PREFACE TO THE GERMAN EDITION 



OF late years the subject of Plant Physiology has been discussed in 

 a succession of admirable treatises. In addition to Pfeffer's Handbook, 

 which laid the foundation of modern Plant Physiology, there are the briefer 

 expositions of the subject in the textbooks of General Botany, such as 

 those of Noll and Wiesner, but a textbook of Plant Physiology of 

 moderate size has been for long a desideratum. The object of the present 

 volume is to introduce the subject to those who are already familiar with 

 the fundamentals of natural science, and inasmuch as it takes the form 

 of lectures which I have been in the habit of giving in this University for 

 a number of years, and is the direct outcome of them, I have styled the 

 book Lectures on Plant Physiology. 



The characteristic feature of such a textbook, apart from the mere 

 mode of presentation, must lie in the selection and arrangement of its 

 subject-matter, and those who are familiar with the works of others will 

 be able to see at once wherein the present treatise differs from them. It 

 is unnecessary for me to refer here to the general line of argument of the 

 book, since that may be readily grasped from a study of the table of con- 

 tents. Still less need I attempt to justify it, for if it does not speak for 

 itself, it will not help matters to go into a detailed explanation of the 

 principles of arrangement and selection in a preface. I may, therefore, 

 confine myself to saying a few words on the treatment of the literature and 

 on the illustrations. 



A bibliography will be found at the end of each lecture. This con- 

 tains, in addition to works of fundamental importance on the subject more 

 immediately concerned, references to numerous special papers recognized 

 as the authoritative statements for individual observations or views. 

 That the selection of the literature must be arbitrary goes without saying ; 

 for it would be possible in the long run to cite one or more authorities for 

 almost every word I have written. The place which Pfeffer's Handbook 

 has taken in modern botanical literature has rendered it necessary to 

 quote from it on almost every page ; rather than pursue this course, the 

 present general reference must suffice ; where, however, it has been specially 

 referred to, the citation is made in the abbreviated form, Pfeffer, 

 Phys.' (Pfeffer, W. Pflanzenphysiologie, ein Handbuch der Lehre vom 

 Stoffwechsel und Kraftwechsel in der Pflanze. Bd. I, 2. Aufl., Leipzig, 

 1897 ; Bd. II, i. Halfte, 2. Aufl., Leipzig, 1901 ; Bd. II, i. Aufl., Leipzig, 

 1881 .) Other works are indicated in the text, as a rule, by the author's name 

 and the year of publication only. The dates are intended to serve merely as 



