576 



WILL AND 



It seems safe to infer, therefore, that these portions of 

 the Brain are in some way related to the production of 

 Movements. The evidence pointing to such a conclusion 

 is, indeed, precisely similar in kind to that which leads to 

 the inference that the Corpora Striata are concerned with 

 the production of Movements. 



It is important, moreover, to mention that Burdon 

 Sanderson* and others have shown that the same special 

 Movements which follow irritation of special limited 

 portions of the Cortex may also he evoked, after removal 

 of this cortex, on stimulating corresponding regions of the 

 subjacent white substance, or even by stimulating portions 

 of the surface of the Corpora Striata themselves. 



It may therefore be regarded as fairly well-established 

 that the great majority of stimuli for the incitation of 

 Movements of the Voluntary and Ideo-motor types pass 

 off from the regions above specified of the parieto-frontal 

 Grey Matter ; that they traverse the intervening * white 

 substance ' to reach the Corpus Striatum of the same side, 

 thence to pursue the course already indicated through the 

 Cerebral Peduncle, the half of the Pons and Medulla, to 

 the opposite half of the Spinal Cord — from whose anterior 

 horns of Grey Matter the continuations of such cerebral 

 stimuli 23ass away by the * anterior roots' and * motor 

 nerves ' to appropriate groups of Muscles. 



So that if, since David Hume's time, we still have 

 not learned, in any full sense of the term, " the means" 

 by which " the motion of our bodies follows upon the 

 command of our Will," we have at least learned something 

 as to the parts chiefly concerned, and thus as to the paths 

 traversed by Volitional Stimuli. And this constitutes an 

 important advance in our knowledge of the mode of action 

 of the Brain as an Organ of Mind. 



* " Proceed, of Eoyal Society," June, 1874. 



