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Letter 1979

Darwin, C. R. to Lubbock, John

27 Oct [1856]

    Summary Add

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    Comments on JL's paper on Daphnia, ["An account of methods of reproduction in Daphnia and of the structure of the ephippium", Philos. Trans. R. Soc. Lond. 147 (1857): 79–100].

Transcription

Down.

Oct. 27th

My dear Lubbock.

I received this morning your paper & have read it attentively. It is to me decidedly interesting, & as a whole very clear. But without some special object (& trusting not much to my own judgment) I shd have almost thought it wd have been better to have waited a little longer before publishing. For you discuss (& in a very interesting manner) such high points towards the close, that the premises ought to be extra certain: in the beginning you put very modestly & candidly the deficiences in your evidence about not having traced every step in the formation of the ephippial eggs, & in regard to impregnation. Certainly if these points could have been more thoroughily cleared up, your paper would have been much more valuable. (V. Back of Page)— But do not think that I wish to underrate the novelty viz about the spermatozoa, male organs, structure of case of ephippium, & the stages, as far as you have traced them, of formation of ephippium.— The two sorts of eggs from a “female” is a new & striking point. To go into a few details.

In p. 1. I shd have thought the expression that “at once evident” that Daphnia was a case of “Lucina sine C.” was rather strong; for why shd not a priori the Ephippium have been produced without impregnation as well as the “ordinary eggs”.— it may be very probable that Daphnia is case in point.—

p. 1. you use word “former”; in my opinion every author who uses “former & latter” ought to be executed; & this wd clear the world of all authors except Maccaulay.—

p. 10 is not very clear in parts, owing, I think, to your varying your terms “cells” “eggs” “darkened” “brown”

p. 18. Surely ought you not to give your own facts pretty full (& references to others) about ova being produced by females for successive times without males.— When I met this page, I turned back, thinking that I had overlooked some whole page.—

I shd have doubted whether it was worth while to have given such long extracts from Baird & M. Edwards, as you state that Straus more accurate.

I have appended a few pencil marks to some sentences, which required twice reading over, which no sentence ought to do.

Do not mistake my first remarks, & suppose for one moment that I do not think your present materials worth publishing: only I shd have liked to have seen them still more perfect;—but it is quite likely that I carry this notion to an extreme.— Trust more to Huxley's opinion than to mine, if you can get him to read the M.S.— — I do most honestly admire your powers of observation & zeal; & you will do, much in Nat. History, notwithstanding your terrible case of “pursuit of knowledge under riches”, as I said the other day.—

Farewell— I am sorry that you are poorly— I hope & fully expect that I shall be well enough to see you on Wednesday if you come

Adios | C. Darwin

The evidence in regard to fecundation & the 2 sorts of eggs is thus, is it not?—

Ordinary eggs are produced for 2 or 3 successive times in same individual without males; but not I suppose for successive generations.— I suppose existence of a spermatheca is very improbable.—

Ephippial eggs are never produced without presence of males, (& you have a good long experience in this?) but the presence of males does not necessarily in your experience, induce ephippial eggs.— ie Whilst males are present & even seen attached to females, “ordinary” eggs are produced.— Is this not so? Certainly evidence seems pretty strong for your view: but yet, if I have put the case right, still further evidence or still longer experience wd be desirable.—

Wd it not be adviseable to give some summing up of evidence

    Footnotes Add

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    f1 1979.f1
    Dated by the reference to the manuscript of Lubbock 1857.
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    f2 1979.f2
    Lubbock sent CD the manuscript of his paper on reproduction in Daphnia (Lubbock 1857). CD communicated the paper to the Royal Society on 22 December 1856 (see Proceedings of the Royal Society of London 8 (1856–7): 352–4). It was published in full in the Philosophical Transactions of the society.
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    f3 1979.f3
    In the closing pages of the published version (Lubbock 1857, pp. 95–9), Lubbock summarised recent work on parthenogenesis in the Articulata, including Crustacea and insects. He drew a parallel between ‘agamic’ reproduction in Daphnia and in plants that apparently produced agamic seeds, and suggested that there was no fundamental difference between the two kinds of eggs produced by Daphnia: the eggs formed ‘parts of one and the same series’ (p. 99).
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    f4 1979.f4
    Lubbock distinguished the common, parthenogenic mode of reproduction in Daphnia from the less frequent and less understood mode of sexual reproduction. Although he stated that had not been able to prove that the ephippial eggs (so named because they were found in a specialised compartment of the animal's carapace known as the ephippium) were the result of sexual reproduction, he presented his reasons for believing that this was the case. He also claimed to have identified the male sexual organs and the animal's spermatozoa, hitherto unobserved.
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    f5 1979.f5
    In the final version of the paper, Lubbock did not use the expression ‘at once evident’ (Lubbock 1857, p. 79).
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    f6 1979.f6
    Thomas Babington Macaulay.
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    f7 1979.f7
    CD refers to the section in Lubbock's paper in which Lubbock described the appearance and subsequent development of agamic eggs after their deposition (Lubbock 1857, p. 83).
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    f8 1979.f8
    Lubbock cited William Baird (Baird 1850) and Henri Milne-Edwards (Milne-Edwards 1834–40) in Lubbock 1857, pp. 84–5, before stating that Hercule Eugène Gregoire Straus-Durckheim's description of the anatomy of the
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    f9 1979.f9
    In the published paper, Lubbock stated his belief that there was no spermatheca in which the female could retain live sperm to fertilise successive broods (Lubbock 1857, p. 88).
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    f10 1979.f10
    Lubbock stated: ‘I have not succeeded in … obtaining ephippial eggs from isolated specimens’ (Lubbock 1857, p. 87). However, he went on to describe experiments in which isolated females developed ephippia and concluded that ‘these experiments prove that ephippia can be produced without male influence. I only, however met with seven instances, though I have had at least 400 broods of agamic eggs produced by females kept separate from males’ (p. 88).
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