IV 



EVOLUTION 



Assuming that the population of the globe 

 is about sixteen hundred millions and that the 

 average length of human life is forty years, a 

 number that represents the present condition 

 in only the more favored states and nations, 

 about forty milHon persons must die annually. 

 Of such persons those who reach maturity 

 have usually gathered about them material 

 devices as protections against the inclemen- 

 cies of nature and as means to their personal 

 comfort. Such persons, moreover, in the course 

 of their lifetime develop or acquire lines of ac- 

 tion which yield continuance of life and hap- 

 piness. At their death their material property 

 is commonly inherited by other members of 

 society, often those to whom the deceased had 

 blood ties ; their lines of action, remembered 

 or otherwise recorded, serve as examples for 

 avoidance, imitation, or improvement. Thus, 

 generation by generation, the composition of 

 human society changes, its material acquisi- 



