60 



BACTERIOLOGY. 



small to be indicated by the gauge; otherwise there is 

 danger of the reservoir becoming dry and the bottom 

 of the apparatus being destroyed by the direct action of 

 the flame. 



A sterilizer that has come into very general use in 

 bacteriological laboratories is one originally intended for 

 use in the kitchen. It is the so-called "Arnold Steam 

 Sterilizer." It is very ingenious in its construction as 

 well as economical in its employment. 



Fig. 9. 



Arnold steam sterilizer. 



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 

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



