CEREBRAL L0( ALIZAT10 



will exclude the corresponding muscular area from participation in 



the fit. 



CLINICAL OBSERVATIONS 



The foregoing results obtained bj experimental stimulation in anim; 

 are very similar to the symptoms observed in man when the cerebral 

 cortex is stimulated by the pressure on it of a meningeal tumor o 

 spicule of bone. Such stimulation causes contraction in the correspond- 

 ing muscular area; the contraction then spreads to aeighborii ups 

 of muscles, and may ultimately involve the whole musculatu 

 body in a convulsive lit, like thai produced in animals. This is known 

 as Jacksonian epilepsy, and it is to be distinguished from ordinary 

 epilepsy by the fad that the patient does uo1 become unconscious dur- 

 ing the fit. Like ordinary epilepsy, however, l! ksonian typ 

 usually preceded l>\ a peculiar sensation of numb] a ing in the 



area thai is to show the first contraction. i of tl • achi< 



ments <>( modern brain surgery is the cure of Jacksonian epilepsy, by 

 trephining the skull over tin- affected center and removing the mening 

 tumor or spicule of bone which is responsible for the stimulation. T 

 enable the surgeon to locate exactly the position of the irritating body, 

 it is necessary to examine the patienl very closely as I ilar 



group which is initially affected during the convulsions, ami then 

 examine an outline map of the cerebral hemisphere indicating the po- 

 sition of the various motor and sensory areas as deduced mainly from 

 experiments on the higher monkeys ami verified by the expe 

 trained by previous operations. Topographic maps indicating the sur- 



e markings corresponding to the various convolutio -ebrum 



must also he used. In such operations the surgeon often has the op. 

 portunity of experimentally verifying the position of various cent. 



