GREAT STEPS IN EVOLUTION 111 



sciously degenerative, and as far as possible, 

 parasitic — the field of effort opens. Hygiene, 

 engineering and irrigation, agriculture and 

 forestry, and all such strenuous careers are 

 already opening perspectives lately un- 

 dreamed by youth, struggles for existence 

 nobler and more sustainedly strenuous than 

 those of war. Practically, the control of the 

 ice-lands and of the tropics, the amend- 

 ment of nature — and above all, specula- 

 tively, the distinction between ascending 

 and deteriorative progress — thus alike be- 

 come more clear. 



