De Vries, Hugo

de Vries, Hugo (hü`gō də vrēs), 1848–1935, Dutch botanist. He opened a new approach to the study of evolution by using the experimental method to investigate the processes of evolution. His study of discontinuous variations, especially in the evening primrose, led to his rediscovery (reported in 1900) of Mendel's laws of heredity and to the development of the theory of mutation, which he expounded in The Mutation Theory (1901–3, tr. 1909–10) and in Plant-Breeding (1907). He maintained that mutations—sudden, unpredictable, inheritable changes in an individual organism—are the chief method by which new species develop in the course of evolution and that each quality subject to change is represented by a single physical unit (which he called a pangen). De Vries's work on osmosis is also important; he coined the term isotonic. He was professor (1878–1918) at the Univ. of Amsterdam, and he established an experimental garden at Hilversum.

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de Vries, Hugo (Marie)

(born Feb. 16, 1848, Haarlem, Neth.—died May 21, 1935, near Amsterdam) Dutch botanist and geneticist. He taught at the University of Amsterdam (1878–1918), where he introduced the experimental study of organic evolution. His rediscovery in 1900 (simultaneously with Carl Erich Correns and Erich Tschermak von Seysenegg) of Gregor Mendel's principles of heredity and his own theory of biological mutation explained concepts about the nature of variation of species that made possible the universal acceptance and active investigation of Charles Darwin's theory of organic evolution. De Vries discovered and named the phenomenon known as mutation, and he also contributed to knowledge of the role of osmosis in plant physiology. See also William Bateson.

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De Vries, Hugo 

Born Feb. 16, 1848, in Haarlem; died May 21, 1935, in Lunteren. Dutch botanist.

Educated at Leiden, Heidelberg, and Würzburg, de Vries was a professor at the University of Amsterdam and director of the botanical garden from 1878 to 1918. Later he continued his work at his estate in Lunteren. De Vries developed a method of determining osmotic pressure in plants and showed that it depends on the number of molecules of matter in a given volume (1877). He was one of the scientists who independently rediscovered Mendel’s laws and a founder of the theory of mutation and evolution (1900). Observing the variability of Oenothera (an evening primrose), de Vries concluded that a species may suddenly break up into a large number of different species. De Vries called this phenomenon mutation and concluded that biological species periodically enter a mutating phase. This view was the basis of de Vries’ “mutation theory,” which is sometimes, wrongly, contrasted with Darwin’s theory. Like Darwin, de Vries believed that adaptation resulted from natural selection. He regarded the species as a narrower taxonomic category than did Darwin.

WORKS

In Russian translation:
Izbrannye proizvedeniia. Moscow, 1932.

REFERENCES

Lehmann, E. Die Theorien der Oenotheraforschung. Jena, 1922.
Hugo de Vries. Stuttgart, 1929.
Stomps, T. J. Fünfundzwanzig Jahre der Mutationstheorie. Jena, 1931.

V. L. RYZHKOV