CEREBRAL CORTEX OF THE HIGHER APES 
57 
from. In accord with the absence of recrudescence of the hand paresis on ablating 
in the third operation the remaining intact part of the arm area, we found that 
faradization of that part (elbow and shoulder) provoked, as usual, movements of 
elbow and shoulder, but not of hand itself, or only of hand late in a general arm 
movement, and that very rarely. In short, neither the ablation or excitation methods 
gave any evidence that the remaining part of the arm area had taken on the functions 
of the ablated hand area. The recovery of the hand movement seems, therefore, 
not due to either the adjacent cortex of the same hemisphere, or the corresponding 
hand area of the cortex of the opposite hemisphere, taking on the functions of the 
ablated cortical hand area. 
Side. Central. Anus r & V<a.gina 
DESCRIPTION OF FIGURE 
Brain of a chimpanzee {Troglodytes niger). Left hemisphere ; mesial surface. The extent of the 
'motor ' area on the free surface of the hemisphere is indicated by the black stippling. On the stippled 
area, ' LEG,' indicates that movements of the lower limb are directly represented in all the regions of the 
'motor' area visible from this aspect. Such mutual overlapping of the minuter sub-divisions exists in 
this area, that the diagram does not attempt to exhibit them. The pointing line from ' Anus, etc.,' 
indicates broadly the position of the area whence perineal movements are primarily elicitable. 
Sulc. Central. = central fissure. Sulc. cakarin. = calcarine fissure. Sulc. parieto occip. — Parieto- 
occipital fissure. Sulc. calloso marg. = Calloso-marginal fissure. Sulc. precentr. marg. — Precentral marginal 
fissure. 
The single italic letters mark spots whence, occasionally and irregularly, movements of the foot 
and leg (ff), of the shoulder and chest (s), and of the thumb and fingers (//) have been evoked by strong 
faradization. Similarly the shaded area marked 'EYES' indicates a field of free surface of cortex, which 
under faradization y ields conjugate movements of the eyeballs. The conditions of obtainment of these 
reactions separates them from those characterizing the ' motor' area. 
I 
