AUTHOR'S PREFACE TO THE ENGLISH 

 EDITION 



It is both a pleasure and a duty to express to my friend, Professor 

 Harvey Gibson, of the University of Liverpool, my sincere thanks for 

 having made my Lectures on Plant Physiology more readily accessible 

 to English readers through the medium of the present translation. 



I have taken the opportunity of making brief alterations, here and 

 there, in the original German text, with the view of correcting errors or re- 

 moving ambiguities. In order to bring the work up to date, and to indicate 

 the more important additions to the science that have been made since 

 the original manuscript was completed (spring of 1903), supplementary 

 notes, distinguished by being enclosed in square brackets, have been 

 appended to or introduced into each lecture. Obviously it is not possible 

 to do more than offer a selection of the extensive current literature in the 

 present translation any more than in the original text. Czapek's Bio- 

 chemie (Jena, 1905, vol. ii) is a work of special importance in relation to 

 Part I, and reference must be constantly made to it. Similarly with 

 regard to Part II, Pfeffer's Plant Physiology, vol. ii (Leipzig, 1904), 

 wiU be found to be equally invaluable as a work of reference. Since the 

 EngUsh translation of that treatise has been already published, it appeared 

 to me unnecessary to introduce special references to it. All those who 

 desire to study the subject of plant physiology more closely are strongly 

 recommended to consult that work. 



LUDWIG JOST. 



Strassburg, 1906. 



