594 CEREBRAL MENTAL SUBSTRATA. 



thing to do with another fact, viz., that the left Hemi- 

 sphere is the most potent, and seems to take the lead i& 

 giving rise to the Voluntary Impulsions which determine 

 the muscular acts involved in Articulate Speech.* 



In regard to our ' ideas ' of "Words the symbols with 

 which our Thoughts are inextricably interwoven these 

 are, for the most part, complex, the components (as in 

 the case of simple Perceptions) being dependent upon the 

 activity of different Centres which need not always act 

 together and in their order of importance are probably 

 to be enumerated as the Auditory, the Visual, and the 

 Kinaesthetic. 



Of these modes of ' ideal ' recall of Words, the two 

 former are distinct and easily recoverable, while the latter 

 is characteristically vague and difficult of conscious 

 realization. Let any one contrast his idea of the sound 

 of the word ' London,' or his idea of the appearance of the 

 word when printed or written, with his idea of the mus- 

 cular and other feelings associated with the articulation of 

 the same word, and the inferiority in definiteness and 

 recoverabiiity of the latter will at once become obvious. 

 There is nothing surprising in this, however, since we 

 know that the tendency of Kinaesthetic Impressions 

 generally is that they should, like Visceral Impressions, 

 soon come to affect the motor machinery of our bodies 

 without arousing our Consciousness. In such animals as 

 are born with their motor acquirements already well-nigh 

 complete (pp. 188, 229), Kinaesthetic Impressions probably 

 enter as little into their conscious Mental Life as mul- 

 titudes of Visceral Impressions enter into our own. 



Speech has already become, for the human race, a 



* See p. 403, and also Dr. Lombard in " Proceed, of the Eoyal 

 Society," 1878, pp. 463, 464. 



