Among others, the following writers are cited: Agassiz, Abbott, Argyle, Askernazy, Balfour, Brewster, Ballard, Bruner, Barrande, Bunge, Brown, Bowers, Bixby, Bonn, Clodd, Conn, Cope, Clarke, Cooke, DeRouge, Dana, Dawson, Dubois, Etheridge, Fovel, Fiske, Gladstone, Galton, Gregory, Hilprecht, Huxley, Howison, Haeckel, Haecke, Harrison, Herschel, Hartman, Harnack, Heer, Humphrey, Hoffman, Hamann, Ingersoll, Jones, Kelvin, Koelliker, Liebig, Lecky, LeConte, Lang, Meyer, Max Mueller, Monier, Murchison, Naegeli, Paulsen, Pfaff, Petrie, Pattison, R. Patterson, Pfliederer, Patton, Parker, Ruskin, Romanes, Reymond, Renouf, Schliemann, Sayce, Starr, Schultz, Sully, Spencer, Schmidt, Sedgwick, Stuckenberg, Snell, See, Townsend, Thomas, Tyndall, Thomson, Virchow, Von Baer, Wallace, Winchell, Warfield, Wright, Whitney, Wagner, Woodrow Wilson, White, Wiseman, Zahm, Zoeckler. I especially acknowledge indebtedness to Prof. George Frederick Wright, of Oberlin College, in revising this book and for his valuable suggestions and corrections, and especially his favorable introduction. To his works confirming many of my conclusions I refer the reader, as follows: The Logic of Christian Evidence, The Scientific Aspects of Christian Evidences, The Ice Age in North America, Man in the Great Ice Age. ALEXANDER PATTERSON. PREFACE TO THIRD EDITION. In issuing a third edition of this book it is proper to state what changes, if any, have occurred in the discussion. While the belief in Evolution is wide-spread, no known cause or causes have yet been discovered by which the supposed changes in species occurred, for "Evolution" is not a force or energy of any kind, but only the name of a theory by which the present order of nature is supposed to have come. The method Darwin proposed was by Natural Selection arising from the prodigality of production, the small variations that occur in living things, the struggle for existence and the survival of the fittest, aided by environment and other causes all of which by slow degrees during infinite ages have produced the progressive order of species. This has been decided to be insufficient and has been abandoned by evolutionary writers. It is now agreed that the changes must have occurred in variations originating in the embryo or in the germ, or in the very substance of which that is composed. But all this is far beyond human ken as all writers admit, as follows: "We are ignorant of the factors which are at work to produce evolution. We do not even know whether the life processes are conducted in accordance with the principles of chemistry and physics, or are in obedience to some more subtle vital principle." (Metcalf, _Organic Evolution_.) President David Starr Jordan and Prof. Vernon Lyman Kellogg, both of Stanford University, say: "These changes or variations, if they do occur, cannot be explained." (_Evolution and Animal Life, p. 112._)