CHAPTER III 



THE DEVELOPMENT OF THE POWER OF GRASP 



WE have noted that the primitive animal we have been 

 picturing could place the palm of its hand against any 

 new hold with which it came into contact, and that the 

 power of rotation possessed by its forearm enabled this 

 contact to take place at a variety of angles. Its palms, 

 for instance, may both be turned inwards so that a branch 

 or other object can be held between their two opposed 

 surfaces. This is a power which remains in the possession 

 of many animals even after they have lost much of the 

 primitive mobility of the fore-limb in quadrupedal life. 

 As a general rule, the hopping animals and the semi- 

 arboreal animals retain sufficient mobility to do this. 

 Some of them can hold their food pressed between the 

 two palms, and so are enabled to sit up and eat food held 

 between their fore-paws. Others, which cannot attain 

 to this, yet preserve sufficient mobility of the fore-limb 

 to enable them to use it for a variety of minor purposes. 

 The more thoroughly quadrupedal the animal is, the less 

 is it able to turn its fore-limb to these minor uses. 

 Familiarly, we may note that the typically quadrupedal 

 dog will use its hind-feet for scratching, even the fore-end 

 of its body; while the cat will scratch and wash its face 

 with its fore-foot. But we are dealing, in possibilities, 

 with something far bigger and more important than such 

 things as these. We must not forget that in rescuing 

 the fore-limb in its primitive mobile stage, before quadru- 

 pedal life had in any way impaired its power of rotation, 

 we saved not only a primitive second segment, but a 

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