ll Intestines.

A, B, tubular glands seen in vertical section with their orifices at C,
opening upon the membrane between the villi, D, villus (Magnified 40
diameters)]

Attached to the caecum is a worm-shaped tube, about the size of a lead
pencil, and from three to four inches long, called the _vermiform
appendix_. Its use is unknown. This tube is of great surgical importance,
from the fact that it is subject to severe inflammation, often resulting
in an internal abscess, which is always dangerous and may prove fatal.
Inflammation of the appendix is known as _appendicitis_,--a name quite
familiar on account of the many surgical operations performed of late
years for its relief.

The large intestine passes upwards on the right side as the ascending
colon, until the under side of the liver is reached, where it passes
to the left side, as the transverse colon, below the stomach. It
there turns downward, as the descending colon, and making an S-shaped
curve, ends in the rectum. Thus the large intestine encircles, in the
form of a horseshoe, the convoluted mass of small intestines.

Like the small intestine, the large has four coats. The mucous coat,
however, has no folds, or villi, but numerous closely set glands, like
some of those of the small intestine. The longitudinal muscular fibers of
the large intestine are arranged in three bands, or bundles, which, being
shorter than the canal itself, produce a series of bulgings or pouches in
its walls. This sacculation of the large bowel is supposed to be designed
for delaying the onward flow of its contents, thus allowing more time for
the absorption of the liquid material. The blood-vessels and nerves of
this part of the digestive canal are very numerous, and are derived from
the same sources as those of the small intestine.

146. The Liver. The liver is a part of the digestive apparatus,
since it forms the bile, one of the digestive fluids. It is a large
reddish-brown organ, situated just below the diaphragm, and on the right
side. The liver is the largest gland in the body, and weighs from 50 to 60
ounces. It consists of two lobes, the right and the left, the right being
much the larger. The upper, convex surface of the liver is very smooth and
even; but the under surface is irregular, broken by the entrance and exit
of the various vessels which belong to the organ. It is held in its place
by five ligaments, four of which are formed by double folds of the
peritoneum.