256 DISEASES OF THE NERVOUS SYSTEM 



In true epilepsy there are no anatomical alterations to be found in 

 the brain itself. Whenever they are found they cause epileptiform con- 

 vulsions. It is therefore certain that in a case of epilepsy it is only due to 

 some temporary irritating condition, and that the membranes of the 

 brain are the starting-point of the irritation. 



The experiments which have been made upon dogs in connection with 

 this disease by Ferrier, Eulenberg, Landois, and others, are very interest- 

 ing. They found that with great irritation of the motor regions of the 

 large brain (the cerebrum) a complete attack could be produced. This 

 begins with twitching of the muscles which belong to that centre. It 

 then becomes extended over the corresponding group of muscles on the 

 other side, producing shocks and twitching of the whole muscular system 

 of the body from tonic and, later, clonic convulsions. The convulsions 

 extend from centre to centre, and they never miss any region, but run 

 consecutively from one to the other. If the chief centre is cut out, the 

 convulsions will not be present in that region during the epileptiform 

 attacks. Irritation of the subcortical white substance of the brain also 

 causes epilepsy. This begins, however, in the muscles of the same side. 

 Bromide of soduim administered for some time has been found very 

 valuable in preventing epilepsy caused by membranous irritation. 



From the above experiments it can be readily understood that the 

 cortex of the cerebrum is the original centre of epileptic attacks. It is 

 hard to explain, however, the actual cause of this irritation. Epilepsy 

 can hardly be caused by overstimulation or feeding, for, as a rule, the 

 largest number of true epileptic subjects are weak, delicate, and anaemic; 

 but at the same time we often see vigorous, well-fed dogs of all ages suffer- 

 ing from this disease. There are many cases in anaemic animals which, 

 under treatment, gradually improve, at the same time the epileptiform 

 attacks becoming less and less as the animal improves. It is doubtful if 

 these cases can 1)0 called true epilepsy. 



Clinical Symptoms and Course of the Disease. — In acute attacks of 

 epilepsy the symptoms begin suddenly, or they may start with slight 

 premonitory symptoms, or we may see both forms alternately in dif- 

 ferent seasons in the same individual. In the early stages the animals 

 run in a circle, are restless, have a staring look out of their eyes, or remain 

 standing with outstretched legs and shake their heads from side to side. 

 We have seen clonic convulsions followed by loss of consciousness, and in 

 some cases a rapid change into tonic convulsions. The muscles of masti- 

 cation are especially affected, the jaws are clamped, the saliva turned to 

 froth, the tongue may be bitten, and the l)lood turns the saliva red. Single 

 muscle contractions follow one another with astonishing rapidity, so 

 that the saliva which lies in the mouth is turned into foam. The convul- 

 sions which are now tonic extend over the whole muscular system. The 



