Chorea. St. Vitus Dance. 65 



be explained by mutual relation of the ganglia of the two sides 

 and their coordination of function. 



The question of the relative importance of the encephalic and 

 spinal lesions has been also debated. Chauveau believed that b}' 

 section of the cord in choreic dogs, he had proved that the spasms 

 were of medullary origin. Wood on the other hand found that 

 the choreic movements persisted after section of the cord, and 

 seemed warranted in the conclusion that the movements origin- 

 ated in the cord. The probability is, that with the cord intact, 

 the primary source of the morbid movement may reside either in 

 the encephalon or the cord. In chorea, following distemper, I 

 have found marked congestion of the encephalon and its men- 

 inges. 



Symptoms. In the dog the twitching may be confined to one 

 fore leg, or it may extend to both and then usuallv implicates the 

 neck and head. In other cases the lower jaw, the head, the eye- 

 lids or even the eyeballs may be the seat of the twitching motions 

 and in still others the hind limbs and trunk are also implicated. 

 In nearly all cases the tendency is to a continuous rhythmic 

 action, which may moderate without actually ceasing while 

 the animal lies down, but which usualh' stops altogether during 

 deep sleep. When it intermits at other times it can commonly be 

 roused into activity' by exciting the animal in an}' wav . 



In the horse the muscles affected may be those of the head and 

 neck, of the fore limb (Hering), of head, limbs and trunk 

 (Ivcblanc). 



In cattle the movements have affected the neck and head and 

 the fore or hind limbs (Anacker, Schleg). 



In young pigs the hind limbs, the neck and head have been 

 chiefly involved in the spasms (He.ss, Vervey). 



If the affection is slight it may not seriouslj^ /mpair the genera 

 health, but in proportion to its severity and the constancy and 

 generalization of the spasms and the consequent muscular waste 

 and exhaustion, the animal becomes gradually worn out and 

 emaciated and dies of paralysis and marasmus. 



Ditration. In favorable cases recovery may ensue in a few 

 weeks ; in others the disease becomes chronic and will last for 

 months or years. 

 4 



