60 BACTERIOLOGY. 



Steam Sterilizer." It is very ingenious in its construc- 

 tion as well as economical in its employment. 



The difference between this apparatus and that just 

 described is that it provides for the condensation of the 

 steam after its escape from the sterilizing chamber, and 

 returns the water of condensation automatically to the 

 reservoir, so that in practice the apparatus requires but 



FIG. 9. 



Arnold steam sterilizer. 



little attention, as with moderate care there is no fear of 

 the water in the reservoir becoming exhausted and the 

 consequent destruction of the sterilizer. 



Fig. 9 shows a section through this apparatus. 



STERILIZATION UNDER PRESSURE. 



For sterilization by steam under pressure several spe- 

 cial forms of apparatus exist. The principles involved 



