The Fruitful Facets of Galton's Polyhedron 419
note: "I know that you are studying hybrids, so perhaps the enclosed reprint of the
year 1865 by a certain Mendel, which I happen to possess, is still of some interest
to you" (quoted in Stomps, 1954—Stomps succeeded de Vries as professor of
botany in Amsterdam). De Vries therefore reported Mendel's forgotten priority as
he began to publish his results in 1900.
The link to Mendel, while surely true, must be labeled as unfair when cited as
an exclusive epitome of de Vries' career. Discovery of the segregation laws did
excite him, but this work represented only a sidelight to his major interest. Most
early studies based on the Mendelian rediscovery did oppose Darwinism at first,
but the deep irony of de Vries's contribution lies in the fact that he had taken up the
study of heredity as a direct consequence of his concern—indeed, in his own
words, his "love"—for Darwin as a man and a scholar. Darwin's theory of
pangenesis (Darwin, 1868) served as de Vries' inspiration—and de Vries' first
major book (his best in the judgment of many distinguished biologists, both then
and now) presented a brilliant reformulation of Darwin's insight (Intracellular
Pangenesis, de Vries, 1889).
De Vries turned to the study of heredity in order to probe the mechanisms of
evolution. But he never considered the Mendelian segregation laws as particularly
relevant to this goal—for these principles only regulated the distribution of
characters by hybridization among differing phenotypes, whereas evolution
required the origin of new variation. De Vries did not continue his work on
Mendel's principles, and his two great books on evolution (de Vries, 1905 and
1909a) cite Mendel only rarely, and only in contexts peripheral to his main
arguments about saltation and evolutionary novelty. De Vries's biographer van der
Pas rightly comments (1970, p. 99): "After the rediscovery of Mendel's laws, many
investigators took up the subject. De Vries was not among them, however. He
believed that hybridization only causes redistribution of existing characters and for
that reason cannot explain the appearance of new species. Therefore, he
concentrated on the phenomenon of mutation, which he believed explained the
origin of new species and therefore gave necessary support to the theory of
evolution."
If Mendel only represented a sidelight in de Vries's career, two main sources
stand out as inspirations for his interests and strategies—his teacher Julius Sachs
and his mentor and guru Charles Darwin. De Vries' long life (1848-1935) spanned
the years from Darwin to Dobzhansky. Unhappy with the quality of his initial
botanical education in the Netherlands, de Vries decided, in the early 1870's, to
continue his studies in Germany. Beginning in 1871, while teaching in an
Amsterdam secondary school, de Vries began spending his long summer vacations
in the laboratory of the leading plant physiologist, Julius Sachs. De Vries wrote a
series of monographs and performed elegant experiments on osmosis in plant cells,
the basis for his later work on the role of cellular turgor in the motions of growing
plants. Sachs considered de Vries as his best student and helped to secure for him
the first instructorship in plant physiology in the Netherlands, when the
Amsterdam Athenaeum became a full university in 1877. De Vries later served as
professor of botany