DISEASES OF HORSES 383 



the most alarming symptoms develop, succeeded by a decrease when 

 coma becomes manifest. The violence and character of the symp- 

 toms greatly depend upon the extent and location of the struc- 

 tures involved. Thus, in some cases there may be marked paraly- 

 sis of certain muscles, while in others there may be spasmodic rigid- 

 ity of muscles, in a certain region. Very rarely the animal be- 

 comes extremely violent early in the attack, and toy rearing up, 

 striking with the fore feet, or falling over, may do himself great 

 injury. Usually, however, the animal maintains the standing 

 position, propping himself against the manger or wall, until he falls 

 from inability of muscular control or unconsciousness. Occasion- 

 ally he may go through a series of automatic movements in his de- 

 lirium, such as trotting or walking, and, if loose in a stall, will move 

 around in a circle persistently. Early and persistent constipation 

 of the bowels is a marked symptom in nearly all acute affections of 

 the brain; retention of the urine, also, is frequently observed. 



Following these symptoms there are depressions, loss of power 

 and consciousness, lack of ability or desire to move, and usually 

 fall of temperature. At this stage the horse stands with legs prop- 

 ped, the head hanging or resting on the manger, the eyes partly 

 closed, and does not respond when spoken to or when struck with a 

 whip. 



Chronic encephalitis or meningitis may succeed the acute stage, 

 or may be due to blood poison, lead poisoning, etc. This form may 

 not be characterized in its initial stages by excitability, quick and 

 hard pulse, and high fever. The animal usually appears at first 

 stupid; eats slowly; the pupil of the eye does not respond to light 

 quickly ; the animal often throws up his head or shakes it as if suf- 

 fering sudden twinges of pain. He is slow and sluggish in his 

 movements, or there may be partial paralysis of one limb, one side 

 of the face, neck, or body. These symptoms, with some variations, 

 may be present for several days and then subside, or the disease may 

 pass into the acute stage and terminate fatally. Chronic encephal- 

 itis may affect an animal for ten days or two weeks without much 

 variation in the symptoms before the crisis is reached. If improve- 

 ment commences, the symptoms usually disappear in the reverse 

 order in which they developed, with the exception of the paralytic 

 effects, which remain intractable or permanent. Paralysis of cer- 

 tain sets of muscles is a very common result of chronic, subacute, 

 and acute encephalitis, and is due to softening of the brain or to 

 exudation into the cavities of the brain. 



Softening and abscess of the brain is one of the terminations 

 of cerebritis. It may also be due to an insufficient supply of blood 

 as a result of diseased cerebral arteries and of apoplexy. The symp- 

 toms are drowsiness, vertigo, or attacks of giddiness, increased tim- 

 idity, or fear of familiar objects, paralysis of one limb, hemiplegia, 

 imperfect control of the limbs, and usually a weak, intermittent 

 pulse. In some cases the symptoms are analogous to those of apo- 

 plexy. The character of the symptoms depends upon the seat of the 

 softening or abscess within the brain. 



