On the Scientific Study of Human Nature. 475 



principle applies, even in a more marked degree, to the 

 cerebral system. Every one knows that hearty digestion 

 and violent exercise lower the mental activity that is, the 

 forces are diverted from the brain, and thrown upon the 

 stomach and muscles. 



That the purely intellectual powers are also subject to 

 limitation is unquestionable. All minds are fissured with 

 incapacities in one direction or another clipped away on 

 this side or on that all are fragmentary. There may be 

 great mathematical ability, but no imagination ; fine 

 poetical gifts, without logical faculty ; large executive 

 power, coupled with deficient judgment. Dr. Whewell 

 had a powerful memory for books, but a very bad one for 

 persons ; Sir William Hamilton cultivated the lore and his- 

 tory of philosophy at the expense of his power of origina- 

 tion and organization ; Prescott was so irresolute that he 

 could only spur himself to his literary tasks by the stimulus 

 of betting with his secretary that he would do a certain 

 amount of work in a given time ; Theodore Parker was 

 loaded with erudition, but exclaimed on his premature 

 deathbed, " Oh, that I had known the art of life, or found 

 some book, or some man to tell me how to live, to study, 

 to take exercise." The greatest men are all dunces in 

 something : Shakespeare and Newton illustrate the law as 

 absolutely as the veriest weakling of the asylum. The 

 full-orbed intellect is yet to come, and will doubtless 

 bring with it the " perpetual motion " and the Jews' 

 " Messias." 



These phenomena find no explanation in the old hypoth- 

 esis of mind as a vague, spiritual entity ; they throw us 

 back immediately on the organism whose acknowledged 

 limitations offer at once a solution of the mystery. These 

 mental inaptitudes may be either organic deficiencies, or a 

 result of concentrating the cerebral energy in certain 

 directions, and its consequent withdrawal from others. 



