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IXTHE LIMITSOF NATURAL SELECTION AS APPLIED TO MANTHROUGHOUT this volume I have endeavoured to show thatthe known laws of variation, multiplication, and heredity,resulting in a " struggle for existence " and the " survival ofthe fittest," have probably sufficed to produce all the varietiesof structure, all the wonderful adaptations, all the beauty ofform and of colour, that we see in the animal and vegetablekingdoms. To the best of my ability I have answered themost obvious and the most often repeated objections to thistheory, and have, I hope, added to its general strength,by showing how colour one of the strongholds of the advocatesof special creation may be, in almost all its modifications,accounted for by the combined influence of sexualselection 1and the need of protection. I have also endeavouredto show how the same power which has modified animals hasacted on man ;and have, I believe, proved that, as soon asthe human intellect became developed above a certain lowstage, man's body would cease to be materially affected bynatural selection, because the development of his mentalfaculties would render important modifications of its formand structure unnecessary. It will, therefore, probably excitesome surprise among my readers to find that I do notconsider that all nature can be explained on the principles ofwhich I am so ardent an advocate ;and that I am now myselfgoing to state objections, and to place limits, to the power ofnatural selection. I believe, however, that there are such1 Since writing this in 1870 I have come to the conclusion that sexualselection has had little, if any, influence on colour. See chap. v. of " TropicalNature " in this volume, and Dantnnism, chap. x.