Part 26 (2/2)

ANEMIA OF THE BRAIN.

This is a physiological condition in sleep. It is considered a disease or may give rise to disease when the circulation and blood supply of the brain are interfered with. In some diseases of the heart the brain becomes anemic, and fainting fits occur, with temporary loss of consciousness. Tumors growing within the cranium may press upon one or more arteries and stop the supply of blood to certain parts of the brain, thus inducing anemia, ultimately atrophy, softening, or suppuration. Probably the most frequent cause is found in plugging, or occlusion, of the arteries by a blood clot.

_Symptoms._--Imperfect vision, constantly dilated pupils, frequently a feeble and staggering gait, and occasionally cramps, convulsions, or epileptic fits occur.

_Pathology._--The exact opposite of cerebral hyperemia. The blood vessels are found empty, the membranes blanched, and the brain substance softened.

_Treatment._--Removal of the remote cause when possible. General tonics, nutritious feed, rest, and removal from all causes of nervous excitement.

HYDROCEPHALUS, OR DROPSY OF THE BRAIN.

This condition consists in an unnatural collection of fluid about or in the brain. Depending upon the location of the fluid, we speak of external and internal hydrocephalus.

External hydrocephalus is seen chiefly in young animals. It consists in a collection of fluid under the meninges, but outside the brain proper.

This defect is usually congenital. It is accompanied with an enlargement of the skull, especially in the region of the forehead. The pressure of the fluid may cause the bones to soften. The disease is incurable and usually fatal.

Internal hydrocephalus is a disease of mature horses, and consists in the acc.u.mulation of an excessive quant.i.ty of fluid in the cavities or ventricles of the cerebrum. The cause of this acc.u.mulation may be a previous inflammation, a defect in the circulation of blood through the brain, heat stroke, overwork, excessive nutrition, or long-continued indigestion. Common, heavy-headed draft horses are predisposed to this condition.

_Symptoms._--The symptoms are an expression of dullness and stupidity, and from their nature this disease is sometimes known as ”dumminess” or ”immobility.” A horse so afflicted is called a ”dummy.” Among the symptoms are loss of intelligence, stupid expression, poor memory, etc.

The appet.i.te is irregular; the horse may stop chewing with a wisp of hay protruding from his lips; he seems to forget that it is there. Unnatural positions are sometimes a.s.sumed, the legs being placed in clumsy and unusual att.i.tudes. Such horses are difficult to drive, as they do not respond readily to the word, to pressure of the bit, or to the whip.

Gradually the pulse becomes weaker, respiration becomes faster, and the subject loses weight. Occasionally there are periods of great excitement due to temporary congestion of the brain. At such times the horse becomes quite uncontrollable. A horse so afflicted is said to have ”staggers.” The outlook for recovery is not good.

Treatment is merely palliative. Regular work or exercise and nutritious feed easy of digestion, with plenty of fresh water, are strongly indicated. Intensive feeding should not be practiced. The bowels should be kept open by the use of appropriate diet or by the use of small regular doses of Glauber's salt.

TUMORS WITHIN THE CRANIUM.

Tumors within the cranial cavity and the brain occur not infrequently, and give rise to a variety of symptoms, imperfect control of voluntary movement, local paralysis, epilepsy, etc. Among the more common tumors are the following:

Osseous tumors, growing from the walls of the cranium, are not very uncommon.

Dentigerous cysts, containing a formation identical to that of a tooth, growing from the temporal bone, sometimes are found lying loose within the cranium.

Tumors of the choroid plexus, known as brain sand, are frequently met with on post-mortem examinations, but seldom give rise to any appreciable symptoms during life. They are found in horses at all ages, and are slow of development. They are found in one or both of the lateral ventricles, enveloped in the folds of the choroid plexus.

Melanotic tumors have been found in the brain and meninges in the form of small, black nodules in gray horses, and in one instance are believed to have induced the condition known as stringhalt.

Fibrous tumors may develop within or from the meningeal structures of the brain.

Gliomatous tumor is a variety of sarcoma very rarely found in the structure of the cerebellum.

Treatment for tumors of the brain is impossible.

SPASMS, OR CRAMPS.

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