Grateful acknowledgment is also here expressed for the personal aid that has been received in the prepara tion of this monograph. Professors Charles A. Ellwood and A. O. Lovejoy, of the University of Missouri, con tributed useful suggestions as to authors; Professor Henry Jones Ford, of Princeton University, read the greater part of the manuscript and supplied valuable criticism. Finally, the writer is peculiarly indebted to Professor William A. Dunning, of Columbia University, whose supervision and sympathetic counsel in all phases of the work have been indispensable.