PRETTY POLL. 77 



with his proverbial courtesy -will kindly pardon me the 

 inevitable use of such very bad words), are essentially 

 tree-haunters ; and the tree-haunting and climbing 

 habit, as is well beknown, seems particularly favourable 

 to the growth of intelligence. Thus schoolboys climb 

 trees but I forgot : this is a scientific article, and such 

 levity is inconsistent with the dignity of science. Let us 

 be serious ! Well, at any rate, monkeys, squirrels, 

 opossums, wild cats, are all of them climbers, and all of 

 them, in the act of clinging, jumping, and balancing 

 themselves on boughs, gain such an accurate idea of 

 geometrical figure, perspective, distance, and the true 

 nature of space-relations, as could hardly be acquired in 

 any other manner. In one word, they thoroughly 

 understand space of three dimensions, and the tactual 

 realities that answer to and underlie each visible appear- 

 ance. This is the very substratum of all intelligence ; 

 and the monkeys, possessing it more profoundly than any 

 other animals, have accordingly taken the top of the form 

 in the competitive examination perpetually conducted by 

 survival of the fittest. 



So, too, among birds, the parrots and their allies climb 

 trees and rocks with exceptional ease and agility. Even 

 in their own department they are the great feathered 

 acrobats. Anybody who watches a woodpecker, for 

 example, grasping the bark of a tree with its crooked 

 and powerful toes, while it steadies itself behind by 

 digging its stiff tail-feathers into the crannies of the 

 outer rind, will readily understand how clear a notion 

 the bird must gain into the practical action of the laws 

 of gravity. But the true parrots go a step further in the 



