162 ORGANIC EVOLUTION — MENTAL 



stimulation. The acquired characteristics of the fully- 

 developed mind, like those of the body, possess a certain 

 fixitj', which, since mind is in a sense the product of a 

 physical structure, the brain, is exactly what was to be 

 expected. Therefore it is that adult animals do not so 

 readily change their acquired mental traits as young 

 animals; therefore do slave-holding ants capture only 

 the pupae of the servile species ; therefore do we usually 

 fail in taming adult wild animals, except in some few 

 cases (e. g. monkeys and elephants), when the power of 

 acquiring mental traits is so great, that new traits may 

 be superimposed even in the adult animal on traits 

 previously acquired in youth ; and therefore is the right 

 training of young human beings so highly important. 



It is within the knowledge of every one that many 

 animals, like men, afford tuition to their offspring, that 

 they endeavour to develop in them the traits that 

 conduce best to survival. The higher the animal, the 

 smaller its equipment of instinct, the greater its power 

 of acquiring mental traits, the more elaborate is the 

 system of education to which it is subjected. The 

 instinct which impels the human mother to teach her 

 offspring is developed in bird and beast as welL 

 Poultry may be seen in every farmyard instructing 

 their broods in the arts of discovering food or of avoiding 

 enemies. In our homes the cat plays a game of hide- 

 and-seek with her kittens, mimicking the hereditary 

 warfare against mice. Books of sport and travel tell 

 how wild dogs, bears, lions, tigers, and especially 

 elephants and monkeys, instruct their young. All 

 higher creatures, in fact, instinctively seek by example 

 to educate the next generation, which by virtue of 

 strong, imitative instincts is able to profit by the 

 lessons. Thus, the instinct of the parent assists in 

 the development of reason in the offspring, but in this 

 the instinct of the offspring also assists. The sports in 



