58 THOMPSON YATES AND JOHNSTON LABORATORIES REPORT 
Faradization of the cortex of the post-central convolution, though not itself 
eliciting movement, when employed at certain places, facilitates the elicitation of move- 
ment by faradization at certain points at about the same horizontal level in the pre- 
central convolution. In other words, from certain parts of the post-central convolution, 
a facilitating influence (bahnung) can be exerted upon somewhat adjacent parts of the 
pre-central convolution. 
Removal of the adjacent levels of the pre-central convolution does not render 
the post-central convolution ' excitable ' ; that is to say, destruction of the pre-central 
convolution does not make it the more possible to obtain movements under faradiza- 
tion from the post-central convolution. 
The motor cortex of the infant chimpanzee, a few weeks old, is readily excit- 
able by faradization. Its reactions do not appear to differ obviously in this respect 
from those obtainable from the adult. The movements it yields are not choreiform 
in character. 
The spinal degeneration ensuing upon ablation of the arm area of the motor 
cortex of the chimpanzee, although it sometimes reveals a large uncrossed ventral 
pyramidal tract (direct Py. Tr.)i does not do so in every case. Even after bilateral 
arm area lesions, the ventral pyramidal degeneration in the spinal cord may be very 
slight. The anthropoid cord resembles the human, therefore, not only in the posses- 
sion of this tract, but in exhibiting in regard to it a remarkable degree of individual 
variation of development, as Flechsig showed to be the case in man. 
The expenses of this research have been in part defrayed by a grant kindly 
allowed by the Scientific Grants' Committee of the British Medical Association. 
