brain is impossible.

SPASMS, OR CRAMPS.

Spasm is a marked symptom in many diseases of the brain and of the
spinal cord. Spasms may result from irritation of the motor nerves as
conductors, or may result from irritation of any part of the sympathetic
nervous system, and they usually indicate an excessive action of the
reflex motor centers. Spasms may be induced by various medicinal agents
given in poisonous doses, or by effete materials in the circulation,
such as nux vomica or its alkaloid strychnia, lead preparations, or an
excess of the urea products in the circulation, etc. Spasms may be
divided into two classes: Tonic spasm, when the cramp is continuous or
results in persistent rigidity, as in tetanus; clonic spasm, when the
cramping is of short duration, or is alternated with relaxations. Spasms
may affect involuntary as well as the voluntary muscles, the muscles of
the glottis, intestines, and even the heart. They are always sudden in
their development.

_Spasm of the glottis._--This is manifested by a strangling respiration;
a wheezing noise is produced in the act of inspiration; extreme anxiety
and suffering for want of air. The head is extended, the body profusely
perspiring; pulse very rapid; soon great exhaustion becomes manifest;
the mucous membranes become turgid and very dark colored, and the animal
thus may suffocate in a short time.

_Spasm of the intestines._--(See "Cramp colic," p. 74.)

_Spasm of the neck of the bladder._--This may be due to spinal
irritation or a reflex from intestinal irritation, and is manifested by
frequent but ineffectual attempts to urinate.

_Spasm of the diaphragm, or thumps._--Spasmodic contraction of the
diaphragm, the principal muscle used in respiration, is generally
occasioned by extreme and prolonged speeding on the race track or road.
The severe strain thus put upon this muscle finally induces irritation
of the nerves controlling it, and the contractions become very forcible
and violent, giving the jerking character known among horsemen as
"thumps." This condition may be distinguished from violent beating of
the heart by feeling the pulse beat at the angle of the jaw, and at the
same time watching the jerking movement of the body, when it will be
discovered that the two bear no relation to each other. (See
"Palpitation of the heart," p. 259.)

_Spasm of the thigh, or cramp of a hind limb._--This is frequently
witnessed in horses that stand on sloping plank f