4 PLANT PHYSIOLOGY. 



m 



of whose physiological phenomena are essentially identical with 

 those of animals, while vastly simpler to investigate and much 

 more practicable to experiment upon. The necessity for a 

 thorough grounding in plant physiology as an integral part of 

 a present-day botanical education, as a basis for physiological 

 investigation and for pathology, perhaps too as a factor in 

 biological training, is so rapidly becoming recognized that 

 soon no institution of the first rank, aiming to put its students 

 in touch with present conditions and progress, will lack 

 thorough practical courses in plant physiology. There is, 

 however, yet another and very important reason why pure 

 physiology is destined to greater expansion in the immediate 

 future, namely, that it is absolutely prerequisite to the suc- 

 cessful understanding and cultivation of the most attractive, 

 promising, and widely interesting field now opening up to 

 botanists and educators alike, that of Ecology. Any one who 

 is following present-day ecological work cannot but be im- 

 pressed by the fact that the best of it rests upon an exact 

 physiological basis (as witness Schimper's admirable new work 

 " Pflanzengeographie auf physiologiscJier Grundlage "), while 

 that which does not is mostly of lesser worth and but tentative. 

 For, in its last analysis, what is Ecology, the science of 

 adaptation, other than the elucidation of the nature of the 

 connection existing between the physiological properties and 

 powers of the plant on the one hand, and the physical proper- 

 ties and processes of its environment on the other ? More 

 than one recent writer has described ecology as at present 

 mostly a series of guesses; and so will much of it continue to 

 be until given logical precision and a firm foundation in exact 

 physiology. 



It will be evident to any physiologist examining the course 

 here outlined that the methods and appliances are sometimes 

 comparatively crude. Hence they may seem to entail inexact 

 results. But it is to be remembered that in elementary or 

 general courses in physiology, as in elementary courses in 

 other subjects, it is mainly qualitative results that are of value, 



