pink color, excepting on
the back of the tongue, where the color is a yellowish gray. As
abnormalities of this region, the chief are diffuse inflammation,
characterized by redness and catarrhal discharge; local inflammation, as
from eruptions, ulcers, or wounds; necrosis of the lower jawbone in
front of the first back tooth; and swellings. Foreign bodies are
sometimes found embedded in the mucous membrane lining of the mouth or
lodged between the teeth.

The examination of the pharynx and of the esophagus is made chiefly by
pressing upon the skin covering these organs in the region of the throat
and along the left side of the neck in the jugular gutter. Sometimes,
when a more careful examination is necessary, an esophageal tube or
probang is passed through the nose or mouth down the esophagus to the
stomach.

Vomiting is an act consisting in the expulsion of all or part of the
contents of the stomach through the mouth or nose. This act is more
difficult for the horse than for most of the other domestic animals,
because the stomach of the horse is small and does not lie on the floor
of the abdominal cavity, so that the abdominal walls in contracting do
not bring pressure to bear upon it so directly and forcibly, as is the
case in many other animals. Beside this, there is a loose fold of mucous
membrane at the point where the esophagus enters the stomach, and this
forms a sort of valve which does not interfere with the passage of food
into the stomach, but does interfere with the exit of food through the
esophageal opening. Still, vomiting is a symptom that is occasionally
seen in the horse. It occurs when the stomach is very much distended
with food or with gas. Distention stretches the mucous membrane and
eradicates the valvular fold referred to, and also makes it possible for
more pressure to be exerted upon the stomach through the contraction of
the abdominal muscles. Since the distention to permit vomiting must be
extreme, it not infrequently happens that it leads to rupture of the
stomach walls. This has caused the impression in the minds of some that
vomiting can not occur in the horse without rupture of the stomach, but
this is incorrect, since many horses vomit and afterwards become
entirely sound. After rupture of the stomach has occurred vomiting is
impossible.

In examination of the abdomen one should remember that its size depends
largely upon the breed, sex, and conformation of the animal, and also
upon