Transcriber’s notes: The text of this book has been preserved as in the original except for correction of some typographic errors (see below) and punctuation inconsistencies. Italic text is denoted by _underscores_ and a caret mark ^ precedes any superscripted character(s). Footnotes have been numbered and positioned below the relevant paragraphs, and some illustration captions have been moved closer to the relevant text. Corrected misspellings include the following: constitutent —> constituent It —> If o —> to endotheliun —> endothelium ecomomy —> economy involutary —> involuntary old factory —> olfactory tacile —> tactile irrevelant —> irrelevant tranverse —> transverse decebrate —> decerebrate Thistleton —> Thiselton opprobious —> opprobrious Duputryen's —> Dupuytren's ditēthēsis —> diēthēsis INITIATIVE IN EVOLUTION BY WALTER KIDD, M.D., F.R.S.E. AUTHOR OF “USE--INHERITANCE,” “DIRECTION OF HAIR IN ANIMALS AND MAN,” “THE SENSE OF TOUCH IN MAMMALS AND BIRDS,” ETC. _WITH NUMEROUS ILLUSTRATIONS_ H. F. & G. WITHERBY 326 HIGH HOLBORN, LONDON 1920 PREFACE. The Great War imposed on speculative biology a moratorium as in the long vacation of lawyers, in which are causes left over to the next term. And so the old case Lamarck _versus_ Weismann was not heard in the Courts of Science during the war. In the present term it is due to be heard afresh, and at some future date to come up for settlement. The chapters that follow comprise some of the pleadings on behalf of the plaintiff and are part of the brief of a junior counsel. This adjective, alas! signifies not the years--for such are often old enough to be the fathers of the leaders--but the standing and attainments of a junior. But in the open Court of Science, and on suited occasions, it may be the business of a junior to question, in the interests of his client, the authority even of Attorneys-General and Lords Chief Justice. In matters of thought and inquiry it is useless to retreat within a stronghold and bar the gates. It may be satisfactory to himself for one Milner to write a book on behalf of a certain body of doctrine and call it _The End of Controversy_, but the book should have held the sub-title _The End of Progress_. The Newtons, Pasteurs and Darwins have seldom wielded the weapon of controversy, though the triumph of _The Origin of Species_ would have been slower without the aid of Darwin’s brilliant champion and candid friend. But, if the leaders seldom need such help, for the Gibeonite it is a matter of course and simple necessity. With all the urbanity due to the great subject-matter should this pleasant duty be performed. Who would not