EMANCIPATION OF THE FORE LIMBS 17 



body weight is temporarily thrown upon its hind-limbs. 

 And, again, in reaching out its fore-limb, the freedom of 

 rotation possessed by the second segment of the limb 

 allows the animal to apply the palmar surface of its 

 " hand " against any new hold which may present itself 

 at almost any angle. 



From such a humble beginning great developments are 

 possible; and here we may observe that, without the 

 apprenticeship served in this lowly clambering, short cuts 

 to tree-climbing have never attained the same ultimate 

 perfection. As arboreal life becomes more complete, the 

 search for a new foothold will become a far more exact- 

 ing business than it is in the mere clambering we have 

 pictured. The more exacting this search becomes, the 

 more will there tend to be developed that most impor- 

 tant factor the, specialization of the functions of the fore 

 and hind limbs. While the animal reaches about with its 

 fore-limb, the hind-limb becomes the supporting organ. 

 With the evolution of this process there comes about a 

 final liberation of the fore-limb from any such servile 

 function as supporting the weight of the body : it becomes 

 a free organ full of possibilities, and already capable of 

 many things. This process I am terming the emancipa- 

 tion of the fore-limb, and its importance as an evolutionary 

 factor appears to me to be enormous. 



It will be noted that in the little picture we have drawn 

 of the process, we have, as it were, rescued the fore-limb ; 

 rescued it while still possessed of all its inherited power 

 of mobility, saved it from becoming an organ of mere 

 stability, and handed it over to an enterprising mammalian 

 stock to adapt to its needs. 



This picture may seem fanciful, and yet in reality it 

 is not so. I have thought it worth while to draw it thus, 

 since, without such a picture, there are many things very 

 difficult to understand. I will instance two such cases. 

 We have hurried almost breathlessly over the process 

 we have pictured, in a mental anxiety to arrive at emanci- 



