4 PREFACE TO THE SECOND EDITION 



to the body and mind. I also attributed some amount of 

 modification to the direct and prolonged action of changed 

 conditions of life. Some allowance, too, must be made for 

 occasional reversions of structure; nor must we forget what 

 I have called "correlated" growth, meaning thereby, that 

 various parts of the organization are in some unknown man- 

 ner so connected, that when one part varies, so do others; 

 and if variations in the one are accumulated by selection, 

 other parts will be modified. Again, it has been said by 

 several critics, that when I found that many details of 

 structure in man could not be explained through natural 

 selection, I invented sexual selection; I gave, however, a 

 tolerably clear sketch of this principle in the first edition 

 of the "Origin of Species," and I there stated that it was 

 applicable to man. This subject of sexual selection has been 

 treated at full length in the present work, simply because an 

 opportunity was here first afforded me. I have been struck 

 with the likeness of many of the half -favorable criticisms on 

 sexual selection with those which appeared at first on natu- 

 ral selection; such as, that it would explain some few de- 

 tails, but certainly was not applicable to the extent to which 

 I have employed it. My conviction of the power of sexual 

 selection remains unshaken; but it is probable, or almost 

 certain, that several of my conclusions will hereafter be 

 found erroneous ; this can hardly fail to be the case in the 

 first treatment of a subject. When naturalists have become 

 familiar with the idea of sexual selection, it will, as I be- 

 lieve, be much more largely accepted; and it has already 

 been fully and favorably received by several capable judges. 



Down, Bbckenham, Kent, 

 Septemlaer, 1874 



