66 
HUGO DE VRIES ON THE eee OF SPECIES 
A VARIETIES BY MUTATION.* 
From the time of Linnaeus (1753) to the time of Darwin 
(1859) it was the general belief that the various species of animals 
and plants had been separately created and that they remained 
forever unchangeable in their essential characters. It seems 
strange to us now, but for those hundred years this doctrine of 
the immutability of species was held to be a necessary test of 
orthodoxy — theological as well as scientific. When Darwin at- 
tacked it, he encountered the vehement an not only of 
eae like the Bishop of Oxford and the Duke of Argyle, 
but also of men of science, like Richard Owen and Loves Agas- 
siz. But notwithstanding the number and strength of his oppo- 
nents, Darwin overthrew the dogma once for all, and thereby 
destroyed, at least in the domain of science, the tyranny of au- 
thority. 
is principal service to pure science was in the establishment 
of the principle of derivation, and the results of his work in that 
direction stand secure, but he also discovered, and placed on a 
firm foundation of proof, the method by which derivative forms 
are made permanent — namely, by what he called “ natural selec- 
or as Herbert Spencer afterwards named it “‘ the survival 
of the fittest.’ It has been mistakenly supposed that Darwin con- 
sidered natural selection as an actual producer of new forms and 
this misapprehension has been to some extent encouteece and. 
fostered by his own plirase ‘the origzz of species” and other 
more or less figurative saben used by him; as a matter 
of fact, however, he correctly conceived that selection could not 
. until there were ieee various forms to select from, 
d he did not attempt to solve the problem of “the origin of 
ie fittest ’’ — to use Professor Cope’s apt designation. Darwin 
id, however, undertake to explain heredity, in his theory of pan- 
genesis, but he seems to have considered variation as inexplic- 
* Species and Varieties, Their Origin by Mutation. Lectures cae aca at the Uni- 
versity of California by Hugo de Vries, Professor of Botany in the University of Am- 
sterdam. Edited by Daniel Trembly MacDougal, Assistant aaa of the New 
York Botanical Garden. Chicago and London, 1905. 
