236 MICRO-ORGANISMS IN WATER 



waters which are either naturally or artificially charged 

 with other gases, more especially carbonic anhydride. 

 On this subject a number of experiments have been 

 made by different investigators. 



Thus, as regards the behaviour of micro-organisms 

 in artificially prepared seltzer-water and carbonated 

 waters generally, experiments have been made by Hoch- 

 stetter, 1 Leone, 2 Pfuhl, 3 Sohnke 4 and Merkel, 5 the re- 

 sults obtained by Leone being the first which appeared. 

 Leone found that whereas the Munich water contained 

 on an average five bacteria per c.c., which on standing 

 multiplied enormously, as we have already seen, in the 

 same water through which carbonic anhydride had 

 been passed no multiplication took place, the bacteria on 

 the contrary steadily declining in numbers. 



In these experiments Leone passed the gas through 

 the water both under and without pressure, and the 

 same results were obtained, showing clearly that the 

 destruction of the bacteria present was due to the action 

 of the gas itself, and not to the removal of the oxygen 

 present. In some experiments by Percy Frankland 

 on the action of different gases on various micro- 



1 ' Ueber Mikroorganismen im kiinstlichen Selterwasser,' Arbeiten 

 a. d. kaiserlichen Gesundheitsamte, vol. ii. p. 1, 1887. 

 ~ Leone, loc. cit. 



3 ' Bakterioskopische Untersuchungen im Winter 1884-85,' Deutsche 

 militararztl. Zeitschrift, 1886, Jahrgang xv. Heft 1. 



4 ' Die Bakterienfrage in Bezug auf kiinstliche Mineral- und Kohlen- 

 saure Wasser,' Zeitschrift filr Minerahvasser-Fabrikation, 1886, Jahr- 

 gang ii. No. 22 and 23. 



5 ' Ueber den Werth der bakteriologischen Untersuchungsmetbode 

 bei der Untersuchung von Trink- und Nutzwassern,' Bericht iiber die 5te 

 Versammlung der freien Vereinigung Bayrischer Vertreter der an- 

 gewandten Chemie zu Niirnberg, 1886 ; Berlin 1887, p. 38. 



(i ' On the Influence of Carbonic Anhydride and other Gases on the 

 Development of Micro-organisms.' Proc. Roy. Soc., vol. xlv., 1889, p. 292. 

 See also Frankl, ' Die Einwirkung der Kohlensiiure auf die Lebens- 

 thatigkeit der Microorganismen,' Zeitschrift filr Hygiene, vol. v., 1889, 

 p. 332. 



