July 24, 1919] 



NATURE 



403 



the account of the cardiometer (Fig. 68) ; it is 

 also unfortunate that reference is not made to 

 the term "premature contraction " as an alterna- 

 tive to "extra systole," as the latttr is 

 objected to by some authorities. These small 

 points are chosen as illustrating the kind of thing 

 which can be readily altered in subsequent 

 editions. The question of the general balance of 

 the book is largely a matter of opinion, and prob- 

 iblv no two readers will agt:ee as to the chapters 

 which might be considered as inadequately 

 treated ; to the present reviewer those on the 

 central nervous system, the kidney, and the 

 physiology of muscle and nerve appear to require 

 expansion. Histological considerations are 

 omitted, no doubt in order to save space, but, 

 nevertheless, there are a large number of illus- 

 trations ; some of these (52, 53, 336, 391-393, 

 399, 400) might perhaps have been omitted with- 

 out much loss, though the excellence of the illus- 

 trations is one of the strong features of the book ; 

 few of them are likely to be familiar to students 

 from perusal of other text-books. 



The book should be much appreciated by 

 advanced students on account of the treatment of 

 some of the sections in a manner new to students' 

 books, and by elementary students owmg to the 

 interestmg manner in which the subject is treated. 



OUR BOOKSHELF. 



Biochemical Catalysts in Life and Industry. 

 Proteolytic Enzymes. By Prof. Jean Effront. 

 Translated by Prof. Samuel C. Prescott, 

 assisted by Charles S. Venable. Pp. xi + 752. 

 (New York : John W^iley and Sons, Inc. ; Lon- 

 don : Chapman and Hall, Ltd., 1917.) Price 

 235. net. 



The name "biochemical catalysts " is used by the 

 author as an alternative for the more usual name 

 of "enzymes," and has the advantage of calling 

 to mind the fact that these are only a particular 

 class of catalysts. The present work is devoted 

 to those enzymes which act on proteins and their 

 degradation products. It includes also a dis- 

 cussion of the phenomena of immunity, as well 

 as of the processes of coagulation of the blood 

 and milk, processes with regard to which some 

 doubt may be felt as to their being catalytic. 

 Urease is also described. 



.An excellent and complete account of the 

 subject is given up to the date of the original 

 French work, which appears to be not later than 

 igi2. It is somewhat unfortunate that the trans- 

 lator has not added supplementary notes to bring 

 the book up to date, an addition that would have 

 much increased its value. Indeed, seme may be 

 inclined to wonder why the mere translation of 

 the original book was considered necessary. All 

 readers interested should be able to read the 

 French edition. The date of the original work 

 doubtless accounts for some statements which are 

 no longer correct. For example, it is said that 

 NO. 2595, VOL. 103] 



enzymes are proteins, and the existence of true 

 anti-bodies to enzymes is accepted. In this con- 

 nection it may be mentioned that British and 

 American work is rather meagrely referred to. 

 On the whole, however, the book will be found 

 a useful one, especially in that part dealing with 

 those industrial processes in which proteolytic 

 enzymes play an important part. Such are brew- 

 ing, cheese- and bread-making, tanning, and their 

 use in therapeutics. The fixation of nitrogen by 

 the soil and the question of the value of amino- 

 acids as exclusive nitrogen food for animals are 

 discussed in some detail. 



An interesting introductory section will be 

 found. We may note that the author is inclined 

 to favour the theory of surface action rather than 

 that of the formation of intermediate compounds 

 of a chemical nature. W. M. B. 



Formulaire de I'Electricien et dti MScanicien. By 

 Hospitalier et Roux. Vingt-neuvi^me Edition 

 (1919). By Gaston Roux. Pp. 11 + 1485. 

 (Paris : Masson et Cie, 1919.) Price 20 francs. 

 The older generation of electricians are well 

 acquainted with the earlier editions of this work ; 

 and much of our standard nomenclature, as well 

 as many of the symbols in everyday use, is due 

 lo Hospitalier. Nowadays numerous other pocket- 

 books partially fulfil the functions of a book of 

 reference for electricians, but not any of them 

 are so complete or so well arranged as this book. 

 We are inclined to grumble at its size — it con- 

 tains now nearly 1500 pages — but it is difficult 

 to find anything that might be cut out with advah- 

 tage, and there are many subjects, like wireless 

 telegraphy and telephony, which one would like 

 to see included. 



The first 500 pages are on purely academic 

 subjects — mathematics, physics, dynamics, etc. 

 — and enable the engineer to refresh his memory 

 of his college studies. The next 600 pages are 

 on electro-technical subjects, and the remainder 

 of the book contains French official documents, a 

 comparison of which with our own Board of Trade 

 regulations is very instructive. A complete index 

 is given. 



In several places theorems have been abbrevi- 

 ated in order to save space, with unfortunate 

 results. For instance, the theorems on the design 

 of networks are almost unintelligible. On p. 856 

 we cannot understand what Santarclli's theorem 

 is. In the first theorem by Bochet there is a fairly 

 obvious misprint in the final formula. In the 

 second it is not stated what condition the 

 conductors have to fulfil in order that their mass 

 may be a minimum; the formulae given, there- 

 "iFore, may well be misleading. From the 1909 

 edition we find that the condition ihey must satisfy 

 is that the sum of the voltage drops is constant. 

 This is quite unpractical. The real condition is 

 that the power expended in them should be a 

 minimum when the maximum voltage drop is 

 fixed. The solution of this problem does not 

 agree with that given on p. 857. A. R. 



