents of plants and animals are so closely allied,
both in properties and composition, that they may be most advantageously
considered together.

_Albumen._--Vegetable albumen is found dissolved in the juices of most
plants, and is abundant in that of the potato, the turnip, and wheat. In
these juices it exists in a soluble state, but when its solution is
heated to about 150 deg., it coagulates into a flocky insoluble substance.
It is also thrown down by acids and alcohol. Coagulated albumen is
soluble in alkalies and in nitric acid. Animal albumen exists in the
white of eggs, the serum of blood, and the juice of flesh; and from all
these sources is scarcely distinguishable in its properties from
vegetable albumen.