FUNCTIONS OF THE MEMBERS. 



dominion over the inferior species, which he never could obtain by 

 his natural strength or swiftness. 



Like that of the superior classes of Mammifers generally, the 

 human body is supplied with four members ; the superior, or arms 

 and hands, and the inferior, or 

 legs and feet. It is found in the 

 works of nature, as in those of art, 

 that the more extensively the 

 principle of the division of labour 

 is carried out, the greater will be 

 the perfection of the instruments. 

 A tool or a machine, which attains 

 two purposes, attains neither of 

 them so perfectly as would two 

 tools or machines especially adapted 

 to the execution of each. Now we 

 find, on comparing man with the 

 inferior animals, that he supplies a 

 solitary example of the rigorous 

 application of the principle of the 

 division of labour in the functions of his members. The neces- 

 sities of its well-being require that the creature should be 

 supplied with members to seize and members to pursue the 

 objects of its nutrition. Hence arises the necessity for members 

 of prehension and members of locomotion. In some of the inferior 

 animals, as, for example, certain quadrupeds, the four members 

 are exclusively locomotive, the act of prehension being confined to 

 the mouth. In others, however, all the four members, besides 

 fulfilling the functions of locomotion, are more or less prehensile, 

 thus serving a double purpose, and therefore, according to the 

 principle explained above, serving it by comparison less perfectly. 

 In some, the prehensile functions of the four members prevailing 

 over their locomotive functions, naturalists have given them the 

 name of quadrumana, or four-handed, in contradistinction to that 

 of quadrupeds, or four-footed, given to those species whose members 

 are more exclusively locomotive. 



9. In man alone are found at once members which are exclu- 

 sively prehensile, and others exclusively locomotive. 



10. The superior members are disposed in a manner most 

 favourable for prehension and touch. By the peculiar mechanism 

 of the shoulder-joint, the arm can be directed with nearly equal 

 facility upwards, downwards, forwards, and backwards. The 

 fore-arm at the same time being hinged upon the elbow, and the 

 hand upon the wrist, a still more varied play is given to the hand, 

 the immediate instrument of prehension. But even with this 



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