EPILEPSY FROM CORTICAL EXCITATION. 719 



Other kinds of irritation of the cortex, and especially prolonged 

 mechanical irritation (such as is liable to be produced by the irritation 

 of a bony splinter from the inner table of the skull) will also produce 

 epileptoid attacks, and the same result may follow experimental lesions of 

 the cortex in animals. 1 Irritation confined to the corona radiata is 

 never followed by epilepsy ; and if a portion of the excitable area 

 of the cortex be removed, such, for example, as the centre excita- 

 tion of which produces movement of one of the opposite limbs, and 

 an epileptic fit be brought about by strong or prolonged excitation of 

 another portion of the cortex, the limb in question remains quiescent. 2 

 Epilepsy, therefore, is essentially a functional disturbance of the cortex 

 cerebri. It does not occur if the Eolandic or motor region of the 

 cortex be removed entirely, although it may be provoked by excitation 

 of other portions of the cerebral surface 3 than this, but not witli the 

 same ease and with a longer interval after the excitation. 



Hughlings Jackson showed 4 that in the pathological condition now named 

 after him Jacksonian epilepsy, the convulsive movements in a fit follow a 

 certain order or "inarch." Thus, if a fit begin by contraction of the thumb 

 flexors, it first spreads to other muscles of the hand and forearm, next to the 

 shoulder muscles, then to the muscles of the face, trunk, and leg in a definite 

 order in each case, passing, if it begin in the hand, up the arm and down the 

 leg ; if it begin in the toes, up the leg and down the arm. When the centres 

 for movements which are bilaterally represented in the cortex are involved, 

 the corresponding muscles of both sides are set in action, and in severe fits all 

 the muscles on both sides of the body may be included. Ferrier's experi- 

 ments 5 upon monkeys and other animals entirely confirmed the observations of 

 Hughlings Jackson upon man, showing that in each case the epileptoid attack 

 began in the muscles corresponding to the motor centre which was stimulated, 

 and spread thence with a definite "march." 6 The "march "is apparently 

 dependent in each case upon the relative propinquity of the several centres in 

 the motor region of the cortex, and, when they are equally close, upon their 

 relative excitability ; it is, however, not interfered with, according to 

 Unverricht, 7 by isolating the centres from one another, and the sequence must 

 therefore be brought about at least under these circumstances by influences 

 passing from one part to another through lower level centres. Section of the 

 corpus callosum does not prevent the spreading of an artificially induced fit 

 from the one side of the body to the other (Unverricht). In dogs, when the 

 side of the brain opposite to that first set in action is involved, the fits always 

 begin with the muscles of the hind-limb, wherever the excitation producing 

 them might have been originally applied on the other side of the brain. ~ 8 



1 Hitzig, "Untersuch. ueber d. Gehirn," Berlin, 1874, S. 271. 



2 It was stated by Muiik, and the statement was confirmed by Bubnoff and Heidenhain 

 (loc. cit.), that if during the progress of an epileptic attack, artificially produced, the 

 cortical centre which was excited is rapidly extirpated, the attack immediately ceases. 

 But Fran9ois-Franck and Pitres (loc. cit.) and Albertoni (loc. cit.) were unable to confirm 

 this statement, and deny that the attack once commenced is modified by the ablation. 



3 Francois-Franck and Pitres (loc. cit.) ; Unverricht, Arch. f. Pyschiat., Berlin, 1883, 

 Bd. xiv. S. 175 ; Rosenbach, Virchow's Archiv, 1884, Bd. xcvii. S. 369. Albertoni (see 

 Brain, London, 1878, vol. i. p. 139) came to a different conclusion regarding the seat of 

 epilepsy, but on apparently insufficient grounds. 



4 Lancet, London, 1873, vol. i. pp. 84, 162, 232. 



5 West Riding Lun. Asyl. Rep., London, 1873. 



6 See also on this subject Albertoni, Ann. univ. di med. e chir., Milano, 1879 ; Luciani, 

 Riv. sper. di freniat., Reggio- Emilia, 1876, p. 617 : and Arch, per le mal. nerv., 1881 ; 

 Beevor and Horsley, Phil. Trans., London, 1887, vol. clxxviii. B. 



7 Loc. cit. 



8 Francois-Franck and Pitres, loc. cit. ; Unverricht, loc. cit. 



