158 



BACTERIOLOGY 



ture. In the top of the chamber is a small opening through 

 which a thermometer projects into its interior. At either 

 corner, leading into the space containing the water, are 



FIG. 28 



Incubator used in bacteriological work. 



other openings for the reception of another thermometer 

 and a thermo-regulator, and for refilling the apparatus as 

 the water evaporates. On the side is a water-gauge for- 

 showing the level of the water between the walls. The 



