Report on the Bacteriology of Water. 



205 



in distilled water was made by one of ns in 1885,* on which occasion it 

 was fonnd that in the conrse of forty-eight hours the number of 

 microbes had increased from 1073 in the cubic centimetre to 48,100 

 in the same volume. Similar instances of multiplication in the pure 

 spring water supplied to Munich were published shortly afterwards, 

 by Leone,t whilst the same phenomenon was observed by Cramer^ in 

 the case of the microbes present in the waters of the Lake of 

 Zurich. 



Similar phenomena formed the subject of more extensive investiga- 

 tions contained in three memoirs, which appeared almost simul- 

 taneously in 1886 by "Wolff hiigel and Riedel,§ by Meade Bolton, || 

 and by one of ua.% Each of these not only confirmed the rapid and 

 extensive multiplication of microbes, even in the purest natural 

 waters, but differed from the predecessors in recording the results 

 of experiments in which specific pathogenic forms were introduced 

 into natural waters of different kinds, including sewage. It will be 

 convenient to discuss, in the first instance, these three contributions 

 to the subject along with another by Heraeus, which appeared shortly 

 afterwards. 



In Meade Bolton's paper,** after referring to the literature regard- 

 ing the general bacterial contents of ordinary waters, and criticising 

 the various methods hitherto in vogue, the following generalisations 

 are made — 



1. Ordinary waters always contain some bacteria. 



2. The numbers of individuals and species vary in different waters, 

 and from time to time. 



3. Certain forms predominate, because they can multiply readily 

 in such waters, as is proved by their rapid increase when the water 

 is allowed to stand for a few days. 



4. After the climax of increased numbers has been obtained, the 

 bacteria gradually diminish in quantity. 



Bolton established the truth of these conclusions, and showed that 

 the growth and increase of these water bacteria differ according to 



* Percy F. Frankland, " The Removal of Micro-organisms from Water," ' Roy. 

 Soc. Proc.,' vol. 38, 1885, p. 387. 



f " Sui Micro-organismi delle Acque Potabili, loro Vita nelle Acque Carboniche," 

 ' Rendiconti della R. Accademia dei Lincei,' 4 Ottobre, 1885 ; ' Chem. News,' 

 vol. 52, p. 275. 



% ' Die Wasserversorgung von Zurich, ihr Zusammenbang mit der Typhusepi- 

 demie d. Jahres 1884,' Zurich, 1885. 



§ ' Arbeiten a. d. K. Gesundheitsamte,' vol. 1, pp. 455 — 480. 

 i| ' Zeitschr. f . Hyg.,' vol. 1, p. 76. 



^ Percy F. Frankland, "The Multiplication of Micro-organisms," 'Roy. Soc. 

 Proc.,' vol. 40, 1886, p. 526. 



** " Ueber das Verhalten verschiedener Bakterienarten im Trinkwasser " 

 C Zeitschr. f. Hyg.,' vol. 1, 1886. pp. 76—114). 



