in] SPREADING 01 



spontaneous variations in every direction ; it is the 

 plasticity of the individuals, their being able to be 

 moulded by circumstances. That this plasticity 

 should react so quickly and to the point, if not 

 impaired or lost by specialisation, is itself the outcome 

 of the long training which protoplasm has undergone 

 since its creation. This very quickness seems to have 

 initiated our mistaking the variations called forth for 

 something latent or preformed. 



In nature's workshop the successful competitor is 

 not he who has ready an arsenal of tools for every 

 conceivable emergency, but he who can make a tool 

 on the spur of the moment. The ordeal of the 

 practical test is Darwin's and Wallace's elaborated 

 conception of natural selection. 



CHAPTER 111 



SPREADING 



SINCE there are now countless species and genera 

 with a very wide, continuous or scattered distribu- 

 tion they must have attained this range by spreading 

 from centres where the respective kinds made their 

 first appearance. The fundamental impulses to all 

 spreading, wandering, migrating are hunger and love 



