82 THE CRITERIA OF LIVINGNESS 



A vivid statement of this characteristic feature of life 

 was given by Huxley in his Crayfish (1880, p. 84) : " The 

 parallel between a whirlpool in a stream and a living being, 

 which has often been drawn, is as just as it is striking. The 

 whirlpool is permanent, but the particles of water which 

 constitute it are incessantly changing. Those which enter 

 it, on the one side, are whirled around and temporarily con- 

 stitute a part of its individuality; and as they leave it on 

 the other side, their places are made good by new comers. 



" Those who have seen the wonderful whirlpool, three 

 miles below the Falls of Niagara, will not have forgotten 

 the heaped-up wave which tumbles and tosses, a very em- 

 bodiment of restless energy, where the swift stream hurrying 

 from the Falls is compelled to make a sudden turn towards 

 Lake Ontario. However changeful in the contour of its 

 crest, this wave has been visible, approximately 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 flowing into the animal on the one side, and stream- 

 ing out on the other." 



Without accepting the view that the organism is exhaust- 

 ively described by calling it " nothing but the constant form 

 of a turmoil of material molecules ", without forgetting that 

 the organism-whirlpool acts on the stream, and gives rise 

 to other whirlpools, we welcome the metaphor as vividly true 



