"possum can circumvent even Uncle 

 Remus himself by his crafty diplomacy. 

 And what is it that makes all the differ- 

 ence between this 'cute marsupial and his 

 backward Australian cousins? It is the 

 possession of a prehensile hand and tail. 

 Therein lies the whole secret. The opos- 

 sum's hind foot has a genuine apposable 

 thumb ; and he also uses his tail in climb- 

 ing as a supernumerary hand, almost as 

 much as do any of the monkeys. He 

 often suspends himself by it, like an ac- 

 robat, swings his body to and fro to ob- 

 tain speed, then lets go suddenly, and 

 flies away to a distant branch, which he 

 clutches by means of his hand-like hind 

 foot. If the toes make a mistake, he can 

 recover his position by the use of his pre- 

 hensile tail. The result is that the opos- 

 sum, being able to form for himself clear 

 and accurate conceptions of the real 

 shapes and relations of things by these 

 two distinct grasping organs, has ac- 

 quired an unusual amount of general in- 

 telligence. And further, in the keen com- 

 petition for life, he has been forced to de- 

 velop an amount of cunning which leaves 

 his Australian poor relations far behind 

 in the Middle Ages of psychological evo- 

 lution. 



At the risk of appearing to forsake my 

 ostensible subject altogether, I must 

 pause for a moment to answer a very ob- 

 vious objection to my argument. How 

 about the dog and the horse ? They have 

 no prehensile organ, and yet they are ad- 

 mitted to be the most intelligent of all 

 -quadrupeds. The cleverness of the horse 

 and the dog, however, is acquired, not 

 original. It has arisen in the course of 

 long and hereditary association with man, 

 the cleverest and most serviceable indi- 

 viduals having been deliberately selected 

 from generation to generation as dams 

 and sires to breed from. We cannot fair- 

 ly compare these artificial human pro- 

 ducts with wild races whose intelligence is 

 entirely self-evolved. In addition, the 

 horse has, to a slight extent, a prehensile 

 organ in his mobile and sensitive lip, 

 which he uses like an undeveloped or ru- 

 dimentary proboscis with which he can 

 feel things all over. We may conclude, 

 I believe, that touch is "the mother- 

 tongue of the senses ;" and that in pro- 

 portion as animals have or have not 



highly developed and serviceable tactile 

 organs will they rank high or low in the 

 intellectual hierarchy of nature. It may 

 well be asked how all this concerns the 

 family of parrots. In the first place, any- 

 body who has ever kept a parrot or a 

 macaw in slavery is well aware that in no 

 other birds do the claws so closely resem- 

 ble a human or simian hand, not indeed 

 in outer form or appearance, but in ap- 

 posability of the thumbs and in perfec- 

 tion of grasping power. The toes upon 

 each foot are arranged in opposite pairs — 

 two turning in front and two backward, 

 which gives all parrots their peculiar 

 firmness in clinging on a perch or on the 

 branch of a tree with one foot only, while 

 they extend the other to grasp a fruit or 

 to clutch at any object they desire to pos- 

 sess. This peculiarity, it must be admit- 

 ted, is not confined to the parrots, for they 

 share the division of the foot into two 

 thumbs and two fingers with a large 

 group of allied birds, called, in the ex- 

 act language of technical ornithology, 

 the Scansorial Picarians, and more gen- 

 erally known by their several names of 

 cockatoos, toucans and wood-peckers. 

 All the members of this great group, of 

 which the parrots proper are only the 

 most advanced and developed family, 

 possess the same arrangement of the 

 digits into front-toes and back-toes, and 

 in none is the power of grasping an object 

 all round so completely developed and 

 so full of intellectual consequences. 



All the Scansorial Picarians are essen- 

 tially tree-haunters ; and the tree-haunt- 

 ing and climbing habit seems specially 

 favorable to the growth of intellect. 

 Monkeys, squirrels, opossums, wild cats, 

 are all of them climbers, and all of them, 

 in the act of climbing, jumping, and bal- 

 ancing themselves on boughs, gain such 

 an accurate idea of geometrical figures, 

 distance, perspective and the true nature 

 of space-relations, as could hardly be ac- 

 quired in any other way. In a few words, 

 they thoroughly understand the tactual 

 realities that answer to and underlie each 

 visible appearance. This is, in my opin- 

 ion, one of the substrata of all intelli- 

 gence; and the monkeys, possessing it 

 more profoundly than any other animals, 

 except man, have accordingly reached a 

 very high place in the competitive ex- 



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