S 6 THE THEORY OF CHANGE OF FUNCTION 



clear that the eye will as a whole have improved 

 and have become more perfect. Similarly with the 

 hand or with any other of the organs of the body ; 

 formerly less complex, it has acquired its present 

 complexity and perfection as the result of accumu- 

 lations of a long series of small but useful modifica- 

 tions. Each of these modifications must give some 

 distinct advantage to its possessor or else it would 

 not be preserved or perpetuated. 



It has been objected that this explanation is not 

 sufficient ; that although it will account for the 

 gradual perfection and increasing complexity of an 

 organ after it has attained a certain size and after 

 it has assumed its definite function, yet that it fails 

 completely to explain the first origin of such 

 organs ; for in their earliest origin they must have 

 been very minute and absolutely incapable of 

 fulfilling or even aiding in the function which they 

 are afterwards destined to perform. 



This objection, which is the one I wish to 

 consider to-night, must be confessed at once to be 

 of very great weight, and is indeed freely acknow- 

 ledged to be so by Darwin himself. By some 

 writers, such as Mivart (almost the only English 

 naturalist of any repute who at the present day 

 rejects the doctrine of Natural Selection), it is 

 indeed considered as absolutely fatal to the whole 

 theory. We shall perhaps get a clearer idea of 

 the nature and force of the objection by consider- 

 ing one or two examples which bring it forward 

 prominently. 



The limb of a Vertebrate in its earliest stage is a 



