CEREBRAL LOCALIZATION 673 



frontal convolution. This conclusion was based in part upon the 

 earlier work of Bouillaud (1825) which tends to show that the speech 

 center is situated in the anterior extremities of the frontal lobes. 

 Furthermore, it was proved by M. Dax and G. Dax (1836) that in 

 right-handed people this area is confined to the left cerebral hemisphere. 

 Attention has also been called repeatedly to the observation of Galenus 

 that a paralysis of the body results in consequence of lesions to the cere- 

 bral hemisphere of the opposite side. These data, however, were 

 not considered of sufficient importance until Broca called special 

 attention to them. 



In 1864 H. Jackson, stimulated by the work of Broca, proved that 

 the muscular spasms characterizing epilepsy, are due to an excitation 

 of the cerebral cortex. A firm basis was given to this view in 1870 

 by Fritsch and Hitzig, 1 who showed that the cortex of the cerebrum 

 is irritable and that its stimulation evokes perfectly definite muscular 

 responses. These tests were first made upon dogs, but were later on 

 extended to other animals and also to the apes and man by Ferrier, 

 Horsley, Schaffer, Sherrington, Luciani, and others. As a direct 

 result of this work, we find a complete abandonment of the doctrine 

 of Flourens and the acceptance of a view which may be said to be more 

 directly in line with the conception of Gall. As has been pointed 

 out above, the latter regarded the cerebrum as a plurality of organs. 

 In its modified form this doctrine holds that the cerebrum is composed 

 of circumscribed areas possessing different sensory and motor func- 

 tions. Emphasis is placed upon the fact that these parts are not 

 separated from one another, but are intimately associated and inter- 

 related with one another so as to yield coordinated function. This 

 fundamental conception is in no way altered by the doctrine of Flechsig 

 (1894) which asserts in addition that the different areas of the cerebral 

 cortex consist of projection and association fields. In other words, 

 the different cerebral spheres seem to be built up of a central core 

 and a peripheral zone which possesses a true psychic character. 



The Location of the Motor Area. The discovery of Fritsch and Hit- 

 zig, that the cortex of the brain is irritable, completely overthrew the 

 old conception of Haller, which assumed that only the underlying 

 white matter is pervious to stimuli. The latter view prevailed for so 

 long a time, because it was advocated by such experimenters as Mag- 

 endie, Longet, Mateucci, Budge and Schiff, and was based chiefly upon 

 their inability to evoke motor reactions by the stimulation of any area 

 of the cerebral surface. As Fritsch and Hitzig made use of the galvanic 

 current, which tends in time to induce electrotonic alterations, their 

 localization left much to be desired. They showed, however, that 

 the muscular effects are confined to the opposite side of the body 

 and may be varied in their intensity by changing the strength of the 



1 Arch, fur Anat. und Physiol., 1870, 300. 

 43 



