onvulsive or spasmodic movements, eyes wide open
with shortness of sight. The animal becomes afraid to have his head
handled. Convulsions and delirium will develop, with inability of
muscular control, or stupor and coma may supervene. When the membranes
are greatly implicated, convulsions and delirium with violence may be
expected, but if the brain substances are principally affected stupor
and coma will be the prominent symptoms. In the former condition the
pulse will be quick and hard; in the latter, soft and depressed, with
often a dilatation of the pupils, and deep, slow, stertorous breathing.
The symptoms may follow one another in rapid succession, and the disease
approach a fatal termination within 12 hours. In subacute attacks the
symptoms are better defined, and the animal seldom dies before the third
day. Within three or four days gradual improvement may become manifest,
or cerebral softening with partial paralysis 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 paralysis of certain muscles, while in others there
may be spasmodic rigidity 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,
propping 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
persistently in a circle. 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 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.