PREFACE. 



XN 1883 one of us began a course of instruction in the 

 physiology of plants, of which the chief feature was the 

 demonstration of experiments in the lecture-room. Some 

 years later a different arrangement was made, the students 

 were required to perform the experiments for themselves ; 

 and at the same time laboratory work in the chemistry of 

 metabolism was organised by one of us. To enable the 

 students to carry out their work, written instructions 

 were needed, and the present book is the result of an 

 extension and elaboration of what we prepared for our, 

 classes. 



The book makes no pretence to completeness, it 

 contains merely such a selection of experimental and ana- 

 lytical work as seems to us suitable for botanical students. 

 Part I, which deals with general physiology, is 

 necessarily of a somewhat more elementary character 

 than Part II, which treats a particular department of 

 physiology in a more special manner, and presupposes a 

 greater amount of knowledge on the part of the student. 

 D. A, b 



