246 



NATURE 



[July 16, 1891 



and the author [proceeds to deal with the carbides of 

 iron, and finally with the well-defined carbides of nio- 

 bium and tantalium, which have respectively the formulae 

 NboCj and Ta^Ca. 



A terse description is then given of the work of Troost 

 and Hautefeuille on the heat of formation of carbides of 

 iron and manganese, which led to the conclusion that the 

 union of carbon and iron is attended with absorption of 

 heat, while in the case of the union of carbon and man- 

 ganese heat is evolved, the evidence leading to the 

 belief that MngC is a true compound possessing con- 

 siderable stability. The action of heat on carbides is 

 then dealt with, and a brief, but sufficient, reference is 

 made to Forquignon's work on the action at a high tem- 

 perature of hydrogen on cast-iron. The section concludes 

 with a description of the modes of preparing carbides, 

 and with a sketch of the formation and properties of 

 the nitrocarbides, more especially those of niobium and 

 titanium. 



The sections of the work devoted to the consideration 

 of tellurides, arsenides, and antimonides, are equally 

 good. With regard to individual metals, in the portions 

 of the work as yet published, only potassium, rubidium, 

 caesium, ammonium, thallium, sodium, lithium and the 

 metals of the alkaline earths, barium, strontium, and 

 calcium are dealt with, but sufficient evidence of the 

 merits of the book has been given in this brief review 

 to show that the rest of it will be gladly welcomed, for 

 Prof. Ditte has earned his place among the great metal- 

 lurgists of France. 



We should be grateful for curves indicating the effect 

 of definite elements on the physical constants of metals. 



Baron Jonstorff's book is of an entirely different cha- 

 racter, though it is not, in its way, less excellent or useful. 

 He says that it issues from an ironworks, and is addressed 

 to practical metallurgists. Its aim is, however, somewhat 

 different from that of most treatises on analytical che- 

 mistry, the author's intention being not merely to guide 

 the chemist in his analytical methods, but to enable a 

 blast-furnace manager or an iron-master to realize what 

 kind of services the laboratory can render, what questions 

 relating to the routine of work the analyst can solve, and, 

 above all, in what way the questions should be put. 



The author deals with the more important special 

 methods of analysis, and of assaying iron and steel, and 

 he gives due attention to the examination of refractory 

 materials — slags, fuel, and gaseous products — and his 

 method is singularly clear and precise. An appendix 

 gives tabular statements which will be useful in daily work. 



The book, as a whole, shows incidentally the great 

 difference between the works-laboratory of the present 

 day and that of twenty years ago. There is still much 

 room for improvement, no doubt, but the laboratory of an 

 ironworks has, in many cases, ceased to be little better 

 than a shed, erected, say, behind the boiler-house, with an 

 analyst and a few boys as the scientific staff. 



Those who have visited the author in his beautifully 

 situated Styrian works, and have seen his manipulation, 

 as the reviewer has, will appreciate the excellence of his 

 labours, and will be glad that a good translation into 

 French will make their results more generally known. 

 W. C. Roberts-Austen. 

 NO. 1133, VOL. 44] 



BACTERIA AND THEIR PRODUCTS. 

 Bacteria and their Products. By Sims Woodhead, M.D. 



Published in the "Contemporary Science Series." 



(London: Walter Scott, 1891.) 

 OCARCELY a year passes in England, France, or in 

 ^ Germany, without the publication of one or more 

 treatises on the fascinating subject of bacteriology. 

 Many of the more recent of these works have been 

 written for the general reader rather than for the student, 

 and have shown a considerable want of accuracy and 

 lucidity, a circumstance which can only be accounted 

 for by the fact that accomplished bacteriologists have 

 not been their authors. 



We have now before us " Bacteria and their Products," 

 a work which we might infer from a glance at the cover, 

 and general arrangement, to be certainly intended for the 

 general reader. This view is strengthened by the several 

 object-lessons and homely similes scattered "throughout 

 the text, with the fitness of which we totally disagree ; 

 witness, for example, the extraordinary comparison of a 

 nodule of Actinomyces with two daisy heads placed 

 base to base, " the sterile flowers in the centre " then 

 corresponding to the club-shaped rays. The comparison 

 is bad, but the botany is worse. Then there is the not 

 very abstruse mathematical problem on p. 24, and the 

 guide-like description of the Pasteur Institute, all in- 

 tended, we must conclude, for the general reader rather 

 than for the student. 



On the other hand, there is a very large collection of 

 facts, much information about fermentation and che- 

 mistry (although the interesting and oft-quoted experi- 

 ments of Raulin are omitted), numerous references, and 

 a very plentiful supply of formulae, the whole requiring, 

 in order to understand and appreciate them, a reader 

 equipped with a thorough knowledge of the sciences 

 bearing on the subject. 



Putting this question aside, however, we candidly con- 

 fess that we do not admire the style or arrangement of 

 the book. There is a conspicuous want of lucidity, and 

 of that accuracy of observation which one would have 

 expected of the author. For instance, "What are Bac- 

 teria? "is the question propounded in chapter ii. ; but 

 the answer to this key-stone question is left in much 

 doubt, as the description of the protoplasm, cell mem- 

 brane, mode of division and reproduction of the " specks," 

 is exceedingly confused. We should not choose Gram's 

 method to demonstrate the capsules of Actinomyces, 

 nor, indeed, any other capsules ; and we have reason to 

 doubt, after the beautiful monograph on Cladothrix by 

 Billet, that the brown colour of that organism is due to 

 iron. Again, what does the author mean when, speaking 

 of cilia, he says, they " appear to develop only in those 

 organisms that have special affinity for oxygen, for, as 

 soon as the ciliated forms reach the surface of a fluid, 

 they lose their cilia or they become much less active,'' 

 &c. 1 Tables of classification are heaped in with scarcely 

 any attempt to sift and reduce them to a form compatible 

 with the scope of the book. Is this done because, as the 

 author says (p. 47), " to the pathologist, however, these 

 classifications are of comparatively little value"? We 

 maintain that for a work of this kind the author has no 

 right to take a one-sided view, and that to the science of 



