410 HEALTH AND DISEASE 



EPILEPSY 



Epilepsy, eclampsia, catalepsy, and chorea (St. Vitus' dance) are all 

 disorders of the nerve centres, and are associated with eccentric muscular 

 action, and often with derangement of consciousness, but horses are very 

 rarely attacked by any of them. 



Epilepsy is a peculiar affection almost unknown in the horse, but not 

 uncommon in the dog. The exact pathological conditions of the brain 

 or spinal cord on which the intermittent attacks or epileptic fits depend 

 are not known, it is even uncertain whether the origin of the malady is 

 centred in the brain or spinal cord, although recent experiments lend 

 considerable force to the view of the brain rather than the spinal cord being 

 the seat of the derangement. Characteristic epileptic fits may be produced 

 in dogs while under chloroform after complete disconnection of the brain 

 from the spinal cord. Injection of a minute dose of absinthe into the 

 circulation in an animal thus prepared is quickly followed by all the signs 

 of epilepsy, and dogs utter maniacal cries, which, of course, are purely the 

 result of reflex action, the dog being at the time unconscious. 



The Symptoms of an epileptic fit are well known. Usually there is 

 no marked premonitory sign of an approaching attack. An animal in a 

 state of health, apparently, may suddenly reel and fall over on its side, in 

 the case of a dog uttering cries which soon cease, while the whole muscular 

 system is in a state of convulsive action. Urine and faeces are involun- 

 tarily discharged; a quantity of foam collects about the mouth. In a 

 short time the convulsions cease and the animal regains consciousness, 

 and is soon restored to its ordinary condition, showing no further symp- 

 toms of illness until the sudden occurrence of another fit. 



Considering the great difficulty of disconnecting severe forms of 

 megrims in the horse from epilepsy, it is not remarkable that some 

 writers record cases of equine epilepsy. It is, however, rarely if ever the 

 case that the horse suffers from this disease, and certainly not in that 

 typical form in which it is seen in the dog. 



Several forms of epilepsy are described by writers, for example, spon- 

 taneous, symptomatic, traumatic, and reflex epilepsy, and in all these the 

 attack may be serious or benign. Spontaneous epilepsy is the result of 

 functional disturbance of the brain, amounting to general irritability, which 

 disposes the subject to an attack under trifling influences, such as fear or 

 any kind of mental excitement. Horses are said to have suffered when 

 alarmed by a display of fireworks, or the passing of a train, or from 

 suddenly passing from a subdued to an intense light. Symptomatic epi- 

 lepsy is the form of the disease which is associated with structural changes 



