WCP1868

Letter (WCP1868.1758)

[1]

Down.

Bromley.

Kent. S.E.

Jan 22. 1866

My dear Wallace

I thank you for your paper on Pigeons,1 which interested me, as every thing that you write does. Who w[oul]d ever have dreamed that monkeys influenced the distribution of pigeons & parrots!

But I have had a still higher satisfaction; for I finished yesterday your paper in Linn[ean]. Trans[actions].2 [2] It is admirably done. I cannot conceive that the most firm believer in Species c[oul]d 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) & sh[oul]d be grateful for [3] 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. 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 [4] 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.

I have been particularly struck with your remarks on Geog[raphical]. Distrib[ution]. in Celebes [Sulawesi]. It is impossible that any thing c[oul]d be better put, & w[oul]d give a cold shudder to the immutable naturalists.

And now I am going to ask a question which you will not like. How does y[ou]r Journal get on? It will be a shame if you do not popuralize [sic] your researches. my [sic] 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 [signature]

1
Wallace, A. R. 1865. On the Pigeons of the Malay Archipelago. Ibis. London: J. van Voorst, 365-400.
2
Wallace, A. R. 1865 [1864]. On the phenomena of variation and geographical distribution as illustrated by the Papilionidae of the Malayan region. Transactions of the Linnean Society of London. 25: 1-71.

Editorial information

Status: Edited (but not proofed) transcription [Letter (WCP1868.1758)]

For more information about the transcriptions and metadata, see https://wallaceletters.myspecies.info/content/epsilon

Revision history

Transcribed by Darwin Correspondence Project [2012-06-29] Transcription checked by Beros, Matt [2019-12-20]

Published letter (WCP1868.5950)

[1] [p. 166]

Down, Bromley, Kent, S.E.

January 22, 1866

My dear Wallace,—I thank you for your paper on Pidgeons,1 which interested me, as everything that you [2] [p. 167] write does. Who would ever have dreamed that monkeys influenced the distribution of pigeons and parrots! But I have had a still higher satisfaction; for I finished yesterday your paper in the Linnaean Transactions.2 It is admirably done. I cannot conceive that the most firm believer in Species could read it without being staggered. Such papers will make many more converts among naturalists than longwinded 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), and should be grateful for an explanation, for I want to fully understand you.3 How can one female form be selected and the intermediate forms die out, without also the other extreme for 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. I quite agree with your distinction between dimorphic forms and varieties; but I doubt whether your criterion of dimorphic forms not [3] [p. 168] produce 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.

I have been particularly struck with your remarks on geological distribution in Celebes. It is impossible that anything could be better put and [it] would give a cold shudder to the ummutable naturalists.

And now I am going to ask a question which you will not like. How does your Journal get on? It will be a shame if you do not popularise your researches.

My health is so far improved that I am able to work one or two hours a day.—Believe me, dear Wallace, yours very sincerely,

Ch.[arles] Darwin

1
Footnote (1) reads: "On the Pidgeons of the Malay Archipelago," Ibis, October, 1865. Wallace points out (p. 366) that "the most striking superabundance of pigeons, as well as of parrots, is confined to the Australo-Malayan sub-regions in which... the forest-hunting and fruit-eating mammals, such as monkeys and squirrels, are totally absent." He points out also that monkeys are "exceedingly destructive to eggs and young birds."—Note, "More Letters," i. 265.
2
Footnote (1) reads: "The Geographical Distribution and Variability of the Malayan Papilionidae," Linn. Soc. Trans., xxv."
3
Footnote (2) reads: "The passage referred to in this letter as needing further explanation is the following: "The last six cases of mimicry are especially instructive, because they seem to indicate one of the processes by which dimorphic forms have been produced. When, as in these cases, one sex differs much from the other, and varies greatly itself, it may be that individual variations will occasionally occur, having a distant resemblance to groups which are the objects of mimicry, and which it is therefore advantageous to resemble. Such a variety will have a better chance of preservation; the individuals possessing it will be multiplied; and their accidental likeness to the favoured group will be rendered permanent by hereditary transmission, and each successive variation which increases the resemblance being preserved, and all variation departing from the favoured type having less chance of preservation, there will in time result those singular cases of two or more isolated and fixed forms bound together by that intimate relationship which constitutes them the sexes of a single species. The reason why the females are more subject to this kind of modification than the males is probably that their slower flight when laden with eggs, and their exposure to attack while in the act of depositing their eggs upon leaves, render it especially advantageous for them to have additional protection. This they at once obtain by acquiring a resemblance to other species which, from whatever cause, enjoy a comparative immunity from persecution."

Editorial information

Status: Draft transcription [Published letter (WCP1868.5950)]

For more information about the transcriptions and metadata, see https://wallaceletters.myspecies.info/content/epsilon

Revision history

Transcribed by Sherwood, Danni [2020-07-28] Transcription checked by Lo, Yen [2020-10-30]

Please cite as “WCP1868,” in Beccaloni, G. W. (ed.), Ɛpsilon: The Alfred Russel Wallace Collection accessed on 20 April 2024, https://epsilon.ac.uk/view/wallace/letters/WCP1868