STERILIZATION 



15 



Exercise 14. Sterilization of Dishes and Instruments by Dry Heat 



The hot-air sterilizer is a double-walled oven constructed of 

 sheet iron or copper and usually covered with asbestos. It is 

 heated by a gas flame. Objects should be sterilized in this 

 oven for one hour at a temperature of 140-150 C. After 

 the temperature of the oven has fallen below 40 0. the 

 objects may be taken out of the sterilizer and used. 



FIG. 11. An oven for dry sterilizing 



Objects to be dry sterilized should be clean, dry, and free from 

 dust. Volumetric pipettes should be put into a sheet-iron box 

 for sterilization. Petri dishes which are to be kept for a time 

 before using, may be separately wrapped in manila paper. 



