INTRODUCTION 6 



of Character. In the next chapter I shall discuss the 

 complex and little known laws of variation and of 

 correlation of growth. In the four succeeding chapters, 

 the most apparent and gravest difficulties on the theory 

 will be given : namely, first, the difficulties of transi- 

 tions, or in understanding how a simple being or a 

 simple organ can be changed and perfected into a 

 highly developed being or elaborately constructed 

 organ ; secondly, the subject of Instinct, or the mental 

 powers of animals ; thirdly, Hybridism, or the in- 

 fertility of species and the fertility of varieties when 

 intercrossed ; and fourthly, the imperfection of the 

 Geological Record. In the next chapter I shall consider 

 the geological succession of organic beings throughout 

 time ; in the eleventh and twelfth, their geographical 

 distribution throughout space ; in the thirteenth, their 

 classification or mutual affinities, both when mature and 

 in an embryonic condition. In the last chapter I shall 

 give a brief recapitulation of the whole work, and a few 

 concluding remarks. 



No one ought to feel surprise at much remaining as 

 yet unexplained in regard to the origin of species and 

 varieties, if he makes due allowance for our profound 

 ignorance in regard to the mutual relations of all the 

 beings which live around us. Who can explain why 

 one species ranges widely and is very numerous, and 

 why another allied species has a narrow range and is 

 rare ? Yet these relations are of the highest importance, 

 for they determine the present welfare, and, as I 

 believe, the future success and modification of every 

 inhabitant of this world. Still less do we know of the 

 mutual relations of the innumerable inhabitants of the 

 world during the many past geological epochs in its 

 history. Although much remains obscure, and will 

 long remain obscure, I can entertain no doubt, after 

 the most deliberate study and dispassionate judgment 

 of which I am capable, that the view which most 

 naturalists entertain, and which I formerly entertained 

 — namely, that each species has been independently 

 created — is erroneous. I am fully convinced that 



