214 DISEASES OF THE HORSE. 
ysis may occur. In all cases of encephalitis there is a marked rise in 
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 certain 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 fali 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 or 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 
