March i8, 1920] 



NATURE 



67 



It is difficult, however, to recommend the book 

 for g^eneral use in schools. Attention has been 

 directed on several occasions to defective figures; 

 in elementary mathematical text-books. In Mr. 

 Milne's book the fault exists in an accentuated 

 degree. No attempt seems to have been made to 

 co-ordinate the diagrams and the letterpress, 

 whilst many of the diagrams printed on squared 

 paper contain actual mistakes. These criticisms 

 apply to diagrams on pp. 3, 34, 35, 36-37, 38, 53, 

 55. 58, 59, 63, 72, 74, 88, 92, 120, 123, 128, 129, 

 143 (a very bad case), 147, 148, 155, 157, 166, 

 179. It is surely not right to place such diagrams 

 before young students. 



If the book were re-issued with correctly drawn 

 diagrams, it would constitute a valuable addition 

 to school and college text-books. 



S. Brodetskv. 



Our Bookshelf. 



I'he British Journal Photographic Almanac and 

 Photographer's Daily Companion, 1920. Edited 

 by George E. Brown. Pp. 912. (London : 

 Henry Greenwood and Co., Ltd.) Price 15. 6d. 

 net. 

 Although this volume has not quite reached its 

 pre-war bulk, it has gone a long way towards 

 it, and appears to be now lacking only a little 

 in its former plethora of advertisements. Un- 

 favourable conditions still hold, but the editor 

 has been able to restore the tables, formulae, and 

 other technical details that photographers have 

 for so many years been in the habit of consulting 

 in their daily work. The " Epitome of Progress " 

 is a good summary of the novelties of the past 

 year, and there is, we think for the first time, 

 a " History in Brief of Photographic and Photo- 

 mechanical Processes." The nine pages devoted 

 to this subject will be of special interest to 

 the student, for they give the dates of a 

 very large number of important facts con- 

 nected with •the development of photography, 

 starting from the very beginning. We notice 

 that sensitol red and sensitol green are ascribed 

 to Prof. Pope in 1917. We always thought 

 that these were pinacyanol and pinaverdol, 

 respectively, of German origin some years 

 previously, and that to Prof. Pope was due the 

 credit of preparing them in this country, and also 

 of introducing sensitol violet, which, however, 

 does not appear to be mentioned. The section 

 on "Beginners' Failures in Photography," by the 

 editor, deserves much appreciation. C. J. 



Toxines et Antitoxires. By M. Nicolle, E. C6sari, 



and C. Jouan. Pp. viii-f-123. (Paris: Masson 



et Cie, 1919.) Price 5 francs net. 



M. Nicolle holds such a high place among those 



who have made contributions of real importance 



to our knowledge of parasites that it seems a 



NO. 2629, VOL. 105] 



pity he should put out this disorderly summary 

 of some of the researches of himself and his col- 

 laborators. It reads like a bundle of notes that a 

 man might make to define the current position of 

 his investigations, and to settle which piece of 

 work he should take up next. With trivial excep- 

 tions M. Nicolle reviews no facts but those of his 

 own discovery, and it is impossible to distinguish 

 between conclusions and hypotheses. He points 

 out, for example, the similarity of symptoms and 

 anatomical lesions produced by various toxins of 

 different origins, and the diversity and specificity 

 of the antibodies which result from their intro- 

 duction into the animal economy. He therefore 

 concludes that toxins consist of two parts, one 

 poisonous and not an antigen, the other inactive 

 and an antigen. This is no more than a pos- 

 sibly fruitful hypothesis on which to base further 

 experimentation. Those who know the subject 

 well might run through the book with advantage ; 

 others had better leave it alone. A. E. B. 



Some Wonders of Matter. By the Right Rev. 

 Dr. J. E. Mercer. Pp. 195. (London : S.P.C.K. ; 

 New York: The Macmillan Co., 1919.) Price 

 55. net. 



Bishop Mercer writes for children, and in a 

 manner in accordance with the Child's Guide of 

 our grandparents rather than with modern educa- 

 tional ideals. His primary concern is to excite 

 the naive wonder which he considers so valuable; 

 so he makes no selection, but ranges apparently 

 at random from Pharaoh's serpents to Browniam 

 motion without giving any clue to the relative 

 importance of the very varied matters at whicb 

 he glances. So wide a range in so small a space- 

 would tax severely the highest powers of exposi- 

 tion, and Bishop Mercer has not the genius for 

 happy analogy that is characteristic of all the 

 most successful writers for the young. Again, 

 though the work is free from serious error, wc 

 judge that its author has not a first-hand acquaint- 

 ance with science. If he had, he would scarcely 

 puzzle the brains of his small charges (and inci- 

 dentally that of the reviewer) by raising questions 

 no serious student of science would ask — those, 

 for example, which give rise to the paradoxes of 

 Berkeleyan idealism. On the other hand, some 

 parents will welcome the definitely religious tone 

 and be gratified that the Divine Intelligence is 

 presented in a form sympathetic to the. simplest.. 



An Arithmetic for Preparatory Schools. With 

 Answers. By Trevor Dennis. Second edition, 

 revised. (Bell's Mathematical Series.) Pp. 

 xiv + 376. (London: G, Bell and Sons, Ltd., 

 1919.) Price 4.">. 6J. 

 Mr. Dennis's "Arithmetic" well deserves 

 the second edition which it has reached. The 

 sequence is based on the syllabus of mathematical 

 teaching for ages nine to sixteen, for non- 

 specialists, issued by the Curriculum Committee of 

 the Headmasters' Conference. Suitably chosen 

 exercises and clear type make the book well 

 adapted for the students for whom it is intended. 



