STERILIZATION BY HOT AIR. 79 



dently of temperature) that is desirable may be main- 

 tained within the sterilizing chamber. These sterilizers 

 are known as " digesters " and as " autoclaves." Their 



FIG. 11. 



Autoclave or digester for sterilizing by steam under pressure. 



construction can best be understood by reference to 

 Figs. 10 and 11. 



STERILIZATION BY HOT AIR. 



The hot-air sterilizers used in laboratories are sim- 

 ply double-walled boxes of Russian or Swedish iron 



