452 



NATURE 



[September 8, 1904 



of species so few details that in its present form it is 

 of little value. This may be the fault of the subject 

 rather than of the authors, but had an attempt been 

 made to give a key-index to the species and their 

 recognition, this would have been of much use. With 

 these reservations, the authors are to be congratulated 

 on having produced a work which must for some time 

 to come remain the standard one on the subject. 



The tubercle and acid-fast bacilli met with in milk 

 and the biology of the tubercle bacillus are fully and 

 adequately treated, and a number of coloured and other 

 illustrations of cultures and colonies are given which 

 will be of the greatest service to those who are unable 

 to consult original papers. As regards the relation of 

 bovine and human tuberculosis, a judicial and judicious 

 summary is given, and the authors express the pro- 

 visional opinion " that tuberculosis in all animals is 

 generally one and the same disease, but that it differs 

 in various ways in different animals and according to 

 the strain and virulence of the infecting bacillus. 

 That human tuberculosis can be transmitted in 

 certain circumstances to animals we do not doubt. 

 There is also prima facie evidence to show that the 

 reverse proposition is true, name!)', that under certain 

 conditions bovine tuberculosis is transmissible to man. 

 We therefore look upon the two diseases as different 

 species or varieties of one and the same generic disease 

 and intercommunicable. Whilst we hold this view in 

 respect to the communicability of tubercle, we do not 

 for one moment suppose that its transmission through 

 milk is very frequent or very widespread. The great 

 field of infection in tuberculosis is from animal to 

 animal, and from man to man, and cross-infection is 

 probably less common than is generally supposed." 



This opinion practically coincides with that expressed 

 in the recent report of the Royal Commission on 

 Tuberculosis. Dealing with outbreaks of epidemic 

 disease due to an infected milk supply, scarlatina, 

 enteric fever, diphtheria, epidemic diarrhoea, cholera, 

 &c., receive attention, and the details of many of the 

 principal outbreaks are summarised. As regards the 

 celebrated Hendon outbreak of scarlatina, the whole 

 of the facts is stated, and not a portion only, as is 

 generally the case, and the authors conclude, " we 

 are of opinion that the exact origin of the London 

 epidemic at that time has not yet been, and now prob- 

 ably never will be, demonstrated." It is to be hoped 

 that future writers on the subject will note this. 



The last portion of the book deals with the control 

 of the milk supply (a) by the State, and (b) by private 

 enterprise, with useful appendices on legal enactments 

 and model regulations for dairies, &c. The summary 

 on milk legislation in the various countries of the 

 world is especially to be commended. Tuberculin is 

 touched upon, and tlie old and the new tuberculins 

 are described, but no mention is made that it is the 

 old tuberculin which is employed for cattle testing. 

 The sections dealing with pasteurised and sterilised 

 milk are very brief, and might well be expanded in a 

 future edition, while condensed milks seem to be un- 

 noticed. The book is well produced and illustrated, 

 but the index might with advantage be fuller. 



R. T. Hkwlett. 

 .\'0. 1819, \OL. 70] 



OUR BOOKSHELF. 



Handbook to the Natural History of Cambridgeshire. 

 Edited by J. E. Marr and .\. E. Shipley. Pp. viii + 



260 : (Cambridge : University Press, 1904.) Price 

 4i. net. 

 The little volume before us affords an excellent 

 example of the thorough-going and careful manner 

 in which every detail connected with the late 

 meeting of the British .Association at Cambridge was 

 thought out and worked out by the responsible 

 executive. .\s a matter of fact, the volume in question 

 is likely to be much more than a mere ephemeral 

 production, and will probably take its place as one of 

 the standard text-books in the scientific teaching of 

 the university ; for it will scarcely be disputed that a 

 thorough knowledge of the natural history of the 

 district in which tlie student resides is one of the very 

 best aids towards attaining a comprehensive grasp of 

 biology and geology in general. The term natural 

 history, it should be mentioned, is employed in this 

 work in its very widest and most extensive sense, 

 embracing not only zoology and botany, but likewise 

 geology and palaeontology ; while the scope of the 

 undertaking is still further increased by an excellent 

 chapter on prehistoric archaeology. 



For the planning and supervision of a work of this 

 nature no better editors could possibly have been found 

 than Messrs. Marr and Shipley, the one gentleman 

 being an eminent authority on geology in general, and 

 that of the district in particular, while the other is 

 no less distinguished as a biologist. Dr. Marr, in 

 collaboration with Mr. Fearnsides, has contributed the 

 introductory chapter on physiography, but Mr. Shipley 

 has contented himself with purely editorial functions. 

 For the other chapters of the work the editors have 

 been fortunate in securing the (gratuitous) services of 

 a number of specialists, at least two of whom happened 

 to be engaged on the natural history of Cambridge- 

 shire for the "Victoria County History," and were 

 permitted by the council of that undertaking to 

 make use of their labours for the benefit of the volume 

 before us. Hitherto no complete lists of the fauna of 

 Cambridgeshire appear to have been published, and 

 Mr. H. H. Evans's account of the birds of the county 

 may be cited as an excellent example of the manner 

 in which such local faunas should be described. It 

 was somewhat unfortunate that in the account of the 

 vertebrate palaeontology of the county the introduction 

 of a personal element was unavoidable ; but the pro- 

 posal contained therein, to name a species after the 

 well known palseontologist whose work is criticised, 

 may be taken as an indication of the absence of any 

 trace of ill-feeling on the part of the writer. 



Both editors and authors are to be congratulated 

 on the production of such an excellent and compre 

 hensive local " natural history " in such a smal 

 compass, the permanent value of the work being 

 largely increased by the beautifully coloured geological 

 map of the county. R. L. 



Thcorie der Elektrizitat und des Magnetismiis. By 



Dr. I. Classen. Band i. Electrostatik und Electro- 



kinetik. Pp. x+184. (Leipzig: G. J. Goschen, 



1903.) 

 The conventional text-book of electricity starts with 

 the supposition that the forces exhibited by electrified 

 bodies can be attributed to a something called 

 electricity which resides on material bodies. Quanti- 

 tative laws are developed, and we are led up to the 

 Faraday-Maxwell conception of the medium as the 

 real seat of electrical action. 



Prof. Classen, like many others, finds this method 

 unsatisfactory. The first view presented is too narrow ; 

 its arbitrary character cannot always be realised, the 



