III. METHODS OF STERILISATION. 



STERILISING AGENTS. 



STERILISATION i. e., the removal or the destruction 

 of germ life may be effected by the use of various 

 agents. As applied to the practical requirements of 

 the bacteriological laboratory, many of these agents, 

 such as electricity, sunlight, etc., are of little value, 

 others are limited in their applications; others again 

 are so well suited to particular purposes that their use 

 is almost entirely restricted to such. 



The sterilising agents in common use are : 



Chemical Reagents. Disinfectants (for the disin- 

 fection of glass and metal apparatus and* of morbid 

 tissues) . 



Physical Agents. HEAT. (a) Dry Heat: 



1. Naked flame (for the sterilisation of platinum 

 needles, etc.). 



2. Muffle furnace (for the sterilisation of filter can- 

 dles, and for the destruction of morbid tissues) . 



3. Hot air (for the sterilisation of all glassware and 

 of metal apparatus) . 



(b) Moist Heat: 



1. Water at 56 C. (for the sterilisation of certain 

 albuminous fluids) . 



2. Water at 100 C. (for the sterilisation of surgical 

 instruments, rubber tubing, and stoppers, etc.) . 



3. Streaming steam at 100 C. (for the sterilisation 

 of media) . 



4. Superheated steam at 115 C. or 120 C. (for the 

 disinfection of contaminated articles and the destruc- 

 tion of old cultivations of bacteria) . 



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