To Asa Gray 4 April 1
Down Bromley Kent
My dear Gray
Your kindness to me is really beyond thanks. Believe me that I feel it. By an odd chance yesterday morning, before I got your letter, I had just written down what I had to say on closely allied species in large genera; & I thought that you had forgotten all about your list, & knowing how hard you were worked, to my credit be it said, I firmly resolved that nothing shd. induce me to remind you. Therefore you may believe how delighted I was to get your list, which is now being tabulated.—2
I am, also, particularly obliged for the answer to my question:3 Hooker & several (not all) other Botanists differ from you & think there would be a strong tendency to omit recording actually existing varieties in the smaller genera. None of them pretend they ever thought of this before I asked the question. From what little systematic work I have done myself, I cannot realise their view; & my tables of several local Floras in several respects contradict them in my opinion, & show that Botanists have worked rather more systematically & regularly in recording varieties than could have been anticipated. This is my view, but what Hooker will say, when he reads, as I hope he will, my discussion on this subject I know not. Taking Books as a guide, I find in local Floras & in the only 2 Entomological works, which I have tried, that the rule is almost universal, that the larger genera have more species with varieties (& a greater average number of varieties to the varying species) than the smaller genera.—4
You ask to see my sheets as printed off; I assure you that it will be the highest satisfaction to me to do so: I look at the request as a high compliment. I shall not, you may depend, forget a request, which I look at as a favour.— But (& it is a heavy “but” to me) it will be long before I go to press: I can truly say I am never idle; indeed I work too hard for my much weakened health; yet I can do only 3 hours of work daily, & I cannot at all see, when I shall have finished: I have done eleven long chapters; but I have got some other very difficult ones, as palæontology, classification & embryology &c, & I have to correct & add largely to all those done. I find, alas, each chapter takes me on average three months, so slow I am. There is no end to the necessary digressions. I have just finished a chapter on Instincts, & here I found grappling with such a subject as Bees cells & comparing all my notes made during 20 years took up a despairing length of time.5
But I am running on about myself in a most egotistical style. Yet I must just say how useful I have again & again found your letters, which I have lately been looking over & quoting; but you need not fear that I shall quote anything you would dislike, for I try to be very cautious on this head.— I most heartily hope you may succeed in getting your “incubus” of old work off your hands & be in some degree a free man.
Agassiz has most kindly sent me his Introduction two first Part; but I confess I am disappointed: I cannot realise his rules on the value of the higher groups, & all his prophetic &c &c types.6
Again let me say that I do indeed feel grateful to you & believe me | My dear Gray | Yours most truly | C. Darwin
Discusses the variation of species in large and small genera.
Thanks AG for his list of close species.
Laments the slow progress he makes with his book [Natural selection].