64: 



NA TURE 



[October 31, 189- 



remain fruitless for an indefinite time. The application 

 of meteorology- to related subjects in general, and to 

 hygiene in particular, may thus be considered doubly 

 welcome. 



Mr. MacDowall's primary object, in the publication 

 before us, is to represent the variations which certain 

 elements of the weather, and the mortality from certain 

 common diseases have undergone during recent years, 

 and it may be to find a connection between the two. 

 The mode of representation which the autlior has 

 adopted is the one now commonly in use of plotting 

 cur\'es on ruled paper, by adjoining points, the ordinates 

 of which are determined by the two quantities to be 

 related, one of which generally refers to date. These 

 curves have as a rule been subjected to a process of 

 smoothing, which, by recording the average of e\ery five 

 or ten (as the case may be) consecutive values, eliminates 

 the fluctuations of short duration, while preserving the 

 more gradual and lasting variations. The great advantage 

 which this method possesses is, it is hoped, to enable 

 the eye at once to detect the more salient features of a 

 general tendency, without the mind being distracted by a 

 mass of details which may be, for the purpose in 

 view, absolutely useless. In this way, within the compass 

 of some twenty curves, the author exhibits the general 

 tendencies which have controlled the principal and most 

 interesting features of the weather : while a further sixteen 

 cur\es show the fluctuations which have taken place in 

 the most important zymotic diseases. 



If we have any fault to find with a \try excellent 

 purpose, on the whole admirably carried out, it would 

 be to remark that the cur\'es would be better if drawn 

 on a larger scale. This would have increased the expenses 

 of production, but the result would be clearer. It would 

 have been of advantage, too, if the numerical details, from 

 which the cur\es have been drawn, had been given ; then 

 any one interested in a particular inquiry could have easily 

 constructed the cur\ e to any desirable scale. This point is 

 of particular importance if the reader wishes to know 

 what is the "probable error" of any point on the smoothed 

 cur\-e, or, in other words, what is the degree of reliance 

 to be placed upon the process of smoothing. For instance, 

 a comparison is instituted, or at least suggested (p. 63) 

 between the curves representing the mortality from 

 (liarrhrca and dysentery, and that showing the mean 

 temperature for July at (ireenwich. There is apparently 

 some resemblance between the two, but the probable 

 error of either curve may be greater than this apparent 

 agreement. If the solution of a system of equations of 

 condition, to which these curves may be compared, 

 yield the quantity sought, accompanied by a probable 

 error as large as the unknown itself, great hesitancy is 

 experienced in accepting the result as a satisfactory 

 solution. 



Mr. MacDowall's aim is apparently a modest one : 

 for the most part he is content to leave his graphic repre- 

 sentations of both kinds of records to speak for them- 

 selves, and invites the reader to study them independently, 

 and to follow up any point which they may suggest. The 

 author's own notes arc not copious, but they arc clear, 

 interesting, and concise. .Some of the curves, too, are 

 very instructive. The opponents to compulsory vacci- 

 nation will not find much to support their views in the 

 NO. 1357, VOL. 52] 



curve tracing the mortality from small-pox through the 

 last two centuries. The steady and consistent improve 

 ment in the twenty years following the introduction of 

 vaccination, in 1798, pleads eloquently in favour of the 

 process. The great decrease shown in the number of 

 deaths from scarlet fever may be misleading, if it be not 

 compared with the sad and alarming increase in the 

 mortality from diphtheria. Previous to 1S59. these two 

 diseases were not separately registered in the Registrar 

 General's Reports ; but if the two curves be combined, 

 the mortality from neither has conspicuously varied. 



The book, small as it is, appears to have been care- 

 fully compiled, and must have involved a considerable 

 amount of labour in its production. It should certainly 

 be consulted by those who are interested in the relations 

 between meteorology and hygiene. W. E. P. 



OUR BOOK SHELF. 



Popular History of Aiiiinals for Voung People. Hy 

 Henry Scherren, F.Z.S. Pp.376. (London : Cassell and 

 Co., Limited, 1895.) 



Wh.\t would have been said a few years ago of a popular 

 history of animals of which the opening chapters were 

 devoted to man and his resemblance to other members 

 of the Order Primates.' In the days when it was the 

 fashion to place man in a separate order of Bimana, 

 while the man-like apes were called Quadrumana, the 

 mere idea of including the human race in the aninml 

 kingdom would have raised a storm of indignation. 

 Yet here we have a book, intended for a popular public, 

 in which the principle of relationship is fully recognised, 

 and man is assigned his proper place in nature. Thus 

 do the scientific ideas which are anathema of one genera- 

 tion become the accepted truths of the next. 



One of the features which distinguish this book from 

 most of the legion of popular works on natural history 

 published in recent years, is that common names of 

 animals are used throughout, and no attempt is made 

 to familiarise the reader with the nomenclature of scientific 

 zoology. This fad will endear the book to all who like 

 to learn a little about the habits of animals, but have 

 no desire to know any details. For such readers the 

 present volume is admirably suited ; it is full of read- 

 able anecdotes about animals, and is illustrated with 

 thirteen coloured plates, as well as numerous figures in 

 the text. Most of the illustrations, both coloured and 

 plain, are old friends, but a few have been reproduced 

 from photographs. We think the volume will be suc- 

 cessful as a pri/e-book and as a book for general 

 readers. 



Simple Methods for Deteeting Food Adiilteralioii. Hy 

 J. .A. Bower. Pp. 118. (London: Society for Pro- 

 moling Christian Knowledge, 1895.) 



The author describes a number of simple tests for de- 

 tecting common adulterations in articles of food. In the 

 main, the tests described ran only be carried out by 

 means of a fairly good microscope, so they are quite 

 beyond the ordinary householder initil he provides him- 

 self with such an instrument, and educ.ites himself in 

 the use of it. Of the thirty-six illustrations in the book, 

 twenty-eight represent microscopic views of various sub- 

 stances, .and it will l)c of little use for any one to set 

 .about detecting fraud until he is perfectly familiar with 

 the varying appearances exhibited not only in the illus- 

 trations, but by actual specimens mounted on slides. 

 Possibly the book will induce young people to determine 

 specific gravities, ,-ind make other simple observations ; 

 and if it does that, it will justify its existence. 



