PX0GJ!ESS70Ar AND COMPETITION 



"• • . . Still better may we compare the ve^retablnl-in, i 

 to a great tree branching from its Le upwar^of ^ '7 



■ s::irre=rr:r^-r 



.conMWlop.thontMr:^^^^^^^^^^ 



o.tnuaS\!r ^"^^■'^'^•^ ^ «-*--. Pnu.e.s the tree 



roll * "" "' '""^■^'^^ ^^^^' -^ P-duces 



an oideUy arrangement with clearly distinguishable parts 



Children who see the gardener daily at his task may weS 



suppose that he is the cause of the formation of the branl 



and twrgs. Yet the tree, without the constant prnZ 



the gardener, would have been much greater, not in height 



biTinr"' ^"' "^ '^^ ""^ ^"^ ''-'^-^ °'°^'^ 



"In the perfecting .process (progression) and adaptation 



>e the mechanical impulses which lead to the abundance of 



forms; m competition and extermination, or in Darwinism 



proper, only the mechanical cause of the formation of gaps in 



the two organic kingdoms." 



ThusNageH's theory attempts principally to explain two 

 points which that of Weismann leaves unexplained, namely 

 the beginning of the formation of characters and the fact of 

 variation i„ definite directions. But Nageli's conception 

 seems to me to rest so much more on assumptions acutely 

 thought out than on facts, that it deserves ratlier to be 

 described as a materialistic-philosophical than as a mechanico- 

 physiological theory. 



