CONSCIOUSNESS AND SENSATION. 105 



elements is very necessary to secure that end. 

 Thus it will be seen that the doctrine of brain- 

 action which is here proposed by no means 

 separates altogether the character of the mind 

 from dependence on that of the brain. There are 

 three elements on which the character of the brain 

 as affecting the mind may be safely presumed to 

 depend, viz., the intensity and ease of action pos- 

 sible to individual brain-elements, the total amount 

 of those elements, and, lastly, but possibly, most 

 important of all, the freedom and perfection of 

 communication of those elements one with an- 

 other. It may well be supposed that this last 

 requisite is more liable to be deficient in large 

 brains, as the distances are greater and the ele- 

 ments to be joined together more numerous in 

 them. 



In the structure of the brain there is the closest 

 affinity to the structure of the rest of the nervous 

 system, and its corpuscles are elements plainly 

 comparable with the living parts or protoplasm- 

 derivatives of other textures, and there is ground 

 to presume that in like manner the impressed 

 condition of nerve-corpuscles, whether in the brain 

 or elsewhere, and of nerve-fibres is analogous to 

 the contraction of muscular fibres and of amaeboid 

 corpuscles : the peculiarity of those of the hemis- 



