July 15, 1909] 



NATURE 



67 



second year's course. The first method of proving the 

 inverse square law for magnetic poles will not con- 

 vince. However, putting aside an occasional criticism 

 of this kind, we think that the book will well serve 

 its purpose of replacing manuscript instruction sheets 

 in a junior laboratory. 



OVR BOOK SHELF. 



Tht^orie des Corps diformables. By E. et F. Cosserat. 



Pp. vi + 226. (Paris: .\. Hermann et Fils, 1909.) 



Price 6 francs. 

 The authors, who are well known by their writings on 

 general elastic theory, here reprint in separate form an 

 appendix contributed by them to M. Chwolson's 

 " Traite de Physique." The kinematical and 

 dynamical theories of the flexible line, the flexible 

 surface, and the deformable three-dimensional medium 

 are discussed in turn in great detail. The dynamical 

 standpoint adopted is that of the principle of action, 

 which forms, in the authors' opinion, the only satis- 

 factory basis for the " deductive " exposition of the 

 subject. In each case the most general form of the 

 function representing the " action " is sought which 

 is consistent with the necessary invariantive relations. 

 This procedure is, of course, not altogether new, and 

 ,-\n expert, turning over the pages, will recognise much 

 that in one form or another is familiar to him. The 

 treatment is necessarily somewhat abstract, and is 

 mathematically very elaborate, Cartesian methods 

 being followed throughout. To many readers the 

 long train of general investigations, unrelieved by a 

 single application, may prove deterrent; but the 

 authors at all events claim that their procedure has 

 never before been carried out so resolutelv and com- 

 pletely, and may justly pride themselves on the mathe- 

 matical elegance of their work. ,\part from its other 

 qu.-ilities, the treatise has a distinct value as a book of 

 reference, and furnishes a whole arsenal of formulifi 

 which may save trouble to future writers. 



The book begins with a kind of philosophical intro- 

 di-ction to which the authors attach great importance. 

 1 his requires to be read in conjunction with a previous 

 treatise, which has also appeared in the French 

 edition of M. Chwolson's work. Those who adopt in 

 its fullest extent the empirical view of mechanics will 

 perhaps consider that too much weight is attached to 

 discussions of this kind. The historical references 

 are, however, interesting, and fairlv complete. The 

 authors are indeed exceptionally well read in the 

 history of their subject, and admirably conscientious 

 in their citation of authorities. In their preface they 

 promise a subsequent treatment of the theories of heat 

 and electricity from a similar standpoint. 



Practical Physiological Chemistry. A Book designed 

 for Use in Courses in Practical Physiological 

 Chemistry in Schools of Medicine and of Science. 

 By Prof. Philip B. Hawk. Second edition, revised 

 and enlarged. Pp. xvi + 447. (London J. and A. 

 Churchill, 1909.) Price i6s. net. 



Prof. Hawk's text-book falls into the front rank 

 with the numerous additions and improvements which 

 have been introduced into the new edition. It is not 

 only a practical guide, and, as such, should be found 

 in all physiological laboratories, but forms a very 

 complete, readable, and up-to-date account of our 

 present knowledge of the chemical side of physiology. 

 A special feature has been made of the illustrations, 

 which are beautifully executed, and most of which 

 will be new to workers in physiological chemistry. 

 The crystalline forms of the manv protein derivatives 

 which the work of Emil Fischer and his colleagues 

 NO. 2072, VOL. Si] 



has been instrumental in rendering familiar to the 

 students of this branch of science will be found among 

 them. 



One small slip we notice in connection, with the 

 matter of protein nomenclature. The initiation of the 

 new system of terminology which is now being 

 adopted for the albuminous substances is wrongly 

 attributed to the British Medical Association. It was 

 really a committee of the Physiological and Chemical 

 Societies of this country which set the ball rolling. 



The mistake is, however, a pardonable one, seeing 

 that it was at the meeting of the British Medical .^sso- 

 ciation held at Toronto in 1906 that the opportunity 

 of presenting the subject to our American colleagues 

 was taken advantage of. The success that has 

 attended this effort to secure uniformity of nomen- 

 clature amongst English-speaking people has been 

 very gratifying; the .American system, adopted under 

 the auspices of the American Phvsiological Society 

 and the .'\merican Society of Biological Chemists, 

 differs in only small and unimportant details from 

 our own. W. D. H. 



Behind the Veil in Bird-land. Some Nature Secrets 

 revealed by Pen and Camera. By Oliver G. Pike, 

 with a number of pen sketches by E. R. Paton. 

 Pp. 106. (London : The Religious Tract Society, 

 1908.) Price lox. 6d. net. 

 Si.vcE the Keartons, some years ago, showed what 

 splendid results could be achieved by an intelligent use 

 of the camera as an aid to the study of natural history, 

 a host of nature-photographers has arisen, but only a 

 very few have attained the high standard of merit set 

 by the founders of this branch of photography. Mr. 

 R. B. Lodge and Miss E. L. Turner in this country, 

 Schillings in Germany, and H. K. Job in .America have 

 in some respects even surpassed the Keartons ; while 

 in this display of resource and dogged persistence 

 in the most trying circumstances they stand un- 

 rivalled. 



Mr. Pike in this rather pretentious volume has 

 given some very excellent photographs, but the 

 " Nature Secrets revealed by Pen and Camera " which 

 he promises in his title-page are conspicuous by their 

 absence. His pag^es contain hardly one single new 

 fact, but a great deal that is banal. He solemnlv 

 assures us, in writing of the kestrel, that " The 

 first summer rose, a delicate pink amidst the sur- 

 rounding green, is a greater picture of spring than 

 ever the sunlit sea could be " — which statement 

 contains a great deal of truth! — "and," he con- 

 tinues, " a kestrel hovering over a meadow, yellow 

 with summer's flowers, tells us a deeper story than 

 the eagle soaring over a wind-swept moor." We fail 

 to grasp why this should be so. 



" Bird-land's veil " is constantly being " lifted up " 

 for him, like the drop-scene at the theatre, and on the 

 stage appear blackbirds, which tell him " the story 

 of the leaves and flowers," and wrens, which reveal 

 " the secrets of the hedgerows," while skylarks, to 

 complete the illusion, like the celebrated Grigolati 

 troupe in the pantomime, fly to and fro across the 

 stage, and sing " happy songs " ! Perfectly charm- 

 ing ! W. P. P. 

 An .[ccount of the Deep-sea Asteroidea collected by 

 the R.I.M.S.S. " Investigator." By Prof. Rene 

 Koehler. Pp. 143 ; 13 plates. (Calcutta : Indian 

 Museum, 1909.) Price 12 rupees. 

 This substantial contribution to the material of the 

 echinoderm " svstem " consists of .126 pages of 

 minute description, and nine pages of general remarks. 

 It is a continuation of certain reports of a preliminary 

 and incentive character published many years ago by 

 the naturalists and pioneers of the Indian Marine 

 Survey, but, except that some doubtful identifications 



