412 RECAPITULATION. Cillt. XIV. 



CHAPTER XIV. 



RECAPITULATIOX AND CONCLUSION. 



Recapitulation of the Ohjoctiors to the Tlieoiy of Natural Selection— Reeapitulafion 

 of the General and Special Circumstances in its favor— Causes of the General Be- 

 lief in the Immutability of Species— How far the Theory of Natural Selection may 

 l>o extended— ElTccts of its Adoption on the Study of Natural History— Concluci- 

 ing Kemarks. 



As this whole volume is one long argument, it may be con- 

 venient to the reader to have the leading facts and inferences 

 briefly recapitulated. 



That many and serious objections ma}- be advanced against 

 the theory of descent with modification through natural selec- 

 tion, I do not den}'. I have endeavored to give to them their 

 full force. Nothing at first can appear more difficult to be- 

 lieve than that the more complex organs and instincts have 

 ])ocn perfected, not by means superior to, though analogous 

 witli, human reason, but by the accumulation of innumerable 

 slight variations, each good for the individual possessor. Nev- 

 ertheless, this difficulty, though appearing to our imagination 

 insuperably great, cannot be considered real if we admit the 

 following propositions, namely, that all ]>arts of the organiza- 

 tion and instincts offer, at least, individual differences — that 

 there is a struggle for existence leading to the preservation of 

 profitable deviations of structure or instinct — and, lastly, that 

 gradations in the state of perfection of each organ may have 

 existed, each good of,its Idnd. The truth of these propositions 

 cannot, I think, be disputed. 



It is, no doubt, extremely difficult even to conjecture by 

 what gradations many structures have been perfected, more 

 especially among broken and failing groups of organic beings, 

 which have suffered much extinction ; but we see so many 

 strange gradations in Nature, that Ave ought to be extremely 

 cautious in saying that any organ or instinct, or the whole 

 structure, could not have arrived at its present state by many 



