BOOK REVIEWS. 



379 



doubt that they play a fundamental part in providing, in conjunction with their 

 specific enzymes, a most delicate controlling mechanism for the various processes 

 of plant metabolism. A thorough knowledge of the chemistry of these bodies 

 is therefore indispensable to the advanced student of, and the research worker 

 in, plant biochemistry and physiology. 



The earlier editions of Dr. Armstrong's book are well known for the valuable 

 survey they gave of this subject, and the edition now before us is thus assured 

 of a warm welcome. In the seven years which have elapsed since the previous 

 edition, much important work has been done, which has materially advanced 

 our knowledge of the carbohydrates and glucosides. The new edition gives an 

 excellent account of this work, and of the new ideas and fields for inquiry it opens 

 out. It is especially gratifying to notice the recognition which is given to the 

 sterling work of Irvine and his school. The plant biochemist will be particularly 

 interested in the final chapter on the function of carbohydrates and glucosides 

 in plants, from which he will obtain much inspiration, for it abounds in stimulating 

 ideas for research. We were, however, surprised to notice that the author appar- 

 ently still regards the anthocyanins' as oxidation products of the flavones, not- 

 withstanding the unquestionable evidence that is now available proving them 

 to be reduction products of the latter. How this is to be reconciled with the 

 almost equally unquestionable correlation which has been found between the 

 distribution of oxidases and anthocyanins remains a matter for research. 



Apart from this, we have nothing but praise for the admirable way in which 

 the author has dealt with a subject which is at once one of the most fascinating 

 and of the most intricate in the whole of chemistry. The volume easily maintains 

 the high reputation deservedly attaching to the series of Monographs on Bio- 

 chemistry of which it forms a part. 



" A Course of Practical Chemistry for Agricultural Students." By H. A. D. 

 Neville and L. F. Newman. Vol. ii., Part i. 8vo. 122 pp. (The University 

 Press, Cambridge, 191 9.) 5s. net. 



This little book consists of a series of practical exercises in pure organic 

 chemistry for agricultural students, and has been written primarily for the use 

 of students taking the course for the degree in Agricultural Science at Cambridge. 

 It therefore labours under the disadvantage of being written to cover a syllabus, 

 which is bound to limit the general utility of a book, and to result in a certain 

 inequality of treatment. 



As pointed out in the preface, the notes which are appended to the practical 

 directions for each day's work are intended " not to supersede lectures," but 

 " to explain just the points ... on which the student usually needs assistance 

 ... to explain the reasons and reactions of the experiments as they are being 

 carried out." Although on the whole the directions and notes are tolerably clear, 

 there many mistakes, both of omission and commission, several of which are by 

 no means unimportant, and which certainly do not fulfil the requirements of the 

 above quotation. For example, the student is led to believe that the iodoform 

 test is specific for ethyl alcohol (p. 24), and no mention is made of its being given 

 also by acetaldehyde (p. 36) and acetone (p. 41). Again, it is stated that hydrolysed 

 amygdalin reduces Fehling's solution on account of the benzaldehyde formed, 

 the glucose produced being apparently neglected. There are other mistakes of 

 this type, besides purely typographical errors which are also to be found. Al- 

 together the book gives the impression of having been somewhat hastily compiled, 

 and although it is doubtless of great value for the purpose for which it is primarily 

 intended, it cannot be given an unqualified recommendation for general use. 

 Lest the size of the book should be overestimated, it should be mentioned that 

 of its 122 pages only 77 are occupied by the text, the remainder being left blank 

 between the exercises for the student's notes. 



" Introduction to Physical Chemistry." By James Walker. Ed. 8. 8vo. 

 xiii + 433 pp. (Macmillan & Co. Ltd. London, 1919.) 16s. net. 



Professor Walker's textbook is too well known to chemists to need any intro- 

 duction. That in the twenty years since its first publication it should have passed 

 through eight editions is sufficiently eloquent testimony. 



The student of plant biochemistry who requires a thorough grounding in 

 physical chemistry — a grounding which the modern trend of research in plant 

 physiology makes all the more necessary — as well as the general scientific reader 

 who requires a readable, accurate, and concise account of, for instance, the latest 

 developments in molecular physics and radioactivity, cannot do better than turn 

 to this new edition of an excellent book. 



VOL. XLV. 



