h the
advantage gained by avoiding frequent repetitions in the details of
symptoms, treatment, etc., are our reasons for treating under a single
head the ailments we have grouped together in the present section.

_Cause._--The great, comprehensive, common cause of, sometimes
permanent, sometimes only transient, disability of the horse is external
traumatism.

Blows, bruises, hurts by nearly every known form of violence, falls,
kicks, lacerations, punctures--we may add compulsory speed in racing and
cruel overloading of draft animals--cover the entire ground of causation
of the diseases and injuries of the joints now receiving our
consideration.

In one case, a working horse making a misstep stumbles, and falling on
his knees receives a hurt, variously severe, from a mere abrasion of the
skin to a laceration, a division of the tegument, a slough,
mortification, and the escape of the synovial fluid, with or without
exposure of the bones and their articular cartilages.

In another case, an animal, from one cause or another, perhaps an
impatient temper, has formed the habit of striking or pawing his manger
with his fore feet until inflammation of the knee joint is induced,
first as a little swelling, diffused, painless; then as a periostitis of
the bones of the knee; later as bony deposits, then lameness, and
finally the implication of the joint, with all the various sequelae of
chronic inflammation of the knee joint.

In another case, a horse has received a blow with a fork from a careless
hostler on or near a joint, or has been kicked by a stable companion,
with the result of a punctured wound, at first mild-looking, painless,
apparently without inflammation, and not yet causing lameness, but
which, in a few hours, or it may be only after a few days, becomes
excessively painful, grows worse, the entire joint swells, presently
discharges, and at last a case of suppurative synovitis is presented,
with perhaps disease of the joint proper, and arthritis as a climax. The
symptoms of articular injuries vary not only in the degrees of the hurt
but in the nature of the lesion.

Or the condition of broken knees, resulting as we have said, may have
for its starting point a mere abrasion of the skin--a scratch,
apparently, which disappears without a scar. The injury may, however,
have been more severe, the blow heavier, the fall aggravated by
occurring upon an irregular surface, or sharp or rough object, with
tearing or cutt