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AUTHOR'S PREFACE TO THE FIRST 

 EDITION 



IT is by no means sufficient for the student of plant physiology 

 to attend lectures, or wade through text-books on the subject. 

 He must endeavour to familiarise himself, from practical experi- 

 ence, with the methods of research. 



Plant physiology is now of such far-reaching significance for 

 students of Natural Science, Agriculture, Forestry, and Medicine, 

 that it has become a matter of importance to devote greater 

 attention to it than hitherto in Universities and other advanced 

 educational institutions. Especially it seems desirable to organise 

 physiological exercises for students, and having myself, with very 

 favourable results, introduced such a course of practical work 

 in the University at Jena, I know from experience that the 

 difficulties of the undertaking, which at first sight appear con- 

 siderable, can be satisfactorily overcome. 



In this book I have set before myself the task of advancing 

 to the best of my ability the study of Plant Physiology. The 

 Practical Plant Physiology, however, is by no means exclusively 

 intended for the use of students. I trust that it may be welcome 

 also to many teachers in higher grade schools. For many 

 reasons Botany forms a particularly suitable subject of study 

 for schools, and a series of physiological experiments not only 

 gives a very special interest to the teaching of Botany, but also 

 enhances its importance as a means of mental development. 



The arrangement of the material in the book is essentially the 

 same as that followed in my Lehrbuch der Pflanzenpliysiologie, 

 published in 1883 by E. Trewendt, Breslau. Theoretical con- 

 siderations, to which in that treatise a considerable space was 

 naturally assigned, are here almost entirely wanting. 



My work during the last four years in the preparation of this 

 Practical Plant Physiology has been very great. It has been 



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