4QO GENERAL BIOLOGY 



often hear on the streets, spoken by the leader of a group of 

 laborers. The efficiency of such symbols depends upon their 

 being understood; there must be general acquiescence in 

 their use. 



How words, as condensed and convenient symbols of 

 experience, have aided mental development has recently 

 been well expressed by a British physiologist, Professor 

 Starling, as follows : 



"A word is a fairly simple motor act, and produces a 

 correspondingly simple sensory impression. Every word, 

 however, is a shorthand expression of a vast sum of expe- 

 rience, and by using words as counters it becomes possible 

 to increase enormously the power of the nervous system to 

 deal with its own experience. Education now involves the 

 learning of these counters and of their significance in sense 

 experience; and the reactions of the highest animal, man, 

 are for the most part carried out in response to words, and 

 are governed by past education of the experience-content 

 involved in each word." 



Without language one may profit by the experience of 

 others only to the extent that he is an observer of that 

 experience; but experience symbolized in words may be 

 dissociated from the individual and told abroad. 



Tool using. — Man is the only animal that uses tools. 

 Monkeys will throw down cocoanuts from trees in imitation 

 of or response to stones thrown up at them: and a little 

 wasp Ammophila uses a pebble held by her jaws to pound 

 down the soft earth over her completed nest. But even so 

 simple an idea as the using of a club for defense appears not 

 to have emerged in the mind of any animal. Man, however, 

 had both more need to supplement his weak powers, and 

 more range for adaptive action provided in the accessory 

 circuits of his brain. 



