i So GRAND STRATEGY OF EVOLUTION 



their greater freedom of movement, and their profit- 

 able response to more subtle internal and external ac- 

 tions. 



This is very largely due to the fact that all plant 

 cells are enclosed in cellulose walls, often of great thick- 

 ness and rigidity. Plants have never been able wholly 

 to shake off this element in their make-up ; and this ele- 

 ment has persistently restricted their mode of growth, 

 their nutrition, and their power to receive, and respond 

 to, external stimuli. Plant cells, coated with cellulose, 

 apparently cannot be spun into nerve fibres, or mus- 

 cles, or blood corpuscles, or eyes and ears, like those 

 so almost universally formed from the naked cells of 

 animals; and all the resources of time and place, hered- 

 ity and environment, have been powerless to remove 

 this firmly established disability. Nevertheless, this 

 very disability has been widely utilized at every stage 

 in the evolution of plant and animal life. 



A pig stands on a much lower level, architecturally, 

 than man because, among other reasons, the adminis- 

 tration of its commissary functions is largely dependent 

 on cloven hoofs, and on the rooting efficiency of a blunt 

 and clumsy implement. The traditional methods of 

 the pig, while not exclusively his own, have helped to 

 perpetuate a flourishing race of highly organized ani- 

 mals. But his hoofs and snout, as purely mechanical 

 instruments for the administration of foreign affairs, 

 cannot compare in efficiency with the hands and tongue 

 of man, because owing to their anatomical position, 

 structure, and internal organic connections they can- 

 not bring the animal into cooperative contact with the 

 outer world in as many different ways or do as many 

 different things. No conceivable improvement in in- 



