June 9, 1905.] 



SCIENCE. 



891 



possible general basis of classification for all 

 chemical phenomena. Its results are purely 

 qualitative, but they are absolute. 



There has been a feeling that there was 

 something antagonistic between the qualita- 

 tive classification of equilibria and the quan- 

 titative study of equilibria. When put in this 

 way, the feeling is seen to be absurd, since the 

 two things supplement each other. It is only 

 by combining the two that we can hope to 

 attain to a quantitative theory of all chemical 

 phenomena. 



Mr. Findlay gives a very clear and ele- 

 mentary statement of the phase rule and its 

 applications. The book can be recommended 

 most heartily. There are a few mistakes here 

 and there, but they are not of serious impor- 

 tance. We have here a most satisfactory in- 

 troduction to the phase rule. It should not 

 be forgotten that the phase rule is valuable 

 in two ways, as a basis of classification and 

 as an instrument of research. It is only the 

 first aspect which has been considered in this 

 volume. This is quite right and proper; but 

 it is as an instrument of research that the 

 phase rule is to come more and more prom- 

 inently to the front in the next decade. The 

 time has not yet come when a book can be 

 written on this; but such a book will be neces- 

 sary before very long, and it is to be hoped 

 that Mr. Findlay may see his way clear to 

 writing it. 



Wilder D. Bancroft. 



czapek's biochemie der pflanzen, vol. I. 



One of the most unsatisfactory chapters on 

 the subject of plant physiology is that relating 

 to the chemical nature of plant substances 

 and the reactions involved in their production 

 and utilization. This situation has been due, 

 not only to the intrinsic diificulties of the 

 problems involved, but also to the unsatisfac- 

 tory condition of the literature on the subject. 

 While the handbook of Pfeffer has given the 

 latitude and longitude of these problems to 

 the student undertaking a serious study of the 

 chemical aspect of plant physiology, the more 

 detailed account of this phase of the science 

 prepared by Czapek will be a most highly ap- 

 preciated resource. 



The first volume of the work under discus- 

 sion reveals the scope of the undertaking. 

 The preface indicates that the author has not 

 proposed to write a text-book introducing the 

 beginner to the subject, but rather to prepare 

 a reference work which shall aid the more 

 advanced investigator to use conveniently the 

 work of his predecessors. This object has been 

 most successfully accomplished, and no stu- 

 dent of plant physiology can afford to miss 

 this book from his list of immediately avail- 

 able helps. 



Czapek's services have not been enumerated, 

 however, when the results of his wide reading 

 and patient summarizing have been recognized, 

 since the work in question is vastly more than 

 a mere compilation. In these days when the 

 democratic spirit of science opens the door of 

 public expression to men of all ranks of 

 scholarship, the task of discriminating accu- 

 rately the raw from the ripe and the hasty 

 from the well wrought is not always readily 

 accomplished, and a proper sorting of the ma- 

 terial at hand by one so well qualified is a 

 genuine service to science. 



Then, again, in this eager time when so 

 many men are straining to get the first 

 glimpse of the real solution of fundamental 

 problems, some are bound to guess shrewdly 

 while others are endeavoring to be sure before 

 speaking. To wisely divide this shrewd guess 

 work from the solid fabric is the work of no 

 mere compiler. In this direction, Czapek has 

 rendered good service. 



The general chapters introducing the book 

 are all worthy, but of the various subjects 

 treated an especial interest at present attaches 

 to the discussion of the fundamental facts of 

 enzyme action, of the bearing of the theory of 

 ionization on physiological processes and the 

 significance of colloids and the colloidal con- 

 dition. These subjects are here treated in an 

 illuminating way. 



The special part discusses in detail fats, 

 lecithins, physosterin and related compounds, 

 carbohydrates and the bodies forming the cell 

 membranes. On the subjects covered by this 

 volume, the student is given a practically com- 

 plete citation of the literature appearing prior 

 to June, 1904. 



