Reprinted from the Proceedings of the Royal Society, Vol. 69, 1901] 
OBSERVATIONS ON THE PHYSIOLOGY OF THE 
CEREBRAL CORTEX OF SOME OF THE 
HIGHER APES 
BY 
A. S. F. GRUNBAUM, M.A., M.D. (Cantab.), M.R.C.P. 
AND 
C. S. SHERRINGTON, M.A., M.D., F.R.S. 
[Received July 20 — Read November 21, 1901.] 
We have been engaged for some time past on inquiry into the physiology of the 
cerebral cortex of the anthropoid apes. We are able to lay before the Society some 
new facts regarding the topographical distribution of function in the anthropoid 
brain. Our experiments have been carried out on individuals representing the four 
species Pitbecus satyrus (Orang), Troglodytes gorilla (Gorilla), Troglodytes niger (Chim- 
panzee), and Troglodytes calvus (Chimpanzee). The specimens so far have included 
ten adult individuals. Of Troglodytes ytiger one individual used was only a few 
months old. 
I. Method Employed 
The method of excitation employed for the cortex has been unipolar faradization, 
in the manner previously adopted by one of us' in examining the cortex cerebri for 
ocular reactions. This method allows of finer localization than that possible with the 
double-point electrodes ordinarily used. The inductorium (Kronecker's pattern and 
scale) has been Helmholtzed. 
II. ' Motor ' (so-called) Area 
This area we find to include continuously the whole length of the precentral 
convolution. It also enters into the whole length of the sulcus centralis, with the 
usual exception of its extreme lower tip and its extreme upper tip. 
1. Sherrington, Roy. Soc. Proc, vol. $2, 189}. 
