Species and Varieties, Their Origin by Mutation

Species and Varieties, Their
Origin by Mutation

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Title: Species and Varieties, Their Origin by Mutation
Author: Hugo DeVries
Release Date: January, 2005 [EBook #7234] [Yes, we are more than
one year ahead of schedule] [This file was first posted on March 30,

2003]
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Produced by Dave Gowan

Species and Varieties Their Origin by Mutation
Lectures delivered at the University of California
By Hugo DeVries Professor of Botany in the University of Amsterdam
Edited by Daniel Trembly MacDougal Director Department of
Botanical Research Carnegie Institution of Washington
Second Edition Corrected and Revised
CHICAGO The Open Court Publishing Company LONDON Kegan
Paul, Trench, Trubner and Co., Ltd. 1906
- - - - -
COPYRIGHT 1904 BY The Open Court Pub. Co. CHICAGO
- - - - -
THE ORIGIN OF SPECIES
The origin of species is a natural phenomenon. LAMARCK
The origin of species is an object of inquiry. DARWIN
The origin of species is an object of experimental investigation.
DeVRIES.
- - - - -
PREFACE BY THE AUTHOR
THE purpose of these lectures is to point out the means and methods by
which the origin of species and varieties may become an object for
experimental inquiry, in the interest of agricultural and horticultural
practice as well as in that of general biologic science. Comparative
studies have contributed all the evidence hitherto adduced for the

support of the Darwinian theory of descent and given us some general
ideas about the main lines of the pedigree of the vegetable kingdom,
but the way in which one species originates from another has not been
adequately explained. The current belief assumes that species are
slowly changed into new types. In contradiction to this conception the
theory of mutation assumes that new species and varieties are produced
from existing forms by sudden leaps. The parent-type itself remains
unchanged throughout this process, and may repeatedly give birth to
new forms. These may arise simultaneously and in groups or separately
at more or less widely distant periods.
The principal features of the theory of mutation have been dealt with at
length in my book "Die Mutationstheorie" (Vol. I., 1901, Vol. II., 1903.
Leipsic, Veit & Co.), in which I have endeavored to present as
completely as possible the detailed evidence obtained from trustworthy
historical records, and from my own experimental researches, upon
which the theory is based.
The University of California invited me to deliver a series of lectures
on this subject, at Berkeley, during the [vii] summer of 1904, and these
lectures are offered in this form to a public now thoroughly interested
in the progress of modern ideas on evolution. Some of my experiments
and pedigree-cultures are described here in a manner similar to that
used in the "Mutationstheorie," but partly abridged and partly
elaborated, in order to give a clear conception of their extent and scope.
New experiments and observations have been added, and a wider
choice of the material afforded by the more recent current literature has
been made in the interest of a clear representation of the leading ideas,
leaving the exact and detailed proofs thereof to the students of the
larger book.
Scientific demonstration is often long and encumbered with difficult
points of minor importance. In these lectures I have tried to devote
attention to the more important phases of the subject and have avoided
the details of lesser interest to the general reader.
Considerable care has been bestowed upon the indication of the lacunae
in our knowledge of the subject and the methods by which they may be
filled. Many interesting observations bearing upon the little known
parts of the subject may be made with limited facilities, either in the
garden or upon the wild flora. Accuracy and perseverance, and a