DISEASES OF HORSES 391 



and consists in the accumulation of an excessive quantity of fluid in 

 the cavities or ventricles of the cerebrum. The cause of this accumu- 

 lation may be a previous inflammation, a defect in the circulation 

 of blood through the brain, heat stroke, overwork, excessive nutri- 

 tion, or long-continued indigestion. Common, heavy-headed draft 

 horses are predisposed to this condition. 



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 appetite 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 assumed, the legs being 

 placed in clumsy and unusual attitudes. 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, respira- 

 tion 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 the staggers. The outlook for recov- 

 ery is not good. 



Treatment is merely palliative. Regular work or exercise and 

 nutritious food 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 salts. 



TUMORS WITHIN THE CRANIUM. 



Tumors within the cranial cavity and the brain occur not in- 

 frequently, and give rise to a variety of symptoms, imperfect con- 

 trol of voluntary movement, local paralysis, epilepsy, etc. Among 

 the more common tumors are the following: Osseous tumors, grow- 

 ing from the walls of the cranium, are not very uncommon. Den- 

 tigerous 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 of slow 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 condi- 

 tion 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 cere- 

 bellum. Treatment for tumors of the brain is impossible. 



SPASMS, OR CRAMPS. 



Causes. Spasm is a marked symptom in many diseases of the 

 brain and of the spinal cord. Spasms may result from irritation of 

 the motor nerves as conductors, or may result from irritation of any 



