The Fruitful Facets of Gabon's Polyhedron 425
somatic to germ cells and provide a mechanism for Lamarckian inheritance. In de
Vries' intracellular pangenesis, pangenes move from the nucleus to the cytoplasm
of the same cell and specify a theory of cellular differentiation.
Yet de Vries insisted on downplaying this difference as a minor variation. For
rhetorical purposes, he asserted that his denial of intercellular movement for
gemmules constituted only a minor reform in Darwin's ideas. His new theory could
therefore remain entirely in Darwin's spirit. Throughout his life, de Vries could not
break verbal fealty with the primary hero and inspiration of his youth. In a late
work of 1922, de Vries wrote:
Freed from the assumption of a transportation of gemmules through the
organism, the conception of Pangenesis is the clear basis of the present
manifold theories of heredity. An organic being is a microcosm, says
Darwin, a little universe, formed of a host of self-propagating organisms,
inconceivably minute, and numerous as the stars of heaven. In honor of
Darwin, I have proposed to call these minute organisms Pangenes, and this
name has now been generally accepted under the shortened form of genes.
They are assumed to be the material bearers of the unit characters of
species and varieties (1922, p. 222).The mutation theory: origin and central tenets
Evolutionists usually assume that, since de Vries ranks within the trio of Mendel's
resurrectionists, his "mutation theory"—with its genetic title and deserved status as
the greatest challenge to Darwinism from the early 20th century—must be
traceable to a Mendelian inspiration. But de Vries always insisted that his theory,
and almost everything else he valued, could boast a Darwinian source. In
particular, he asserted later in his career that the root of the Mutation Theory lay in
an insight about two distinctly different kinds of variation that he had obtained
from Darwin's theory of pangenesis, and then developed within his own
Intracellular Pangenesis of 1889. I am not confident that this link can be defended,
for considerable (and rather tortured) exegesis must be applied to so interpret the
actual text of de Vries' 1889 book, whatever his later memories. But de Vries' debt
and psychological fealty to Darwin can only be called pervasive, while the timing
of de Vries' interpretation can also be defended (for the Mendelian discovery
postdated the genesis of the mutation theory).
In the English version (1910) of Intracellular Pangenesis, de Vries wrote a
note to his translator, pointing to a passage that he identified as the source of the
Mutation Theory: "An altered numerical relation of the pangenes already present,
and the formation of new kinds of pangenes must form the two main factors of
variability" (1910, p. 74). De Vries interpreted this passage as presaging the key
claim of his later mutation theory—that new species arise suddenly by a distinct
and special kind of saltational variation (called mutation), while ordinary,
imperceptible, omnipresent, Darwinian variability cannot forge evolutionary
novelties. Late in his career, de Vries wrote (1922,