PROFESSOR DE VRIES has rendered an additional service to all naturalists
by the preparation of the lectures on mutation published in the present
volume. A perusal of the lectures will show that the subject matter of
"Die Mutationstheorie" has been presented in a somewhat condensed form,
and that the time which has elapsed since the original was prepared has
given opportunity for the acquisition of additional facts, and a
re-examination of some of the more important conclusions with the result
that a notable gain has been made in the treatment of some complicated
problems.
It is hoped that the appearance of this English version of the theory of
mutation will do much to stimulate investigation of the various phases
of the subject. This volume, however, is by no means intended to
replace, as a work of reference, the larger book with its detailed
recital of facts and its comprehensive records, but it may prove a
substitute for the use of the general reader.
The revision of the lectures has been a task attended with no little
pleasure, especially since it has given the editor the opportunity for
an advance consideration of some of the more recent results, thus
materially facilitating investigations which have been in progress at
the New York Botanical Garden for some time. So far as the ground has
been covered the researches in question corroborate the conclusions of
de Vries in all important particulars. The preparation of the manuscript
for the printer has consisted chiefly in the adaptation of oral [xii]
discussions and demonstrations to a form suitable for permanent record,
together with certain other alterations which have been duly submitted
to the author. The original phraseology has been preserved as far as
possible. The editor wishes to acknowledge material assistance in this
work from Miss A.M. Vail, Librarian of the New York Botanical Garden.
D.T. MacDougal.
New York Botanical Garden, October, 1904.