52 



NA TURE 



[May 2 1, 1896 



raising the standard of the articles made, and at the same 

 time of improving' the prosperity and health of those who 

 are eni])loyed in making them. The volume now before 

 us shows the application of science to the art of liread- 

 making, and a glance at its size and contents will at once 

 show all those who are entering into this business that 

 there is a very large amount of scientific knowledge 

 required to equip a man efficiently to succeed in the 

 keen competition of the present day. 



The chemistry of the subject is very fully dealt with, 

 with valuable suggestions for practical work ; and we 

 have also a chapter on bacteriology, in which the history 

 of our present knowledge of fermentation is clearly given 

 up to date. Fermentation is, of course, an important 

 process in bread-making, and a chapter on technical 

 researches in this subject is given. The use of the 

 microscope is also pointed out in the examination of 

 different starches, &c. In addition to these principles, 

 which may be said to form the groundwork of the 

 subject, the more practical side also finds a place, such 

 as commercial testing of wheat and flours, different 

 methods of baking, both by machinery and otherwise ; 

 and, lastly, there are a few paragraphs on adulterations 

 and the methods for recognising them. Numerous good 

 illustrations are scattered throughout the book. This 

 work will doubtless appeal to all those connected with the 

 business of bread-making, and we imagine it will also 

 find a place on the book-shelves of many medical and 

 other scientific men. 



LETTERS TO THE EDITOR. 

 \The Editor does 710I hold himself responsible for opinions ex- 

 pressed by his correspondents. Neither can he undertake 

 to return, or to correspond with the writers of, rejected 

 manuscripts intended for this or attv other part of NATURE. 

 JVo notice is taken of anonymous coininiinicatious.'\ 



Koch's Gelatine Process for the Examination of 

 Drinking Water. 



Dr. Edward Franki.and, in a discourse delivered at Ihe 

 Royal Institution on February 21 (see Nature, April 30), paid 

 a just tribute to the work of the late Dr. Angus Smith, for he 

 stated that Dr. Koch's invention was first made known and 

 practised in England in 1882 by Dr. Angus Smith. 



On the other hand, Dr. Percy Frankland has put forward a 

 claim, in his work on " Micro-organisms in Water" (page 119), 

 that Koch's method was introduced into this country by himself 

 —a claim reiterated in his evidence before the Royal Com- 

 mission on Metropolitan Water Supply at Question 1 1099 (Prof. 

 Dew^ar). " I believe you tell us that you were the first jjerson 

 in this country who adopted the Koch method, and applied it 

 to the London Water Supply?" " Yes, thai is so." 



As I was scientific assistant to the late Dr. Angus Smith, and 

 worked with him on Dr. Koch's gelatine method, I should lilce 

 to state tliat not only was the method applied by Dr. Angus 

 Smith to the London Water Supply in February 1S83, but also 

 to a variety of waters from different parts of tlie country. The 

 results of Dr. .'\ngus Smith's work are to be found in the second 

 Report of the Local Government Board R. P.P. Act, 1876. 



Ellerslie, Alderley Edge, May 6. Frank Scudder. 



I AM much indebted to Mr. Scudder for furnisliing an oppor- 

 tunity for calling attention to a misapprehension which appears 

 fo exist in some quarters as to the time and manner in which Dr. 

 Ixoch's method of water examination by the process of gelatine- 

 I'late-cullure was introduced into this country, as but for his 

 letter I .should not have thought it worth while to discuss a matter 

 which must he sufficiently well known to all who are really 

 conversant with the development of bacteriological inquiry in 

 (ireat Britain during the past fifteen years. In the first place, 

 I would point out that in making the statements referred to 

 by Mr. Scudder, I did so with the full cognisance of the late 

 Dr. Angus Smith's work as published by him in his second 

 Report to the Local Government Board, and in an article of his 

 which ap])eaied in the Sanitary Record in 1883. In this wiirk 

 I was so much interested that I at once, in the same year, set 



NO. 1386, VOL. 54] 



about applying the method described by Dr. Angus Smith to 

 a number of the samples of London and other waters which 

 were being subjected to analysis in my private house at the 

 time. These experiments yielded, however, such indefinite and 

 unintelligible results that I entirely abandoned Dr. .Smith's 

 process, and it was not until the sununer of the following year 

 (l884)th.at I became really acquainted with Koch's method of 

 plate-cuUivaling bacteria through the now classical demonstra- 

 tions given by .Mr. Watson Cheyne at the Health Exhibition. 

 It was this method of gclatine-plate-cuUure which I then im- 

 mediately applied to the investigation of a number of problems 

 connected with the bacterial purification of water by filtration, 

 precipitation, cVc, both on the laboralDry and on the industrial 

 scale, and the results of which I placed in the hands of the 

 Royal Society in May 18S5, in a paper entitled " The Removal 

 of Micro-organisms from Water." It is this paper which I 

 believe to be the first puljlished account in this country of the 

 application of what is now universally understood as " Koch's 

 gelatine-plate-process " to the examination of water, and the 

 first to contain numerical determinations of the bacteria present 

 in a given volume of the various waters supplied to London. 

 In the autumn of the same year (1885) I undertook, at the 

 request of the late Sir Francis Bolton, then Water Examiner 

 for the Metropolis, to make for the Local Government Board 

 regular monthly examinations by this process of the various 

 waters, both before and after filtration, supplied by the several 

 London Water Companies, and the results of these were regularly 

 published in the monthly reports issued by the Local Govern- 

 ment Board. 



That I do not stand alone in viewing Dr. Angus Smith's 

 method and that of Dr. Koch as distinct, will be apparent from 

 the following words, extracted from Dr. Smith's above-mentioned 

 Report to the Local Government Board : — " I do not know, 

 even now, if I employ the method which Dr. Koch would con- 

 sider the best, but the book on the subject promised by himself 

 and his coadjutor not having appeared, I consider myself 

 liberty to proceed with my inquiries" ; and in point of fact, if 

 any competent bacteriologist will take the trouble to read Dr. 

 Angus Smith's report, he will see that although both processes 

 of course involve the use of gelatine, they are in many important 

 respects widely divergent. In the first place, the medium 

 employed by Dr. Angus .Smith contained gelatine only, and was 

 destitute of the nutrient constituents — meat-broth and peptone; 

 so that the appearance of colonies in his process would thus 

 partly depend upon the chemical composition of the water, a 

 condition of things which tends to defeat the object in view, 

 viz. the discovery of the living as distinguished from the dead 

 and unorganised matter in the water. Indeed Dr. Angus Smith 

 distinctly deprecates rendering the medium more nutritive, e.g. 

 by the .addition of sodium phosphate .and sugar, which he 

 employed in some of his experiments. On the other hand, one 

 of the cardinal principles of Koch's method is the use of as 

 highly nutrient a medium as possible, so as to render the cultiva- 

 tion results alisolutely independent of the chemical composition 

 of the water. Again, of fundamental importance in the Koch 

 method is the cultivation in such a thin stratum of the solid 

 medium that all parts of it shall be pr.actically under identical 

 conditions and plentifully supplied with oxygen. Dr. Angus 

 Smith, on the other hand, cultivated in test-tubes eight inches 

 in depth, and the disadvantage of this he appears to have him- 

 self realised, as he points out that the cultures of very impure 

 waters suffer from want of oxygen in the depth, and thus lead to 

 erroneous results. In fact I have failed to find in Dr. Angus 

 Smith's publications any mention whatsoever of cultivation on 

 plates or their e(iuivalents in any shape or form, which I hold to 

 be the essence of the process which bears the name of Koch, and 

 to which modern bacteriology is so jjrofoundly indebted. 

 Without, therefore, in any way wishing to detract from the 

 interest attaching to Dr. Angus Smith's independent investiga- 

 tions on the application of gelatine to water examination, it 

 appears to me that as he seems not to have been acquainted 

 witli what is known and described in text-books as Koch's 

 method of water examination, he cannot obviously be said to have 

 introduced it info this country. Indeed, I cannot personally find 

 any more justification for the statement that Dr. Angus Smith 

 practised Koch's method of gelatine-plate-culture in 1882, than 

 there would be for saying that Hero drove a steam locomotive in 

 Alexandria more than a century before the Christian era. 



Percv F. Frankland. 

 Mason College, Birmingham, May 12. 



