M. Frederic Cuvier. 7 



penetration, his cunning, his address ; but when he reaches his 

 adult state, he is nothing else but an animal, gross, brutal, and 

 untractable. And it is the same with all Monkeys as with the 

 orang-outang. In the whole of them intelligence diminishes 

 in proportion as their strength increases. An animal, con- 

 sidered then as a pei'fectible being, has a limit marked not only 

 according to his kind, but also as to his individuality. The 

 animal of the greatest intelligence is possessed of this intel- 

 ligence only in its younger years. 



After having fixed the limits which distinguish the intelli- 

 gence of the different species, M. F. Cuvier investigated the 

 limit which separates instinct from intelligence r and it was 

 particularly in respect to the beaver that he prosecuted his ob- 

 servations on this point. 



The beaver is a mammal of the order Bodentia, that is 

 to say, of that order which, as we have seen, has the smallest 

 share of intelligence ; but he has a wonderful amount of in- 

 stinct, whereby he constructs a hut, builds it in water, guards 

 it with dykes, and supplies it with causeways, and all this with 

 an industry which would undoubtedly lead us to assign a very 

 superior degree of intelligence to this animal, if that industry 

 depended upon intelligence. The important matter was to 

 prove that it had no such dependence, and this M. F. Cuvier 

 accomplished. He took beavers while still very young, and 

 reared them far from their parents, where of course they could 

 receive no instruction from them ; and these beavers, thus iso- 

 lated and solitary, confined to a cage, for the very purpose 

 that they might have no occasion to build, notwithstanding did 

 build, impelled by a mechanical and blind force ; in a word, 

 by a pure instinct. 



The most complete opposition distinguishes instinct from in- 

 telligence. In instinct all is blind, necessary, unchanging ; in 

 intelligence all is elective, conditional, and modifiable. The 

 beaver who constructs his hut, and the bird which makes its 

 nest, act solely by instinct. The horse and dog, which readily 

 learn the meaning of many of our words, and which obey us, 

 do so in virtue of intelligence. Every thing in instinct is in- 

 nate ; the beaver constructs without having been taught : 

 all is ordained ; the beaver builds overpowered by a force 



