26S 



NA TURE 



[January 19, 1899 



appear to be purely chemical, but in fact it is not ; for 

 although the chemical nature of the several substances 

 and the more exact methods employed for their Cjualita- 

 tive and quantitative determination are carefully re- 

 corded, the whole is looked at always fioni the purely 

 physiological point of view of animal metabolism. 



Ur. Hottazzi deserves special praise for having clearly 

 realised the importance of the application of the more 

 elementary ideas of physical chemistry to physiological 

 and biological problems. He has hence given us here 

 and there throughout this work concise but very clearly 

 written statements of those conceptions of physical 

 chemistry which are essential to the study of the pro- 

 perties of livmg matter, and which have so far never 

 appeared in any existing text-book of either physiology or 

 physiological chemistry. Thus in chapter ii. (pp. 37-64) 

 he has dealt with the ideas which have led to the estab- 

 lishment of the modern theory of solutions, such as 

 osmotic pressure, vapour tension, freezing-point, electrical 

 conductivity, internal friction and viscosity. In chapter 

 vi. (pp. 392-405) he gives the phenomena and laws of 

 diffusion, dialysis, osmosis, and imbibition. This chapter 

 is, moreover, of peculiar interest as dealing specially 

 with the colloids as a group, and in a way not found in 

 other textbooks. This is most valuable when we remember 

 that the animal organism is chiefly composed of colloidal 

 substances, that they possess peculiar physical and 

 chemical properties, due to the nature of their molecular 

 aggregation, independently of those due to their con- 

 stituent elements, and that these properties, continually 

 making themselves felt, must play an important part in 

 determining the mode of recurrence of vital processes. 



The second volume opens with a long chapter (pp. 

 1-108) on "The chemistry of the living cell," as a 

 suitable connecting link between the general physio- 

 logical chemistry dealt with in the first volume and the 

 special treatment in the second. In this the author has 

 endeavoured, and with great success, to bring together 

 all the scattered knowledge bearing upon the subject of 

 the cell as the living unit, or, as he says, on the general 

 problems of biological chemistry. This chapter is most 

 instructive, and well worth reading from every point of 

 view. Here again we find excellently clear explanations 

 and applications of the phenomena of surface-tension, 

 diffusion, osmosis in its strictest sense, and diosmosis: 

 of plasmolysis and isotonicity. The succeeding chapters 

 deal consecutively with the special subjects of blood, 

 lymph chyle and serous fluids, the fluids of the organism 

 in general, connective tissue, muscle, nerve, sense-organs, 

 internal secretions, and so forth. The last three chapters 

 treat of the digestive secretions, the liver, kidneys 

 and urine. 



In both volumes the several chapters conclude with a 

 copious, well selected and representative bibliography 

 of the subject-matter, carefully quoted in chronological 

 order. 



This book is full of good things, clearly slated and 

 discussed suggestively. It would be easy to make a 

 selection of them ; but the list would be long, and we 

 refrain from giving it in the hopes that thereby curiosity 

 may be whetted and a desire aroused to read the 

 original. S. L. 



NO. 1525, VOL. 59] 



OUR BOOK SHELF. 

 Flashlights on Nature- By Grant Alleiv. With 150 

 illustrations by Frederick Enock. Pp. viii + 312. 

 (London : George Newnes, Ltd., 1899.) 



This is a bright and amusing account of a number of 

 natural structures and problems. The economy of 

 aphides, shrikes, earwigs, wasps, gnats, spiders and Hes- 

 sian flies, of the -Alpine Soldanella, clover, gorse, and 

 water-weeds in winter is described in lively words and 

 illustrated by figures, which are often both attractive and 

 novel. The drawings of the earwig and Hessian fly are 

 well worth the attention of professed naturalists ; those 

 of the gnat contain some small errors. Mr. Grant Allen 

 has banished nearly every one of the technical terms 

 which impede unlearned readers. In this he has done 

 well, though we think that a technical name here and 

 there in a footnote might have guided some i^w readers 

 to fuller information. 



Authors of elementary books do not feel bound to give 

 chapter and verse for all their statements. But Mr. 

 Grant Allen has gone too far in leaving out. He has re- 

 written Kerner's account of the Soldanella, the frog-bit 

 and the curled pondweed, and adapted Kerner's figures 

 of all three, without one word of acknowledgment. 



L. C. M. 



Spherical Trigonometry (Theoretical and Practical). 

 Pp. viii -t- 1 16. By W. W. Lane. (London : Macjnillan 

 and Co., 1898.) 



The author of this book, who is one of the naval 

 instructors on H.M.S. Britannia., has brought together 

 the most important rules which are used in the solution 

 of spherical triangles, and, after demonstrating the theory 

 of each, introduces worked-out exercises for illustrating 

 their actual use. The arrangement of the text seems to 

 be well done, the student being led first to understand 

 the geometrical relations between circles of a sphere, 

 their spherical triangles, and after that the geometrical 

 relations between the sides and angles of spherical 

 triangles. Chapter iv. introduces for the first time the 

 trigonometrical ratios, and this is followed by chapters 

 in which the solutions of various types of triangles are 

 dealt with. Throughout these the author makes the 

 solution of the \ arious problems very clear to the student 

 by means of the figures which accompany the text, but 

 the reader is now here directly advised to always construct 

 figures for himself 



.Although the author demonstrates and illustrates the 

 use of the L haversine and tabular versed sine tables 

 (tables which, by the way, are not used at examinations 

 by the Civil Service Commissioners), he assumes that the 

 reader knows the meanings of these terms. Perhaps it 

 would have been more complete if these terms had been 

 again defined. Thus we find that up to the end of the 

 sixth chapter the beginner has been working with sines, 

 cosines, tangents and their reciprocals ; but in the next 

 chapter, in the solution of a certain triangle, he is 

 immediately confronted with 



hav .•^ = 



vers A 1 - cos A 



, &c. , 



without any previous hint as to what hav A or vers .\ 

 means, although a more advanced student could find 

 this out for himself. This, however, is a somewhat 

 minor point, for the author provides other rules in- 

 dependent of these terms. Those, however, for w-hon* 

 this book is intended — namely, students preparing for 

 examinations at the Royal Military Academy, I-ieutenant 

 R.N., H.A. London, &c. — will find the present treatise an 

 excellent guide to the solution of spherical triangles, and 

 the large number of well-chosen examples which are 

 appended should prove useful. 



