DISEASES OF THE NERVOUS SYSTEM. 223 



may often be followed by encephalitis or cerebritis, and will then 

 have to be treated accordingly. For this reason the stimulants 

 should not be administered too freely, and they must be abandoned 

 as soon as reaction is established. There is no need for further 

 treatment unless complications develop as a secondary result. Bleed- 

 ing, which is so often practiced, proves almost invariably fatal in 

 this form of brain affection. We should also remember that it is 

 never safe to drench a horse with large quantities of medicine when 

 he is unconscious, for he is very liable to draw the medicine into the 

 limgs in inspiration. 



Prevention. — Young horses, when harnessed or bitted for the first 

 few times, should not have their heads checked high, for it fre- 

 quently causes them to rear up, and, being unable to control their 

 balance, they are liable to fall over sideways or backwards, thus 

 causing brain concussion when they strike the ground. 



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 tem- 

 porary 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 sub- 

 stance 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 com- 

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

 proper. This defect is usually congenital. It is accompanied with 



