INTRODUCTION. 19 



place. This is illustrated by the fact that as long as parents main- 

 tain their health and vigor, the older they are at the time of repro- 

 duction, the greater is the average length of life of their offspring. 

 It is not necessary to recount here all of the facts set forth 

 nor the corollaries to be drawn from them, but we will turn our 

 attention to some of the processes by which the race has risen to 

 its present plane, and to some of the processes by which it may be 

 raised to still higher planes. 



INFLUENCES AFFECTING HEREDITY. 



In the early history of the race men grouped themselves into 

 communities, and not having to fight for their lives against superior 

 animals they perfected military organizations for the purpose of 

 fighting each other. The young men joined these organizations, 

 and the training they necessarily received developed them phys- 

 ically and mentally. In communities like Greece and Rome it 

 became customary for young men not to marry until after they had 

 returned from the wars. Wars and the training for wars, there- 

 fore, not only increased the activity of the individuals, but operated 

 to delay reproduction until considerable development had occurred. 

 The result of this we see in the fact that the most warlike races 

 have been the most progressive races. In modern times the mili- 

 tary training given by Germany not only develops her young men, 

 but operates to delay the average age of marriage, and consequently 

 the average age at which reproduction takes place. The result of 

 this will be a rise in the average intelligence of the German people. 



Religious movements, from that of Moses down to that of the 

 pestiferous charlatan who claims to be a re-incarnation, have each 

 added to the intellectual activity of the community and consequently 

 have been factors in human progress. The same may be said of 



