DE VRIES, HUGO. — Dutch botanist and biologist, b. in Haarlem on 16 February 1848, d. in Lunteren on 20 May 1935; he was professor of botany at Amsterdam from 1878 to 1918. Two periods may be distinguished in his scientific activity: the first (1877–88) concerned chiefly cellular physiology, the second (1889–1918) the origin of forms of plant life through “mutation.”
Conceptually, the work of D. V. Darwinism. Darwin had perceived the varieties of nascent species; D. V. starts from the observation that, in horticulture, varieties arise suddenly, in a single season, without gradual transitions and without the need for long periods of time.
He found in the Oenothera Lamarckiana a plant that in nature displays rapid variations of characteristics and that, when cultivated, lends itself to the experimental study of these mutations, which give rise to good races that he called elementary species, absolutely constant from the outset. These would coincide with pure lines. Mutation theory (1901–1906), having encountered Mendelism and genetics, represented a significant phase in the history of biology and for a moment offered the hope of creating new species rationally and experimentally, of finally bringing evolutionism within inductive, experimental science. But when doubts began to arise that the plant carefully chosen by D. V. for study, the Oenothera, was hybrid, and that the new forms to which it gives rise were in reality the original species, mutationism in its primitive sense lost much of its appeal (cf. Lotsy).
Moreover, just as all partial and interpretative hypotheses, throughout the history of biology, take turns in constituting the more general hypothesis of evolution, so mutationism too has been judged in opposite ways by theorists of the various schools. F. Le Dantec saw in it a tendency toward antitransformism and denounced it as a factor in the crisis of transformism. Others see in random mutations as a factor of evolution the triumph of chance and of the atheological, that is, of the true and profound motives of classical evolutionism. Today mutation is understood as a hereditary variation. But whether a new species has ever arisen through mutation remains a matter of debate. It is certain that new organs do not originate through mutation.