148 STUDIES, SCIENTIFIC AND SOCIAL chap. 



besides the two hands on their fore-limbs, they have also 

 two hands in place of feet on their hind-limbs. Modern 

 naturalists have given up the use of this term, because 

 they say that the hind extremities of all monkeys are 

 really feet, only these feet are shaped like hands ; but this 

 is a point of anatomy, or rather of nomenclature, which 

 we need not here discuss. 



Let us, however, before going further, inquire into the 

 purpose and use of this peculiarity, and we shall then see 

 that it is simply an adaptation to the mode of life of the 

 animals which possess it. Monkeys, as a rule, live in 

 trees, and are especially abundant in the great tropical 

 forests. They feed chiefly upon fruits, but occasionally 

 eat insects and birds'-eggs, as well as young birds, all of 

 which they find in the trees ; and, as they rarely have 

 occasion to come down to the ground, they travel from 

 tree to tree by jumping or swinging, and thus pass the 

 greater part of their lives entirely among the leafy 

 branches of lofty trees. For such a mode of existence, 

 they require to be able to move with perfect ease upon 

 large or small branches, and to climb up rapidly from one 

 bou^h to another. As they use their hands for gathering 

 fruit and catching insects or birds, they require some 

 means of holding on with their feet, otherwise they would 

 be liable to continual falls, and they are able to do this 

 by means of their long finger-like toes and large opposable 

 thumbs, which grasp a branch almost as securely as a 

 bird grasps its perch. The true hands, on the contrary, 

 are used chiefly to climb with, and to swing the whole 

 weight of the body from one branch or one tree to 

 another, and for this purpose the fingers are very long 

 and strong, and in many species they are further strength- 

 ened by being partially joined together, as if the skin of 

 our fingers grew together as far as the knuckles. This 

 shows that the separate action of the fingers, which is so 

 important to us, is little required by monkeys, whose hand 

 is really an organ for climbing and seizing food, while 

 their feet are required to support them firmly in any 

 position on the branches of trees, and for this purpose it has 

 become modified into a large and powerful grasping hand. 



