PREFACE 9 



on many sources which cannot be thus acknowledged. He un- 

 blushingly confesses that when he hears or reads a good idea he 

 often assimilates it, and later gives it out as if it were his own, 

 not knowing where or when it came to him. So to the great host 

 of persons who have unconsciously given him help he offers his 

 thanks, with the hope that they may not object to his use of 

 their ideas. 



Washington, D. C. 

 December, 1918. 



