April 



920] 



NATURE 



195 



Our Bookshelf. 



The Engines of the Human Body : Being the 

 Substance of Christmas Lectures Given at the 

 Royal Institution of Great Britain, Christmas, 

 1916-1917. By Prof. Arthur Keith. Pp. 

 xii + 284 + 11 plates. (London: Williams and 

 Norgate, 1919.) Price 12s. 6d. net. 

 Works on physiology commonly appeal either to 

 the usual types of student, or else to those engaged 

 in teaching or research work. The work before 

 us claims to appeal in the first place to the general 

 reader " who desires to know what modern medical 

 teachers think of the marvellous contrivances of 

 the human machine." The title of the book, with 

 the foregoing quotation, indicates the spirit in 

 which the author has approached the subject. 

 Prof. Keith's fertile imagination has sought analo- 

 gies between the various functions of the organs 

 on one hand, and divers mechanisms of human 

 design on the other, and he certainly never 

 seems at a loss for them. In so far as' the general 

 reader has no previous knowledge of the subject, 

 the method of treatment by analogy alone seems 

 calculated to give rise to an abundant harvest of 

 grotesque misconceptions, as all those who have 

 taught elementary physiology are well aware ; 

 but the book should be truly welcome to a teacher 

 who, while having some acquaintance with the 

 subject, is yet lacking in the knowledge or 

 imagination necessary to evolve instructive 

 analogies to help to fasten in the pupil's mind 

 what he wishes to impart. 



Many of the mechanical analogies are quite 

 new and should be worth adopting, but others 

 seem superfluous or misleading ; for example, 

 the comparison of muscular tissue with an 

 internal-combustion engine is a sound and gener- 

 ally recognised conception, up to a certain point ; 

 but to refer to tendons as "piston cords," or to 

 arteries and veins as supply and exhaust pipes, 

 is pushing a good analogy to the point of whim- 

 sicality. For the first thirteen chapters, however, 

 in spite of this, the reader should go along 

 smoothly enough, but after this point, when 

 analogies fall thick as autumn leaves, the general 

 reader is likely to lose sight of the track. There 

 are some inexactitudes in the book v/hich do not 

 fall in the category of bad analogies ; for example, 

 the statement that the velocity of the nerve impulse 

 is four miles a second, that nerves are "living and 

 pulsating," and that nerves are subject to fatigue 

 (p. 263). The historical fragments which are fre- 

 quently introduced are of considerable merit, 

 partly on account of the relief experienced by the 

 reader in meeting plain, unveiled fact, but chiefly 

 because thev are exceedingly well chosen. 



C. L. E. 



A Class-book of Organic Chemistry. By Prof. 

 J. B. Cohen. Vol. ii. : For Second-Year Medical 

 Students and Others. Pp. vii+156. (London: 

 Macmillan and Co., Ltd., 1919.) Price 45. 6d. 



The average medical student is inclined to regard 

 NO. 2633, VOL. 105] 



chemistry as a subject which has to be studied in 

 order to pass certain examinations, and having 

 passed these, he dismisses the subject from his 

 mind. This is in large measure due to the fact 

 that the text-book he has come across has failed 

 to stimulate his interest, and the probability is that 

 he will get rid of the book at the earliest oppor- 

 tunity. 



The little volume under review, however, is 

 one that we venture to think the student will not 

 be likely to part with, as it gives a very clear, 

 concise, and readable account of the subject, 

 which may stand him in good stead in his future 

 studies ; it is divided into ten chapters, as 

 follows : Synthesis, The Oils and Fats, The 

 Carbohydrates, Some Natural Organic Bases, 

 The Pyrimidine and Purine Groups, The 

 Proteins, Fermentation and Enzyme Action, 

 The Essential Oils, The Alkaloids, and Syn- 

 thetic Drugs. Each of the sections is 

 thoroughly up-to-date, and we know of no 

 book which, within so small a compass, deals 

 with such varied subjects as, for example, the 

 Grignard reaction, the synthesis of disac- 

 charides, the origin of uric acid in the animal 

 organism, and the theory of alcoholic fermenta- 

 tion, besides giving the constitutional formulae, 

 so far as they are known, of yeast-nucleic acid, 

 haemin, setiophyllin, and the more important 

 alkaloids, such as strychnine and morphine. The 

 last chapter, in addition to giving the constitution 

 of many of the better-known synthetic drugs, 

 contains a short account of the more recent anti- 

 septics, suoh as chloramine-T, and the dyestuffs 

 malachite green, acriflavine, etc., as well as a 

 brief sketch of the trypanocidal action of the 



I organic arsenic compounds. 



The first volume, published in 1917, was meant 



I to serve as an introduction to organic chemistry, 

 and the two volumes together can be thoroughly 

 recommended as a most excellent and handy little 

 compendium, which should find great favour 

 among students and teachers alike. 



Examples in Electrical Engineering. By J. F. 

 • Gill and F. J. Teago. Pp. 173. (London : 



Edward Arnold, 1920.) Price 75. 6d. net. 

 A BOOK of this kind, which consists of a collec- 

 tion of model examination papers, followed by 

 model replies, should be not without its uses to 

 those who are obliged to study the art of passing' 

 examinations, as well as the principles of elec- 

 trical engineering, as a careful perusal of its 

 contents will enable the student not only to 

 practise his knowledge of the various parts of 

 the subject, but also to form good habits in the 

 way of presentation of the solution of the problems 

 in a clean form and logical sequence. The drawing 

 of good diagrams and the frequent use of 

 graphical methods are very rightly insisted on, and 

 admirable conciseness is observed. The papers 

 cover both "intermediate" and "advanced" 

 standards, and relate on the whole to practical 

 applications rather than to theory. 



