x THE FORE-BRAIN 575 



their tendency to spread to adjacent groups of muscles till they 

 become general, as if the stimulus only discharged an excitatory 

 process which develops independently of external stimuli. 



The epileptic discharge due to cortical faradisation always 

 liegins in the. muscular group which corresponds to the cortical 

 motor centre stimulated. According to the strength and duration 

 of the stimulus, or the excitability of the centre stimulated, it 

 may remain limited to a single group of muscles, or extend to 

 all the muscles of one half of the body, or involve the muscles of 

 both sides. 



The epileptic discharge follows a certain order in spreading, 

 which almost always corresponds to the anatomical arrangement 

 of the motor centres in the cortex. This fact, which is brought 

 out by the observations of Ferrier, Luciani and Tamburini, and 

 Unverricht, proves that the spread of the attack depends on the 

 propagation of the active epileptic state from the cortical centre 

 directly excited to the contiguous centres in the motor area. 



It is important also to note the mode in which the epileptic 

 attack spreads from one half of the body to the other. According 

 to the observations of Unverricht, which were confirmed by 

 Francois- Franck and Pitres, the epileptic attack always invades 

 the other half of the body in a typical and constant manner, no 

 matter where the fit may start. After involving all the muscles 

 of one side in the ascending or in the descending order, the attack 

 invariably spreads to the other side in the ascending order, viz. 

 from the muscles of the posterior to those of the anterior limb, and 

 from there to the muscles of the neck, face, etc. This rule for the 

 spread of the convulsions in experimental epilepsy, holds good also 

 with very rare exceptions for the spread of the convulsions of 

 epilepsy in man. 



The duration of each experimental fit varies from a few seconds 

 to two or more minutes. Sometimes after the attack is over, it 

 recurs spontaneously after a brief pause ; at other times the 

 animal may pass into a true epileptic state (status epilepticus), in 

 which the convulsions diminish or become more severe, but do not 

 cease entirely. The animal of course becomes exhausted and dies 

 after a few hours. 



It is interesting to note that both in simple epileptic seizures, 

 and in recurrent attacks, or in the epileptic state, the muscles are 

 not all equally involved in the convulsions. This agrees with the 

 fact that the excitability of the various cortical motor centres is 

 not uniform, but varies in different individuals and in the same 

 individual at different periods of the experiment. Often indeed a 

 current of moderate strength will not elicit an attack when applied 

 to one focus, while a weak current will suffice to provoke the 

 attack if applied to another centre. 



According to Unverricht, the body-temperature rises from 



