THE MULTIPLICATION OF MICRO-ORGANISMS 233 



Further experiments were made to ascertain how 

 long one of the samples of distilled water was capable 

 of affording means of multiplication to these remarkable 

 bacteria. For this purpose, after the water had been 

 used once for their support, it was resterilised and used 

 again, this being repeated no less than six times in 

 succession. No difference whatever was apparent be- 

 tween the multiplication of these organisms in the 

 sample used for the first and that used for the sixth 

 time. 



In a paper by Wolffhugel and Eiedel l experiments 

 are recorded which were made with one individual 

 water-organism which was inoculated into sterilised 

 distilled water, and kept at from 30 to 35 C. The 

 numbers rose from two on the day of inoculation to, on 

 the first day, 80, the second day 750, the third day 

 1,260, the fourth day 1,600. These . results, although 

 not so striking as those of Meade Bolton's, yet also ex- 

 hibit the power of certain bacteria to multiply in the 

 absence of almost all organic matter. 



Rosenberg, 2 again, introduced a series of water- 

 organisms, which he had isolated from the river Main, 

 into sterilised distilled water, and found that, whilst the 

 majority of the individual varieties underwent rapid 

 multiplication in a short time, three of the species em- 

 ployed quickly died off in the distilled water. 



Since these results were published, it has been con- 

 clusively proved that there are some organisms which 

 will live in the absence of all organic matter ; amongst 

 these the nitrifying organisms stand oat prominently. 3 



1 ' Die Vermehrnng der Bacterien im Wasser,' Arleiten a. d. kaiser- 

 lichen Gesundheitsamte, vol. i. p. 460, 1886. 



2 ' Ueber die Bakterien des Mainwassers.' ArcJiiv fur Hygiene, 188G. 



3 ' The Nitrifying Process and its Specific Ferment,' Percy Frankland, 

 Phil. Trans. 1890, vol. clxxxi. p. 107 ; Winogradsky, Annales de Vlnstitut 

 Pasteur, vol. iv. 1890, p. 213, 257, 760. Vol. v. p. 92, 577 ; also Archives 



