THEORY OF EVOLUTION 



^ 





n 



i' 





i 



t 



I 





luimrjn. tmp /-puTiirik^- 



Fig. 2. Evolution of pole arms. (Metropolitan Museum. 

 After Dean.) 



shall see that this human idea of purpose recurs 

 in many forms, suggesting that man has often 

 tried to explain how organic evolution has 

 taken place by an appeal to the method which 



