The thin front edge of the liver reaches just below the bony edge of the
ribs; but the dome-shaped diaphragm rises slightly in a horizontal
position, and the liver passes up and is almost wholly covered by the
ribs. In tight lacing, the liver is often forced downward out from the
cover of the ribs, and thus becomes permanently displaced. As a result,
other organs in the abdomen and pelvis are crowded together, and also
become displaced.

147. Minute Structure of the Liver. When a small piece of the liver
is examined under a microscope it is found to be made up of masses of
many-sided cells, each about 1/1000 of an inch in diameter. Each group of
cells is called a _lobule_. When a single lobule is examined under the
microscope it appears to be of an irregular, circular shape, with its
cells arranged in rows, radiating from the center to the circumference.
Minute, hair-like channels separate the cells one from another, and unite
in one main duct leading from the lobule. It is the lobules which give to
the liver its coarse, granular appearance, when torn across.

[Illustration: Fig. 58.--Diagrammatic Section of a Villus

A, layer of columnar epithelium covering the villus;
B, central lacteal of villus;
C, unstriped muscular fibers;
D, goblet cell
]

Now there is a large vessel called the portal vein that brings to the
liver blood full of nourishing material obtained from the stomach and
intestines. On entering the liver this great vein conducts itself as if it
were an artery. It divides and subdivides into smaller and smaller
branches, until, in the form of the tiniest vessels, called capillaries,
it passes inward among the cells to the very center of the hepatic
lobules.

148. The Bile. We have in the liver, on a grand scale, exactly the
same conditions as obtain in the smaller and simpler glands. The
thin-walled liver cells take from the blood certain materials which they
elaborate into an important digestive fluid, called the bile.[23]
This newly manufactured fluid is carried away in little canals, called
_bile ducts_. These minute ducts gradually unite and form at last one main
duct, which carries the bile from the liver. This is known as the hepatic
duct. It passes out on the under side of the liver, and as it
approaches the intestine, it meets at an acute angle the cystic duct which
proceeds from the gall bladder and forms with it the common bile
duct. The common duct opens obliquely into the horsesh