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ourselves, we have the fore limbs more or less differentiated in function 

 from the hind limbs, and set apart for the use of the brain as grasping 

 organs. In man himself, as you all know, this is carried on to its very 

 highest limit. Except when we are little children we do not run upon 

 our fore feet ; we have lost the use of our fore limbs as feet, and we 

 retain our hand as the highest characteristic man can possess of his 

 great origin — the servant of his brain, a perfect instrument for carrying 

 out the conceptions of the brain and of the intelligence with which he 

 is endowed. We might therefore expect, and I did expect, to find, if 

 I compared the hands and feet of higher groups of animals together, 

 great differences in these tendons. A certain amount of friction must 

 take place round the ankle-joint and round the wrist-joint ; and, as 

 friction helps the weaker force, I foresaw, if my principle of least 

 action were correct, that I should find, in the case of a hand or fore 

 limb of an animal, that the united strength of the tendons passing from 

 the muscles to the common tendon would be greater than the united 

 strength of the cross tendons applied to the toes or fingers. When I 

 grasp an object in my hand the force comes from the muscles of the 

 arm, passes through the tendons, and is then applied to the object 

 grasped. If the principle of least action in nature be true, the united 

 strength of the tendons above my wrist and below my wrist will not be 

 the same ; but advantage will be taken by nature of the necessary fric- 

 tion that takes place at the wrist to make the tendons in the fingers less 

 than the tendons in the arm by exactly the extent to which they are 

 relieved by friction. On the other hand, in using my leg as an instru- 

 ment of locomotion, the force comes by reaction from the ground up- 

 ward : the ground by reaction presses upon my foot ; the strength of 

 the tendons between the foot and ankle is exactly what is necessary to 

 prevent their rupture or injury ; and, in passing beyond my ankle into 

 the calf of the leg, I should expect, if the principle of least action be a 

 true principle, able to unlock the secrets of animal construction, to 

 find the reverse of what I found in the hand ; I should expect to find 

 the tendons which pass from the foot into the muscles having a less 

 cross-section than those which pass from the toes into the common tendon. 

 And this is actually the fact. I have examined upwards of eighty animals, 

 and I find that animals might be very fairly classified, according to 

 this peculiar arrangement of tendons in the hand or foot, as animals 

 that possess a grasping power and use their hands as hands, and animals 

 that are of a lower organisation, and use their fore feet not as hands 

 but as organs of locomotion. In the hand of the tiger there is a friction 

 of 22. 7 per cent; in the foot of 46 per cent. But those frictions, you will 

 observe, are reversed. The tendons of the fingers in the tiger's hand 

 are less than the tendons in the forearm ; and, vice versa., the tendons 

 of the toes of the tiger are greater than those of the leg ; so that, 



