My dear Mr Darwin

I have received two letters and a note from you lately for which I am very much obliged.¹ It was very gratifying to have, in your judgment, added anything positive, or otherwise than as a critic of the controversy, to the discussions of natural selection. I have sent copies of my paper to the Societies which you were so kind as to suggest.² I had previously sent one to Professor Dickson whose memoir I saw and read cursorily in a copy lent me by Dr Gray while my paper was going through the press.³ I saw that the direction of his studies was exactly the reverse of mine; expanding the theory of Phyllotaxy to a still greater degree of subtilty than ever it was, I imagine, inflated before;—actually presuming that a set of numerical laws, assumed as ultimate in nature, and without any uti⁠⟨⁠lity or⁠⟩⁠ ulterior reference, ought to hold in some way even in the production of irregular growths or monstrous forms. It is surprising to what lengths these type-struck thinkers and even observers will go! I have never read Prof. Cope’s essays,⁴ but have heard of them from a clever friend who attempted in vain to comprehend them, and also failed to get from conversations with the author himself any clear ideas of his views.

I shall make a point of reading Mr Steven’s essay in Fraser’s at the earliest opportunity.⁵

Almost immediately after writing to you I determined upon answering Mr Mivarts communication. I was repelled at first by the tone of his reply; but on reflection I concluded that this very tone ought to be answered, and in a different tone. The essay was hastily written and almost as speedily put into print. I sent you a proof of it last week. My promptness rather than the merits of the paper accounts for its apparently prominent position as Art. I of the Review.⁶ I wished to have it off my hands that I might be free to make arrangements and preparations for ⁠⟨⁠my⁠⟩⁠ long anticipated trip to Europe which is now definitively fixed for the 2^d. of July.

While reflecting upon the subject of fixedness in the characters of species an analogy occurred to me for which I did not find a place in my article: But what you say about the effect of the long-continued transmission of characters by inheritance recalls it.⁷ The relative fixedness of different kinds of characters, the homological and the adaptive appeared like the stability if different geological strata, the underlying and the superficial. Adaptive characters are generally superposed on genetic ones, (like new and changeable formations in geology on earlier and consolidated ones,) thus giving them an indirect utility and preserving them, as the new strata cover and protect the older ones.⁸ It would not be correct from this point of view to speak of any characters as merely genetic or useless, except those that are more or less aborted. Those characters, which are not only useless in themselves but no longer serve as the bases of later and useful ones, would of course be subject to similar mutations as the latter through the causes of variation; as geological forces ⁠⟨⁠act⁠⟩⁠ alike on older and newer formations when both are alike exposed. But the older formations are the harder and will not be worn away so fast as the new; and for a similar reason rudimentary characters in organisms offer great resistance to the destructive agencies of variation. Yet there is a limit to the hardness which any rock can have; and this agrees with what you say on the effect of hereditary transmission,—that a 1000 generations may be as good as 100,000 for fixing a character in this way. It struck me that this analogy carried out might furnish at least a provisional representation of the relations of variations to their unknown causes. Analogies are, it is true, blind guides; But then in the dark blind guides are as good as the keenest-sighted ones; better perhaps than the ideas of those who imagine they can see.

Very sincerely yours | Chauncey Wright