~ o- THE 

 UNIVERSITY 



^ 



PREFACE 



The course in Plant Physiology which I have given for the 

 last five years at Stanford University has impressed upon 

 me the need of a text-book which treats the subject less ex- 

 haustively than Pfeffer's Handbuch and more fully than 

 Noll's section of the Bonn text-book.* As I did not know 

 of such a book in any language, I began to write my lec- 

 tures. These lectures, after repeated working over, have 

 finally taken this definite form. 



My intention has been to present the main facts of plant- 

 physiology and the saner hypotheses regarding them, striv- 

 ing to express safe views rather than to echo the most re- 

 cent, attempting here and there to suggest definite problems 

 for investigation, and everywhere trying to avoid giving the 

 impression that the science or any part of it has reached 

 ultimate knowledge and final conclusions. 



I have purposely made no attempt to give directions for 

 experiments, believing that a laboratory manual and a text- 

 book must meet such different needs that the style of the 

 one is impossible for the other. . This book must, however, 

 be supplemented by actual laboratory work by the reader, 

 under the guidance of a teacher or of some of the laboratory 

 manuals mentioned on page 27, or both. 



No one can work on the physiology of plants nowadays 

 without being conscious of his indebtedness to Pfeffer. If 

 Pfeffer had done nothing else, the preparation of the two 

 editions of his Handbuch, in which the literature of the sub- 

 ject is brought together, and the present status of the sci- 

 ence is well set forth, would secure him an honored place. I 

 cannot refrain from acknowledging my personal as well as 



*Lehrbuch der Botanik. Strasburger, Noll, Schenck, Schimper. Five 

 editions. English translation by Porter. 



