386 DARWINIANA. 



Darwinian doctrine in this respect. It may be briefly 

 illustrated thus: Natural selection is not the wind 

 which propels the vessel, but the rudder which, by 

 friction, now on this side and now on that, shapes the 

 course. The rudder acts while the vessel is in mo- 

 tion, effects nothing when it is at rest. Variation 

 answers to the wind : " Thou hearest the sound there- 

 of, but canst not tell whence it cometh and whither it 

 goeth." Its course is controlled by natural selection, 

 the action of which, at any given moment, is seem- 

 ingly small or insensible ; but the ultimate results are 

 great. This proceeds mainly through outward influ- 

 ences. But we are more and more ^ convinced that 

 variation, and therefore the ground of adaptation, is 

 not a product of, but a response to, the action of the 

 environment. Variations, in other words, the differ- 

 ences between individual plants and animals, however 

 originated, are evidently not from without but from 

 within not physical but physiological. 



We cannot here assign particularly the reasons 

 for this opinion. But we notice that the way in 

 which varieties make their appearance strongly sug- 

 gests it. The variations of plants which spring up in 

 a seed-bed, for instance, seem to be in no assignable 

 relation to the external conditions. They arise, as we 

 say, spontaneously, and either with decided characters 

 from the first, or with obvious tendencies in one or 

 few directions. The occult power, whatever it be, 

 does not seem in any given case to act vaguely, pro- 

 ducing all sorts of variations from a common centre, 

 to be reduced by the struggle for life to fewness and 

 the appearance of order ; there are, rather, orderly in- 



