FUNCTIONS OF THE BRAIN. 563 



The question, however, still recurs; — What 

 relation does all this artificial intertexture and 

 accumulation of fibres bear to the mental opera- 

 tions of which we are conscious, such as memory, 

 abstraction, thought, judgment, imagination, vo- 

 lition ? Are there localities set apart for our 

 different ideas in the store-house of the cerebral 

 hemispheres ; and are they associated by the 

 material channels of communicating fibres ? 

 Are the mental phenomena the effects, as was 

 formerly supposed, of a subtle fluid, or animal 

 spirits, circulating with great velocity along 

 invisible canals in the nervous substance; or 

 shall we, with Hartley, suppose them to be the 

 results of vibrations and vibratiuncles, agitating 

 in succession the finer threads of which this 

 mystic web has been constructed ? A little 

 reflection will suffice to convince us that these, 

 and all other mechanical hypotheses, which the 

 most fanciful imagination can devise, make not 

 the smallest approach to a solution of the diffi- 

 culty ; for they, in fact, do not touch the real 

 subject to be explained, namely, how the affec- 

 tions of a material substance can influence and 

 be influenced by an immaterial agent. All that 



generally supposed. He observed that its fibres are interlaced 

 in the most intricate manner ; resembling the plexuses met with 

 among the nerves, and establishing the most extensive and 

 general communications between every part of the cerebral 

 mass. 



