246 



NATURE 



[October 31, 19 12 



We have some difficulty in judging adequately of 

 this book, since sixteen pages have been left out 

 in binding up the review copy. 



(2) For the most part Dr. Hegner's book runs 

 on the familiar lines of comparative anatomy, and 

 his treatment of the structure of animal phyla 

 does not differ essentially from that adopted in 

 any of the recent text-books of zoology, to which, 

 indeed, he is indebted for most of his subject- 

 matter and illustrations. The feature that he 

 claims to be distinctive in this work is the con- 

 sideration of animal physiology alongside of animal 

 structure. The difficulty has been to compress a 

 treatment of two such large subjects into the 

 compass of a handy volume. Comparative physio- 

 logy is in itself a large and new subject and would 

 easily require a whole volume of this size. The 

 author has cut the knot by reducing both anatomy 

 and physiology to a condensed form that can 

 scarcely be assimilated by any student. The physio- 

 logical paragraphs deal mainly with responses to 

 simple forms of stimulation — the behaviour of 

 Paramecium and of Hydra are excellent examples 

 of this — but they do not attempt to show the 

 evolution of physiology amongst animals as do 

 the sections upon anatomy. 



Some useful sections are devoted to showing the 

 economic bearing of zoological knowledge. The 

 statement of the food of birds is a good instance 

 of this, though here, again, the need for brief 

 summaries has precluded the insertion of much 

 interesting matter. The remarks on the damage 

 due to insects, for example, are too brief to be of 

 much value. 



Compression has been carried too far in the 

 case of invertebrates of uncertain affinities in 

 chapter ix. Either these groups should have been 

 omitted or treated more fully. On the whole the 

 chapter on insects strikes one as being the best 

 in the work, and the treatment of the affini'ties 

 of animal phyla as the least satisfactory feature of 

 it. The use of the terms "efferent" and "affer- 

 ent " in connection with the circulation of the 

 crayfish, on p. 2S3, is the converse of general 

 usage and may lead to considerable confusion. 

 The illustrations are very good and clear ; those 

 of the honey-bee, though not original, are sure 

 to be welcome. Fig. 369 is turned upside down. 

 Perhaps the greatest appeal of this very carefully 

 compiled work will be to those who wish to have 

 a book on comparative anatomy in one volume. 



(3) This work, by the director of the Natural 

 History Museum at Hamburg, has run into three 

 editions in less than six years, and its success 

 is due to the clear and well-balanced treatment 

 Tliat it contains of bolli hrnnches of biology. In 

 the present edition Ihc sc<-lii)ns on comparative 



NO. 2244, VOL. go] 



anatomy and on the early races of mankind have 

 been expanded and brought up to date so as to 

 make an exceptionally attractive and very cheap 

 work. Dealing, as the book does, mainly with 

 general problems, it seems rather a pity that the 

 statement of Mendel's method is not clearly given. 

 The essence of the method and its importance can 

 be slated quite simply without going into details. 

 The account that is given here, printed, as it is, in 

 minute type and dealing with a single case, will 

 no doubt be expanded or altered in the next 

 edition. 



PHYSICS: OLD AND NEW. 

 (i) liuiior Magnetism and Electricity. By Dr. 

 R. li. Jude and Dr. J. Satterly. Pp. vii + 288. 

 (London : W. B. Clive, University Tutorial 

 Press, Ltd., 1912.) Price 2s. 6d. 



(2) All Introduction to Practical Physics jar 

 Colleges and Schools. By Prof. E. H. Barton 

 and Dr. T. P. Black. Pp. vii+ 188; illustrated. 

 (London: Edward Arnold, 1912.) Price 3s. 6d. 



(3) Memoires sur I'Electricite et I'Optique. By 

 A Potier. Publies et Annotes par A. Blondel. 

 Avec une Preface de Henri Poincare. Pp. 

 XX + 330. (Paris: Gauthier-Villars, iQi^-) 

 Price 13 francs. 



(4) Treatise on Light. In which are explained the 

 causes of that which occurs in Reflexion, and in 

 Refraction, and particularly in the strange 

 Refraction of Iceland Crystal. By Christiaan 

 Huygens. Rendered into English by Silvanus 

 P. Thompson. Pp. xii+ug. (London: 

 Macmillan and Co., Ltd., 1912.J Price i05. net. 



(5) Intermediate Physics. By Prof. W. Watson, 

 F.R.S. Pp. xiii+564. With diagrams. 

 (London: Longmans, Green and Co., 1912.) 

 Price 6,';. net. 



(6) Lehrbuch der Pliysik. By Prof. Eduard 

 Riecke. Erster Band. Mechanik, Molekular- 

 erscheinungen und Akustik. Optik. Zweiter 

 Band. Magnetismus und Elektrizitat. Warme. 

 Fiinfte, verbesserte imd vermehrte Auflage. 

 Pp. xvi + 6oo + xii + 775 ; illustrated. (Leipzig: 

 \'eit and Co., 1912.) Price 26 marks. 2 \'ols. 



(7) Physik in g.raphischen Darstcllungen. By Felix 

 .Vuerbach Pp. x + 28 + 213 plates. (Leipzig 

 and Berlin : B. G. Teubner, 1912.) Price 

 9 marks. 



(i) O O many elementary text-books of this kind 

 kjj appear from time to time (one of the 

 present authors is already responsible for two) 

 that it is very difficult to judge vi'hethcr or not 

 a new publication possesses advantages over its 

 predecessors. The scope of the subject is so 

 limited that all of them are bound to be very much 

 alike, and in any one book there can only be a 



