REVIEWS 179 



will find such ample treatment of the large amount of recent work upon the 

 chemical problems involved in plant metabolism. Most of the chief groups of 

 organic substances of importance in the plant are passed in review in turn, and 

 discussed in the first place from the chemical standpoint, and then in relation 

 to their role within the plant. 



Strictly speaking, the scope of the book would be better indicated by such 

 a title as " Materials for the Study of Plant Products," as it is essentially a 

 compilation, and lacks that very valuable element in an introduction to the 

 subject, the challenging statement of current hypothesis and controversy which 

 leads the reader to pursue the subject further. 



Regarded as a compilation, there are certain criticisms which seem to the 

 reviewer valid. 



In the first place, in spite of the statement in the preface that a knowledge 

 of elementary chemistry is assumed, there is some very elementary chemical 

 explanatory matter in the text. It is questionable whether it is a healthy tendency 

 in the botanist that he should be satisfied to have one of the most funda- 

 mental underlying sciences of his subject presented to him entirely through 

 the medium of his special literature. To take a concrete case, it is surely not 

 desirable that the student of plant physiology should arrive at the conception 

 of an ester simply through a consideration of the very brief exposition of the 

 formation of salts which precedes it on page 5. Far better that, if the con- 

 ception of an ester be a new one, elucidation should be sought from general 

 chemical literature. 



The book also suffers from one of the defects, perhaps constitutional to 

 compilation, that the various sections do not seem adequately welded together. 

 This is perhaps a defect in the subject-matter at the present stage rather than 

 in its treatment, but the chapter on colloids, for instance, arrives most un- 

 expectedly, and seems to remain very aloof from the many physiological 

 problems it must ultimately help to solve. 



The publication of a book of this type, with its valuable references to 

 original papers, tends to make the reader think that the citation of literature 

 is exhaustive ; but papers appear on these subjects in such widely different 

 journals that completeness of treatment is probably impossible. In some 

 sections, indeed, the present work is rather misleading, owing to the absence of 

 reference to important papers upon the subjects discussed. The tests given for 

 the detection of small quantities of formaldehyde, for instance, by no means 

 exhaust the possibilities of the subject, and Bokorny has given a more complete 

 account. 



In the section upon the quantitative estimation of sugars, no reference is 

 made to important series of investigations by Brown and Morris and by Parkin, 

 in which the quantitative distribution of sugars in plant tissues was studied 

 Their conclusion that cane sugar is to be regarded as the essential sugar in 

 the up-grade series also receives inadequate treatment. 



The section on proteins has necessarily been so condensed that the presen- 

 tation of the subject is incomplete on many points. It will obviously mislead 

 if the few paragraphs upon the formation of salts by proteins are regarded as 

 an adequate treatment of the subject. 



Finally, it seems clear that if books are to keep pace with the rapid progress 

 of the subject, it is to the special monograph, readily revised, that we must look 

 for accurate information. Thus it is probably hardly the authors' fault that, in 

 producing a work of this scope, important facts, in the light of recent work, 



