Photo >iy De Graaff, Amsterdam 



PROFESSOR HUGO DEVRIES 

 DIRECTOR OF THE LABORATORY OF PLANT ANATOMY AND PHYSIOLOGY AT THE 

 UNIVERSITY OF AMSTERDAM. CHAMPION OF THE MUTATION THEORY IN EVOLUTION 



[Professor De Vries lectured December 6 before members of the New York Academy of 

 Sciences and (he American MiiseuDi of Xatural IJistorij] 



