4 The Descent of Man 



the action of ' natural selection.' For though the ' survival 

 of the fittest ' is a truth which readily presents itself to any 

 one who considers the subject, and though its converse, the 

 destruction of the least fit, was recognised thousands of years 

 ago, yet to Mr. Darwin, and (through Mr. Wallace's reti- 

 cence) to Mr. Darwin alone, is due the credit of having first 

 brought it prominently forward and demonstrated its truth 

 in a volume which will doubtless form a landmark in the 

 domain of zoological science. 



We find even in the third edition of his Origin of Species 

 the following passages : — ' Natural selection can act only by 

 taking advantage of slight successive variations ; she can never 

 take a leap, but must advance by short and slow steps' 

 (p. 214). Again he says : — ' If it could be demonstrated that 

 any complex organ existed, which could not possibly have 

 been formed by numerous, successive, slight modifications, 

 my theory would absolutely break down. But I can find out 

 no such case ' (p. 208). He adds : — 



' Every detail of structure in every living creature (making some 

 Httle allowance for the direct action of physical conditions) may be 

 viewed, either as having been of special use to some ancestral form, 

 or as being now of special use to the descendant of this form — either 

 directly, or indirectly through the complex laws of growth ; ' and ' if 

 it could be proved that any part of the structure of any one species 

 had been formed for the exclusive good of another species, it would 

 annihilate my theory, for such could not have been produced through 

 natural selection.' — P. 220. 



It is almost impossible for Mr. Darwin to have used words 

 by which more thoroughly to stake the whole of his theory on 

 the non-existence or non-action of causes of any moment 

 other than natural selection. For why should such a pheno- 

 menon ' annihilate his theory ' ? Because the very essence of 

 his theory, as originally stated, is to recognise only the con- 

 servation of minute variations directly beneficial to the 



