Perhaps the opossum is the very best and most crucial instance that could possibly be adduced of the intimate connection which exists between touch and intellect. For the opossum is a marsupial; it belongs to the same group of lowly-organized, antiquated, and pouch-bearing animals as the kangaroo, the wombat, and the other belated Australian mammals. Now everybody knows the marsupials as a class are nothing short of preternaturally stupid. They are just about the very dullest and silliest of all existing quadrupeds. And this is reasonable enough, when one comes to think of it, for they represent a very antique and early type, the first rough sketch of the mammalian idea, if I may so describe them, with wits unsharpened as yet by contact with the world in the fierce competition of the struggle for life as it displays itself on the crowded stage of the great continents. They stand, in short, to the lions and tigers, the elephants and horses, the monkeys and squirrels, of Europe and America, as the Australian blackfellow stands to the Englishman or the Yankee. They are the last relic of the original secondary quadrupeds, stranded for ages in a remote southern island, and still keeping up among Australian forests the antique type of life that went out of fashion in Europe, Asia, and America before the chalk was laid down or the London Clay deposited on the bed of our northern oceans. Hence they have still very narrow brains, and are so extremely stupid that a kangaroo, it is said--though I don't vouch for it myself--when struck a smart blow, will turn and bite the stick that hurts him instead of expending his anger on the hand that holds it.
Now, every Girton girl is well aware that the opossum, though it is a marsupial too, differs inexpressibly in psychological development from the kangaroo and the wombat. Your opossum, in short, is active, sly, and extremely intelligent. He knows his way about the world he lives in. 'A 'possum up a gum-tree' is accepted by the observant American mind as the very incarnation of animal cleverness, cunning, and duplicity. In negro folk-lore the resourceful 'possum takes the place of Reynard the Fox in European stories: he is the Macchiavelli of wild beasts: there is no ruse on earth of which he isn't amply capable, no artful trick which he can't design and execute, no wily manoeuvre which he can't contrive and 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 Yankee marsupial and his backward and belated Australian cousins? Why, nothing but the possession of a prehensile hand and tail. Therein lies the whole secret. The opossum's hind foot has a genuine opposable thumb; and he also uses his tail in climbing as a supernumerary hand, almost as much as do any of the monkeys. He often suspends himself by it, like an acrobat, swings his body to and fro to get up steam, then lets go suddenly, and flies away to a distant branch, which he clutches by means of his hand-like hind feet. If the toes play him false, he can 'recover his tip,' as circus-folk put it, with his prehensile tail. The consequence 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 of the American continent, he has been forced to develop an amount of cleverness and low cunning which leaves his Australian poor relations far behind in the Middle Ages of evolution.