BTRAIN OF PSO^ MUSCLES. 245 



weiglit, and general paralysis does not supervene for montlis or 

 even years. There is then a gradual and progressive loss of the 

 power of co-ordination in the acts of volition. An awkward 

 unsteady gait is the earliest indication of such progressive para- 

 lysis. At first the feet are moved in a slatternly manner, the 

 heels lounging on the ground, and then, as the disease advances, 

 they are thrown involuntarily to the right or left without pur- 

 pose, and without the power of restraining their irregular move- 

 ments. The act of turning round is performed with great 

 difficulty. . . . If the patient is put on his legs with his eyes 

 shut, and his feet close together, it is seen that, although he has 

 the muscular power he has not the muscular sensibility to pre- 

 serve his body from falling, or to guide him in taking even a 

 few steps forward with his eyes closed. He will reel and tumble 

 about like a drunken man." 



Functional irregularity of muscular action may arise from 

 fatty degeneration of the muscles, without any disease being 

 found in the nerves or nervous centres. 



CIIOBEA. 



Definition. — An irregular convulsive clonic action of the volun- 

 tary muscles, confined generally in the horse to the posterior 

 extremities — constituting " stringhalt,^' and in the dog as a sequel 

 to distemper — to the anterior ones, neck, and face, by which they 

 ore withdrawn from the control of volition, more especially 

 during sleep. 



Many pathological views are entertained regarding this disease. 

 By some it is regai-dcd as entirely functional, and independent of 

 organic change. By others it is held that it is due, at least in 

 some cases, to some disease of the blood, the precise nature of 

 wliich is as yet unknown, and that it may be associated with, 

 some diseases, as rheumatism and diseases of the heart, 



Professor Dick was of opinion that it was due to the pre- 

 sence of tumours in the lateral ventricles of the brain, and 

 supported his views by a post mortem proof. But tumours vx 

 the ventricles may be present without chorea, and chorea is 

 very often present without such tumours. Other ^vriter3 have 

 traced its origin to a hypertrophied condition of the nerves 

 given off from the lumbar plexus, to the pressure of some 



