Species and Varieties 



Their Origin by Mutation 



By HUGO DE VRIES 



Professor of Botany in the University of Amsterdam 



Edited by DANIEL TREMBLY MacDOUGAL 



Assistant Director of the New York Botanical Garden 



Cloth, gilt topt xxUi+830 pages. 



HUGO DE VRIES 



Reduced from a late photograph of Professor de Vries, 

 published by the Open Court Publishing Company and sup- 

 plied on orders for $i.oo, or to subscribers to "Species and 

 Varieties" for 50c Size 10" x 12" unmounted. 



Price, postpaid, $5.00 {2ts.) 



*'Prof. de Vries may 

 well be regarded as the 

 foremost advocate of ex- 

 perimental evolution, the 

 man, moreover, who gave 

 us the mutation theory of 

 organic evolution. The 

 volume before us is a 

 splendid scientific plea 

 for the experimental study 

 of organic life. ' ' 



— Scientific A 7neric an. 



''It will be seen that 

 Professor Vries has made 

 an important contribution 

 to science and thought. 

 It is a masterly work and 

 it is attractive because of 

 the popular style in which 

 the experiments are de- 

 scribed and the conclu- 

 sions stated. Every stu- 

 dent of science will wel- 

 come it." 



— The Scotsman, 

 Edinburgh. 



The Open Court Publishing Co 



1322 Wabash Avenue, Chicago 



