ORGANIC MOVEMENTS 93 



the enormous manifoldness of cerebral connexions it can 

 very well be imagined that certain apoplectical or experi- 

 mental disturbances will render functional reparation 

 impossible. In such cases there is no longer any connexion 

 between the points A and B, and clinical or experimental 

 defects are permanent. 



Specific Functions in the Adult 



But the permanency of such defects generally seems to 

 have other reasons, and I hope we shall learn to understand 

 them, if we now turn to study the second fundamental 

 feature concerned in cerebral organisation. The brain is 

 not only a system of connexions : it is something more. 

 The specific differences of sensations, to speak psychologically, 

 seem to require some specific arrangement in organisation, 

 specifically localised, which render the brain mequipotential 

 to a certain extent. 



And these arrangements are really found to exist. 

 Certain specific parts of the brain seem to have a specific 

 functional value that is more than a mere locality of specific 

 connexion, at least in the adult. Disturbances of these 

 " spheres," as they are called, by disease or experiment are 

 to a great extent irreparable. These cerebral specificities 

 would seem to be responsible for the specificity of " sensation," 

 and to justify as much of the old law of Johannes Mueller 

 as will stand criticism, at least with regard to the adult. 

 But they are not the only factors concerned in specific 

 sensation : the specificity of the process of centripetal 

 nervous conduction is another factor of importance. It is 

 now granted by the first authorities in this field that at 



