left. The liver has two coats, the _serous_, which is a complete
investment, with the exception of the diaphragmatic border, and the
depression for the gall-bladder, and which helps to suspend and retain
the organ in position; and the _fibrous_, which is the inner coat of the
liver, and forms sheaths for the blood-vessels and excretory ducts. The
liver is abundantly supplied with arteries, veins, nerves, and
lymphatics. Unlike the other glands of the human body, it receives two
kinds of blood; the arterial for its nourishment, and the venous, from
which it secretes the bile. In the lower surface of the liver is lodged
the gall-bladder, a membranous sac, or reservoir, for the bile. This
fluid is not absolutely necessary to the digestion of food, since this
process is effected by other secretions, nor does bile exert any special
action upon, starchy or oleaginous substances, when mixed with them at a
temperature of 100° F. Experiments also show that in some animals there
is a constant flow of bile, even when no food has been taken, and there
is consequently no digestion to be performed. Since the bile is formed
from the venous blood, and taken from the waste and disintegration of
animal tissue, it would appear that it is chiefly an excrementitious
fluid. It does not seem to have accomplished its function when
discharged from the liver and poured into the intestine, for there it
undergoes various alterations previous to re-absorption, produced by its
contact with the intestinal juices. Thus the bile, after being
transformed in the intestines, re-enters the blood under a new form, and
is carried to some other part of the system to perform its mission.

The _Spleen_ is oval, smooth, convex on its external, and irregularly
concave on its internal, surface. It is situated on the left side, in
contact with the diaphragm and stomach. It is of a dark red color,
slightly tinged with blue at its edges. Some physiologists affirm that
no organ receives a greater quantity of blood, according to its size,