In Pursuit of the Gene

54 ¨ GALTON’S DISCIPLES
would not expect to see any decrease in variation in the dimension of a
character that played a less crucial role in the crab’s survival. As Weldon reported
in February 1895, his measurements on Plymouth crabs provided
striking confirmation of his hypothesis. In particular, he found a significant
decrease in frontal breadth variation and no decrease at all in the other
character, which was presumably less important to the crab’s survival.
While the result did not rule out the possible effect of occasional sports, it
seemed to show that small variations played a central role in evolution.
In the March 14, 1895, issue of Nature, William Turner Thiselton-Dyer,
who was co-director of Kew Gardens and son-in-law of Joseph Hooker, the
famous Darwinist, gave a ringing endorsement of Weldon’s result, which he
said “deserves to rank amongst the most remarkable achievements in connection
with the theory of evolution.” 22 With the authority of his position
as a director of Kew Gardens, Dyer rejected out of hand the possibility that
sports, which he asserted were rare in the vegetable kingdom, played any
significant role in evolution. In support of his view, he referred to a recent
meeting of the Royal Society where he exhibited the enormous differences
between the flowers in the wild and cultivated forms of the tropical plant
Cineraria. These differences, he asserted without evidence, were brought
about by the systematic human selection of small variations.
The following month Bateson wrote a long letter to the editor of Nature
contesting Dyer’s account of the cultivated Cineraria and in its place, giving
a detailed history of the origin of the modern plant. Contrary to Dyer’s assertion,
Bateson’s exhaustive research using country records, horticultural
treatises, and gardening magazines and manuals, some of which dated back
to the end of the eighteenth century, made it clear that cultivated Cinerarias
arose as hybrids of several very distinct species. Furthermore, sports of
an extreme kind appeared after hybridization in the early years of “improvement”
of the plants. More generally, Bateson contended, modern
flowers arose first very rapidly due to sporting, and the new forms were
subsequently perfected by the long, slow process of selection of small variations.
The indignant Dyer rushed his reply into the next issue of Nature. With
the assistance of members of his large staff, Dyer had examined each of the