ii8 GRAND STRATEGY OF EVOLUTION 



new combinations of germinal materials, inevitably 

 quickens or releases some new form of growth, local 

 or general. These new products may, or may not, be 

 of immediate constructive value, but in any case their 

 presence upsets preexisting relations, and inevitably 

 creates, elsewhere, new checks, or releases, to the lurk- 

 ing power of growth. Moderate impact, stress, and 

 strain modify the growth of the parts so affected, and 

 thereby modify their resistance, or their response, to 

 these strains and stimuli. All actions and reactions 

 tend to take the shortest route, and the easiest way. The 

 pathways of exchange are laid out,, cleared, and 

 strengthened by using, and they are preempted, or com- 

 mandeered for service, according to their cooperative 

 value and prior constructive necessity. 



Thus growth itself creates a diversified internal en- 

 vironment, and this internal environment controls the 

 progress of growth, because it controls the administra- 

 tion of supplies to its constituent parts. Each point 

 that is better served promptly responds by increased 

 growth, and increased power of service. It dwindles 

 when poorly served; and as it dwindles, so do its de- 

 mands for service. Thus the service of the served 

 flourishes apace; and the servant is fortified by his own 

 service. But the servant that is unserved perishes, and 

 his power to serve perishes with him. 



III. The External Administration of Life 



Thus while the internal environment of the indi- 

 vidual is self-created, this is by no means the case with 

 its external environment. Life cannot create, nor can 

 it modify, except to a very limited extent, its external 



