NA TURE 



169 



THE CHEMISTRY OF PLANTS. 

 Biochemte der Pflansen. Vol. i. By Prof. Friedrich 

 Czapek. Pp. xv + 584. (Jena: Gustav Fischer, 

 1905.) Price 14 marks. 



THIS work forms a new type among those on 

 physiological botany : in some degree it re- 

 sembles " Die Pflanzenstoffe " of Husemann and 

 Hilger, and " Die rohen Stoffe des Pflanzenreiches " 

 of Wiesner; but whereas the bias of the former is 

 pharmacological, and that of the latter economic, the 

 subject is treated in this volume more from the 

 chemical standpoint. 



The author states that his book is not to be regarded 

 as a treatise or handbook for students, but as a work 

 for reference, and that he has endeavoured to show 

 in it what results the application of chemical methods 

 to the problems of botanical physiology have yielded. 



The subject-matter is divided into three parts — a 

 historical introduction of 19 pages; a general part of 

 62 pages ; and a special part of 489 pages. The 

 general part is divided into two chapters, dealing 

 respectively with the substratum of chemical processes 

 in the living organism, and with the processes them- 

 selves. The first chapter treats of protoplasm and its 

 constituents, colloids, then protoplasmic structures 

 and their biochemical import; the second of reactions 

 from the standpoint of general chemistry, a survey of 

 the conditions of reactions, ionic reactions in the 

 living cell, the velocities of reactions, catalysis, the 

 general chemistry of enzymes, cj'totoxins, and 

 similar substances being here made. 



The special part is concerned with the occurrence, 

 metabolism, and metastasis of aliphatic substances in 

 detail. The general arrangement of this part is in 

 the first order chemical : the first section is devoted 

 to fats, lecithins, phytosterins, and waxes ; the 

 second to carbohydrates, commencing with the simpler 

 sugars, and ending with the substances forming the 

 skeletal structure of plants. In the second order the 

 arrangement is mixed; the chapters deal in part with 

 the taxonomic, in part with the morphological, ana- 

 tomical, and histological distribution of substances, 

 and further with the physiology of the various bodies 

 considered. 



Photosynthesis receives considerable attention, and 

 is regarded in all aspects ; in connection with it the 

 physics and chemistry of chlorophyll are discussed at 

 length, and other pigments are also dealt with. The 

 treatment of the physics and chemistry of starch is 

 also fairly extensive. An index of the subjects and 

 authors will be given at the end of the completed 

 work. 



The general nature and structure of the book having 

 been reviewed, passage to criticism of it will now be 

 convenient. A work of this kind, involving the two 

 main ideas of chemistry and plants, requires, if it is 

 to yield its full value, so to be arranged as to enable 

 the composition or metabolism of a plant (in so far 

 as this is known), as well as the distribution of a 

 substance or a process, to be ascertained with equal 

 NO. i860, VOL. 72] 



ease. But this is not the case with this work owing 

 to its arrangement ; the mode of treatment is analytic 

 rather than synthetic. In " Die Pflanzenstoffe " one 

 volume deals with the material from the chemical, 

 the other from the taxonomic standpoint ; but this 

 method, although very convenient, necessitates dupli- 

 cation. The difficulty could have been here met 

 through use of a suitable and strictly methodical 

 arrangement, had the divisions of various orders of 

 magnitude been formed from different standpoints, 

 and had those which constituted each order been of 

 similar kind and value. The end can be still attained 

 here by aid of a copious and well-arranged index of 

 the subject-matter. 



Printers' errors are not very numerous, and occur 

 chiefly in the earlier part of the book. 



Discrepancies and slips of the pen are noticeable 

 here and there. For example, on p. 7 Priestley is 

 given as the discoverer of oxygen, but on p. 12 

 Scheele ; on p. 144 anaerobem should be aeroheni ; 

 Bedeutung on p. 434 should be Beleiichtung. From 

 the structure of a sentence on p. 39 one might sup- 

 pose that ethyl-ether was insoluble in water. Further, 

 the last paragraph on p. 313 is hardly consonant 

 with the author's apparent acceptation of Meyer's 

 hypothesis of the structure of starch-granules on 

 p. 312. 



Since the work is one for reference, hence a com- 

 pilation, and since the author has intentionally almost 

 entirely avoided critical remarks on the subject-matter, 

 the reviewer can only consider the selection from a 

 critical standpoint. It may be said, on the whole, that 

 the selection has resulted in a very representative 

 collection of diverse opinions on controverted ques- 

 tions, and in many cases almost an exhaustive one. 

 As a result of this, condensation is, in the case of 

 manv papers, extreme, and at times there is omission ; 

 but this is almost a necessary consequence of the mass 

 of literature consulted. 



One disadvantage, which is, however, common to 

 all books of this class, is the slight indication of the 

 relative values of the various works cited; all emerge 

 with equal distinctness, except in so far as more space 

 is given to some than to others ; beyond this clue 

 there is no guide to their relative worth. This is 

 well shown in the case of the chemistry of starch and 

 some of the pigments ; a chemist or botanist who had 

 not devoted any special attention to these substances 

 would rise from a perusal of the epitome here given 

 under the impression that there was only chaos. 



In connection with the chemistry of starch the 

 author does not seem to have had at hand all the 

 works of H. T. Brown and his collaborators, G. H. 

 Morris and J. H. Millar, or to have grasped their 

 views quite clearly. 



Enzymes are stated to be colloidal catalysors, and 

 their colloidal state is said to be of import. In the 

 opinion of the reviewer there is no sufficient evidence 

 to show that any enzyme is a colloid, and, indeed, 

 considerable reason why many should not be so. 

 There is even no sufficient evidence that enzymes are 

 chemical compounds ; they may be essentiallv mi.x- 

 tures, or merely functions of special conditions. 



In the consideration of the action of accelerators 



I 



