458 EPILEPSY. 



beats violently. The convulsive phenomena speedily sub- 

 side and the animal regains its feet, and if loose is apt to 

 run from any one near it, or, in other cases, to fall into a 

 deep sleep. In severe forms of epilepsy, the convulsions 

 recur after, and the animal soon dies. In others, the fits 

 grow weaker and less frequent until they disappear alto- 

 gether. Each fit may last from a few minutes to about 

 lalf an hour, though rarely as long as this. 



Epilepsy is a disease due to a variety of lesions of the 

 nervous system, and to peculiar conditions of the blood. 

 Its attacks seem to commence often on the surface of the 

 body, or from some special centre within. In man some 

 part is first felt in a state of spasm, or is the seat of an un- 

 defined sensation varying in different cases. Such a sensa- 

 tion is termed the aura epileptica, and is of course not 

 usually recognised in the lower animals. It is evident, 

 however, from its manifestations, that epilepsy may be 

 either of centric or peripheric origin. 



Dr Brown-Se'quard published in 1857 some interesting 

 researches on epilepsy, recording specially the results of 

 experiments on animals. He says : " I have found that 

 the following kinds of injury to the spinal cord are able to 

 produce epilepsy, or at least a disease resembling epilepsy, 

 in animals belonging to different species, but mostly upon 

 guinea-pigs : 



" 1st, A complete transversal section of a lateral half of 

 this organ. 



" 2d, A transversal section of its two posterior columns, 

 of its posterior cornua of gray matter, and of a part of the 

 lateral columns. 



" 3d, A transversal section of either the posterior columns 

 or the lateral, or the anterior alone. 



" 4:th, A complete transversal section of the whole organ. 



