1915] East,— Dr. Gates's Mutation Factor in Evolution 235 
Tue Mutation Factor IN EVOLUTION: WITH PARTICULAR REFER- 
ENCE TO OENOTHERA. By R. HucGGLES GarEs. Since DeVries 
discovered the two aberrant forms of Oenothera Lamarckiana that he 
called brevistylis and laevifolia at Hilversum in 1887, the genus Oeno- 
thera probably has been studied more intensively than any other 
similar group of plants. As evidence of this analytic activity a litera- 
ture of some five hundred titles has been produced. Every botanist 
appreciates the numerous facts that have been brought to light re- 
garding the classification, distribution, gross morphology, cytology 
and genetics of the genus, and owing to the volume of the publications 
everyone is thankful when compilations are made. DeVries has 
brought together the greater part of these facts in Die Mutations- 
theorie and Gruppenweise Artbildung. The volume under considera- 
tion supplements these two works by a fairly complete consideration 
of the taxonomy, cultural history and cytology of the group. In 
addition the author brings together the data from his own extensive 
pedigree culture, and urges, rather didactically at times, the con- 
clusions he has drawn from them. 
The book purports to be a reconnaisance of the theory of Evolution 
by Mutation, it really is wholly a consideration of the biology of the 
Oenotheras. The author rests his case on the one group of facts. 
DeVries did not make this mistake; for, as Cervantes says, “ It is the 
part of a wise man to keep himself today for tomorrow, and not to 
venture all his eggs in one basket.” DeVries did indeed lay great 
stress upon his work with the evening primroses, but he did not over- 
look numerous other props for his hypothesis, — props so sturdy that 
in the opinion of some, the Oenothera investigations might be disre- 
garded without weakening the edifice. Perhaps few biologists adhere 
strictly to DeVries’ views of Evolution. In particular it might be 
mentioned that he did not go far enough in distinguishing between 
germinal and somatic variations, and that he has not kept pace with 
the facts regarding inheritance. At the same time, it must be ad- 
mitted that in addition to the great stimulus to experimental biology 
that his work effected, DeVries made two great general contributions. 
He showed the frequency with which germinal changes of compara- 
tively great size occur, and why they are not swamped by intercrossing. 
But these generalizations make no new Evolution theory. They 
merely extend and modify Darwin’s ideas insofar as these new facts 
tend to change the emphasis the latter placed upon particular types 
of variation. 
These changes in viewpoint may be made with total disregard for 
the Oenothera work. In fact, perhaps few angiosperm genera could 
have been selected which are so fundamentally unsuited for genetic 
work from which broad conclusions are to be drawn as Oenothera. 
As Gates shows, numerous aberrant types of chromosome distribution 
occur at gametogenesis. Presumably many of the daughter cells 
1 London. Macmillan, 1915. pp. I-XIV +353. Figs. 114. 
