212 



Profs. P. F. Frankland and Marshall Ward. 



waters, but concluded that it does not multiply in them unless appre- 

 ciable quantities of organic food materials are present : he found that 

 ■^i^th part of bouillon added to the water induced vigorous growth 

 and multiplication. 



He concludes that cholera germs cannot multiply in ordinary 

 waters, under ordinary conditions; but the temperature, the nature 

 of the competing bacteria, and the vitality of the cholera germs them- 

 selves affect the question. 



Among other factors which influence the life of microbes in water, 

 carbon dioxide may be assumed to be of importance : most forms are 

 influenced more or less adversely, whilst perhaps some are not sus- 

 ceptible to its presence.* Light is of no consequence in this respect. 



Ferrari, in a paper dealing with the effect of various fluids employed 

 in surgery on pathogenic organisms, observed that Staphylococcus 

 pyogenes aureus rapidly multiplies in distilled water, f and this to 

 such an extent that the effects were observable during several days, 

 and the numbers were so large by the fifth day that they could no 

 longer be estimated. 



At the same time, the preliminary diminution of numbers during 

 the first hours or days in these cases (and in similar experiments 

 of numerous other observers already referred to) suggests the 

 suspicion that some of the increase at least must be attributed to the 



* Kolbe (' Journ. f . Praktische Chemie,' N.F., 1882, vol. 26, and 1886, vol. 28) 

 had already pointed out the antiseptic action of carbonic anhydride, in connexion 

 with the preservation of beef, and Leone (loc. cit.) showed how the number of 

 microbes in water underwent rapid diminution on saturating the latter with carbonic 

 anhydride at ordinary pressures ; although the complete destruction of germs cannot 

 be relied on by this agency, it points, at any rate, to the greater safety of carbonated 

 waters, more especially if they have been kept for some time in stock. Systematic ex- 

 periments have also been made on the action of carbonic anhydride on specific micro- 

 organisms, pathogenic and harmless, by C. Fraenkel (" Einwirkung der Kohlensaure 

 auf die Lebensthatigkeit der Mikro-organismen," ' Zeitschr. f. Hyg.,' vol. 5, 1889, 

 p. 332), and by one of us (Percy F. Frankland, " On the Influence of Carbonic An- 

 hydride and other Grases on the Development of Micro-organisms," 'Roy. Soc. Proc.,' 

 vol. 45, 1888, p. 292, ' Zeitschr. f. Hyg.,' vol. 6, p. 13). These investigations show 

 that by far the greater number of known bacteria, both pathogenic and otherwise, 

 have their growth arrested by carbonic anhydride, although many of them subse- 

 quently revive on exposure to air. The most important papers on the effect of this 

 gas, in mineral waters, on bacteria are Hochstetter (" TJeber Mikro-organismen im 

 kiinstlichen Selterwasser nebst einigen vergl. TJnters. u. ihr Verhalten im Berl. 

 Leitungswasser u. im dest. Wasser," ' Arb. a. d. Kais. Gresundheitsamte,' vol. 2, 

 1887, H. 1 and 2) ; Reinl (" Die gebrauchlichsten kohlensaurehaltigen Luxus- und 

 Mineral- Wasser vom bakteriol. Standpunkte," ' Wiener Med. Wochenschr.,' 1883, 

 Nos. 22 and 23) ; Fazio (' I Microbi delle Acque Minerali,' Naples, 1888). 



f "TJeber das Verhalten von Pathogenen Mikroorganismen in den subcutan 

 einzuspritzenden Flussigkeiten " (' Centr. f. Bakt.,' vol. 4, 1888, p. 744). It should 

 be pointed out that in this respect his results are in direct antagonism to Meade 

 Bolton's with the same organism. 



