REVIEWS 143 



reasonable account of the subject of " the concentration of hydrogen ions " 

 to be found in any English textbook known to the reviewer. The subject 

 is treated with admirable lucidity both from the theoretical and practical 

 points of view, and descriptions are given of the apparatus and methods 

 employed in measuring hydrogen on concentration by means of indicators ; 

 throughout the subsequent chapters this subject is kept before the reader 

 in such a manner as to make him realise its practical bearing in problems of 

 physiological chemistry and biochemistry. Chapter 1 1 , entitled ' ' The Proteins, ' ' 

 contains substantially the same as the first chapter of the old edition with 

 the exception of the nucleoproteins, which are dealt with in the third chapter 

 together with nucleins and nucleic acid. Chapter IV, which is the only other 

 new one, is entitled " The Preparation and Properties of Certain Amino 

 Acids " ; here will be found valuable and in many cases first-hand informa- 

 tion concerning the preparation of the more important amino acids set 

 forth with all essential practical details. The arrangement of the remain- 

 ing ten chapters and appendix more or less follows that of the previous 

 edition, but throughout a number of improved methods have been 

 introduced to replace older ones which have become obsolete ; new and 

 valuable features are also sections on bacterial decompositions in the intes- 

 tine, on autolysis, and on oxidases and peroxidases. While written primarily 

 for medical students, the author has not lost sight of the interests of other 

 workers in biochemistry, and to all of these the book can be confidently 

 recommended as a most valuable laboratory manual and adjunct to their 

 library. P. H. 



Notions Fondamentales de Chimie organique. Par Charles Moureu, 

 Membre de ITnstitut et de 1' Academic de Medecine. [Pp. viii -f 552.] 

 Sixth Edition. (Paris: Gauthier-Villars et Cie, 1920. Price 16 frs.) 



In the preface to the first edition published in 1902 the author stated that 

 his object in writing this book was to set forth the principal theories of 

 organic chemistry and to introduce the student step by step to the more 

 important transformations of matter as a preparation for the study of the 

 larger textbooks. It must be acknowledged that the author has been most 

 successful in carrying out the task he has set himself. The book contains 

 a remarkable amount of information for its size and is replete with novel 

 methods of interpreting the mechanism of reactions ; the style throughout 

 is simple and the method of presentation is clear, and a perusal of the pages 

 of the book will repay many a teacher. While it cannot be denied that 

 many branches of the subject have been treated somewhat briefly, sound 

 judgment has on the whole been exercised in the selection of the material. 



The book is divided into seven chapters deaUng with general theories, 

 hydrocarbons, oxygen compounds, nitrogenous compounds, organo-metallic 

 compounds, heterocyclic compounds and dyes respectively, but a mere recital 

 of these conveys a very imperfect idea of the amount of information con- 

 tained in them. The practice of quoting the names of authors without 

 dates or references is regrettable, but this may, of course, have been necessi- 

 tated by considerations of space. p, jj. 



GEOLOGY 



Petrology for Students. An Introduction to the Study of Rocks under the 



Microscope. By Alfred Harker, M.A., LL.D., F.R.S. Fifth 



Edition. [Pp. viii + 300, with 99 figures.] (Cambridge : at the 



University Press, 1919. Price 8s. 6d. net.) 



For more than twenty years this textbook has been widely used in this 



country, and the part which it has played in the training of so many British 



