It can be readily understood from this brief statement of the nature of the
liver functions, that any functional disorder of the liver may be far
reaching in its effect. In many of the diseases that involve other organs,
the liver may be primarily affected. It is difficult to diagnose functional
disorders of the liver that are responsible for a diseased condition of
some other body organ. A knowledge of the physiology and pathology of the
liver is of the greatest importance in the diagnosis of this class of
disorders.

In the larger domestic animals, symptoms of liver diseases are more obscure
than in the small animals. In certain parasitic diseases and in mixed and
specific infectious diseases, the liver may show marked pathological
changes.

COMMON CAUSES OF LIVER DISORDERS.--Domestic animals commonly live under
very unnatural conditions. Ill results do not follow unless these
conditions are so extreme as to violate practically all of the health laws.
Pampered animals are especially prone to liver disorders. The feeding of
too heavy and too concentrated a ration together with insufficient exercise
is one of the most common causes of disorders of the liver. The feeding of
a ration that is unsuitable for that particular species is a common source
of disease in animals. For example, the feeding to carnivora of a ration
made up largely of starchy feed, and the feeding of a ration containing an
excessive quantity of protein to herbivorous animals may result in
intestinal, liver and nervous disorders. Spoiled feed may prove highly
injurious. Catarrhal inflammation of the intestine and intestinal parasites
may obstruct the bile duct, and interfere seriously with the functions of
the liver.

_Symptoms_.--In diseases of the liver the appetite is irregular or the