and cats’ skins from the interior of Borneo and from Singapore.  Can you tell me positively that black jaguars or leopards are believed generally or always to pair with black?  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?  I remember a case of parrots with (I think) poison from some toad put into hollow whence primaries had been removed.

One of the subjects on which I have been experimenting, and which cost me much trouble, is the means of distribution of all organic beings found on oceanic islands; and 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, and 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.

* * * * *

LETTER II

C. DARWIN TO A.R.  WALLACE

Down, Bromley, Kent.  December 22, 1867.

My dear Sir,—­I thank you for your letter of Sept. 27th.  I am extremely glad to hear that you are attending to distribution in accordance with theoretical ideas.  I am a firm believer that without speculation there is no good and original observation.  Few travellers have attended to such points as you are now at work on; and indeed the whole subject of distribution of animals is dreadfully behind that of plants.  You say that you have been somewhat surprised at no notice having been taken of your paper in the Annals.  I cannot say that I am; for so very few naturalists care for anything beyond the mere description of species.  But you must not suppose that your paper has not been attended to:  two very good men, Sir C. Lyell, and Mr. E. Blyth at Calcutta, specially called my attention to it.  Though agreeing with you on your conclusions in the paper, I believe I go much further than you; but it is too long a subject to enter on my speculative notions.  I have not yet seen your paper on distribution of animals in the Aru Islands:  I shall read it with the utmost interest; for I think that the most interesting quarter of the whole globe in respect to distribution; and I have long been very imperfectly trying to collect data from the Malay Archipelago.  I shall be quite prepared to subscribe to your doctrine of subsidence:  indeed from the quite independent evidence of the coral reefs I coloured my original map in my Coral volumes colours [sic] of the Aru Islands as one of subsidence, but got frightened and left it uncoloured.  But I can see that you are inclined to go much further than I am in regard to the former connection of oceanic islands with continents.  Ever since poor E. Forbes propounded