To Alfred Russel Wallace 22 January 1866
Down. | Bromley. | Kent. S.E.
Jan 22. 1866
My dear Wallace
I thank you for your paper on Pigeons, which interested me, as every thing that you write does.1 Who wd ever have dreamed that monkeys influenced the distribution of pigeons & parrots!2
But I have had a still higher satisfaction; for I finished yesterday your paper in Linn. Trans.3 It is admirably done. I cannot conceive that the most firm believer in Species cd read it without being staggered. Such papers will make many more converts among naturalists than long-winded books such as I shall write if I have strength.
I have been particularly struck with your remarks on Dimorphism; but I cannot quite understand one point (p. 22) & shd be grateful for an explanation for I want fully to understand you.
How can one female form be selected & the intermediate forms die out, without also the other extreme form also dying out from not having the advantages of the first selected form; for as I understand, both female forms occur on the same Island.4 I quite agree with your distinction between dimorphic forms & varieties; but I doubt whether your criterion of dimorphic forms not producing intermediate offspring will suffice; for I know of a good many varieties which must be so called, that will not blend or intermix, but produce offspring quite like either parent.5
I have been particularly struck with your remarks on Geog. Distrib. in Celebes. It is impossible that any thing cd be better put, & wd give a cold shudder to the immutable naturalists.6
And now I am going to ask a question which you will not like. How does yr Journal get on?7 It will be a shame if you do not popuralize your researches. my health is so far improved that I am able to work one or 2 hours a day—
Believe me dear Wallace | yours very sincerely | Ch. Darwin
Welcomes ARW’s paper on pigeons ["On the pigeons of the Malay Archipelago", Ibis 1 (1865): 365–400].
Influence of monkeys on distribution of pigeons and parrots.
Asks ARW to explain a passage in his paper on Malayan Papilionidae [Trans. Linn. Soc. Lond. 25 (1866): 1–71] on how dimorphic forms are produced. CD knows of varieties "that will not blend or intermix", but which produce offspring quite like either parent.
ARW’s remarks on geographical distribution in Celebes "will give a cold shudder to the immutable naturalists".
Presses ARW to work on his travel journal.