STERILIZATION BY HEAT. 59 



flame through the action of draughts. The apparatus 

 is simple in construction, and the only point which is to 

 be observed while using it is the level of the water in 



Steam sterilizer, pattern of Koch. 



the reservoir. On the reservoir is a water-gauge which 

 indicates at all times the amount of water in the appa- 

 ratus. 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 

 bacteriological laboratories is one originally intended 

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



