Skip to main content

Müller, Fritz (Johann Friedrich Theodor)


(b. Windischholzhausen, Thuringia, Germany, 31 March 1822; d. Blumenam Brazil, 21 May 1897)

natural history.

Although described by Blandford in Nature (1897) as “one of the greatest and most original naturalists” of the nineteenth century, Müller’s reputation has always been overshadowed by those of his illustrious scientific contemporaries. His innate modesty, complete indifference to fame, and physical isolation in southern Brazil further contributed to obscure the significance of his work. His book, Für Darwin (1864), however, was a fundamental contribution to evolutionary biology at a critical moment during its infancy; and his name has been immortalized in scientific literature with the term “Müllerian mimicry.”

Müller was born in a small village outside Erfurt. His father, Johann Friedrich Müller, was a minister, and his mother was the daughter of the distinguished Erfurt chemist and pharmacist J. B. Trommsdorff. Both parents had a strong interest in natural history, and his father in particular greatly influenced Fritz and his younger brother Hermann, who became a wellknown botanist at Lippstadt.

Müller’s early formal education began at the village school of Mühlberg and continued at the Erfurt Gymnasium (1835–1840), where his extraordinary linguistic ability—he learned Italian, Russian, Syriac, Arabic, English, and later Portuguese—became evident. After studying pharmacy or one year at Naumburg, he began advanced work at the University of Berlin, where he studied mathematics and the natural sciences. His anatomy professor was Johannes Müller. He spent the following academic year (1842–1843) at the University of Greifswald, then returned to Berlin, where he completed the Ph.D. on 14 December 1844. His dissertation, “De hirudinibus circa Berolinum hucusque observatis,” dealt with the leeches found near Berlin. He continued work at Berlin for his advanced teaching certificate (Oberlehrerexamen) before returning to the Gymnasium at Erfurt for his teaching period as a probationary candidate (1845). Later that year, however, he decided to study medicine, with the intention of becoming a ship’s surgeon and seeing the world, especially the tropics, where he hoped to study zoology.

Returning to the University of Greifswald (1845–1849), Müller completed all the work for his medical degree except for the state certification examination (Staatsexamen). The Ministry of Education would not allow him to take the examination because he had sided with the democrats in the Revolution of 1848 and had refused to take a religious oath recognizing the established church and orthodox religious views, (Müler believed in free love, and Katherine Töllner bore three of their ten children out of wedlock.) In 1849, unable to obtain his degree, Müller in October became a private tutor at Roloffshagen (near Grimmen). He eventually received honorary medical degrees from Bonn in 1868 and from Tübingen in 1877. Prussian religious intolerance finally led mü o abandon his homeland in 1852 and sail to Blumenau, Brazil, on the Itajai River near the coast between Rio de Janeiro and Buenos Aires. Most of his important scientific work was done in South America, where he spent the rest of his life.

Despite his superb education, Müller lived there as a farmer until 1856, when he was appointed mathematics teacher at the provincial lyceum at Desterro (now Florianópolis), Santa Catarina Island. Various conflicts—particularly with the Jesuits— led to the termination of his employment in 1867, and he returned to Blumenau, where he worked as a civil servant for the provincial government until 1876. Müller was then appointed traveling naturalist for the National Museum in Rio de Janeiro, a post which he lost (including the pension) in 1891 when he refused to move to Rio de Janeiro. His last years in Blumenau were marred by a variety of misfortunes— imprisonment and trial by rebels, and the death of both his wife and his daughter— although he resumed his work before his death.

Müller’s scientific contributions ranged from anatomical work on Coelenterata, Annelida, and especially Crustacea to entomology, emphasizing mimicry, and to botany, particularly in his later years. After moving to Desterro, he began to study the marine invertebrates of the Brazilian coastal waters. Darwin’s Origin of Species (1859) led Müller to test those evolutionary ideas by applying them to the Crustacea. He traced the genealogies of various groups, hoping to uncover affinities and the origins of fundamental (primitive) forms. While Darwin offered general propositions, Müller provided a specific test case in the development of the Crustacea. His verdict was rendered in favor of Darwin’s views: “In one thing, I hope, I have succeeded,—in convincing unprejudiced readers, that Darwin’s theory furnishes the key of intelligibility for the developmental history of the Crustacea” and “many other facts [are] inexplicable without it” (Für Darwin, 1869 translation, p. 141). Publication of such enthusiastic, sympathetic views led to a lengthy correspondence with Darwin, who provided the financial backing for the English translation of Für Darwin in 1869, frequently sent Müller’s letters to journals for publication, and quoted him extensively in his own work.

During the 1870’s and 1880’s Müller published many articles on entomology, the most famous of which discussed mimetic phenomena. In 1862 the English naturalist Henry Walter Bates had first published his own observations concerning examples of relatively scarce, palatable, and defenseless species of insects (primarily) which closely resembled other species which were plentiful and relatively unpalatable or were protected in some other manner. He thought such situations arose through the process of evolution by means of natural selection; that is, those mimics which most closely resembled the protected species would be rejected by predators and therefore survive, but those which varied greatly in appearance from the protected species would be eliminated in the struggle for existence. Bates, however, did not explain why two or more distasteful but unrelated species resembled one another.

In a series of articles beginning in 1878, Müller explained that predators must learn through warning characteristics which species are palatable, and that in this process some of the prey population must be sacrificed. If there are two or more similar, unpalatable species, then predators will be educated faster by the warning characteristics, the similar species will be better protected, fewer deaths will result, and the losses will he absorbed by a larger group. These views

were quickly adopted and expanded by other evolutionists, including A. R. Wallace and E. B. Poultun, and form an important part of contemporary literature in evolutionary biology.

Müller’s botanical work dealt mainly with the fertilization of plants, with discussions of hybridization and sterility, including self-sterility. Darwin cited this work frequently in his book The Effects of Cross and Self Fertilisation in the Vegetable Kingdom (1876).

Altogether, Müller published almost 250 articles in which he demonstrated extraordinary powers of observation, while his book Für Darwin and his articles on mimicry reflect his considerable ability to formulate perceptive conclusions. In general, however, he was content to allow others to build upon his smaller, albeit valuable, contributions.


I. Original Works. All of Müller’s works were conveniently collected by his nephew, Dr. Alfred Möller, Fritz Müller. Werke, Briefe und Leben, 3 vols. in 4 plus atlas (Jena, 1915–1921). His works are in vol. I (in two pts., plus an atlas of plates [1915]). Für Darwin (Leipzig, 1864) was trans. into English as Facts and Arguments for Darwin (London, 1869; repr., 1968) and into French. The rich and extensive correspondence, including letters to Charles Darwin and many German biologists, is in vol. II (1921); and his biography is in vol. III (1920), with a valuable map of his excursions. MS letters and additions to Für Darwin are in the Darwin Papers, University Library, Cambridge.

Important early articles on mimicry are “Ueber die Vortheile der Mimicry bei Schmetterlingen,” in Zoologischer Anzeiger, 1 (1878), 54–55; a note on a remarkable case of mimicry of Eueides pavana with Acraea thalia referred to in Proceedings of the Entomological Society of London (1879), ii; and particularly “Ituna and Thyridia; a Remarkable Case of Mimicry in Butterflies,” ibid., pp. xx-xxviii, discussion pp. xxviii-xxix—the article first appeared in Kosmos, 5 (1879), 100–108. The latter two articles were trans. by R. Meldola. English trans. of some other entomological articles appear in George B. Longstaff, Butterfly-Hunting in Many Lands. Notes of a Field Naturalist. To Which Are Added Translations of Papers by Fritz Müller on the Scentorgans of Butterflies and Moths: With a Note by E. B. Poulton, D.Sc., F.R.S. (London-Bombay-Calcutta, 1912). Numerous letters exchanged by Darwin and Müller appear in both Francis Darwin, ed., The Life and Letters of Charles Darwin, 3 vols. (London, 1887); and Francis Darwin and A. C. Seward, eds., More Letters of Charles Darwin, 2 vols. (New York, 1903).

II. Secondary Literature. The best biography of Müller is Alfred Möller’s Leben (vol. III of the Works). He also lists some obituaries on p. 163, two of which are F. Ludwig, “Ueber das Leben und die botanische Thätigkeit Dr. Fritz Müller’s.” in Botanisches Centralblatt, 71 (1897), 291–302, 347–363, 401–408, plus 4 plates, (100 articles are listed on pp. 404–408); and W. F. H. B. [Walter F. H. Blandford], “Fritz Müller,” in Nature, 56 (1897), 546–548. Blandford’s observations on mimicry are quite interesting, as are those of Roland Trimen, “President’s Address. Mimicry in Insects,” in Proceedings of the Entomological Society of London (1897), lxxiv-xcvii. Also on mimicry, see Mary Alice Evans, “Mimicry and the Darwinian Heritage,” in Journal of the History of Ideas, 26 (1965), 211–220. For additional references on mimicry, see H. Lewis McKinney, “Henry Walter Bates,” Dictionary of Scientific Biography, I, 504. For Müller’s work on botany, see the article by F. Ludwig cited above.

H. Lewis McKinney

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"Müller, Fritz (Johann Friedrich Theodor)." Complete Dictionary of Scientific Biography. . 21 Sep. 2018 <>.

"Müller, Fritz (Johann Friedrich Theodor)." Complete Dictionary of Scientific Biography. . (September 21, 2018).

"Müller, Fritz (Johann Friedrich Theodor)." Complete Dictionary of Scientific Biography. . Retrieved September 21, 2018 from

Learn more about citation styles

Citation styles gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA).

Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list.

Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, cannot guarantee each citation it generates. Therefore, it’s best to use citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites:

Modern Language Association

The Chicago Manual of Style

American Psychological Association

  • Most online reference entries and articles do not have page numbers. Therefore, that information is unavailable for most content. However, the date of retrieval is often important. Refer to each style’s convention regarding the best way to format page numbers and retrieval dates.
  • In addition to the MLA, Chicago, and APA styles, your school, university, publication, or institution may have its own requirements for citations. Therefore, be sure to refer to those guidelines when editing your bibliography or works cited list.