I thank you for your criticisms on the "Origin," and which I have not time to discuss; but I cannot help doubting, from your expression of an "INNATE...selective principle," whether you fully comprehend what is meant by Natural Selection. Certainly when you speak of weaker (i.e. less well adapted) forms crossing with the stronger, you take a widely different view from what I do on the struggle for existence; for such weaker forms could not exist except by the rarest chance. With respect to utility, reflect that 99/100ths part of the structure of each being is due to inheritance of formerly useful structures. Pray read what I have said on "correlation." Orchids ought to show us how ignorant we are of what is useful. No doubt hundreds of cases could be advanced of which no explanation could be offered; but I must stop. Your letter has interested me much. I am very far from strong, and have great fear that I must stop all work for a couple of months for entire rest, and leave home. It will be ruin to all my work. LETTER 166. TO J.D. HOOKER. Down, April 23rd [1863]. The more I think of Falconer's letter (166/1. Published in the "Athenaeum" April 4th, 1863, page 459. The writer asserts that Lyell did not make it clear that certain material made use of in the "Antiquity of Man" was supplied by the original work of Mr. Prestwich and himself. (See "Life and Letters," III., page 19.)) the more grieved I am; he and Prestwich (the latter at least must owe much to the "Principles") assume an absurdly unwarrantable position with respect to Lyell. It is too bad to treat an old hero in science thus. I can see from a note from Falconer (about a wonderful fossil Brazilian Mammal, well called Meso- or Typo-therium) that he expects no sympathy from me. He will end, I hope, by being sorry. Lyell lays himself open to a slap by saying that he would come to show his original observations, and then not distinctly doing so; he had better only have laid claim, on this one point of man, to verification and compilation. Altogether, I much like Lyell's letter. But all this squabbling will greatly sink scientific men. I have seen a sneer already in the "Times." LETTER 167. TO H.W. BATES. At Rev. C. Langton, Hartfield, Tunbridge Wells, April 30th [1863].