THE ELEMENTS OF MIND 223 



These experiments show that animals of almost 

 proverbial density may learn with surprising 

 quickness. English sparrows and other avian 

 inhabitants of the city learn to live tranquilly 

 along the busiest thoroughfares, exposed to all 

 sorts of dangers, and subjected to what would be 

 to many birds the most terrifying circumstances. 

 Whizzing trolleys, tramping multitudes, and 

 screaming engines have no terrors for them. They 

 simply exercise the caution necessary to keep from 

 being run over. They boldly build their nests 

 right under passing elevated cars, where the roar 

 is sufficient to scare the life out of an ordinary 

 country bird. I have seen these testy little chaps 

 sit and feed and jabber to each other in a perfectly 

 unconcerned way within ten or fifteen feet of a 

 thundering express train. They do not do these 

 things from instinct : they learn to do them. 

 They know that a diabolical-looking locomotive 

 is harmless, because they have seen it before; 

 and they know that an insignificant urchin with 

 a savage heart and a sling is not harmless, and 

 they know it simply because they have previously 

 had dealings with him. English sparrows will 

 disappear completely from a neighborhood if a 

 few of them are killed. Cats, dogs, horses — all 

 animals, in fact — acquire during life a fund of 

 information as to how to act in order to avoid 

 harm and extinction. If they did not, they would 

 not live long. And they do it just as man does it, 

 by memory and discrimination, by retaining im- 

 pressions made upon them, and acting differently 



