ago. Hence they have brains of poor quality, a fact amply demonstrated by the 

 kangaroo when one watches his behavior in the zoological gardens. 



Every high-school graduate is well aware that the opossum, though it is a 

 marsupial, differs in psychological development from the kangaroo and the wom- 

 bat. The opossum is active and highly intelligent. He knows his way about the 

 world in which he lives. *'A 'possum up a gum tree" is accepted by observant 

 minds as the very incarnation of animal cunning and duplicity. In negro folk- 

 lore the resourceful 'possum takes the place of the fox in European stories ; he 

 is the Macchiavelli of wild beasts ; there is no ruse on earth of which he is not 

 amply capable ; and no wily manoeuvre exists which he cannot carry to an end 

 successfully. All guile and intrigue, the 'possum can circumvent even Uncle 

 Remus himself by his crafty diplomacy. And what is it that makes all the 

 difference between this 'cute marsupial and his backward Austrahan cousins? 

 It is the possession of a prehensile hand and tail. Therein lies the whole secret. 

 The opossum's hind foot has a genuine apposable thumb; and he also uses his 

 tail in climbing as a supernumerary hand, almost as much as do any of the mon- 

 keys. He often suspends himself by it, like an acrobat, swings his body to and 

 fro to obtain 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 prehensile tail. The result is that the 

 opossum, 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 

 acquired an unusual amount of general intelligence. And further, in the keen 

 competition for life, he has been forced to develop an amount of cunning which 

 leaves his Australian poor relations far behind in the Middle Ages of psycho- 

 logical evolution. 



At the risk of appearing to forsake my ostensible subject altogether, I must 

 pause for a moment to answer a very- obvious objection to my argument. How 

 about the dog and the horse? They have no prehensile organ, and yet they are 

 admitted 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 service- 

 able individuals having been deliberately selected from generation to generation 

 as dams and sires to breed from. We cannot fairly compare these artificial 

 human products 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 rudimentary 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 proportion 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, anybody who has ever kept 

 a parrot or a macaw in slavery is well aware that in no other birds do the claws 



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