ANIxMAL PSYCHOLOGY. 265 



ually or meclianically must first be learned by an 

 exercise of intelligence. It is a very unsatisfactory 

 explanation of the works of a beaver, to affirm that 

 he was endowed at his birth with a mechanical skill 

 which, by the laws of mind, must be acquired by 

 experience. An assertion that the acts of a beaver in 

 felling a tree, in constructing a dam, or in excavating a 

 canal, are beyond his intelligence, is mere assumption, 

 as well as a contradiction of terms. This conclusion 

 flows legitimately from the original blunder of at- 

 tempting arbitrarily to endow animals with a super- 

 natural principle, which enables them to perform 

 ignorantly and blindly works of intelligence and 

 knowledge. While this mysterious "agent" performs 

 its office intelligently, the animal is a mere machine, 

 according to the theory of Descartes. In other words, 

 he is made a dwelling for a principle of intelligence; 

 but this principle being superior to, and in some way 

 independent of, the mute, holds no other relation to 

 him than that of master and guide. Can anything 

 be found in the whole range of human speculation 

 more feeble than this expedient of human reason to 

 explain a class of phenomena as simple as the sim- 

 plest in the natural world? 



The practice of beavers, while moving their short 

 cuttings by water, of placing one end against the 

 throat and pushing it from behind, of carrying mud and 

 stones under their throats, holding them there with 

 the paws, and of packing mud upon their lodges and 

 dams by a stroke of the tail, have elsewhere been ex- 

 plained. They are severally intelligent acts, performed 

 sensibly and rationally. Their method of shoving or 

 rolling the larger billets of wood with their hips is 



