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Show viii PREFACE I thus take up Darwin's earlier position, from which he somewhat receded in the later editions of his works, on account of criticisms and objections which I have endeavoured to show are unsound. Even in rejecting that phase of sexual selection depending on female choice, I insist on the greater efficacy of. natural selection. This is pre-eminently the Darwinian doctrine, and I therefore claim for my book the position of being the advocate' of pure Darwinism. I wish to express my obligation to Mr. Francis barwin for lending -me some of his father's unused notes, and to many other friends for facts or information, which have, I believe, been acknowledged either in the text or footnotes. Mr. James Sime has kindly read over the proofs and given me many useful suggestions; and I have to thank Professor Meldola, Mr. Hemsley, and Mr. Ft. B. Poulton for valuable notes or corrections in the later chapters in which their special subjects are touched upon. GODALMING, March 1889. CON~rENTS CHAPTER I WHAT ARE " SPECIES " AND WHAT IS MEANT BY THEIR "ORIGIN" Definit~on . of sp.ec~es-Special creation-The early transmuta.tionistsSctenhfic opmwn before Darwin-The problem before Darwin- The change of opinion effected by Darwin-The Darwinian theory-Proposed mode of treatment of the subject . Pages 1-J 3 CHAPTER II THE STRUGGLE FOR EXISTENCE Its importance-The struggle among plants-Among animals-Illustrative ca~es-Succession of trees in forests of Denmark-The struggle for ex1~tence on the Pamp~s-;-Increase of organisms in a geometrical ra.tw-Examples of raptd mcrease of animals-Rapid increase and wtde spread of plants-Great fertility not essential to rapid increase -Struggle between closely allied species most severe-The ethical aspect of the struggle for existence . 14-40 CHAPTER III THE VARIABILITY OF SPECIES IN A STATE OF NATURE Importance of variability-Popular ideas regarding it-Variability of the lower animals-The variability of insects-Variation among lizards- |