II
HUMAN TRAITS OF CHARACTER INHERITED FROM APES
The mental character of anthropoid apes—Their muscular strength—Their expression of fear—The awakening of latent instincts of man under the influence of fear
The facts of which I have given a résumé serve to show that evolution always leaves definite traces indicating its successive stages in the form of rudiments. It is probable, therefore, that the pre-human mental functions or psycho-physiological qualities, which have so long a history behind them, have also left more or less appreciable traces. These, however, must be more difficult to find than rudimentary organs which can be made visible by dissection.
If we turn first to the animals most nearly related to man, we find that the living anthropoid apes show in the clearest way their close relationship with the human race, and suggest that their kinship with our remoter ancestors must be even greater.
The anthropoid apes alive to-day are animals inhabiting chiefly virgin forests, and feeding on fruits and shoots, although they do not despise eggs or even little birds. To satisfy their wants, they climb with the greatest ease. Orang-outans and chimpanzees climb slowly and carefully, whilst gibbons show a greater agility and more perfect acrobatic power. They may be seen throwing themselves from branch to branch across spaces of forty feet with the greatest precision. They play at the top of very tall trees, hardly grasping the branches through which they pass, making leaps of from twelve to eighteen feet for hours together with little apparent exertion.
To give an idea of the dexterity and swiftness of gibbons, Martin took the case of a female which he observed in captivity. One time she hurled herself from a perch across a space at least twelve feet wide, against a window which one would have thought would have been immediately broken. To the great surprise of the spectators it was not broken. The gibbon seized with her hands the narrow board between the panes, and then in an instant twisted herself round and jumped back to the cage she had left, performing this manœuvre with great strength and the most marvellous precision.
The muscular force implied in the above narrative is possessed by all the anthropoid apes. Battel, an English sailor who gave the first description of the gorilla in the beginning of the 17th century, stated that the strength of that animal was so great that ten men could hardly master an adult specimen. The other anthropoids, although not so strong as the gorilla, nevertheless display surprising force.
Edouard, the young male chimpanzee which I used in my experiments on syphilis, struggled so much at the least touch that it took four men to master him. I had to give up allowing him to leave his cage because there was no way of getting him back to it. Even quite young chimpanzees, females not yet two years old, cannot be handled easily. Although they are very friendly, my specimens used to resist with all their strength when it was necessary to put them back in their cages for the night. Two men had much ado to shut them up.