110 LIFE IN NATURE. 



But, in truth, neither general arguments, nor 

 even an array of instances, are needed to give 

 conclusiveness to the evidence that the forms of 

 living bodies are mechanically determined. Startling 

 as the proposition may seem when it is first uttered,* 

 we no sooner clearly grasp the conception and see 

 what it means, than it becomes self-evident. It 

 is, indeed, an axiom, and is capable of being ex- 

 pressed in the most simple terms. The phenomena 

 of organization are in this respect an instance of 

 the necessary characters of motion. For it is the 

 nature of motion that it takes the direction of least 

 resistance. This is less a " law " of motion than 

 a part of its definition. No law can be imposed 

 on it, which can override this character ; for that 

 would be to alter the nature of motion itself: it 

 would be to assert for it a self-directive power. 

 In truth, the law of least resistance is involved in 



* The surprise with which it affects us is similar to that which 

 we feel, or might well feel, when we reflect that our sensations of 

 light or colour, of music or of warmth, are referred to motion. 

 The cause appears altogether inadequate to the effect. But we 

 have in science to accept many such strange things as at least 

 scientifically true. 



