8 



CLINICAL BACTERIOLOGY AND 



or wood. The water is heated at the bottom of the in- 

 cubator by a gas, oil, or electric lamp. The top of the 

 incubator has three circular holes in it, one for the insertion 



Fig. 2. — Incubator. 



of a thermo regulator, one for the thermometer, and a third 

 for the filling of the water chamber. The thermo regulator 

 is composed of a mercurial bulb which passes through a 



