“Writing in Letters of Blood”: Manners in Scientific Dispute in Nineteenth-Century Britain and the German Lands

Thanks to Elisabeth Neswald and Will Thomas for their comments on earlier versions of this article.

Huxley Thomas , “The coming of age of the origin of species”, Nature, 6 May 1880, 1.

Popper Karl Raimund , Conjectures and refutations (London, 1963); Dascal Marcelo , “The study of controversies and the theory of the history of science”, Science in context, xi (1998), 1998–54; Dascal Marcelo Zhang Hanliang (eds), Traditions of controversy (Amsterdam and Philadelphia, 2007).

Bloor David , Knowledge and social imagery (Oxen, 1976); Golinski Jan , Making natural knowledge: Constructivism and the history of science (Chicago and London, 2005), 21–29.

Shapin Steven Schaffer Simon , Leviathan and the air-pump: Hobbes, Boyle, and the experimental life (Princeton, 1985).

Respectively: Biagioli Mario , Galileo, courtier: The practice of science in the culture of absolutism (Chicago and London, 1994); Goldstein Catherine , “Weder öffentlich noch privat — Mathematik im Frankreich des frühen 17. Jahrhunderts”, in Wobbe Theresa (ed.), Zwischen Vorderbühne und Hinterbühne. Beiträge zum Wandel der Geschlechterbeziehungen in der Wissenschaft vom 17. Jahrhundert bis zur Gegenwart (Bielefeld, 2003), 41–72.

See also Shapin Steven , A social history of truth: Civilty and science in seventeenth-century England (Chicago and London, 1994).

Babbage Charles , Reflections on the decline of science in England, and some of its causes (London, 1830), 158.

See e.g. Cunningham Andrew Williams Perry , “De-centering the big picture: The origins of modern science and the modern origins of science”, The British journal for the history of science, 26 (1993), 407–32.

Pickstone John , “Science in nineteenth-century England: Plural configurations and singular politics”, in Daunton Martin (ed.), The organisation of knowledge in Victorian Britain (Oxford, 2005), 32.

Morell Jack Thackray Arnold , Gentlemen of science: Early years of the British Association for the advancement of science (Oxford, 1981); Secord James , Controversy in Victorian geology: The Cambrian-Silurian dispute (Princeton, 1986); Yeo Richard , “Scientific method and the rhetoric of science in Britain, 1830–1917”, in Schuster John A. Yeo Richard R. (eds), The politics and rhetoric of scientific method: Historical studies (Dordrecht, 1986), 259–97; Secord James , Victorian sensation: The extraordinary publication, reception, and secret authorship of Vestiges of the natural history of creation (Chicago and London, 2000); Thackray John C. , To see the Fellows fight: Eye witness accounts of meetings of the Geological Society of London and its Club, 1833–1868 (Oxford, 2003); Barton Ruth “‘Men of science’: Language, identity and professionalization in the mid-Victorian scientific community, History of science, xlii (2003), 2003–119; idem, “Scientific authority and scientific controversy in Nature: North Britain against the X Club”, in Henson Louise (eds), Culture and science in the nineteenth-century media (Aldershot, 2004), 223–35; Lightman Bernard , Victorian popularizers of science (Chicago and London, 2007).

Daston Lorraine Sibum H. Otto , (eds), Scientific personae, a special issue of Science in context, xvi (2003); Bordogna Francesca , “Scientific personae in American psychology: Three case studies”, Studies in history and philosophy of science part c: Studies in history and philosophy of biological and biomedical sciences, xxxvi (2005), 2005–134.

On this topic: St George E. A. W. , The descent of manners: Etiquette, rules and the Victorians (Cambridge, 1993).

Hedge Levi , Elements of logick; or, a summary of the general principles and different modes of reasoning (Boston, 1824), 157–62. This edition is a reworked version of a book of 1816 carrying the same title.

Stewart Dugald , The philosophy of the active and the moral powers of man (London, 1828), ii, 300–2.

Stewart Dugald , Outlines of moral philosophy, for the use of students in the University of Edinburgh (Edinburgh, 1793), 240–2; For quotations, see a.o.: Nicholson William , “Philosophy, moral”, in British encyclopedia or dictionary of arts and sciences; Comprising an accurate and popular view of the present improved state of human knowledge (London, 1809), v, paragraph 85.

Paley William , Sermons on various subjects (London, 1825), i, 139–49.

Hey John , Lectures in divinity delivered in the University of Cambridge (Cambridge, 1822, 2nd edn), 412.

Rashid Salim , “Dugald Stewart, ‘Baconian’ methodology and political economy”, Journal of the history of ideas, xlvi (1985), 245–57; Nuovo Victor , “Rethinking Paley”, Synthèse, xci (1992), 1992–51.

Yeo Richard , “An idol of the market-place: Baconianism in nineteenth-century Britain”, History of science, xxiii (1985): 251–98; idem, Defining science: William Whewell, natural knowledge and public debate in early Victorian Britain (Cambridge, 1993), 137–40. See also Bord Joe , Science and Whig manners: Science and political style in Britain, c. 1790–1850 (London, 2009), 72–78.

See amongst others: Scrivener Micheal , Seditious allegories: John Thelwall and Jacobin writing (Pennsylvania, 2001); Russell Gillian Tuite Clara (eds), Romantic sociability: Social networks and literary culture in Britain 1770–1840 (Cambridge, 2002).

Stewart , op. cit. (ref. 16), iv.

The citation comes from a letter by Lord Will Craig of 15 February 1794, quoted in MacIntyre Gordon , Dugald Stewart: The pride and ornament of Scotland (Brighton, 2003), 89.

Kant Immanuel , Announcement of the near conclusion of a treaty for the eternal peace in philosophy [1796] , in Fenves Peter (ed.), Raising the tone of philosophy: Late essays by Immanuel Kant, Transformative critique by Jacques Derrida (Baltimore and London, 1993), 83–100, particularly 84. For the precise context of Kant's article, in which the philosopher attacked the Christianizing Platonist Joan Georg Schlosser, see the introduction and footnotes of this edition.

See e.g. Kant Immanuel , Critik der reinen Vernunft (Riga, 1781), 738–58; Fries Jakob Friedrich , Polemische Schriften (Halle and Leipzig, 1824), III—XII.

Krug Wilhelm Traugott , “Neueste Geschichte der Proselytenmacherei in Deutschland, nebst Vorschlägen gegen dieses Unwesen. (1827)”, in Versammelte Schriften: Theologische Schriften (Braunschweig, 1830), i, nr. 2, 239.

von Schelling Friedrich Wilhelm , Betrachtungen über den gegenwärtigen Zustand der Philosophie in Deutschland (Nürnberg, 1813), 49–51.

See Beiser Frederick C. , German idealism: The struggle against subjectivism, 1781–1801 (Cambridge, MA, 2000); Ameriks Karl (ed.), The Cambridge companion to German idealism (Cambridge, 2002).

The citation obviously comes from Kant's Was ist Aufklärung? The quote has to be read as an endorsement of the ideas of Frederick II of Prussia. See Kant Immanuel , “What is Enlightenment?” in Beck Lewis White , On history: Immanuel Kant (Indianapolis, 1963), 5.

Wilhelm Georg Hegel Friedrich , Enzyklopädie der philosophischen Wissenschaften, first published in 1817. The passage is quoted in Harold Mah, Enlightenment phantasies: Cultural identity in France and Germany, 1750–1914 (Ithaca, 2003), 65. Mah refers to similar stereotypes in the work of Johann Gottfried Herder and Johann Gottlieb Fichte.

On this persona see Clark William , Academic charisma and the origins of the research university (Chicago and London, 2006). On competition in the German research university see also Turner R. Steven , “The growth of professorial research in Prussia, 1818 to 1848: Causes and context”, Historical studies in the physical sciences, iii (1971), 1971–82.

Kant , op. cit. (ref. 25), 757.

Hey , op. cit. (ref. 18), 291.

Schweizer Johann Conrad , Wörterbuch zur Erklärung fremder aus andern Sprache in Deutsche aufgenommener Wörter und Redensarten (Zürich, 1811), 283; Real-Encyclopädie oder Conversations-Lexicon (Leipzig, 1819), ii, 784; Allgemeine deutsche real-Encyclopädie für gebildeten Stande (Leipzig, 1824), ii, 754.

Krug argued that it was particularly the theologians who had appropriated the word in the German lands. Krug Wilhelm Traugott , Allgemeines Handwörterbuch der philosophischen Wissenschaften nebst ihre Literatur und Geschichte (Leipzig, 1827), i, 256. If in Britain the term “rules of controversy” was used it was mostly in relation to theological polemics. See e.g. Rev. Daubeny Charles , Vindiciae Ecclesiae Anglicanae (London, 1803), 163; “Review of new publications: State of the Calvinistic controversy”, The Christian spectator, vi (1824), 1824–37; Williamson David , Reflections on the four principal religions which we have obtained in the world (London 1824), 266.

See Gaukroger Stephen , Francis Bacon and the transformation of early-modern philosophy (Cambridge, MA, 2001), 10–11.

Report of the third meeting of the British Association for the Advancement of Science (London, 1834), xxix, cited amongst others in Secord, op. cit. (ref. 11), 15.

Fitton William , “Address delivered to the anniversary”, Proceedings of the Geological Society of London, vi (1828), 61, cited in Rudwick Martin , The great Devonian controversy: The shaping of scientific knowledge among gentlemen specialists (Chicago and London, 1985), 25.

Secord , op. cit. (ref. 11), 15–17; Thackray , op. cit. (ref. 11), v—xii.

Babbage , op. cit. (ref. 8), x, xii–xiii, 2 and 219.

Morrell Thackray , op. cit. (ref. 11), 37–42.

Morrell Thackray , op. cit. (ref. 11), 141.

The quotations are from respectively William Charles Henry and George Biddell Airy, who, in letters to the then Secretary of the Association, William Vernon Harcourt defended the rhetoric of their reports. Airy to Harcourt 5 Sept. 1832; Henry to Harcourt 23 Oct. 1833, in Morell Thackray (eds), op. cit. (ref. 11), 152 and 181.

Bord , op. cit. (ref. 20), 71–72.

Strube Wilhelm , “Naturwissenschaftliche Gesellschaften in Deutschland von 1800 bis 1870: Zu ihrer Vorgeschichte, Entwicklung und Bedeutung”, Jahrbuch für Wirtschaftsgeschichte (1979), iv, 73–96. More in particular for the Dresden area see Philips Denise , “Friends of nature: Urban sociability and regional natural history in Dresden”, Osiris, 2nd series, xviii, Science and the city (2003), 43–59.

See for example te Heesen Anke , “From natural historical investment to state service: Collectors and collections of the Berlin Society of Friends of Nature Research, c. 1800”, History of science, xlii (2004), 113–31.

In the early nineteenth century this started to become an object of criticism: Schweiger Salomo Christoph , “Vorschläge zum Besten der Leopoldinisch-Carolinischen Akademie der Naturforscher”, Journal für Chemie und Physik (1818), 350–82.

Schmitt Wolfgang , “Konstituierung der Gesellschaft Deutscher Naturforscher und Ärzte”, in Schipperges Heinrich (ed.), Die Versammlung Deutscher Naturförscher und Ärzte im 19. Jahrhundert (Stuttgart, 1968), 31–42.

Oken Lorenz , “Versammlung der deutschen Naturforscher und Aerzte zu Leipzig am 18 Sept. 1823”, Isis von Oken, viii (1823), 552–9.

Oken Lorenz , Erste Ideen zur Theorie des Lichts, der Finsterniss, der Farben und der Wärme (Jena, 1808), 6–7.

Oken , op. cit. (ref. 49), 553–5.

Jackson Myles W. , “Harmonious investigators of nature: Music and the persona of the German Naturforscher in the nineteenth century”, Science in context, xvi (2003), 121–45. For the quote (from the song “Zur Weihe des Tages”), see p. 128; For the issue of correspondence and isolation, see p. 124. See also more elaborately, idem, Harmonious triads: Physicists, musicians and instrument makers in nineteenth-century Germany (Cambridge, MA, 2009), 45–74.

Publishing administrative reports or dissertations, Oken elaborated, did not make you an author. Oken , op. cit. (ref. 50), 6–7; idem, op. cit. (ref. 49), 555.

On Oken see Butscher Heidrose Brandt , “Oken (or Okenfuss), Lorenz”, in Complete dictionary of scientific biography, xxiii (Detroit, 2008), 331–5.

Charles Babbage reported enthusiastically on both the meeting and Humboldt's lecture: [Charles Babbage] “Account of the Great Congress of Philosophers at Berlin on the 18th September 1828”, Edinburgh journal of science, x (1829), 225–34.

von Humboldt Alexander , Rede, gehalten bei der Eröffnung der Versammlung deutscher Naturforscher und Ärzte (Berlin, 1828), 6–8.

The philosophical disagreements between Whewell and Mill are extensively dealt with in Snyder Laura , Reforming philosophy: A British debate on science and society (Chicago and London, 2006).

Respectively in Whewell William , The philosophy of the inductive sciences, founded upon their history (London, 1840), ii, 173; Mill John Stuart , A system of logic, ratiocinative and inductive, being a connected view of the principles of evidence and the methods of scientific investigation (London, 1851), 3rd edn, viii.

The quote comes from Mill, op. cit. (ref. 58), viii. Whewell would, as late as 1867, defend the subject of his book On the plurality of worlds by stressing he believed it “eminently fitted for calm discussion, and … little likely to excite angry controversy”. Whewell William , Of the plurality of worlds (London, 1867), 5th edn, vii.

Cf. his letter to Auguste Comte, 5 October 1844, cited in Snyder , op. cit. (ref. 57), 99.

[ Sedgwick Adam ], “Vestiges of the natural history of creation”, The Edinburgh review, lxxxii (1845), 1–85. For the wider context: Secord, op. cit. (ref. 11). The image of science as a thorny hill, inaccessible for women is an old one, dating back to at least the seventeenth century. See Goldstein , op. cit. (ref. 6), 626.

Anonymous , “A discourse on the studies of the University of Cambridge, by Adam Sedgwick”, The British quarterly review, xii (1850), 360–82.

Holyoake George , Rudiments of public speaking and debate, or, hints on the applications of logic (London, 1849).

On Holyoake and the British secularist Movement see Royle Edward , Victorian infidels: The origins of the British Secularist Movement, 1791–1861 (Manchester, 1974), 72–162.

“Improvement class: For the study of literary composition, logic, and oral investigation conducted by Mr. G. Jacob Holyoake. Prospectus.”, Holyoake Archive, Bishopsgate Institute London (HA), Printed Material 3/1/56.

Holyoake George , Why do the clergy avoid discussion and the philosophers discountenance it? (London, 1852).

Holyoake George , “Editorialities”, The reasoner: And “Herald of Progress”, i (1846), 1.

Idem, op. cit. (ref. 66), 21.

Holyoake , op. cit. (ref. 69), 76.

“Constitution and objects of secular societies”, HA, Printed material 3/2/16.

The Rev. Brewin Grant, for example, was attacked in a secularist pamphlet for his “vulgar and ungentlemanly language”. He was accused, amongst others, for having called Holyoake a “Liar”, “Hypocrite” and “English Sepoy”. “Mr. Brewin Grant's trick to get an audience”, HA, Printed material, 3/2/48.

“Popular Lectures on Grammar, Logic and Rhetoric”, HA, Printed material, 3/1/76.

See also Secord , op. cit. (ref. 11), 309–10.

There is some discussion on the extent to which the audience of the Mechanic's Institutes was from working class background. See Royle Edward , “Mechanics' Institutes and the working classes, 1840–1860”, The historical journal, xiv (1971), 305–21; Laurent John , “Science and politics in late nineteenth-century England: A further look at Mechanic's Institutes”, Social studies of science, xiv (1984), 1984–619.

In one of the prospectuses of his classes, he stated: “Aristotle gave us the fictions — Bacon the facts of logic.” “London Theological Association. Improvement class: For the study of literary composition, logic, and oral investigation conducted by Mr. G. Jacob Holyoake. Prospectus”, HA, Printed Material, 3/1/56.

Report of the Third Meeting of the British Association for the Advancement of Science (London, 1831), xxix.

One of the lectures he toured with in 1849 was called “Revolution by force contrasted with revolution by reason”, HA, Diaries, 2/1, 1 Jan. 1849.

HA, Diaries, 2/3, 13 April 1853.

[ Holyoake George ], “Editorialities”, 1.

Wagner Rudolf , Menschenschöpfung und Seelensubstanz (Göttingen, 1854). For the wider context of the materialism debate see Gregory Frederick , Scientific materialism in nineteenth century Germany (Dordrecht, 1977); Bayertz Kurt Gerhard Myriam Jaeschke Walter (eds), Weltanschauung, Philosophie und Naturwissenschaft im 19. Jahrhundert. Band 1: Der Materialismus-Streit (Hamburg, 2007).

Hermann Irène “Carl Vogt, les réfugiés et Genève”, in Pont Jean-Claude (eds), Carl Vogt: Science, philosophie et politique (1817–1895) (Geneva 1989), 47–65.

Vogt Carl , Bilder aus dem Thierleben (Frankfurt am Main, 1852), ii, 173, 317, 367, 423 and 451–2.

Vogt Carl , Köhlerglaube und Wissenschaft: Eine Streitschrift gegen Hofrath Rudolph Wagner in Göttingen (Giessen, 1855), 4th edn, 16.

Idem , Köhlerglaube, ix, 5–13.

See a.o. idem, Bilder, ii and 421; idem, Köhlerglaube, 2, 32 and 37.

Idem , Köhlerglaube, liii.

Wagner Rudolf , “Erklärung”, Allgemeine Zeitung, lxxxviii (1855), 1406.

von Reichenbach Freiherrn Karl , Köhlerglaube und Afterweisheit. Dem Herrn C. Vogt in Genf zur Antwort (Vienna, 1855), 2; Wagner Andreas , Naturwissenschaft und Bibel. Im Gegensatze zu dem Köhlerglauben des Herrn Carl Vogt (Stuttgart, 1855), 10.

The quote comes from an undated letter of Moleschott to Vogt [1867?]. Similar expressions can be found in Moleschott to Vogt 5 Jan. 1861, and Vogt to Moleschott 6 Nov. 1852 Kockerbeck Christoph (ed.), Carl Vogt- Jacob Moleschott — Ludwig Büchner — Ernst Haeckel: Briefwechsel. (Marburg, 1999), 88, 101.

Kölliker Albrecht , “Ueber den Bau der Cutispapillen und die sogenannten Tastkörperchen R. Wagner's”, Zeitschrift für wissenschaftliche Zoologie, iv (1853), 43–52; Nyhart Lynn , Biology takes form: Animal morphology and the German universities, 1800–1900 (Chicago and London, 1995), 70–72.

Reichenbach , op. cit. (ref. 88), 3 and 45.

Vogt , op. cit. (ref. 83), 3 and 21. Kant Immanuel , Anthropologie in pragmatischer Hinsicht (Königsberg, 1800), 2nd edn, 163.

James Secord has indicated that gentility changed in the 1840s, referring increasingly to character and decreasingly to birth and wealth. But obviously this did not mean that it immediately lost all its connotations of class. It did not in Britain, nor did it in the German lands. Secord , op. cit. (ref. 11), 405–6.

Barr Alan P. , “‘Common sense clarified’: Thomas Henry Huxley's faith in truth”, in Barr Alan P. (ed.), Thomas Henry Huxley's place in science and letters (Athens, Georgia, 1997), 9–30; White Paul , Thomas Huxley: Making the “Man of Science” (Cambridge, 2003), 34.

On the writers see St George , op. cit. (ref. 13), 233–55; With regard to the shift in political style, e.g. Jenkins Terence Andrew , Parliament, party and politics in Victorian Britain (Manchester, 1996), 23, 111–41.

Matthew H. C. G. , “Rhetoric and politics in Great Britain, 1860–1950”; in Waller P. J. , Politics and social change in modern Britain essays presented to A. F. Thompson (Brighton and New York, 1987), 34–58.

Vogt was particularly linked to the X-Club through Huxley, whose Lectures of Man he would translate into German. According to one of his students Huxley always regarded Vogt as “a tower of strength and in certain sense a genius”. He added: ” and in truth it must be admitted that there was much in Vogt that reminded me of Huxley. Like the latter, he was fearlessly outspoken in his utterances.” Heilprin Angelo , “A students recollection of Huxley”, Popular science, xlviii (1896), 331–2. On Holyoake's relationship with Tyndall and Huxley, see a.o. Dawson Giwan , Darwin, literature and Victorian respectability (Cambridge, 2007), 151.

Tyndall John , Fragments of science: A series of detached essays, addresses and reviews (London, 1867), 5th edn, 533.

Desmond Adrian Moore James , Darwin's sacred cause: How a hatred of slavery shaped Darwin's views on human evolution (Boston and New York, 2009), xvi.

Darwin to Henslow , 30–1 Oct. 1836, published in Burkhardt Frederick (ed.), The correspondence of Charles Darwin, i, 1821–1836 (Cambridge, 1985), 514.

Darwin to Hooker , 30–1 Oct. 1836, published in Burkhardt Frederick (ed.), The correspondence, xi, 1856–1857 (Cambridge, 1990), 111–12.

Darwin to Haeckel , 12 April 1867, published in Burkhardt Frederick (ed.), The correspondence, xv, 1867 (Cambridge, 2005), 218–19.

Darwin Charles , The descent of man, and selection in relation to sex (London, 1872), ii, 385.

Haeckel to Darwin , 12 May 1867, published in Burkhardt (ed.), The correspondence, xv, 254–7.

For a general overview of this clash: di Gregorio Mario , From here to eternity: Ernst Haeckel and scientific faith (Göttingen, 2005), 338–63; Richards Robert J. , The tragic sense of life: Ernst Haeckel and the struggle over evolutionary thought (London and Chicago, 2008), 312–29.

Haeckel Ernst , “Ueber die heutige Entwicklungslehre im Verhältnisse zur Gesamtwissenschaft”, Amtlicher Bericht der 50. Versammlung Deutscher Naturforscher und Aerzte in München (Munich, 1877), 14–22. The quote comes from a letter to Hermann Allmers, 2 Dec. 1877, published in Richards, op. cit. (ref. 106), 324–5.

Virchow Rudolf , “Die Freiheit der Wissenschaft im modernen Staatsleben”, Amtlicher Bericht der 50. Versammlung Deutscher Naturforscher und Aerzte in München (Munich, 1877), 65–78.

Haeckel Ernst , Freie Wissenschaft und freie Lehre: Eine Entgegnung auf Rudolf Virchow's Münchener Rede über, Die Freiheit der Wissenschaft im modernen Staat (Stuttgart, 1878). I used the English translation: Idem, Freedom in science and teaching (New York, 1879), xxiv and 17–21.

Haeckel , Freedom in science (ref. 108), xviii, 21, 27, 29, 44 and 103. More generally on the relationship between Huxley and Haeckel: Di Gregorio , “Thomas Henry Huxley and German science”, Barr (ed.), op. cit. (ref. 94), 159–81.

See a.o: Finchman Martin , “Biology and politics: Defining the boundaries”, in Lightman Bernard (ed.), Victorian science in context (Chicago and London, 1997), 94–118.

Huxley Thomas , “Illustrations of Mr. Gladstone's controversial method”, The popular science monthly, xxxix (1891), 532.

See Haeckel , Freedom in science (ref. 108), xvii, xxiv and 95.

Haeckel to Huxley , 12 May 1865, Huxley Papers, Imperial College London Archives (ICLA). Haeckel referred to Gegenbaur's criticism in this letter. His “Saracen fanaticism” would be a continuous nuisance for Gegenbaur in the decades to come. Di Gregorio, op. cit. (ref. 105), 290–2.

Huxley to Haeckel , 20 May 1865, in Leonard Huxley, Life and letters of Thomas Henry Huxley (New York, 1901), i, 309–10.

Haeckel to Huxley , 28 June 1865, Huxley Papers, ICLA.

In his letters to Haeckel, Darwin cautiously translated this as: “too profound and too long for our English country-men.” Darwin to Huxley, 22 Dec. 1866; Darwin to Huxley, 7 Jan. 1867; Huxley to Darwin, 7 Jan. 1867; Darwin to Haeckel, 8 Jan. 1867, published in Burkhardt Frederick (ed.), The correspondence of Charles Darwin, vol. 6 1856–1857 (Cambridge, 2004), 437–8; idem, The correspondence, xv, 12–17.

Huxley to Haeckel , 13 Nov. 1868, Huxley , op. cit. (ref. 114), 327–8.

Haeckel to Huxley , 23 Feb. 1869, Huxley Papers, ICLA.

Darwin to Carus , 11 April 1867, published in Burkhardt (ed.), The correspondence, xv, 217–18.

It was Carus and Gegenbaur, who incited Darwin to use his influence over Haeckel to tone the latter down. Carus to Darwin, 5 and 15 April 1867, published in Burkhardt (ed.), The correspondence, xv, 219–21 and 223–4.

Huxley Thomas , Essays upon some controverted questions (London, 1892), 2.