To Alfred Russel Wallace 1 May 1857
Down Bromley Kent1
May 1.— 1857
My dear Sir
I am much obliged for your letter of Oct. 10th. from Celebes received a few days ago:2 in a laborious undertaking sympathy is a valuable & real encouragement. By your letter & even still more by your paper in Annals, a year or more ago,3 I can plainly see that we have thought much alike & to a certain extent have come to similar conclusions. In regard to the Paper in Annals, I agree to the truth of almost every word of your paper; & I daresay that you will agree with me that it is very rare to find oneself agreeing pretty closely with any theoretical paper; for it is lamentable how each man draws his own different conclusions from the very same fact.—
This summer will make the 20th year (!) since I opened my first-note-book, on the question how & in what way do species & varieties differ from each other.— I am now preparing my work for publication, but I find the subject so very large, that though I have written many chapters, I do not suppose I shall go to press for two years.—4
I have never heard how long you intend staying in the Malay archipelago; I wish I might profit by the publication of your Travels there before my work appears, for no doubt you will reap a large harvest of facts.—5 I have acted already in accordance with your advice of keeping domestic varieties & those appearing in a state of nature, distinct; but I have sometimes doubted of the wisdom of this, & therefore I am glad to be backed by your opinion.— I must confess, however, I rather doubt the truth of the now very prevalent doctrine of all our domestic animals having descended from several wild stocks; though I do not doubt that it is so in some cases.— I think there is rather better evidence on the sterility of Hybrid animals that you seem to admit: & in regard to Plants the collection of carefully recorded facts by Kölreuter & Gærtner, (& Herbert) is enormous.—6
I most entirely agree with you on the little effects of “climatal conditions”, which one sees referred to ad nauseam in all Books; I suppose some very little effect must be attributed to such influences, but I fully believe that they are very slight.—7 It is really impossible to explain my views in the compass of a letter on the causes & means of variation in a state of nature; but I have slowly adopted a distinct & tangible idea.— Whether true or false others must judge; for the firmest conviction of the truth of a doctrine by its author, seems, alas, not to be slightest guarantee of truth.—
I have been rather disappointed at my results in the Poultry line; but if you shd. after receiving this stumble on any curious domestic breed, I shd be very glad to have it;8 but I can plainly see that this result will not be at all worth the trouble which I have taken.— The case is different with the domestic Pigeons; from its study I have learned much.— The Rajah has sent me some of his Pigeons & Fowls & Cats skins from interior of Borneo, & from Singapore.—9
Can you tell me positively that Black Jaguars or Leopards are believed generally or always to pair with Black?10 I do not think colour of offspring good evidence.— Is the case of parrots fed on fat of fish turning colour, mentioned in your Travels?11 I remember case of Parrot with, (I think,) poison from some Toad put into hollow whence primaries had been removed.
One of the subjects on which I have been experimentising & which cost me much trouble, is the means of distribution of all organic beings found on oceanic islands; & any facts on this subject would be most gratefully received: Land-Molluscs are a great perplexity to me.—
This is a very dull letter, but I am a good deal out of health; & am writing this, not from my home, as dated, but from a water-cure establishment.
With most sincere good wishes for your success in every way I remain | My dear Sir | Yours sincerely | Ch. Darwin
Reports long preparation of work on how species and varieties differ. Agreement with Wallace’s conclusions as reported in Annals and Magazine of Natural History and in his letter to CD of 10 0ct . On distinction between domestic varieties and those in "a state of nature".
On mating of jaguars and leopards, the breeding of poultry, pigeons, etc.
Requests help for his experimenting on means of distribution of organic beings on oceanic islands.