214 DISEASES OP THE HOESE. 



ysis may occur. In all cases of encephalitis there is a marked rise ii^ 

 temperature from the very onset of the disease, with a tendency to 

 increase until the most alarming symptoms develop, succeeded by a 

 decrease when coma becomes manifest. The violence and character of 

 the symptoms greatly depend upon the extent and location of the 

 structures involved. Thus, in some cases there may be marked paral- 

 ysis of certata muscles, while in others there may be spasmodic rigid- 

 ity of muscles in a certain region. Very rarely the animal becomes 

 extremely violent early in the attack, and by rearing up, striking 

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

 Usually, however, the animal maintains the standing position, prop- 

 ping himself against the manger or wall, until he falls from inability 

 of muscular control, or from unconsciousness. Occasionally, in his 

 delirium, he may go through a series of automatic movements, such 

 as trotting or walking, and, if loose in a stall, will move around per- 

 sistently in a circle. Early and persistent constipation of the bowels 

 is a marked symptom in nearly all acute affections of the brain ; re- 

 tention of the urine, also, is frequently observed. , 



Following these symptoms there are depression, 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 propped, 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 stable miasma, blood poison, narcotism, lead poison- 

 ing, 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 his head up 

 or shakes it as if suffering 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 encephalitis may effect an animal for ten days or two weeks 

 without much variation in the symptoms before the crisis is reached. 

 If improvement commences, the symptoms usually disappear in the 

 reverse order to that in which they developed, with the exception of 

 the paralytic effects, which remain intractable or permanent. Paral- 

 ysis of certain 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 or arachnoid space. 



Softening and abscess of the brain are terminations of cerebritis. 

 It may also be due to an insufficient supply of blood as a result 



