202 THE FOUNDATIONS OF ZOOLOGY W: 



is there any occasion upon which the reflex mechanism concerne 

 therein can ever have been of adaptive tisef Until a man's leg 

 have been paralyzed as to their voluntary motion, he will alway 

 promptly withdraw his feet from any injurious source of irritatio 

 by means of his conscious intelligence. True, the reflex mechar 

 ism secures an almost inappreciable saving in the time of respons 

 to a stimulus as compared with the time required for response t 

 an act of will; but the difference is so exceedingly small, that w 

 can hardly suppose the saving of it in this particular case can b 

 a matter of any adaptive — much less selective — importance. 



" Nor is it more, easy to suppose that the reflex mechanisr 

 has been developed by natural selection for the purpose of repla( 

 ing voluntary action when the latter has been destroyed or sm 

 pended by grave spinal injury, paralysis, coma, or even ordinar 

 sleep. In short, even if for the sake of argument we allow it t 

 be conceivable that any human being, ape, or still more distar 

 ancestor, has ever owed its life to the possession of this mechar 

 ism, we may still be certain that not one in a million can hav 

 done so. And if this is the case with regard to the mechanisr 

 as fully constructed, still more must it have been the case wit 

 regard to all the previous stages of construction. For here, wit! 

 out elaborating the point, it would appear that a process of cor 

 struction by survival of the fittest is incomprehensible." ^ 



As Romanes says that this is a typical illustration of the diff^ 

 culty he finds in explaining the production of reflex actions i 

 general by selection alone, it may be worth while to examine it 

 although the source of Romanes's difficulty is hard to discover. 



When all the complicated muscles of the foot and leg an 

 trunk are at rest, the irritation of the sole may be followed by vie 

 lent retraction of the foot, but when they are brought into ba 

 anced action in the complex movements of walking or running ^ 

 this does no more than to counterbalance and thus arrest som 

 of these movements. The importance of perfect locomotor cooi 

 dination is so clear to all that a moment's thought must sho\ 

 that the past history of our race has furnished abundant oppoi 

 tunities for the perfection of this coordination by selection. N 

 one who reflects how often the life of a barefooted savage ajy 



1 '* Darwin and after Darwin," II., pp. 73-77. 



