INTRODUCTION. 3 



confidently been asserted that man's origin can never be 

 known: but ignorance more frequently begets confidence 

 than does knowledge: it is those who know little, and not 

 those who know much, who so positively assert that this or 

 that problem will never be solved by science. The con- 

 clusion that man is the co-descendant with other species of 

 some ancient, lower, and extinct form, is not in any degree 

 new. Lamarck long ago came to this conclusion, which 

 has lately been maintained by several eminent naturalists 

 and philosophers; for instance, by Wallace, Huxley, Lyell, 

 Vogt, Lubbock, Biichner, Rolle, etc.,* and especially by 

 Hackel. This last naturalist, besides his great work, 

 "Generelle Morphologic" (1866), has recently (1868, 

 with a second edition in 1870), published his " Natiirliche 

 Schopfungsgeschichte," in wnich he fully discusses the 

 genealogy of man. If this work had appeared before my 

 essay had been written, I should probably never have com- 

 pleted it. Almost all the conclusions at which I have 

 arrived I lind confirmed by this naturalist, whose knowl- 

 edge on many points is much fuller than mine. Wherever 

 I have added any fact or view from Prof. Hackel's writ- 

 ings, I give his authority in the text; other statements I 

 leave as they originally stood in my manuscript, occasion- 

 ally giving in the footnotes references to his works, as a 

 confirmation of the more doubtful or interesting points. 



During many years it has seemed to me highly probable 

 that sexual selection has played an important part in 

 differentiating the races of man; but in my " Origin 

 of Species" (first edition) I contented myself by 

 merely alluding to this belief. When I came to apply this 

 view to man, I found it indispensable to treat the whole 



*As the works of the first-named authors are so well known, I 

 need not give the titles ; but as those of the latter are less well 

 known in England, I will give them : " Sechs Vorlesungen liber die 

 Darwin'sche Theorie," zweite Auflage, 1868, von Dr. L. Biichner ; 

 translated into French under the title " Conferences sur la Theorie 

 Darwinienne," 1869. " Der Mensch, im Lichte der Darwin'sche 

 Lehre," 1865, von Dr. F. Rolle. I will not attempt to give references 

 to all the authors who have taken the same side of the question. 

 Thus G. Canestrini has published (" Annuario della Soc. d. Nat.," 

 Modena, 1867, p. 81), a very curious paper on rudimentary characters, 

 as bearing on the origin of man. Another work has (1869) been 

 published by Dr. Francesco Barrago, bearing in Italian the title 

 of " Man, made in the image of God. was also made in the image of 

 the ape." 



