Special Report on Diseases of the Horse | Page 5

the skin is likely to be increased.
Sometimes, however, as a result of poor circulation and irregular
distribution of the blood, the body may be warmer than normal, while
the extremities (the legs and ears) may be cold. Where the general
surface of the body becomes cold it is evident that the small blood
vessels in the skin have contracted and are keeping the blood away, as
during a chill, or that the heart is weak and is unable to pump the blood
to the surface, and that the animal is on the verge of collapse.
The skin is moist, to a certain degree, at all times in a healthy horse.
This moisture is not in the form of a perceptible sweat, but it is enough
to keep the skin pliable and to cause the hair to have a soft, healthy feel.
In some chronic diseased conditions and in fever, the skin becomes dry.
In this case the hair has a harsh feel that is quite different from the

condition observed in health, and from the fact of its being so dry the
individual hairs do not adhere to one another, they stand apart, and the
animal has what is known as "a staring coat." When, during a fever,
sweating occurs, it is usually an indication that the crisis is passed.
Sometimes sweating is an indication of pain. A horse with tetanus or
azoturia sweats profusely. Horses sweat freely when there is a serious
impediment to respiration; they sweat under excitement, and, of course,
from the well-known physiological causes of heat and work. Local
sweating, or sweating of a restricted area of the body, denotes some
kind of nerve interference.
Swellings of the skin usually come from wounds or other external
causes and have no special connection with the diagnosis of internal
diseases. There are, however, a number of conditions in which the
swelling of the skin is a symptom of a derangement of some other part
of the body. For example, there is the well-known "stocking," or
swelling of the legs about the fetlock joints, in influenza. There is the
soft swelling of the hind legs that occurs so often in draft horses when
standing still and that comes from previous inflammation (lymphangitis)
or from insufficient heart power. Dropsy, or edema of the skin, may
occur beneath the chest or abdomen from heart insufficiency or from
chronic collection of fluid in the chest or abdomen (hydrothorax,
ascites, or anemia). In anasarca or purpura hemorrhagica large soft
swellings appear on any part of the skin, but usually on the legs, side of
the body, and about the head.
Gas collects under the skin in some instances. This comes from a local
inoculation with an organism which produces a fermentation beneath
the skin and causes the liberation of gas which inflates the skin, or the
gas may be air that enters through a wound penetrating some
air-containing organ, as the lungs. The condition here described is
known as emphysema. Emphysema may follow the fracture of a rib
when the end of a bone is forced inward and caused to penetrate the
lung, or it may occur when, as a result of an ulcerating process, an
organ containing air is perforated. This accident is more common in
cattle than it is in horses. Emphysema is recognized by the fact that the
swelling that it causes is not hot or sensitive on pressure. It emits a

peculiar crackling sound when it is stroked or pressed upon.
Wounds of the skin may be of importance in the diagnosis of internal
disease. Wounds over the bony prominence, as the point of the hip, the
point of the shoulder, and the greatest convexity of the ribs, occur when
a horse is unable to stand for a long time and, through continually lying
upon his side, has shut off the circulation to the portion of the skin that
covers parts of the body that carry the greatest weight, and in this way
has caused them to mortify. Little, round, soft, doughlike swellings
occur on the skin and may be scattered freely over the surface of the
body when the horse is afflicted with urticaria. Similar eruptions, but
distributed less generally, about the size of a silver dollar, may occur as
a symptom of dourine, or colt distemper. Hard lumps, from which
radiate welt-like swellings of the lymphatics, occur in glanders, and
blisterlike eruptions occur around the mouth and pasterns in horsepox.
THE ORGANS OF CIRCULATION.
The first item in this portion of the examination consists in taking the
pulse. The pulse may be counted and its character may be determined at
any point where a large artery occupies a situation close to the skin and
above a hard tissue, such as a bone, cartilage, or tendon. The most
convenient