700 PHYSIOLOGY. 



Cortical Epilepsy. 1 Fritsch and Hitzig observed that, through 

 continued irritation of the cortex of the cerebrum, the animal 

 became convulsed not only in the muscles whose centers were 

 irritated, but in all the muscles of the body. The convulsive move- 

 ment always began in the muscles which were innervated by the cen- 

 ter irritated, and then spread from this in a regular and systematic 

 manner to the remaining muscles. For example: when an animal 

 had the left cortical center for the eyelids irritated, the convulsive 

 movement began in the muscles of the eyelid of the opposite side, 

 and then spread to the other facial muscles ; next, the head was bent 

 to the right; then, first the right anterior and next the right pos- 

 terior extremities were seized with convulsions; after this the con- 

 vulsive movement began in the muscles of the left side and from 

 below upwards, first the left posterior extremity, then the left 

 anterior, and last the muscles of the left eyelid. The convulsive 

 movements are first tonic, and then they become clonic and the ani- 

 mal becomes sleepy. 



If an injury is produced in the motor area and the animal lives, 

 then a spontaneous epilepsy can ensue with cortical irritation. 



In the cortex of man similar results ensue from an irritation 

 of the motor centers, except that the man usually feels conscious of 

 the attacks in the beginning of the fit and takes care that he shall 

 not be injured by the attack. 



Cortical epilepsy can ensue from irritation of other convolutions 

 than the motor, but these convolutions must be in a physiological 

 association with the motor centers. The spread of the convulsive 

 movements to different muscles can take place even after extirpation 

 of the opposite motor area. If the motor area of a defined group 

 of muscles is extirpated, and on an adjacent motor area another 

 group of muscles are convulsed by an irritation, then these convul- 

 sions spread to the muscles whose motor area has been extirpated. 

 Hence the irritation can spread to the subcortical centers and cause 

 general convulsions, even when the original motor center which has 

 caused the convulsions is extirpated. 



Extirpation of the Motor Area. 1 When in a dog the motor area 

 of one hemisphere has been extirpated completely or in part, then 

 shortly after the operation there are considerable disturbances of 

 the movements of the opposite side. But soon the animal is able to 

 move the muscles of the opposite side, and after a time the mus- 



Tigersted's "Physiology" has been drawn upon for the data. 



