WAYS OF NATURE 



shallow its wit. When a cat or a dog, or a horse or 

 a cow, learns to open a gate or a door, it shows a 

 degree of intelligence — power to imitate, to profit 

 by experience. A machine could not learn to do 

 this. If the animal were to close the door or gate be- 

 hind it, that would be another step in intelligence. 

 But its direct wants have no relation to the closing 

 of the door, only to the opening of it. To close the 

 door involves an after-thought that an animal is not 

 capable of. A horse will hesitate to go upon thin ice 

 or upon a frail bridge, even though it has never had 

 any experience with thin ice or frail bridges. This, 

 no doubt, is an inherited instinct, which has arisen 

 in its ancestors from their fund of general experience 

 with the world. How much with them has depended 

 upon a secure footing! A pair of house wrens had 

 a nest in my well-curb ; when the young were partly 

 grown and heard any one come to the curb, they 

 would set up a clamorous calling for food. When I 

 scratched against the sides of the curb beneath them 

 like some animal trying to climb up, their voices 

 instantly hushed; the instinct of fear promptly 

 overcame the instinct of hunger. Instinct is intelli- 

 gent, but it is not the same as acquired individual 

 intelligence; it is untaught. 



When the nuthatch carries a fragment of a hick- 

 ory-nut to a tree and wedges it into a crevice in the 

 bark, the bird is not showing an individual act of 

 intelligence : all nuthatches do this ; it is a race 

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