376 



NATURE 



[August 20, 1896 



of a particular sample of aerated water, the results are in the 

 first instance dependent upon the bacterial quality of the original 

 water employed, and the nature of the (particular microbes pre- 

 sent, whilst it must be acknowledged that a considerable element 

 of chance is introduced into the results, inasmuch as they so 

 greatly depend upon the time at which the examination ha[jpens 

 to be made. 



Thus in the above example, where such enormous multiplica- 

 tion was observed, no one would hesitate, on the strength of 

 such figures, to condemn that water from a bacterial ])oint of 

 view, whilst if its examination had been longer postponed until 

 it yielded only 46 microbes per c.c. , as unhesitating a favourable 

 verdict might have been pronounced upon it. As regards the 

 influence of the bacterial purity of the original water upon the 

 finished article, we have frequent evidence of the paucity of 

 bacteria present when the raw water employed has been deprived 

 of all microbial life by boiling or distillation ; but even when 

 such precautions are taken in the first instance, we often 

 find that very considerable numbers of bacteria are present in 

 this water after aeration, a fact which is to be ascribed to the 

 bacterial contamination which subsequently obtains in the pro- 

 cess of manufacture. Such contamination may be due to various 

 causes ; the storage of the water in reservoirs in the factory has 

 been shown in some cases to be responsible for this result, whilst 

 Dr. Abba has recently called attention to the condition of the 

 bottle-syphons used for the distribution of aerated waters as 

 frequently contributing to bring about this condition of things. 



These syphons, he states, in his important report on the aerated 

 waters supplied to Turin, are not only left unsterilised after use, 

 but they are neither washed out nor even emptied completely ; 

 hence a deposit is always present, which furnishes ample material 

 for the bacterial contamination of the freshly added water. 

 Another factor which contiols to a certain extent the bacterial 

 contents of aerated waters is the amount of carbonic anhydride 

 which is present. This point has been well illustrated by .Slater, 

 and Dr. Abba has confirmed his results. Thus : — 



-Amount of 

 carbonic anhydride Bacteria 



present per Hire. per c.c. 



(Grammes.) 



15-08 299 



I2'IO ... ... ... ... 3SS 



1174 435 



9-07 1207 



S-oi 1354 



6-90 15S0 



603 2032 



Whether the above rise in the bacterial contents on the release 

 of the gas present is due to the diminution of the pressure or to 

 the specific action of the gas being modified, it is difficult to say ; 

 probably both causes co-operate in bringing about the result. At 

 ]3resent we have no authoritative experimental observations to 

 decide this point. 



That carbonic anhydride is capable of exercising very specific 

 action in the case of some micro-organisms in the absence of 

 pressure, was shown some years ago by Dr. Percy Frankland in 

 his experiments on the influence of carbonic anhydride and other 

 gases on the development of micro-organisms (/'/'^i". Roy. Soc, 

 1889). Three microbes were experimented with — Koch's cholera 

 bacillus, Finkler-I'rior's bacillus, and the Bacillus pyocyaiieus, 

 an organism frequently found in green pus. 



These bacteria were exposed on gelatine surfaces to the action 

 of the gas in closed vessels, andaftera time they were transferred 

 to vessels containing air only. 



In the ca.se of Koch's bacillus and- Finkler-Prior's bacillus, no 



its means, but the absence of oxygen can also not be held 

 entirely responsible for the deleterious action of carbonic an- 

 hydride ; thus, in an atmosphere deprived of oxygen by mean- 

 of hydrogen, Dr. Percy Frankland found that the growth of 

 Koch's cholera bacillus was not interfered with at all, but we 

 have seen hosv fatally it was affected in the absence of oxygen 

 by the carbonic anhydride. Mere, then, clearly the presence or 

 absence of oxygen would appear to have no voice in the result- 

 olitained. 



As regards the behaviour of pathogenic bacteria in c.ir 

 bonated waters, the results so far obtained are decidedl) more 

 unanimous. 



There is no doubt that a very general impression prevails tliat 

 a bairier of no mean obstructive power is placed betsveen the 

 consumer and zymotic disease, by the substitution of aiirated 

 waters for ordinary drinking-water, at any rate during times of 

 epidemics. 



This impression is to a certain extent justified by investigation, 

 but can at the same time only be encouraged to a moderate extent, 

 as the following researches will sufficiently show. 



When anthrax bacilli are introduced into ordinary seltzer 

 water, they do not live more than from fifteen minutes to one 

 hour ; when the spores, however, are similarly treated, they 

 survive upwards of 154 days. 



As, however, anthrax in the condition of bacilli devoid ••' 

 spores is only very exceptionally met with, we cannot deriv 

 much comfort from using seltzer water ; fortunately, howevci 

 so far the communication of anthrax is not associated with drink 

 ing-water, and from a hygienic point of view the above resuU- 

 may be regarded as of, perhaps, more theoretical than practical 

 interest. 



Our position with reference to cholera germs and water is, 

 however, on quite a diflerent footing, and it is extremely re- 

 assuring to learn, on the authority of such investigators as Hoch- 

 stetter. Slater, and Abba, that in ordinary seltzer and soda 

 water, cholera bacilli cannot live longer than three hours. Dr. 

 Abba records some curious results, in which he states tlii 

 in sterilised tap-water gaseously aerated cholera bacilli pci 

 sisted as long as forty-eight hours, whilst if such sterili-i ' 

 aerated water is rendered alkaline by the addition of i |ier 

 1000 bicarbonate of soda, their life was prolonged for as much 

 as twelve days. 



It would appear that sterilisation, or the removal of competing 

 water b.icteria, materially assisted the life of cholera bacilli ; and 

 this impression is confirmed by another experiment with alkalised 

 water, in which the water was not sterilised first, and in which 

 the vitality of the baciUi, instead of reaching twelve, was cut 

 down to seven days. 



Unfortunately, as regards typhoid infected water, we cannot 

 resort with any degree of security to carbonated waters, unless 

 we have proof that the manufactured article has been stored tor 

 at least a fortnight before use. 



Slater observed typhoid bacilli alive in ordinary aerated water 

 as long as eleven days, and both Abba and Hochstetter record 

 a vitality of five days. In some cases, however, they appear to 

 disappear much more rapidly, and doubtless a great deal depends 

 upon the initial vital condition of the particular cultivation of 

 typhoid bacilli employed. 



Here again Dr. Abba finds in sterilised, alkalised, aerated 

 water, that the persistence of the typhoid bacilli is superior 

 to that observed in similar waters not deprived of their bacterial 

 life. 



Dr. Abba has also experimented in a similar manner w ith the 

 B. coli Lomniunis, and finds that, beyond its exhibiting the 

 customary character of superior hardiness under adverse circum- 

 stances to its near relative, the typhoid bacillus, its behaviour 



growth whatever appeared in the carbonic anhydride vessel, I resembled that of the latter. Although storage even for such 



neither did any sign of vitality make its appearance when the 

 bacilli in question were subsequently transferred to the air 

 vessel. 



The case was, however, different with the green-pus bacillus, 

 for although no growths appeared in the presence of the gas, 

 on being removed to the air-vessel, growths did manifest them- 

 selves, showing that the carbonic anhydride had not succeeded 

 in destroying the bacilli as it had done the two others. 



Here, then, we have an examjile of the specific action of the 

 gas being controlled by the character of the particular microbe 

 to be dealt with. .Some authorities ascribe the action of carbonic 

 anhydride simply to the bacteria being de|irived of oxygen by 



NO. 1399, VOL. 54] 



msiderable periods of time as over two years cannot, as we have 

 seen — at any rate in some ca,ses — secure the entire elimination 

 of ordinary water microbes, yet storage of considerably shorter 

 duration is of undoubted service in the destruction of disease 

 germs, as far as our information at present goes. 



It would appear reasonable, therefore, to make a practice 

 of storing such waters before distribution, a measure recom- 

 mended 'many years ago by Duclaux, and which, in the absence 

 of preliminary precautions, such as the removal of all bacteria 

 present by boiling, distillation or efficient filtration, would appear 

 to be a measure of great hygienic importance. 



r,. C. Frankland. 



