198 



but the cramp may return soon after the effect has passed off, which 

 in many cases it does very quickly. 



Convulsions. — Although there is no disease of the nervous system 

 which can be properly termed convulsive, or justify the use of the word 

 convulsion to indicate any particular disease, yet it is often such a 

 prominent symptom that a few words may not be out of place. Gen- 

 eral, irregular muscular contractions of various parts of the body, with 

 unconsciousness, characterize what we regard as convulsions, and like 

 ordinary spasms are dependent upon some disease or irritation of the 

 nervous structures, chiefly of the brain. No treatment is required; in 

 fact, a general convulsion must necessarily be self-limited in its dura- 

 tion. Suspending, as it does, respiratory movements, checking the 

 oxygenation and decarbonization of the blood, the rapid accumulation 

 of carbonic acid gas in the blood and the exclusion of oxygen quickly 

 puts the blood in a condition to produce the most reliable and speedy 

 sedative effect upon the nerve excitability that could be found, and 

 consequently furnishes its own remedy, so far as the continuance of 

 the convulsive paroxysm is concerned. Whatever treatment is insti- 

 tuted must be directed towards a removal of the cause of the convulsive 

 paroxysm. 



CHOREA. 



Chorea is characterized by involuntary contractions of voluntary 

 muscles. This disease is an obscure disorder, which may be due to 

 pressure upon a nerve, cerebral sclerosis, small aneurisms in the brain, 

 etc. Choreic symptoms have been produced by injecting granules of 

 starch into the arteries entering the brain. Epilepsy and other forms 

 of convulsions simulate chorea in appearance. 



Stringhalt is by some termed chorea. This is manifested by a sudden 

 jerking-up of one or both hind legs when the animal is walking. This 

 symptom may be very slight in some horses, but has a tendency to in- 

 crease with the age of the animal. In some the catching-up of the af- 

 fected leg is very violent, and when it is lowered to the ground the 

 motion is equally sudden and forcible, striking the foot to the ground 

 like a pile-driver. Very rarely chorea may be found to affect one of the 

 fore legs, or the muscles of one side of the neck or the upper part of the 

 neck. Involuntary jerking of the muscles of the hip or thigh is seen 

 occasionally, and is termed shivering by horsemen. 



Chorea is often associated with a nervous disposition, and is not so 

 frequent in animals with a sluggish temperament. The involuntary 

 muscular contractions cause no pain, and do not appear to produce 

 much exhaustion of the affected muscles, although the jerking may be 

 regular and persistent whenever the animal is in motion. 



Treatment.— In a few cases, early in the appearance of this affection, 

 general nerve tonics may be of benefit, viz, iodide of iron, 1 dram ; pul- 

 verized nux vomica, 1 dram ; pulverized Scutellaria, 1 ounce. Mix, and 

 give in the feed once a day for two weeks. If the cause is connected 

 with organic brain lesions treatment is usually unsuccessful. 



