STERILIZATION. 



57 



cover or hood. The inner cylinder has an opening in the bot- 

 tom through which steam may enter, the steam coming from 

 a small chamber underneath with a copper bottom to which 

 the flame is applied. The peculiarity of this form of sterilizer 

 consists in the fact that the steam which escapes from the ster- 

 ilizing chamber condenses beneath the outer cover or hood and 

 falls back upon the pan over the chamber in which the steam is 



FIG. 12. Diagram of the Arnold steam sterilizer. 



generated. The bottom of this pan is perforated with three 

 small holes, which allow the water of condensation to return 

 into the chamber where the steam is generated. The sterilizer, 

 therefore, to a certain extent, supplies itself with water, al- 

 though not by any means perfectly. It is, however, less likely 

 to boil dry than other forms of sterilizers, and it has the ad- 

 vantage of being reasonably cheap and quite effective. The 



