STERILIZATION BY HEAT 89 



The water is heated by a gas-flame placed in an enclosed 

 chamber, upon which the apparatus rests, which serves to 

 diminish the loss of heat and deflection of the flame through 

 the action of draughts. The apparatus is simple in con- 

 struction, and the only point which is to be observed while 

 using it is the level of the water in the reservoir. On the 

 reservoir is a water-gauge which indicates at all times the 



FIG. 9 



Arnold steam sterilizer. 



amount of water in the apparatus. The amount of water 

 should never be too 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 bac- 

 teriological laboratories is one originally intended for use 



