DISEASES OF THE BRAIN. 205 



GliomMoiis tumor is a variety of sarcoma very rarely found in the 

 structure of the cerebellum. 



Treatment for tumors of the brain is impossible. 



SPASMS, OR CRAMPS. 



Causes. — Spasm is a marked sj^mptom 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 circvdation, 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: Tonio 

 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 respira- 

 tion ; 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. 



Spasms of the intestines. — (See " Cramp colic," p. 58.) 



Spasms of the neck of the hladder. — This may be due to spinal irri- 

 tation or a reflex from intestinal irritation, and is manifested by fre- 

 quent 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. 236.) 



Spasm, of the thigh, or cramp of a hind limb. — This is frequently 

 witnessed in horses that stand on sloping jjlank floors — generally in 

 cold weather — or it may come on soon after severe exercise. It is 

 probably due to an irritation of the nerves of the thigh. In cramps 

 of the hind leg the limb becomes perfectly rigid, and attempts to flex 



