PHEFACE 



THIS book is intended primarily for students of Botany. Such a 

 student's knowledge of plant products is usually obtained, on the 

 one hand, from Organic Chemistry, on the other hand, from Plant 

 Physiology ; between these two standpoints there is a gap, which, it is 

 hoped, the following pages may help to fill. It is essentially a text-book 

 for practicai work, an aspect of Plant Biochemistry which has received up 

 to the present time very little consideration in teaching. A number of 

 experiments have been devised and have been actually tested in practical 

 classes. These experiments should enable a student to extract from the 

 plant itself the chemical compounds of which it is constituted, and to learn 

 something of their properties. An elementary knowledge of Organic 

 Chemistry on the part of the student has been assumed, as it appeared 

 superfluous to incorporate the material which has already been so amply 

 presented in innumerable text-books. 



My sincerest thanks are due to Dr F. F. Blackman, F.R.S., for criticism 

 and many suggestions throughout the writing of the book. I am further 

 indebted to Mr H. Raistrick, M.A., for help in various ways, especially in 

 reading the proof-sheets. I wish, in addition, to express my gratitude to 

 Professor F. G. Hopkins, F.R.S., for the great interest he has always shown 

 in the subject and for his kind and stimulating advice in connexion with 

 the scheme of teaching presented in the following pages. 



M. W. O. 



Cambridge, 



February, 1920. 



