Dear Darwin

Many thanks for giving me the opportunity to read at my leisure the very talented article of Mr C. Wright. His criticism of Mivart, though very severe, is, I think in most cases sound; but I find the larger part of the article so heavy and much of the language & argument so very obscure, that I very much doubt the utility of printing it separately.¹ I do not think the readers of Mivart would ever read it in that form, and I am sure your own answers to Mivart’s arguments will be so much more clear & to the point, that the other will be unnecessary. You might extract certain portions in your own chapter such as the very ingenious suggestion as to the possible origin of mammary glands; as well as the possible use of the rattle of Rattlesnake &c.²

I cannot see the force of Mivarts objection to the theory of production long neck of Giraffe (suggested in my first Essay) & which C. Wright seems to admit, while his “watch tower” theory seems to me more difficult & unlikely as a means of origin. The argument—“why haven’t other allied animals been modified in the same way”?—seems to me the weakest of the weak.³

I must say also I do not see any great reason to complain of the “words” left out by Mivart as they do not seem to me materially to affect the meaning.⁴ Your expression “and tends to depart in a slight degree”, I think hardly grammatical;—a tendency to depart, cannot very well be said to be in a slight degree;—a departure can, but a tendency must be either a slight tendency or a strong tendency, the degree to which the departure may reach must depend on favourable or unfavourable causes in addition to the tendency itself. Mivart’s words “and tending to depart from the parental type” seem to me quite unobjectionable as a paraphrase of yours, because the “tending” is kept in;—and your own view undoubtedly is that the “tendency” may lead to an ultimate departure to any extent. Mivart’s error is, to suppose that your words favour the view of sudden departures, and I do not see that the expression he uses really favours his view a bit more than if he had quoted your exact words. The expression of yours he relies upon is evidently—“the whole organism seeming to have become plastic”—and he argues, no doubt erroneously, that having so become “plastic”,—any amount or a large amount of sudden variation in some direction is likely.—

Mivarts greatest error,—the confounding “individual variations” with “minute or imperceptible variations”—is well exposed by C. Wright⁵ & that part I should like to see reprinted,—but I always thought you laid too much stress on the slowness of the action of Nat. Select. owing to the smallness and rarity of favourable variations. In your chapter on Nat. Selectⁿ. the expressions—“extremely slight modifications”—“every variation even the slightest”—“every shade of constitutional difference”—occur,—& these have led to errors such as Mivart’s.⁶ I say all this because I feel sure that Mivart would be the last to intentionally misrepresent you, and he has told me that he was sorry the word “infinitesimal”—as applied to the variations used by natural selection—got into his book, & that he would alter it, as no doubt he has done, in his second edition.⁷

Some of Mivart’s strongest points—the eye & ear, for instance,—are unnoticed in the Review. You will of course reply to these.⁸ His statement of the “missing link” argument is also forcible, & has I have no doubt much weight with the public.⁹ As to all his minor arguments, I feel with you, that they leave Nat. Selectⁿ. stronger than ever,—while the two or three main arguments do leave a lingering doubt in my mind of some fundamental organic law of development of which we have as yet no notion.

Pray do not attach any weight to my opinions as to the “Review”. It is very clever,—but the writer seems a little like those critics who know an author’s or an artist’s meaning better than they do themselves.

My house is now in the hands of a contractor, but I am wall-building &c. & very busy.¹⁰ | With best wishes | Believe me Dear Darwin | Yours very faithfully | Alfred R. Wallace