DISEASES OF THE NERVOUS SYSTEM 411 



in the central nervous system, as thickening of the membranes ol the brain, 

 deposits of pus, or the presence of parasites. Traumatic epilepsy is due 

 to injury, as, for example, blows upon the cranium causing compression 

 of the nerve structures from effusion of blood or the depression of the 

 bony boundaries of the cavities in which the brain and spinal cord are 

 contained. Keflex epilepsy may occur in consequence of irritation affecting 

 the terminal branches of nerves in remote parts. Such irritation depend- 

 ing upon pressure exercised by foreign bodies, irritation caused by parasites 

 in the digestive organs, affections of the mouth due to the changes which 

 occur in course of dentition. All the above forms of epilepsy, when con- 

 nected with special liability to nervous excitement, may be considered as 

 hereditary. 



ECLAMPSIA 



This disease borders so closely upon the one previously considered, 

 epilepsy, that its manifestations are allowed to be identical with those of 

 reflex epilepsy. It is also stated that eclampsia may be transferred into 

 true epilepsy; the main distinction appears to be that the convulsive 

 .spasms affect chiefly the extensor muscles, and appear without any disturb- 

 ance of the mental conditions and independent of any structural alterations. 

 In fact, the disease is really one of pure motor-nervous excitability. 



CHOREA (ST. VITUS' DANCE) 



This disease is perfectly well known as it affects the dog. It is fre- 

 quently one of the results of distemper; its chief manifestation is constant 

 rhythmical contraction and spasm of some of the muscles of the neck or 

 extremities, usually the fore extremities. Animals which suffer from this 

 disease frequently retain their health for a considerable time, but when 

 chorea affects dogs which have recently recovered from distemper, the 

 constant excitement arising from the incessant muscular spasms interferes 

 with the complete restoration of the animal, and occasionally ends in fatal 

 paralysis. Cases of localized muscular spasm have been described in the 

 horse under the name of chorea, but it must be allowed that the disease 

 in that animal, if it occurs at all, is extremely rare. 



STRINGHALT 



This condition, which is very well known to horsemen, is another of the 

 ill-defined aff'ections of the nervous system. The condition is indicated by 

 spasmodic movement of the muscles of one, sometimes of both hind-legs, 

 and occasionally one or both of the fore-legs. The effect of the spasm is to 



