NATURE 



513 



THURSDAY, OCTOBER i, 1891. 



THE BACTERIOLOGICAL EXAMINATION OF 

 WA TER. 



Manuel Pratique d^ Analyse Bacteriologique des Eaux. 

 Par le Dr. Miquel. (Paris : Gauthier-Villars et Fils, 

 1891.) 



THERE is probably no body of scientific men amongst 

 whom national feeling and prejudice are so little 

 under control as the workers in the domain of bacterio- 

 logy. In perusing memoirs, text-books, dictionary-articles, 

 and literature of every kind bearing upon this infant 

 science, the reader must almost invariably take into con- 

 sideration the language in which they are written, more 

 especially whether German or French; and if the author 

 belongs to neither of these rival nationalities, it is not 

 unfrequently desirable to ascertain in which of the two 

 camps he has been educated, for, unless this be made 

 allowance for, a warped and often erroneous impression 

 will be carried away. 



The present work certainly forms no exception to this 

 state of things ; indeed, this phenomenon of party-spirit 

 is regrettably prominent. Thus, in reading one of the 

 first paragraphs, beginning with " Les premieres statis- 

 tiques relatives a la richesse bacterienne des eaux furent 

 publides par moi," and, indeed, throughout these pages we 

 are reminded of the words of the deeply lamented savant 

 who commenced his monumental work with " La chimie 

 est une science fran^aise," and perhaps even more of the 

 famous utterance, " L'^tat, c'est moi ! " 



Dr. Miquel's treatise, consisting of 194 pages, is divided 

 into five chapters, dealing respectively with (i) the col- 

 lection of samples, (2) the transport of the collected water, 

 (3) the quantitative analysis, (4) the qualitative analysis, 

 (5) the interpretation of the results obtained. On these 

 subjects Dr. Miquel should be well qualified to write, 

 because, as he informs us, it is only in his laboratory at 

 Montsouris that the bacteriological examination of water 

 has been carried on over a period of eleven years. In- 

 deed, we know of no bacteriologist who has so entirely 

 devoted his attention to the subject of micro-organisms 

 in air and water as Dr. Miquel, whose name is so in- 

 separably connected with "les organismes vivants de 

 I'atmosphere." His energies have, however, apparently 

 not been so successfully directed to the aquatic as to the 

 aerial microbes, for we do not connect Dr. Miquel's name 

 with any of the more important advances that have been 

 made in our knowledge of the bacteria in water during 

 the past ten years. The comparative sterility of Dr. 

 Miquel's researches in this direction is perhaps partially 

 to be accounted for through the extraordinarily cumbrous 

 method of water-examination which he formerly exclu- 

 sively employed, and which has placed him at a great 

 disadvantage by the side of those investigators who at 

 once availed themselves of Koch's methods, which Dr. 

 Miquel, like many other French bacteriologists, has only 

 adopted with reluctance, or almost under compulsion. 

 The chief interest attaching to the bacteriological ex- 

 amination of water lies in its application to the hygiene 

 of water-supply, inasmuch as it is all but certain that two 

 at least of the most fatal zymotic diseases — cholera and 

 NO. 1 144, VOL. 44] 



typhoid — can be, and are, constantly propagated through 

 the presence of specific micro-organisms in water, and 

 indeed the majority of bacteriologists are agreed as to the 

 particular forms responsible for these diseases. On this 

 account it is conceived by many that the primary object 

 of the bacteriological examination should be the search 

 for such pathogenic microbes. This view is apparently 

 endorsed by Dr. Miquel when he says, " Le but que doit 

 poursuivre le micrographe dans les analyses bactdrio- 

 logiques de I'eau est sans contredit la d^couverte des 

 organismes pathog^nes " ; although the logical conclusion 

 to be drawn from the pages which follow, and in which 

 he details the methods to be pursued in this quest, is 

 that such an investigation is generally fraught with in- 

 superable difficulties, and, for sanitary purposes, prac- 

 tically worthless. Thus, without wishing to detract from 

 the importance of the discovery by Chantemesse, Widal, 

 and others of the typhoid bacillus in certain waters which 

 had been suspected of propagating this disease amongst 

 their consumers, it is surely obvious that, even if this 

 organism could be detected with unerring certainty in 

 any water in which it was present, a search for this 

 bacillus in the ordinary course of water examination 

 would still have only a very subsidiary interest. Waters 

 are surely not only to be condemned for drinking-pur- 

 poses when they contain the germs of zymotic disease 

 at the time of analysis, but in all cases when they are 

 subject to contaminations which may at any time contain 

 such germs. Sewage-contaminated waters must on this 

 account be invariably proscribed, quite irrespectively of 

 whether the sewage is, at the time that the water is sub- 

 mitted to examination, derived from healthy or from 

 diseased persons. In the present state of our knowledge 

 there can be no doubt that chemical analysis affords us 

 in general a better, although a far from perfect, indication 

 of sewage contamination than do the results of bac- 

 teriological examination. The real value of these bac- 

 teriological investigations, if judiciously applied, consists 

 in their power of furnishing us with information as to the 

 probable fate of dangerous organisms, should they gain 

 access to drinking-water. It is by their means that we 

 have learnt that many such organisms can preserve their 

 vitality, nay, in some cases can actually undergo mul- 

 tiplication, in ordinary drinking-water ; that they are 

 destroyed by maintaining the water at the boiling-point 

 for a short time ; and that they are more or less perfectly 

 removed by some processes of filtration and precipitation, 

 whilst other processes of the same nature are worthless, 

 or even worse. 



These important results are of the greater value 

 inasmuch as they have been obtained not only by ex- 

 perimenting with the few pathogenic organisms with 

 which we are at present acquainted, but by studying the 

 effect of these several processes on the complex mixtures 

 of micro-organisms that are to be found in natural waters. 

 The rapidity with which this knowledge has been ac- 

 quired is due to the quantitative accuracy combined with 

 facility of manipulation which characterize the method of 

 gelatine-plate culture. It has been repeatedly urged 

 against this method that it is incapable of revealing many 

 well-known forms of bacteria which either do not grow in 

 the gelatine-peptone medium at all, or at any rate not at 

 those temperatures at which it still remains solid, and it 



Z 



