DISEASES OF THE NERVOUS SYSTEM. 249 



cutting the nerves proceeding from this part, or better, by h'ght 

 firing with an iron at a red or white heat. 



CHOREA. ST. VITUS'S DANCE. ST. GUY'S DANCE. 



. Mainly seen in the dog and horse. Occurs in subjects 

 debilitated or worn out by disease, as in dogs by distemper. 

 There is no constant structural change in the brain, but the 

 occurrence of the disease as a consequence of exhausting dis- 

 orders and the excess of urea, etc , in the urine, may be taken 

 as implying an altered state of the blood, and of the processes 

 of sanguification. 



6;rw//(?;;/y.— Momentary spasms of the voluntary muscles, 

 leading to jerking of one or more limbs, of the head, or of the 

 entire body. This continues without intermission in sleep as in 

 waking, and, by wearing the subject out, increases the disorder. 

 In the horse it occurs mainly in the hind limbs, but will also 

 attack the fore, and temporarily the muscles of the body. 



7';-frt'/;//<'«A— Re-establish health and vigour by abundant 

 nourishment, open air exercise, tonics (sul[)hate and carbonate 

 of iron, cascarilla, quinia), cold baths, rubbing dry afterwards, 

 and strychnia. Nerve sedatives (chloral hydrate) may be given 

 to check or moderate the spasms, 



VERTIGO. MEGRIMS IN HORSES. 



An equine disease characterised by sudden and temporary 

 loss of sensation and voluntary motion, with trembling, and it 

 may be champing of the jaws, but without the general spasms 



of epilepsy. 



Causes — 'Qrd.xn disorders such as tumours, congestions, 

 effusions, etc., or modified circulation from compression of the 

 jugular veins, or disease of the heart. Plethora is a frequent 

 cause in the young. 



Symptoms.— The animals drawing a load, especially uphill, 

 with a tight collar, driven hurriedly in extreme heat, or in a 



