in the seeds and in their
coverings, seldom in the perispemium (poppy), and in the fleshy
substance surrounding the seed (olive). The fat in the seed is mostly
enclosed in cells with a proteine compound. In the animal kingdom
certain parts of the body are quite filled with fat-cells, particularly
under the skin (_Paniculus adiposus_), in the cavities of the abdomen,
in the so-called _omentum_, in the kidneys and the tubulated canals of
the bones. Fat is also enclosed in cells (fatty globules) in milk.

It is established, without a doubt, that a greater portion of the fat
which exists in the animal kingdom originates from the vegetable
kingdom, for it is introduced into the body cotemporaneously with the
proteine compounds of that kingdom. A portion of the fat as well as wax
is formed in the animal organismus, as shown by a number of
observations, and in most cases it is unquestionable that the
non-nitrogenous nutriments, as starch, serve for the formation of fat by
a process of deoxidation; nevertheless, the formation of fat in the
animal body appears only to take place when the substances containing
starch enter the body simultaneously with fat.

If the fat existing in the animal body is contained in cellular tissue,
its separation may be simply effected by placing the incised tissue in
hot water. The cells burst and the fat collects itself on the surface of
the water. If vegetable substances contain fat in large quantity, as,
for example, seeds, it may be obtained by expression. The dried seeds
are bruised and expressed between either cold or hot metallic plates.
Olives are laid in heaps before expression; when they begin to ferment,
they can be completely expressed. If animal and vegetable substances
contain only a little fat, it must be extracted by ether.

In the pure condition the fats are mostly odorless and tasteless; when
they possess an odor, it arises mostly from the presence of small
quantities of volatile fatty acids, as butyric acid, capric acid, &c.;
which becomes free through the decomposition of their oxide of glycyl
combinations. This ensues by the presence of water and air through a
kind of fermentation, and as it appears, by the presence of a
nitrogenous substance. The fats are insoluble in water, and, with the
exception of castor oil, are taken up by cold alcohol in very small
quantities, however, more in proportion as they contain oleine. In
boiling alcohol they are dissolved, but are, for the mo