514 



NATURE 



[October i, 1891 



is in this respect that Dr. Miquel claims superiority for 

 his infinitely more laborious method of " ensemencements 

 fractionnds " in bouillon. It is obvious that labour must 

 be no consideration if any great scientific advantage is to 

 be attained ; but, on the other hand, the unnecessary 

 complication of processes, without corresponding benefits, 

 must invariably lead to the retardation of scientific pro- 

 gress. Now, it would certainly appear that the benefits 

 obtained by Miquel's process are in no way commen- 

 surate with the additional labour which it entails. Thus, 

 his process is also incapable of revealing all the mi- 

 crobes which may be present in water, and yields at best 

 only a closer approximation to the total number than 

 does the gelatine method. For the general purposes of 

 the bacteriological examination of water, however, it is of 

 very little consequence whether the method employed 

 reveals, say, 30, 50, 70, or 90 per cent, of the total number 

 of microbes present, all that is required being a result 

 which will serve for comparison. Thus, supposing it is 

 desired to ascertain the efficiency of some process of 

 filtration, provided that the unfiltered and filtered waters 

 respectively are submitted to the same method of ex- 

 amination, the comparative result will be the same 

 whether 50 per cent, only or all the microbes present are 

 in both cases enumerated. Thus putting this statement 

 to the test of actual experiment, from the results of the 

 gelatine-plate method of examination I reported to the 

 Local Government Board in 1886 that the average reduc- 

 tion in the number of micro-organisms present in Thames 

 water effected by the sand-filtration of the several London 

 water companies amounted to — 



98 '6 per cent, for the Chelsea Company, 

 99'i ,, ,, West Middlesex Company, 



96*7 ,, ,, Southwark Company, 



98"2 ,, ,, Grand Junction Company, 



96*2 ,, ,, Lambeth Company, 



whilst Dr. Miquel in 1890 gives as the effect of sand- 

 filtration on the water of the River Loire a reduction 

 of 99 '3 percent, in one case, and 994 per cent, in another 

 case. A concordance more complete than this can cer- 

 tainly not be demanded. Similarly it can be shown that 

 Dr. Miquel's method of water examination has not yielded 

 any results of importance which had not already been 

 arrived at before by other investigators using the more 

 expeditious method of plate cultivation. It is indeed only 

 for such differential experiments as that referred to above 

 that the bacteriological examination of water, in the 

 present state of our knowledge, is really of much value, 

 for any judgment as to the purity or otherwise of a sample 

 of water based upon the actual number of microbes found 

 in a given volume of it, is liable to lead to the most serious 

 errors, in consequence of the remarkable power which 

 some bacteria possess of multiplying to an extraordinary 

 extent in waters of the greatest organic purity ; in fact, it 

 is precisely in the purest waters that such multiplication 

 is often most pronounced. It is the possibility of such 

 multiplication taking place which renders it imperative 

 that samples of water should be submitted to bacterio- 

 logical examination within a few hours of their collection. 

 In order to overcome this difficulty, which has hitherto 

 debarred the examination of waters from distant sources. 

 Dr. Miquel has the samples transmitted in a box sur- 

 rounded with ice ; to this there are manifold objections, 

 NO. I 1 44, VOL. 44] 



for the low temperature thus secured by no means 

 completely arrests the multiplication of some bacteria, 

 whilst it causes the destruction of others. Dr. Georg 

 Frank, of Berlin, on the other hand, seeks to overcome 

 the difficulty by deputing to persons-on the spot the task 

 not only of collecting the samples, but also of prepar- 

 ing the plate-cultures ; but, considering the nature of the 

 instructions which he finds it necessary to give to the 

 novices to whom this work may fall, the expedient does 

 not appear very promising. The following is a verbatim 

 extract from these instructions recently published in 

 a German scientific journal of repute, which surely 

 demands no comment : — 



" The person commissioned with the collection of the 

 sample takes off his coat, turns up his shirt-sleeves on 

 both arms, fastening them so securely that they cannot 

 fall down of themselves. Then he washes his hands and 

 arms most carefully with soap and brush to above the 

 elbow-joint. Special care must be bestowed upon the 

 cleansing of the finger-nails, which must if necessary be 

 treated with the nail-file. Finally, the person in question 

 dries himself with a clean towel." 



We take it that the value of results depending upon 

 manipulations carried out by persons requiring these 

 instructions would be such that it would be no loss if they 

 were dispensed with altogether. Indeed, unless the 

 bacteriological examination of water be invariably carried 

 out by qualified persons, and by them employed only in 

 cases where it is really capable of rendering service, it is 

 certain to fall into that disrepute which has so frequently 

 been drawn down upon the chemical examination of 

 water through incompetent analysts. Indeed the bac- 

 teriological method has already seriously suffered in 

 public estimation through the contradictions which have 

 resulted from the attempts made in some quarters to 

 classify waters according to the number of microbes 

 revealed on cultivation. Such arbitrary standards have 

 already done much mischief in the case of the chemical 

 analysis of water ; in the bacteriological examination they 

 are still more reprehensible, and it is deeply to be re- 

 gretted that Dr. Miquel, in this most recent work on the 

 subject, should seek to perpetuate a system of standards 

 which experience shows to be quite untenable. 



The work concludes with some excellent recommenda- 

 tions as to the sterilization of water for drinking-purposes, 

 a subject which cannot be too frequently brought into 

 public notice, for, using Dr. Miquel's own words, " la vie 

 d'un homme a bien sa valeur a cotd du prix insignifiant 

 auquel revient le litre d'eau purgee de germes qu'il peut 

 consommer en vingt-quatre heures." 



Percy F. Frankland. 



EPIDEMIC INFLUENZA. 

 Epidemic Influenza : Notes on its Origin and Method of 

 Spread. By Richard Sisley, M.D. (London : Long- 

 mans, Green, and Co., 1891.) 

 THE object of this brief treatise, which was prepared 

 before the issue of the Report of the Local Govern- 

 ment Board, is to prove the doctrine, widely held by 

 physicians of eminence in the eighteenth century, that 

 influenza is contagious, or, more strictly speaking, in- 

 fectious, and therefore, in the ^opinion of the author, fit 



