PREFACE 



THE author has had in mind a two-fold purpose in the prep- 

 aration of this book. First, it is hoped that it may serve as a 

 text or reference book for collegiate students of plant science 

 who are seeking a proper foundation upon which to build a scien- 

 tific knowledge of how plants grow. The late Dr. Charles E. 

 Bessey, to whom I owe the beginning of my interest in plant life, 

 once said to me: " The trouble with our present knowledge of 

 plant science is that we have had very few chemists who knew 

 any botany, and no botanists who knew any chemistry." This 

 may have been a slightly exaggerated statement, even when it 

 was made, several years ago. But it indicated a very clear rec- 

 ognition by this eminent student of plants of the need for a better 

 knowledge of the chemistry of plant cell activities as a proper 

 foundation for a satisfactory knowledge of the course and results 

 of plant protoplasmic activities. It is hoped that the present 

 work may contribute something toward this desired end. 



Second, the purpose of the writer will not have been fully 

 accomplished unless the book shall serve also as a stimulus to 

 further study in a fascinating field. Even the most casual perusal 

 of many of its chapters cannot fail to make clear how incomplete 

 is our present knowledge of the chemical changes by which the 

 plant cell performs many of the processes which result in the pro- 

 duction of so many substances which are vital to the comfort and 

 pleasure of human life. Studies of the chemistry of animal life 

 have resulted in many discoveries of utmost importance to human 

 life and health. It requires no great stretch of the imagination 

 to conceive that similar studies of plant life might result in 

 similar or even greater benefit to human lif e, or society, since it 

 is upon the results of plant growth that we are dependent for 

 most of our food, clothing, and fuel, as well as for many of the 

 luxuries of life. 



The material presented in the book has been developed from a 



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