Prefatory Note ix 



ceased to insure that its better elements have 

 a dominant fertility has destroyed itself far 

 more effectually than its foes could ever hope 

 to destroy it in the battlefield ? 



If the reprint of this lecture, of which the 

 first edition has been for some time exhausted, 

 should in the least help to quicken public 

 opinion on this all-important point, then its 

 purpose will have been amply fulfilled. The 

 topic is a complex and weighty one, and my 

 address was only a hasty talk, and not a 

 treatise providing elaborate investigation and 

 statistical proof of its statements. Still, most 

 of its unproved assertions are based on 

 results which the author has elsewhere pub- 

 lished, or for which he has unpublished 

 statistical warranty. But he would ask his 

 readers to take nothing on faith; he would 

 beg them solely to realize that there is a 

 problem of the most urgent national im- 

 portance involved in the mere possibility 

 that while modern social conditions are re- 



