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A MANUAL OF BACTERIOLOGY 



doubt that it is a means by which microbes may be 

 absolutely removed from water in the laboratory. 



(b) Heat. Heat is a means of destroying microbes 

 in water, but many microbes require a temperature 

 above the boiling point before they are destroyed. 

 Dr. Miquel 1 has shown that the number of microbes 

 or colonies decreases gradually as the temperature 

 of the water is raised. The water of the Seine, 

 obtained from two different sources, gave the fol- 

 lowing results : 



Although some microbes are capable of withstand- 

 ing the action of boiling water for 15 minutes, they 

 are all destroyed when the temperature is raised to 

 110 115 C. for the same space of time. MM. 

 Rouart and Geneste-Herscher have devised an ap- 

 paratus in which large quantities of water may be 

 sterilised by the action of heat (see Miquel's book, 

 loc. cit., p. 188). 



1 Manuel Pratique d' Analyse Bactdriologique des JEaux, 

 p. 182. 



