In Pursuit of the Gene

MENDEL © 97
inherent incompatibility between the vast collection of Gaertner’s observations
and Mendel’s own results. On the contrary, it was possible that if his
experiments were repeated and properly designed, Gaertner’s results would
provide confirmation of Mendel’s theory.
A committed believer in the priesthood of science, who traveled only
in the most illustrious scientific circles, Naegeli did not consider the work of
a mere high school teacher worthy of his full attention, and Mendel waited
more than three months for Naegeli’s reply, which was dated February 27,
1867. 43 Although he addressed Mendel as “honored colleague,” and showed
sufficient interest in his work to request samples of the seeds in order to attempt
to duplicate his results, his letter showed Naegeli’s utter failure to
grasp the significance of Mendel’s work. Naegeli rejected the key result—
that self-fertilized hybrids produced pure-breeding progeny—and ignored
the mass of evidence amounting to more than 355 artificial fertilizations
and 12,980 recorded observations that Mendel had conducted to support his
theory. Even more distressing was his injunction to Mendel that he “should
regard the numerical expressions as being only empirical, because they can
not be proved rational,” which implied that Naegeli had rejected Mendel’s
underlying “rational” model. 44
With respect to Mendel’s plan to test his theory in other species,
Naegeli confidently predicted that “with these forms you will get notably
different results (in respect of inherited characters).” In particular, Naegeli
recommended Hieracium, commonly known as hawkweed, an unprepossessing
flowering perennial bearing a resemblance to the dandelion, for Mendel’s
consideration. As the world authority on the hybridization of hawkweed,
Naegeli was certain that Mendel would not find confirmation of his 3:1 law in
Hieracium hybrids. In fact, Mendel was well aware of the existence of hybrids
that defied explanation under his theories. Already in his Pisum monograph,
he’d mentioned certain hybrids whose progeny were “exactly like the hybrid
and propagate unchanged,” and in his letter to Naegeli he’d speculated
that some species of Hieracium might also produce “nonvariable progeny.”
Although Naegeli’s letter must have been a crushing blow, Mendel
quickly regained his stride, and six weeks later he had completed a twelvepage,
single-spaced reply. 45 He fully understood Naegeli’s tone of “mistrustful
caution,” Mendel wrote, and he would undoubtedly have felt the same