4 s 4 



NA TURE 



[March 26, 1903 



been relegated to the category of merely commercial 

 designations, the rating bearing no more precise rela- 

 tion to the real thing than does the term ' best ' as 

 applied to flour or other commodities," a description 

 fully realised when one sees a nominal iooo candle- 

 r arc blinking with a feeble 200 candle-power 

 duty. 



The book is so good, and deals with such a little 

 studied subject, that it is to be hoped that the author 

 will add to the value of the work in its next edition by 

 cither giving full references to the original papers or 

 adding a short bibliography! It is undoubtedly a book 

 which should take its place as a work of reference 

 in the library of everyone interested in artificial illu- 

 mination. 



PHYSIOLOGICAL HISTOLOG\. 



Methods and Theory of Physiological Histology By 



Gustav Mann, M.D., CM., D.Sc. Pp. xv~+ 488. 

 (Oxford : Clarendon Press, 1902.) Price 15^. net. 



\ FIRST attempt at scientific research in a new field 

 ■f*- should always command our respect, and this book, 

 professing to expound the methods of physiological 

 histology with their underlying reasons, is no exception 

 to the rule. The author has with incredible labour col- 

 lected all the current information on physical chemistry 

 colloids, histology and the chemistry of dye-stuffs, and 

 has endeavoured to combine these into one harmonious 

 and coherent whole, and to deduce from them reasonable 

 answers to all the questions that have arisen on the 

 subjects of the fixation and staining of animal tissues. 

 That the explanations of the observed facts in histology 

 have so far been fragmentary, incomplete and unsatis- 

 factory, no one will deny, and if this work has hardly as 

 yet brought us to a final and definite conclusion, the fault 

 must be laid to the door of our collective ignorance of 

 the matters involved rather than to the writer of the 

 present volume. 



A considerable space has been allotted to subjects 

 which bear more or less directly on the theories after- 

 waids propounded, and, as a rule, these are admirable 

 summaries of the work already done. The chapter on 

 colloids is especially worthy of praise. The chapters 

 containing the accounts of the author's own carefully 

 performed experiments are also very interesting, though 

 whether all his readers will or will not agree with his 

 conclusions is quite another matter. However, there is 

 no question as to the success of the fixing fluids which 

 have been proposed as a result of these researches, and 

 the practical directions accompanying them will be of 

 value to everyone who is not familiar with the processes 

 employed. This comment applies also to all the methods 

 recommended for staining, which give the result of a 

 long and thorough experience in the various processes, 

 and, speaking generally, we know of no better practical 

 guide than is to be found here. 



Then follow pages — very many pages — devoted to 



microchemical reactions, the theory of staining, and, as 



an appendix one-third as large as the book, on the 



chemistry of the coal-tar colours and similar matters, 



NO. 1743, v OL. 67] 



which space will not permit us to refer to at length. 

 They will well merit careful study, but the question 

 obtrudes itself as to whether the author has not gone a 

 little too far afield, and whether it is really necessary to 

 cover so many pages with chemical details already well 

 known to experts and unintelligible to the ordinary 

 reader without their context. 



We regret that the author's modesty has not permitted 

 him to add some account of intra-vilam staining and 

 the examination of fresh tissues ; we trust that in the 

 future he may see his way to do so. 



There are singularly few details to which exception 

 can be taken, and small errors and misprints are con- 

 spicuously absent. The paper and general appearance 

 of the book are, however, surely too meagre for the 

 importance of the contents, and drawings of the author's 

 preparations would be vastly more interesting than the 

 illustrations of obsolete microtomes with which we are 

 favoured. One page — 460 — must have been composed 

 during a nightmare ; we cannot imagine it represents the 

 author's real views. It purports to treat of electrical 

 measures. The ampere is defined as "a current which 

 passes in every second at the rate of one coulomb through 

 a conductor " ! Ohm's law has a whole line to itself, 

 and is thus printed : — "Ohm's law = 



electromotive force 

 resistance 



ampere 



volt „ 

 ohm 





It is very kind to tell us what a " macrocallory " is ; we 

 might otherwise have supposed it to be a kind of eel ; in 



neither case is it a unit of electricity. Also but we 



decently conceal the rest. 



There is a very good index, and as a whole the book 

 is one that is a most valuable contribution to our know- 

 ledge of physiological histology. 



OUR BOOK SHELF. 



Tin- Figures, Facts, and Formulae of Photography. 

 Edited by H. Snowden Ward. Pp. 166. (London : 

 Dawbarn and Ward, Ltd., 1903.) Price is. net. 



There is probably no other art that is so encumbered 

 with formulas as photography. Every maker of sensi- 

 tive material seems to consider it his duty to supply his 

 own particular formulas for its use, and no doubt this 

 has something to recommend it, but even conveniences 

 may be multiplied until they result in confusion. Many 

 formula for developers, for example, differ only in the 

 methods of expressing them, except to an inappreciably 

 small extent due to the use of different weights and 

 measures. And when it is borne in mind that by far 

 the greater number of formulae are not based on a 

 systematic trial of the effects of varying each of its 

 constituents, as all ought to be, the value of even 

 notable differences disappears. 



But to eliminate useless formulas is practically im- 

 possible, as it would introduce differences of opinion 

 as well as of fact. We think, therefore, that the com- 

 piler of this volume has done quite right in including 

 the " instructions " of the various manufacturers, and 

 we should have preferred that he had gone even further 

 than he has, and given the formulas recommended bv 

 foreign as well as English houses. Of other formulas 

 for developers, we find those adopted by Messrs. Bur- 

 roughs Wellcome and Co. for their " tabloid " pre- 

 parations described as " standard " formulas, though 



