originates from the brain. Coordination, or harmony of
movement, is controlled by the rear portion of the brain, known as the
cerebellum.
The meninges are the membranes, three in number, which envelop the brain
and spinal cord, and separate them from the bones which form the walls of
the cranial cavity and spinal canal.
The sympathetic, also called the ganglionic, division of the nervous system
consists of two chains of ganglia, reaching from the head to the tail,
situated beneath the spinal column, one on either side. The presence of the
ganglia or enlargements on the cords give them their chainlike appearance.
The sympathetic nerves are closely connected with the cerebrospinal
nerves, but are not under the control of the will.
INFLAMMATION OF THE BRAIN AND ITS MEMBRANES (STAGGERS).
Inflammation of the brain is technically termed encephalitis and of its
membranes cerebral-meningitis, but as both conditions usually occur
together, and since it is practically impossible to distinguish one from
the other by the symptoms shown by the diseased animal, they may as well be
considered together here as varieties of the same disease. Staggers, coma,
frenzy, etc., are terms that are sometimes applied to this disease in its
different forms or stages.
_Causes._--Severe blows on the head with a hard object, or the head coming
violently in contact with the ground or other hard substance in a fall, may
be followed by encephalitis. Irritation caused by tumors in the brain may
produce inflammation. Feed containing deleterious matters--for example,
ergot (see Pl. V) and other fungi which contain a narcotic principle--is
the most frequent cause of this affection, and hence it is often called
"grass staggers" and "stomach staggers." Highly nitrogenous feeds are
blamed for causing this disease. Parasites, mineral and narcotic poisons,
hot weather, and severe exertion or excessive excitement may cause this
condition. Inflammation of the brain may occur as a complication of some
infectious disease or may follow some forms of indigestion. In many
localities certain plants have the reputation of causing staggers.
_Symptoms._--The symptoms vary much, but a careful observer will detect a
trouble connected with the nervous system without much uncertainty. The
first signs may be those of frenzy, but generally at the start the animal
is dull and sleepy, with little or no inclination to move about; the head
may be pressed against the
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