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Darwin Correspondence Project

From Thomas Wright   27 February 1863

St. Margarets Terrace | Cheltenham

Feb 27/63

Dear Sir

The statement referred to in your favor of the 25th. inst. was not made by me, perhaps Dr. Perceval Wright F.L.S. was the observer, as I was not present at the Meeting for 1860.1 If I had any observations or experiments upon the subject I should be delighted to place them at your disposal as I am sure no Naturalist makes a better use of his facts than yourself.

I am grateful to have it in my power to tell you that your valuable ⁠⟨⁠work⁠⟩⁠ on the Origin of Species has done excellent service to Natural Histo⁠⟨⁠ry;⁠⟩⁠ and even to those who are not disposed to agree with you in all your Conclusions relative to transmutation. It has I am happy to say given a great check to species manufacture and induced persons who formerly could see nothing but a new form in every slight variation of structure to reconsider their facts before proposing new sp to our already crowded lists   this I think is a matter of great practical value for at the rate at which we were proceeding in former years nothg but confusion could have been the result. now I find that the good old doctrine I have been endeaving to inculcate for 30 years begins to get a fair hearing, namely that the forms ⁠⟨⁠c⁠⟩⁠alled species appear in all time to have had ⁠⟨⁠cer⁠⟩⁠tain limits of variations which they have ⁠⟨⁠exhi⁠⟩⁠bited under the influence of physical condit⁠⟨⁠ion⁠⟩⁠s and which limits are not the same for every sp. some forms presenting wide deviation from what may be called their typical characters, whilst others move in very limited orbits. I have endeavoured to inculcate this in my Monograph on the Echinodermata and have illustrated it very many examples.2

For some years past I have been studying the Ammonites with the view to publish a Monogr. on them but among them this law of variation is very great indeed so much so that I have not been able to collect materials for more than a very small number of sp. for unless I can obtain an Ammonite in its young, growing, adult and ancient condition I hold that no one is competent to speak of it as a species   this I have been able to do with a few only out of the so called 100ds. of sp⁠⟨⁠.⁠⟩⁠ contained in the lists3

in much haste believe me always Yours Most truly | Thomas Wright

I expect if I am fortunate in obtaining a sufficient amount of material & make a beginning we shall have fine weeping and waling over “good species” which alas only turn out to be variations of other forms.— I expect my Monogr. on the Oolitic Asteridæ which has been done 8 Mos. and ought to have been out long ago will shew likewise that with a disposition to change there is likewise a law of constancy for you will find in some of the skeletons of the old Starfishes the persistent types of existing structures which have not changed during all that vast period of time which has elapsed between the Liassic and the present period4

T. W.


CD’s letter has not been found. Wright refers to the meeting of the British Association for the Advancement of Science held at Oxford between 26 June and 3 July 1860, at which Edward Perceval Wright served as one of the secretaries of Section D, ‘Zoology and botany, including physiology’. On Tuesday 2 July 1860 in Section D, in the debate following Philip Lutley Sclater’s paper on the geographical distribution of animals (Sclater 1860), the origin of species was discussed. A report of the exchanges in the Athenæum noted that Thomas Henry Huxley had challenged the assertion that domesticated forms, when allowed to run wild, returned to their primitive type; it was reported that Dr Wright replied: ‘that he had tried experiments on the cultivated cabbage, and, although it degenerated, it never assumed the form of the genuine wild plant, Brassica oleracea’ (Athenæum, 14 July 1860, p. 65). CD had probably written to Thomas Wright for clarification of the statement, unaware that he had mistaken the identity of the author.
Wright refers to his monograph on oolitic echinodermata, the first volume of which had been published in parts by the Palaeontographical Society (T. Wright 1857–80). See also n. 4, below.
The first part of the second volume of Wright’s monograph on oolitic Echinodermata (see n. 2, above), was devoted to the ‘Asteroidea’ (starfishes), and was published in 1863 (T. Wright 1857–80). The Liassic denotes a period synonymous with the early Jurassic epoch, a period of geological time now defined as beginning 210 million years ago (Collins dictionary of geology).


Collins dictionary of geology. By Dorothy Farris Lapidus. London and Glasgow: HarperCollins. 1990.

Wright, Thomas. 1857–80. Monograph on the British fossil Echinodermata of the Oolitic formations. 2 vols. London: Palaeontographical Society.

Wright, Thomas. 1878–86. Monograph on the Lias ammonites of the British islands. With a volume of plates. London: Palaeontographical Society.


Regrets he did not make the statement [unspecified] referred to by CD.

Believes the Origin has been very valuable, even among those not disposed to agree with transmutation, in giving a great check to "species manufacture".

Letter details

Letter no.
Thomas Wright
Charles Robert Darwin
Sent from
Source of text
DAR 181: 178
Physical description
ALS 4pp

Please cite as

Darwin Correspondence Project, “Letter no. 4016,” accessed on 5 December 2022,

Also published in The Correspondence of Charles Darwin, vol. 11