DE FRIS of Hugo (De Vries Hugo, 1848 — 1935) — the Dutch botanist.
Having got an education in Holland (Leiden) and Germany (Heidelberg, the Würzburg), worked as the teacher' in real school (Amsterdam). Since 1877 the privatdozent in Halle; since 1878 professor of phytophysiology, and later professor of botany un-that and the director of a botanic garden in Amsterdam. In 1918 retired and worked in the manor in Lyunterna. Its first scientific works are devoted to physiology of a beetroot, potatoes and other cultivated plants. Studied a plasmolysis of plants, osmotic properties of various substances in connection with molecular weight, developed a method of determination of osmotic pressure at plants (1877); published work about factors of the ancestral features which are contained, in his opinion, in kernels of cells in not active state, but at an exit in plasma of the cells of an organism showing activity and defining, thus, properties. In the light of modern experimentally reasonable theory about formation of so-called information RNA in a kernel and about an exit it in cytoplasm the theory of an intracellular pangenesis should be considered as scientific anticipation. In 1900 X. de Fris along with Korrens (To. Correns) and E. Tschermak for the second time opened the laws of transfer of ancestral features forgotten by all earlier formulated by G. Mendel.
On the basis of long-term overseeing by variability of a sundrops (Oenothera lamarkiana) in 1901 formulated the mutational theory (see. Mutation ).
Works: Intracellular pangenesis, Jena, 1889, Chicago, 1910; Mutationstheorie, Bd 1 — 2, Lpz., 1901 — 1903; Species and varieties, Chicago, 1905; The Chosen works, the lane with in., M., 1932.
Bibliography: Ryzhkov V. L. Life and de-Friz's doctrine, in book: De-Friz G. Izbr. proizv., the lane with in., page 5, M., 1932; H f-1 e of To. Hugo de Vries, Protoplasma (Wien), Bd 3, S. 605, 1928.