Chorea. St. Vitus Dance. 63 



gray matter. It is interesting to note in this connection that the 

 evacuation of the cerebral fluid, which removes the soft support 

 of the water cushion and allows the brain to come in contact with 

 the hard bony walls, determines an access of convulsions. In 

 cases of convulsions attendant on mechanical injury to the cra- 

 nium surgical interference will be in order. 



CHOREA. ST. VITUS DANCE. 



Definition. Susceptible animals. Causes: nervous lesions inconstant, 

 youth, debility, ansemia, niicrobian toxins, cerebral embolism, rheumatism, 

 trophic alterations in nerve cells, fright. L,esions : variable in seat and 

 character, congestion of perforated space, corpus striatum. Sylvian convo- 

 lutions, gray matter at root of posterior horn of spinal cord, etc., experi- 

 ments of Chauveau and Wood. Symptoms : dog, local twitching, fore limb, 

 one or both, neck, head, maxilla, eyelids, eyeballs, hind limbs, trunk, 

 rhythmic, less when recumbent, usually absent in sheep, roused by excite- 

 ment : horse, head neck, fore limb, trunk: cattle, head, neck, limbs: 

 swine, hind limbs, neck, head : severe cases lead to exhaustion, emaciation, 

 marasmus, paralysis. Duration : weeks, months, years. Treatment : laxa- 

 tive, tonic, hygienic, arsenic zinc sulphate, strychnia, sedative, belladonna, 

 conium, cannabis Indica, chloral, acetanilid, trional, etc., icebags or ether 

 spray to spine, cold douches, outdoor life. 



Definition. A neurosis characterized by constant twitching of 

 muscles or of groups of muscles, and which usually ceases during 

 sleep. 



Animals Susceptible. This disease is especially common in the 

 dog, but has been recognized also in the horse, ox, cat and pig. 



Causes. Much difference of opinion exists as to the true cause 

 of chorea. In many cases no nervous lesion has been fotmd and 

 therefore the disease has been pronounced purely functional. 

 The victims are as a rule the young, weak and debilitated so that 

 anaemia has been held to be the main causative factor. Then in 

 dogs the affection is a common sequel of distemper and hence it 

 has been attributed to toxic matters (microbian, etc.) in the blood. 

 It sliould be added that European writers attribute the rhythmic 

 spasms which follow di.stemper to eclampsia, epilepsy or tic, and 

 claim that the contractions must be irregular or arhythmic in order 



