12 THE BIOLOGY OF THE SEASONS 



Huxley compared a living creature to a whirlpool in 

 a river ; it is ceaselessly changing, yet always apparently 

 the same ; matter and energy stream in and stream out ; 

 it is the unessential flotsam that has most permanence ; 

 the whirlpool has an individuality and in varying degrees 

 a unity, yet it is wholly dependent upon the surrounding 

 currents. One may push the whirlpool metaphor too far, 

 so as to give a false simplicity to the facts, for there is no 

 denying that when vital whirlpools began to be, there also 

 emerged what cannot be discerned in the crystal or in the 

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

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

 whirlpool is a creative agent as well as a creature. To 

 ignore this is to attempt a falsely simple natural history. 

 But what Huxley's metaphor of the whirlpool does vividly 

 express is a great commonplace and a great truth the 

 fundamental dependence of living creatures upon their 

 surroundings. We cannot understand either the whirlpool 

 or the trout apart from the stream. 



A very important corollary of this fundamental every- 

 day relation has to do with development. In some way 

 which we cannot picture, the fertilised egg-cell contains 

 the potentiality of a particular living creature a tree, a 

 daisy, a horse, a man. If this inheritance is to be realised 

 there must be an appropriate environment, supplying not 

 merely food and oxygen, but essential liberating stimuli 

 of many kinds. Without this "nurture" the inherited 

 " nature " can achieve nothing. The development of 

 every character implies the interaction of the two sets of 

 factors the internal organisation and the external sphere 

 of influences. 



Since the " nurture " that plays an essential part in 

 the development of " nature " is changeful, it often induces 

 modifications in the young organism, and this modifiability 



