inctly, the ear applied against the chest will detect a to-and-fro
friction sound, corresponding to the beats of the heart. This sound is
produced by the rubbing of the internal surface of the heart bag against
the external surface of the heart. During the first stages of the
inflammation these surfaces are dry, and the rubbing of one against the
other during the contraction and relaxation of the heart produces this
sound. The dry stage is followed by the exudation of fluid into the heart
sac, and the friction is not heard until the fluid is absorbed sufficiently
to allow the surfaces to come in contact again. But during the time the
friction sound is lost a sound which has been called a "churning noise" may
take its place.

The friction sound of pericarditis can not be mistaken for the friction
sound of pleurisy if the examination is a careful one, because in the heart
affection the sound is made in connection with the heart beats, while in
the pleuritic affection the sound is synchronous with each respiration or
breath of air taken in and expelled from the lungs.

_Treatment._--When pericarditis is complicated with rheumatism or other
diseases the latter must be treated as directed in the description of them.
The animal must be kept in a quiet, comfortable place, where it will be
free from excitement. Warm clothing should be applied to the body, and the
legs should be hand-rubbed until the circulation in them is reestablished,
and then they should be snugly bandaged. The food should be nutritive and
in moderate quantity. Bleeding should not be performed unless the case is
in the hands of an expert.

At the beginning give as a purgative Epsom salt--1 pound to an
average-sized cow--dissolved in about a quart of warm water and
administered as a drench. When there is much pain 2 ounces of laudanum,
diluted with a pint of water, may be given every three hours until the
animal is better. Do not give the laudanum unless demanded by the severity
of the pain, as it tends to constipate. Give one-half ounce of nitrate of
potassium (saltpeter), dissolved in drinking water, four or five times a
day. After the attack has abated mustard mixed with water may be rubbed
well over the left side of the chest to stimulate the absorption of the
fluid within the pericardium. The other medicines may be discontinued and
the following administered: Sulphate of iron, 2 ounces; powdered gentian,
6 ounces; mix and make 8 powders. Give one powder