ig8 THE BIOLOGY OF THE SEASONS 



contour of its crest, this wave has been visible, approxi- 

 mately in the same place, and with the same general form, 

 for centuries past. Seen from a mile off, it would appear 

 to be a stationary hillock of water. Viewed closely, it is 

 a typical expression of the conflicting impulses generated by 

 a swift rush of material particles. 



" Now, with all our appliances, we cannot get within a 

 good many miles, so to speak, of the crayfish. If we could, 

 we should see that it was nothing but the constant form 

 of a similar turmoil of material molecules which are con- 

 stantly blowing into the animal on the one side, and stream- 

 ing out on the other." 



While we agree that the metaphor is just and striking, 

 we feel that it has, like every other metaphor, its risks and 

 limitations. As we have said in another place, " One may 

 push the whirlpool metaphor too far, so as to give a false 

 simplicity to the facts, for when vital whirlpools began to 

 be, there also emerged what cannot be discerned in crystal 

 or dewdrop the will to live, a capacity of persistent experi- 

 ence, and the power of giving rise to other lives." 



But what especially concerns us at present is, that our 

 outlook on the animate world around us shows us at every 

 turn the contrast which we have reiterated the contrast 

 between constancy and novelty, between continuity and 

 new departures, between inertia and changefulness. On 

 the one hand, there is the remarkable constancy between 

 successive generations, the persistence of a specific average, 

 the racial inertia ; on the other hand, there is the continual 

 emergence of the new, the abundant crop of new departures, 

 the racial mutability. Commonly, but not very accurately, 

 the contrast is stated as that between heredity and varia- 

 tion. More accurately, it is the contrast between 

 vital arrangements which tend to preserve an already 

 established order, and others which provide the raw 



