186 GROWTH OF THE ORIGIN OF SPECIES, [ch. x. 



rectly opposite conviction, is that species are mutable, and 

 that allied species are co-descendants from common stocks. 

 I know how much I open myself to reproach for such a 

 conclusion, but I have at least honestly and deliberately 

 come to it. I shall not publish on this subject for several 

 years. 



C. Darwin to L. Jenyns* Down [1845?] 



With respect to my far distant work on species I must 

 have expressed myself with singular inaccuracy if I led you 

 to suppose that I meant to say that my conclusions were 

 inevitable. They have become so, after years of weighing 

 puzzles, to myself alone ; but in my wildest day-dream, I 

 never expect more than to be able to show that there are 

 two sides to the question of the immutability of species, i.e. 

 whether species are directly created or by intermediate laws 

 (as with the life and death of individuals). I did not ap- 

 proach the subject on the side of the difficulty in determin- 

 ing what are species and what are varieties, but (though 

 why I should give you such a history of my doings it would 

 be hard to say) from such facts as the relationship between 

 the living and extinct mammifers in South America, and 

 between those living on the Continent and on adjoining' 

 islands, such as the Galapagos. It occurred to me that a 

 collection of all such analogous facts would throw light 

 either for or against the view of related species being co- 

 descendants from a common stock. A long searching 

 amongst agricultural and horticultural books and people 

 makes me believe (I well know how absurdly presumptuous 

 this must appear) that I see the way in which new varieties 

 become exquisitely adapted to the external conditions of life 

 and to other surrounding beings. I am a bold man to lay 

 myself open to being thought a complete fool, and a most 

 deliberate one. From the nature of the grounds which 

 make me believe that species are mutable in form, these 

 grounds cannot be restricted to the closest-allied species; 

 but how far they extend I cannot tell, as my reasons fall 

 away by degrees, when applied to species more and more 

 remote from each other. Pray do not think that I am so 

 blind as not to see that there are numerous immense diffi- 

 culties in my notions, but they appear to me less than on 

 the common view. I have drawn up a sketch and had it 



* Rev. L. Blomefield. 



