214 BOTANICAL GAZETTE [SEPTEMBER 
study of the effects of varying conditions upon the production of the 
various phases of cell activity would seem to be the fertile direction of 
cytology at present. Certain it is that through such investigations 
only will an approach be made to the fundamental principles. Such 
investigation has far more direct bearing upon the great problems of 
variation and heredity than any amount of examination of cell mate- 
rials and of inference as to their relationships. 
IN REFERENCE to the conventional physiology the same general 
statements are appropriate. Instead of attacking large problems, 
much of the work is advancing along purely mechanical lines in the 
record of isolated details. In other words, the outlying and endless 
details of expression of a few underlying principles are being cata- 
logued, important enough in a way, but merely an incident in the 
progress of the real physiology. The fundamental problems are 
brought into view from the ecological standpoint. There is need of a 
renascence of physiology, for there has been a long period of sterility. 
The founders of modern plant physiology are being followed in the 
mechanical phases of their work rather than in their fructifying ideas. 
