instance, to introduce the principle of “compensation,” instead of the lex talionis, and later on, the pardon of offences, or a still higher ideal of equality before the human conscience, in lieu of “compensation,” according to class-value.  But at the very same time, another portion of the same individual rebels endeavoured to break down the protective institutions of mutual support, with no other intention but to increase their own wealth and their own powers.  In this three-cornered contest, between the two classes of revolted individuals and the supporters of what existed, lies the real tragedy of history.  But to delineate that contest, and honestly to study the part played in the evolution of mankind by each one of these three forces, would require at least as many years as it took me to write this book.

Of works dealing with nearly the same subject, which have been published since the publication of my articles on Mutual Aid among Animals, I must mention The Lowell Lectures on the Ascent of Man, by Henry Drummond (London, 1894), and The Origin and Growth of the Moral Instinct, by A. Sutherland (London, 1898).  Both are constructed chiefly on the lines taken in Buchner’s Love, and in the second work the parental and familial feeling as the sole influence at work in the development of the moral feelings has been dealt with at some length.  A third work dealing with man and written on similar lines is The Principles of Sociology, by Prof.  F.A.  Giddings, the first edition of which was published in 1896 at New York and London, and the leading ideas of which were sketched by the author in a pamphlet in 1894.  I must leave, however, to literary critics the task of discussing the points of contact, resemblance, or divergence between these works and mine.

The different chapters of this book were published first in the Nineteenth Century ("Mutual Aid among Animals,” in September and November 1890; “Mutual Aid among Savages,” in April 1891; “Mutual Aid among the Barbarians,” in January 1892; “Mutual Aid in the Medieval City,” in August and September 1894; and “Mutual Aid amongst Modern Men,” in January and June 1896).  In bringing them out in a book form my first intention was to embody in an Appendix the mass of materials, as well as the discussion of several secondary points, which had to be omitted in the review articles.  It appeared, however, that the Appendix would double the size of the book, and I was compelled to abandon, or, at least, to postpone its publication.  The present Appendix includes the discussion of only a few points which have been the matter of scientific controversy during the last few years; and into the text I have introduced only such matter as could be introduced without altering the structure of the work.

I am glad of this opportunity for expressing to the editor of the Nineteenth Century, Mr. James Knowles, my very best thanks, both for the kind hospitality which he offered to these papers in his review, as soon as he knew their general idea, and the permission he kindly gave me to reprint them.