Produced by Marilynda Fraser-Cunliffe, LN Yaddanapudi and the Online Distributed Proofreading Team at http://www.pgdp.net (This file was made using scans of public domain works from the University of Michigan Digital Libraries.) _CONTRIBUTIONS TO_ THE THEORY OF NATURAL SELECTION. A Series of Essays. BY ALFRED RUSSEL WALLACE, AUTHOR OF "THE MALAY ARCHIPELAGO," ETC., ETC. _SECOND EDITION, WITH CORRECTIONS AND ADDITIONS._ New York: MACMILLAN AND CO. 1871. [_The Right of Translation and Reproduction is reserved._] LONDON: PRINTED BY HEAD, HOLE & CO., FARRINGDON STREET, AND IVY LANE, E.C. PREFACE. The present volume consists of essays which I have contributed to various periodicals, or read before scientific societies during the last fifteen years, with others now printed for the first time. The two first of the series are printed without alteration, because, having gained me the reputation of being an independent originator of the theory of "natural selection," they may be considered to have some historical value. I have added to them one or two very short explanatory notes, and have given headings to subjects, to make them uniform with the rest of the book. The other essays have been carefully corrected, often considerably enlarged, and in some cases almost rewritten, so as to express more fully and more clearly the views which I hold at the present time; and as most of them originally appeared in publications which have a very limited circulation, I believe that the larger portion of this volume will be new to many of my friends and to most of my readers. I now wish to say a few words on the reasons which have led me to publish this work. The second essay, especially when taken in connection with the first, contains an outline sketch of the theory of the origin of species (by means of what was afterwards termed by Mr. Darwin--"natural selection,") as conceived by me before I had the least notion of the scope and nature of Mr. Darwin's labours. They were published in a way not likely to attract the attention of any but working naturalists, and I feel sure that many who have heard of them, have never had the opportunity of ascertaining how much or how little they really contain. It therefore happens, that, while some writers give me more credit than I deserve, others may very naturally class me with Dr. Wells and Mr. Patrick Matthew, who, as Mr. Darwin has shown in the historical sketch given in the 4th and 5th Editions of the "Origin of Species," certainly propounded the fundamental principle of "natural selection" before himself, but who made no further use of that principle, and failed to see its wide and immensely important applications.