DISEASES OF THE BRAIN AND NERVOUS 8YSTRM. HI 



expressions o£ great pain, as if the animal had been sharply "wounded 

 with a cutting instrument. 



These symptoms may alternate "with interyals of quietude, when the 

 animal will fall into the comatose condition. The pulse may then fall 

 below its natural standard, and the respiratory movements may become 

 slower than natural, with heavy, deep inspirations. The various secre-( 

 tions are, in all cases, suspended, and the animal gradually sinks from 

 increasing brain pressure, or suddenly from renewed extravasation. 



Apoplexy differs from coma and encephalitis in rendering the animal 

 totally unconscious. If relief is obtained, which, however, is rare, the 

 case usually resolves itself into a state of partial coma, more or less 

 intense. 



CHOREA. 



Synonym. — Stringhalt. 



Definition. — A convulsive, involuntary twitch of the muscles which 

 flex the leg, by which the foot is pulled up with a sudden jerk and higher 

 than natural, and replaced with considerable force. 



Etiology. — It is due to some affection of the nerves wnich is not yet 

 clearly understood. 



In some cases it may be traced to the pressure of some bony growth 

 on a nerve; but as a general rule we are unable to account for the affec- 

 tion, nor do post-mortem examinations always show any abnormal state 

 of the nerves. 



The disease varies very much in degree or intensity in various cases, 

 but most generally affects both hind legs and becomes worse with age. It 

 is occasionally noticed in the foreleg. 



In the early stage it is most easily detected, when the animal is first 

 put in motion. 



Sometimes the horse will take a number of steps without showing any 

 evidence of it, and then the foot will be suddenly Jerked from the ground; 

 so, too, he will sometimes exhibit signs of the disease only in turning 

 round from right to left or vice versa, the unnatural gait not always ac- 

 companying both motions. 



No treatment produces any beneficial effect. 



