468 CROSS- AND SELF-FERTILISATION. [1877. 



I should be very well contented to deserve a fraction of your 

 praise. I have also been much interested, and this is better 

 than mere pleasure, by your argument about the separation 

 of the sexes. I dare say that I am wrong, and will hereafter 

 consider what you say more carefully : but at present I can- 

 not drive out of my head that the sexes must have originated 

 from two individuals, slightly different, which conjugated. 

 But I am aware that some cases of conjugation are opposed 

 to any such views. 



AVith hearty thanks, 



Yours sincerely, 



Charles Darwin. 



