48 BACTERIOLOGY. 



always be given to the condition of the copper bottom ; 

 for the direct application of the heat to the sheet-iron 

 plate upon which the substances to be sterilized stand, 

 results not only in destruction of the apparatus, but 

 frequently in destruction of the substances undergoing 

 sterilization. 



Since the temperature at which this form of steriliza- 

 tion is usually accomplished is high 150 to 180 C. 

 it is well to have the apparatus encased in asbestos 

 boards, to diminish the radiation of heat from its sur- 

 faces. This not only confines the heat to the apparatus, 

 but guards against the destructive action of the radiated 

 heat on woodwork, furniture, etc., that may be in the 

 neighborhood. 



