692 SCIENCE PROGRESS 



The authors have endeavoured to effect, probably for the first time, a survey 

 of the whole subject of oils, fats, and waxes in a single treatise. Those familiar 

 with the complete but necessarily bulky works of Lewkowitsch and others will 

 welcome the attempt made by the authors to summarise the present state of 

 knowledge in the industry within a few hundred pages. 



Section I. gives a general introduction to the subject, Section II. discusses the 

 chemistry of the oils, fats, and waxes, Section III. deals with their testing and 

 analysis, Section IV. gives the classification on a basis of glyceroids and non- 

 glyceroids, Section V. discusses the production and refinement of oils, fats, and 

 waxes, and Section VI. mentions shortly the oleo-resins and essential oils. 



A large number of excellent diagrams are given at the end of the volume 

 showing the latest form of apparatus and machinery used in manufactures, and 

 in addition an endeavour has been made, by the preparation of a number of 

 coloured tables, towards assisting in the rapid identification of unknown oils and 

 fats. The printing and general arrangement of the book are good, and the volume, 

 with the forthcoming second volume on the practical analytical work, should make 

 it a very useful addition to the chemist's library. 



F. A. M. 



The Method of Enzyme Action. By James Beatty, M.A., M.D., D.P.H., with 

 an Introduction by Prof. E. H. Starling, M.D., Sc.D., F.R.S. [Pp. vi + 

 143.] (London : J. & A. Churchill, 191 7. Price $s. net.) 



The author formulates the hypothesis that all enzyme action, whether of hydro- 

 lysis, synthesis, oxidation, or reduction, can ultimately be traced to the same 

 causes — namely, the addition or removal of hydrogen or hydroxyl radicles in the 

 hydrolysis or synthesis and the replacement of H by OH or — OH by H in 

 oxidation or reduction respectively. All these processes can take place in the 

 absence of catalysts, but as life developed and increased in complexity the 

 necessity for catalysts, such as the enzymes, arose in order to increase the speed 

 of reactions and also to limit their sphere of action, since a reaction which at one 

 place would be beneficial might at another be injurious. This limitation of sphere 

 of action is secured by the colloidal nature of enzymes whereby reactions are 

 brought about as the result of surface adsorption. The elaboration of this hypo- 

 thesis is preceded by a number of interesting sections devoted to the subjects of 

 catalysis, colloids, adsorption, and the properties of enzymes, each section being 

 followed by a useful summary. Each one of these subjects is dealt with in a 

 most lucid and instructive manner, and the book is worth reading for these 

 sections alone if for no other. 



The ultimate proof of an hypothesis is, according to the author's own words, 

 " the demonstration of the deductions made from it, and if the hypothesis . . . 

 is a correct explanation of enzyme action it ought to be possible to manufacture 

 enzymes"; and in support of this statement he points to the experiments of 

 Dony Herault and others who have succeeded in producing artificial oxidases. 



A special interest attaches to the fact that the book was written in the intervals 



of active service at Salonica, and in view of these circumstances the very greatest 



credit is due to the author for producing what must undoubtedly be regarded as an 



able and suggestive monograph which deserves to receive the serious attention 



of those engaged in work on enzymes, and may be thoroughly recommended 



to all who wish to have a clear and concise account of the known properties of 



these substances. 



P. H. 



