The following monograph was written while the author was a student in the "Harvard Annex" as a study in the Seminary course given by Professor Albert Bushnell Hart. The work has continued during parts of the four years since 1887. The effort has been to trace in some measure the development of public sentiment upon the subject, to prepare an outline of Colonial legislation and of the work of Congress during the entire period, and to give accounts of typical cases illustrative of conditions and opinions. Only a few of the more important cases are described minutely, but a critical list of the authorities may be found in the bibliographical appendix.

The thanks of the author are due first to Professor Hart, under whose direction and with whose assistance and encouragement the monograph has been prepared; then to Miss Anna B. Thompson, without whose careful training in the Thayer Academy and continued sympathy, the work could not have been undertaken. Many thanks are due also to the authorities of the Library of Harvard College for the use, in the alcoves, of their large and conveniently arranged collection of books and pamphlets on United States History, and to the assistants in the Boston Public and Massachusetts State Libraries for courteous aid. Colonel T. W. Higginson has kindly examined the chapter on the cases from 1850 to 1860, suggesting some interesting details; and Mr. Arthur Gilman has read the whole in proof, and made many valuable suggestions.

MARION GLEASON McDOUGALL.

Rockland, Mass., April 2, 1891.