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Lotsy, Jan Paulus

Lotsy, Jan Paulus

(b. Dordrecht, Netherlands, 11 April 1867; d. Voorburg, Netherlands, 17 November 1931)


Born into a patrician family, Lotsy devoted himself to biological research against the wishes of his father. He studied botany with Beyerinck at the Wageningen Agricultural College and continued his studies at the University of Göttingen, from 1886 to 1890. His doctoral thesis was on German lichens. From 1890 to 1895 he was in the United States as a lecturer at Johns Hopkins University. He showed his versatility in working on the food supply of the adult oyster, the nitrogen assimilation of mustard, a study on the root formation of the swamp cypress, toxic substances of the pear-blight bacteria, the staining of diatoms, the fixing of cells of red algae, the significance of herbaria for botany, and a taxonomical revision of some Euphorbiaceae from Guatemala.

From 1895 to 1900 Lotsy was in Java, where he worked on the localization, physiology, and secretion of quinine in Cinchona species at the Cinchona Experiment Station (for which he received a gold medal). He was later invited by Treub to work in the Botanic Gardens at Buitenzorg (Bogor) and the mountain garden connected with it at Tjibodas. While there, he wrote a basic work on the life history of the genus Gnetum, the detailed anatomy and taxonomy of some Balanophoraceae, and sketches of Javanese forest plants. After an attack of malaria he returned to the Netherlands and from 1901 on lived at Leiden.

On his initiative the Association Internationale de Botanistes was founded, for which he edited the journal Progressus rei botanicae, which was comparable in scope to the present Botanical Review. This association also bought the Botamsches Cemralblatt (1902), of which Lotsy was also the editorial secretary. In 1904 he was appointed lecturer of plant systematics at Leiden University and in 1906, in addition, director of the Rijksherbarium. He held these posts until 1909, when he entered a new phase. This was a time of great ferment and reform in biological research owing to the rediscovery of Mendel’s laws, the publication of De Vries’ mutation theory, the recognition of the role of chromosomes, and the close study of haploid and diploid generations in cormophytes. He viewed systematics in a wide sense, and thought that it should be combined with genetics to produce a phytogeny based on evolution. As early as 1903 Lotsy had given a lecture on the implications of the mutation theory, genetics, and hybridization for plant breeding. For teaching he composed in an incredibly short time two major handbooks— lectures on descent theories (1906-1908) and lectures on botanical phytogeny (1907-1911)—which were frequently used for university lectures.

After concluding that knowledge of dicotyledons was insufficient to establish their ancestry, Lotsy switched to a third phase of scientific research, the experimental approach to the mechanism of evolution. At Leiden he wanted a new herbarium with a garden attached for experimental taxonomy. Unfortunately the House of Commons rejected his plan, partly because of the opposition of De Vries, who saw it as a competitive threat. Lotsy and his close friend J. W. C. Goethart then offered to construct the garden from private means, but to no avail. Disgusted by this obstruction he resigned in 1909 from his official functions and with his own funds erected experimental gardens at Haarlem and later at Velp.

About 1912 Lotsy became convinced that species originated and evolved because of hybridization, and the development and advocacy of this theory occupied him for the rest of his life. He defined more precisely the concepts jordanon, linneon, and syngameon to tie systematics to genetics, and thus became a pioneer of modern research. Possibly he and his close collaborator Goethart obtained experimentally allopolyploid new species of Antirrhinum and Scrophularia. Though the creation of an official center of experimental taxonomy in the Netherlands was frustrated, Lotsy created a forum for genetics with the journal Genetica (1919), later adding Resumptio genetica and Bibtiographia genetica. In the years 1920 to 1930 he traveled to North America, New Zealand, South Africa, and Egypt to disseminate his ideas and to test his theories, thus stimulating much research in experimental taxonomy.

Lotsy’s writings were prolix and vague. His alternative hybridization theory and equally untenable ideas found in his writings— Homo sapiens as a genus; linneons are homozygous— arose largely as a critical response to De Vries1 mutation theory. Although Lotsy was not held in high esteem in the Netherlands, abroad he had many friends—William Bateson, Erwin Baur, Heribert Nilsson, Karl von Goebel, Richard von Wettstein, Leonard Cockayne—who admired him for his many-sided initiatives, energy, and stimulating spirit.


There are 135 books and papers of Lotsy listed by W. A. Goddijn in his “In Memoriam,” in Genetica,13 (1931), i-xx. Lotsy’s major works are: Vorlesungen über Deszeadenz theories 2 vols. (Jena, 1906; 1908); Vorträge über botanische Stammesgesehiehtet3 vols. (Jena, 1907-1911); Van den Ailantischen Oceaan naar de Stille Zuidzee in 1922 (’s Gravenhage, 1922); and “Voyages of Exploration to Judge of the Bearing of Hybridisation Upon Evolution. 1 . South Africa,” in Genetica,10 (1928), 1-315, written with W. A. Goddijn. Also important are his shorter works; De kruisingstheorie, een nieuwe theorie over het ontstaan der soorten (Leiden, 1914); Evolution by Means of Hybridisation (’s Gravenhage, 1916); Over Oenothera Imnarekiana als type van een nieuwe groep van organismen, die der kernchimeren (’s Gravenhage, 1917); De wereldbeschouwing van een natuuronderzoeker (’s Gravenhage, 1917); Het evolutievraagstuk (’s Gravenhage, 1921); Evolution Considered in the Eight of Hybridisation (n.p., 1925); “Versuche über Artbastarde und Betrachtungen über die Mügiiehkeit einer Evolution trotz Artbeständigkeit,” in Zeitschrift für induktwe Abstammungs–Vererhungslehre,8 (1912), 325-333; “La théorie de croisement,” in Archives nùerlandaises des sciences exactes et naturelles, ser. IIIB, 2 (1914), 1-61; “Qu’est ce qu’une espéce,” in Archives néerlandaises des sciences exactes et naturelles, sér. IIIB, 3 (1916), 57-110; “Evolution im Lichte der Bastardierung betrachtet”, in Genetica,7 (1925), 365-470; “Kreuzung und Deszendenz” in Ber. Bot Ges. Zürich 1924/26 (1926), 16-47; and the Cawthorn Lecture: “A Popular Account of Evolution” (Nelson, New Zealand, 1927), 1-22.

C. G. G. J. Van Steenis

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