During the summer of 1904 Professor Hugo DeVries 
of the University of Amsterdam, Holland, delivered a 
series of lectures at the Universit^^ of California in elucida- 
tion of his now well-known mutation theory of the origin 
of species and the subsequent publication of these lectures 
bv the Open Court Publishing Company of Chicago has 
given American students a much desired opportunity to 
carefully examine the evidence upon which his theory 
rests. Dcirwin's investigation of this subject left little 
doubt in the mind of students as to the general way in 
which the various forms of animate creation have been 
produced but there has alwa^^s existed some question as 
to whether natural selection, as he defined it, accounts 
entirely for the great diversit\^ of form in animal and plant 
life. DeVries thinks it does not and in the eight hundred^ 
pages of ''Species and Varieties" which is essentially his 
earlier work " Die Mutationstheorie " with the statistics, 
omitted, he attempts to show that species and varieties^ 
have arisen from one another by a series of leaps or 
mutations. 
* * 
* 
Every field botanist is familiar with the fact that the 
individuals of certain species differ among themselves very 
noticeably in such matters as hairiness, color, size, shape 
of parts, etc., but it has remained for DeVries to show by 
a great number of cultural experiments that these varia- 
tions are constant and may be reproduced regularly from 
seed. In addition he has shown that many striking forms 
may originate directly from other species without the 
intergrading forms and the long periods of time that 
Darwin supposed necessary. Several species Have been 
found to be constantly giving off such forms, most or all 
of which die for want of proper surroundings. Since these 
forms continue to reproduce themselves when cared for 
