Ɛpsilon

To Gaston de Saporta   10 September 1876

Down, | Beckenham, Kent.

Sep. 10. 1876

Dear and much honoured Sir,

Your letter appears to me full of the most interesting and important points, and I hope that some day you may publish a full discussion on these subjects.1 I have noticed observations in your works on the long persistence of certain varieties; & this is a subject which has perplexed me during many years. The cases which I had in my mind were chiefly drawn from the animal kingdom, such as the fossil land-shells of Madeira & of certain marine tertiary shells, which formerly presented the same range of variation as they now do.2 With respect to sub-species, races, varieties etc., I dare say you are acquainted with Nägeli’s discussion on Hieracium which interested me greatly;3 and if I had been a younger man I would have experimentally investigated such closely related forms. The subject of one species varying in such a manner as to resemble another allied form, whether called a species, race etc. has long been familiar to me, and I have given a few instances in several of my works under the heading of “analogous variation”.4

With respect to the sudden development of dicotyledenous plants, which view Heer likewise maintains, I confess that I am sceptical.5 It is of course a mere conjecture, but I imagine that this great group of plants must have been slowly developed in some part of the globe which was formerly more completely isolated from all other regions than any part of the land now is. I have always felt the keenest interest in your observations on the very gradual change of species during the later Tertiary periods; and I observe that A. de Candolle has likewise been struck with these observations which are strongly opposed to Heer’s belief of great & abrupt specific changes.6 I venture to repeat my hope that you may induced to write a special essay on these difficult & very interesting points.

With much respect, I remain | Dear Sir, | Yours very faithfully | | Charles Darwin

LS

2
CD mentioned the relation between the extinct and living land shells of Madeira in his discussion of the persistence of varieties in Origin 6th ed., pp. 310–12.
3
Carl Wilhelm von Nägeli had discussed variation in Hieracium (the genus of hawkweeds) in ‘Ueber die systematische Behandlung der Hieracien rücksichtlich der Mittelformen’ (On the systematic treatment of Hieracium with regard to intermediate forms; Nägeli 1866a), ‘Ueber die systematische Behandlung der Hieracien rücksichtlich des Umfanges des Species’ (On the systematic treatment of Hieracium with regard to the range of species; Nägeli 1866b), and ‘Ueber die Innovation bei den Hieracien und ihre systematische Bedeutung’ (On innovation in Hieracium and its systematic significance; Nägeli 1866c). The first two of these papers were included in a collection of Nägeli’s papers that Nägeli had sent CD in 1867 (Nägeli 1863–81, vol. 2; see this volume, Supplement, letter from C. W. Nägeli, 31 March 1867).
4
CD had discussed analogous variation in Origin, pp. 162, 168–9, Variation 2: 348–52, and Descent 2: 136.
5
Oswald Heer had remarked on the sudden development of dicotyledons (flowering seed-plants or angiosperms characterised by the presence of two embryonic seed-leaves or cotyledons) in a letter to CD of 1 March 1875 (Correspondence vol. 23). In his response, CD conjectured that the plants had first developed in an isolated region and then spread quickly when geographical conditions became favourable (Correspondence vol. 23, letter to Oswald Heer, 8 March [1875]).
6
Alphonse de Candolle had supported CD’s view that evolutionary change had been gradual in opposition to Heer’s theory that there had been long periods of stability with occasional brief explosions of change in Histoire des sciences et des savants depuis deux siècles (History of the sciences and scientists for two centuries; A. de Candolle 1873, pp. 11–14).

Please cite as “DCP-LETT-10591,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-10591