EVOLUTIONARY SIGNIFICANCE OF HUMAN CHARACTER. 389 



history of the Vertebrata and of man, and is most developed in 

 the young, and better developed in women than in men. 



Tenacity has an opposite significance, being an especial charac- 

 teristic of maturity in the human mind. Hence it may have been 

 more general in early ages than at present, but could have little 

 value so long as the mind remained small in quantity. Curiously, 

 it is a quality which may co-exist with a good deal of impressibility. 



Fineness can only be a quality of full development, and is 

 totally independent of the other qualities. It is unknown among 

 savages, and is developed apparently in a few animals. Of inten- 

 sity it is difficult to say much definitely. The nervous operations 

 of animals often display the highest degree of this quality, and it 

 is not unlikely that its appearances differ as much in savages as 

 in civilized people. Its importance in mental action depends of 

 course on the kind and amount of mental function which exhibits 

 it. The same may be said of speed. The faculties which exist 

 are more or less affected by it. In the well-formed reason it is an 

 important characteristic, and a special form of development. 



Having gone as far into the origin and developmental relation 

 of mental functions and qualities as the nature of this sketch per- 

 mits, I refer briefly to the stimulus to their growth ; always re- 

 membering that the percentage of inherited qualities is much 

 larger in a given character than that of acquired ones. On this 

 head one word expresses a good deal, and that word is use. No 

 truth is better known than this one, that mental faculties develop 

 with use more rapidly than those of any other organ of the human 

 body. Brain and nerve are apparently the most plastic of all tis- 

 sues ; the one which retains the properties of the primitive pro- 

 toplasm, multiplied and intensified a thousand fold. It has al- 

 ways been the seat of creation, throwing off its " formed matter " 

 in useful directions. It is still doing so ; and in the human 

 brain, ever creating itself, is in addition the seat of a new creation, 

 which it executes through its instruments, the other organs of 

 the body. Hence the greatest sin against the brain is idleness, 

 or disuse. The brain activity of to-day is an indication of health 

 and happiness beyond what the world has seen hitherto. 



The greatest stimulus to exercise of the brain is human soci- 

 ety. Hence the greatest developments of mind have always been 

 in the centers of population. Whatever may be the passive vir- 

 tues of country life, it is the cities that furnish both the stimulus 

 and the field for the triumphs of mind. 



