62 BOTANICAL GAZETTE [JANUARY 
The mutation theory 
In rgor the first volume of DEVriEs’s Mutationstheorie was published, and 
was reviewed in this journal.? It put the doctrine of evolution upon an experi- 
mental basis and has been the stimulus of a large amount of important investi- 
gation. Such a contribution to biology is of the first order, whether the theory — 
of mutation proves to be a general explanation of the origin of species or not. 
It has been unfortunate that many who are interested in evolution, even investi- 
gators, have not understood fully the theory of mutation, because they know of it 
only from condensed statements or reviews. ‘This applies to all who do not read 
German or who do not read it with facility. This condition has now been remedied 
by the appearance of an Engish translation’ of this great work. It is possible 
now for all English-reading biologists to judge of the theory from the full pre- 
sentation by its author, and to substitute knowledge for superficial familiarity. 
The full review of the original volume by this journal makes it necessary only 
to announce the appearance of the translation. And yet, eight years have 
elapsed since the theory was formally proposed and much could be said of its 
standing and influence. During the same period DeVriks has twice visited the 
United States, and by conversation and lecture and personality has impressed 
himself and his views in a peculiar way upon American biologists. His influence 
upon scientific plant and animal breeding in this country has been very great, 
_and the general result has been an increasing conviction that his views and his 
example have advanced biological science immensely. 
The thesis of this first volume, as its author states, is the promulgation of the 
principle of unit characters. At the time of its announcement in 1900 this view 
was in opposition to the current belief; but the author is convinced that it has now 
gained almost universal acceptance. This conception that ‘‘the attributes of 
organisms consist of distinct, separate, and independent units” was derive 
chiefly from three sources: (1) an analysis of the processes of selection in practical 
plant breeding; (2) the experimental evidence afforded by Oenothera; and (3) 
Mendelism. This means that the origin of species by mutation is only one feature 
connected with the more fundamental conception of unit characters, and that a 
wide range of problems is opened up to experimental investigation. The only 
important change introduced into the translation is the incorporation of NILSSON ’s 
results in the selection and improvement of cereals in Sweden. 
The selection of translators could not have been more happy and effective; 
and the publishers are to be congratulated, not only for the worthy appearance of 
this book, but also-for their real contribution to the advancement of knowledge 
in assuming the responsibility of publication. 
2 BOT. GAZETTE 332236—239. 1902. 
3 DeVries, Huco, The mutation theory; experiments and observations of the 
origin of species in the vegetable kingdom. Translated by J. B. FARMER and A. D. 
DarBISHIRE. Vol. I. The origin of species by mutation. 8vo. pp. xv +582. color ed 
pls. 6. figs. 119. Chicago: The Open Court Publishing Company. 1909. $4.00 : 
