DISEASES OF THE HUESE. 203 



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. Probabl}^ the most frequent cause 

 is found in plugging, or occlusion, of the arteries by a blood clot. 



Symjytoms. — Imperfect vision, constantly dilated pupils, frequently 

 a feeble and staggering gait, and occasionally cramps, convulsions, or 

 epileptic fits occur. 



Pathology. — The exact opposite of cerel^ral hyperemia. The blood 

 vessels are found empty, the membranes blanched, and the brain sub- 

 stance softened. 



Treatment.- — Removal of the remote cause when possible. General 

 tonics, nutritious food, rest, and removal from all causes of nervous 

 excitement. 



IIYDllOCErnALUS, OR DROPSY OF THE BRAIX. 



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 hj^drocephalus. 



External hydrocephalus is seen chiefly in young animals. It con- 

 sists in a collection of fluid under the meninges, but outside of the 

 brain proper. This defect is usually congenital. It is accompanied by 

 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 accumulation of an excessive quantity of fluid in the cavities or 

 ventricles of the cerebrum. The cause of this accumulation 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, heav3'-headed draft horses are predisposed to 

 this condition. 



The synqytoms are an expression of dullness and stupidity, and from 

 their nature this disease is sometimes known as "dumminess" or 

 "immobilit}".-' Ahorse so afflicted is called a "dumm3\" Among 

 the symptoms are loss of intelligence, stupid expression, poor memorj', 

 etc. The appetite is irregular; the horse may stop chewing with a 

 wisp of ha}' 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 readil}' to the word, to pressure of the 

 bit, or to the whip. Graduall}^ 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. 



