THE PATH OF EVOLUTION 



tective and the destructive forces of nature. Atavism 

 may be viewed as the reversal of the processes of 

 evolution, often injurious in its action ; yet it is the 

 conservative power that in the plant world restrains 

 the unlimited and often undesirable exercise of the 

 power of variation that the changes of sexual condi- 

 tions and climatic influences exert, and which would 

 retard rather than ultimately advance the benefits of 



evolution. 



270 



