“DIE LOKALISATION IM GROSSHIRN”’ 497 
groups of afferent impulses from different sources are said to be 
concerned have involved more or less of a subjective element in 
the demonstration. It is, however, possible to get a purely 
objective demonstration of the fact that afferent impulses from 
at least two different sources are involved in postural activity, 
to use Sherrington’s terminology, of the muscles which maintain 
the position of the head. If one otic labyrinth of a cat is ex- 
tirpated, there is torsion of the head, the occiput being turned 
‘toward the injured side and the nose toward the sound side. 
If, after an interval varying from one hour to several months, 
the dorsal roots of the cervical nerves of the opposite side are 
divided, the torsion of the head disappears (Prince, 716). Sub- 
sequent experiments have shown that the processes of compensa- 
tion are related to a considerable degree to the cerebral hemi- 
spheres (Prince, 717). There is a strong presumption, at least, 
that afferent impulses from divers peripheral sources are nor- 
mally involved in the control of any motor reaction. All of these 
impulses of various kinds are necessary for the normal perform- 
ance of such a motor act. There is also a strong presumption 
that when one of these afferent channels is blocked by accident 
or disease, certain of the other channels may, by an increase in 
the quantity of energy which passes over them, compensate, in 
part at least, for the loss of the impulses which formerly came in 
over the damaged pathway. What is commonly called vicari- 
ous assumption of function may be a reality in this sense and 
in this degree. But it is not necessary to postulate the partici- 
pation in this process of compensation of any system or group of 
fibers which is not normally concerned in the control of the 
reactions in some degree. A more detailed account of this 
phase of the question will be presented in a forthcoming dis- 
cussion of some unpublished experiments on the otic labyrinth. 
(See also Wilson and Pike, °12.) 
I wish to say here, however, that the minimal deficiency of 
function would be an incorrect index of the actual function of 
such an organ as the otic labyrinth, as the index would be too 
low. I may remark in passing that Prince’s results effectually 
dispose of the italicized portions of Edinger’s remarks on the 
