The Explanation of Adaptations. 611 



in the first part of the first volume (p. 198). and our 

 consideration of those species which, are rich in suhonh- 

 nate forms, as well as the results ohtained with Oenothera 

 Laniarckiana have justified this claim. Thus we see that 

 the current form of the theory of selection cannot sui)i)lv 

 the kind of variability which the theory demands, whil^1L 

 the doctrine of mutation can supply it, as we know from 

 actual observation. 



III. The first insignificant beginnings of nezv charac- 

 ters do not come under the operation of natural selection 

 since they are of no significance in the struggle for ex- 

 istence. This is the best known objection against the 

 prevailing form of the theory of selection. It has been 

 elaborated by many authors and admirably expressed by 

 Conn in his w^ork cited above, so that we need not deal 

 with it further here. It ultimately leads every th<niglitl'ul 

 investigator to the view that every organ must have its 

 origin in a discontinuous variation.^ The doctrine of mu- 

 tation alone can overcome these difficulties although we 

 must not forget that the objection is directed only against 

 the present form of the theory of selection and not against 

 Darwin's own conception of it; for if the sieve of selec- 

 tion does no more than eliminate those of less fitness, and 

 if its function is merely to increase the mean of th(\se 

 that remain, even the very slightest average progress 

 must have a result, as Darwin so frequently insisted. 



In the doctrine of mutation, however, these >;low tran- 

 sitions and these slight advantages have no place. Spe- 

 cies-forming variability sim])ly omits these, both in rx- 

 pcrimcnt and in liorticultural experience, so that they 

 constitute no obstacle to the theorv." 



' CoxN, toe. cit., p. 134. 



'Tt IS ill tlic explanation of instinct tliat tlic current form of tlic 



