Genetic Analysis 253organs). Hugo de Vries’s theory ofIntacellulare Pangenesis[de Vries, 1889], de-
veloped in the last decades of the nineteenth century, which was both reductionist
and preformationist, was intended to replace, or at least update Darwin’s hypoth-
esis of evolution by continuous variation. It had little impact when first published.
However, at the turn of the century the attitude towards reductionism in the
life sciences changed. When in 1900 de Vries “rediscovered” Mendel’s paper he
presented it as a significant contribution to his own conception of evolution and
differentiation:
According to pangenesis the total character of a plant is built up of
distinct units. These so-called elements of the species, or its elementary
characters, are conceived of as tied to bearers of matter, a special
form of material bearer corresponding to each character. Like chemical
molecules, these elements have no transitional stages between them.
[de Vries, 1900/1966, 106].De Vries explicitly suggested a bottom-up, reductionist alternative to Darwin’s
theory of evolution by natural selection. Whereas his program pointed to the
process of species formation, Mendel’s theory was for him merely a theory of
inheritance [Brannigan, 1979]. Thus, he ignored Mendel’s painstaking method-
ological design, like the selection of seven traits that could be gainfully analyzed
by his experiments, and imputed to Mendel the confirmation of his viewpoint
that “the concept of species recede into the background in favor of the consider-
ation of a species as a composite of independent factors” [de Vries, 1900/1966,
108]. De Vries continued to promote his conceptions of evolution by discontinuous
mutations — this time with considerable success — in the voluminous tomeDie
Mutationstheorie: Versuche und Beobachtungen ̈uber die Entstehung von Arten im
Pflanzenreich[de Vries, 1902–3] (The English version was entitledSpecies and Va-
rieties: Their Origin by Mutation; see de Vries [1912]). The title of volume I was
an explicit rephrasing (in German) of Darwin’sDie Enstehung der Arten durch
nat ̈ uliche Zuchtwahl, namelyDie Entstehung der Arten durch Mutation,paying
little attention to Mendel’s hypothesis or experimental design.
On the other hand, Carl Correns — another “rediscoverer” of Mendel’s over-
looked paper — admitted that he had discovered for some time the same “reg-
ularity of the phenomena” as Mendel did, but “did not consider it necessary to
establish [his] priority” [Correns, 1900/1966, 120], obviously did not appreciate the
power of this analytic instrument. Thus, he joined, rather than established the sci-
ence of heredity as a discipline of its own (see also [Falk, 1991; 1995b]). Although
Correns contributed significantly to the experiments and theory of genetic analysis
[Correns, 1924a; 1924b; Rheinberger, 2000b], his interest was primarily that of a
physiologist, and rather less in the mechanics of hereditary transmission. (For the
role of Tschermak in the “rediscovery” of Mendel, see Stern and Sherwood [1966,
x-xii]; Olby [1985]).
The person who immediately grasped the analytic power of Mendel’s work (upon
reading de Vries’ paper) for the study ofinheritancewas William Bateson. Bateson