hide behind the curtains and pretend to be in great alarm when discovered. Probably the readiness with which infants play at "bo-peep," and peer round the edge of a cradle curtain, and then suddenly draw back into hiding, is traceable to a much earlier ancestor. Here we see the remains of a habit common to nearly all arboreal animals, and the cradle curtain, or chair, or what not, is merely a substitute for a part of the trunk of a tree behind which the body is supposed to be hidden, while the eyes, and as little else as possible, are exposed for a moment to scrutinize a possible enemy and then quickly withdrawn.
It is remarkable how quickly very young children notice and learn to distinguish different domestic animals. I have known several cases in which an infant under a year old, which could not talk at all, has recognized and imitated the cries of sheep, cows, dogs, and cats, and evidently knew a horse from an ox. Not infrequently I have heard great surprise expressed by parents at the quickness with which a baby would perceive some animal a long distance off, or when from other causes it was so inconspicuous as to escape the eyes of older persons. Pictures of animals, too, have a great fascination, and the child is never tired of hearing its playmate roar like a lion or bray like an ass when looking at them in the picture-book. This may seem of trivial import; but it is worth while to remember that the baby's forefathers for several thousand generations depended upon their knowledge of the forms and ways of wild beasts in order to escape destruction, either from starvation or from being overcome and devoured in contests with them; and that any and every individual who was a dunce at this kind of learning was in a short time eliminated. Hence an aptness to notice and gain a knowledge of different animals was essential to those who wished to survive, and a faculty so necessary, and so constantly operative through long ages, would be likely to leave traces in after-generations.
Among all arboreal apes the ability firmly to hold on to the branches is, of course, extremely important, and in consequence they have developed a strong power of grip in the hands. The late Frank Buckland compares the hands of an anthropoid ape to grapnels, from their evident adaptation to this end. Nor does this power exist only among adults, for although most apes, when at rest, nurse their young on one arm, just as does a mother of our own species, when, as often happens, they are fleeing from an enemy, such as a leopard or some other tree-climbing carnivorous animal, the mother would need all her hands to pass from branch to branch with sufficient celerity to escape. Under such circumstances the infant ape must cling on to its mother as best it can; and naturalists who have repeatedly seen a troop of monkeys in full flight state that the young ones as a rule hang beneath the
