IOO 



BACTERIOLOGY, 



stage returns to be reheated by the flame g. At d 

 is a gas regulator, so that a constant temperature 

 at any desired point can be maintained. 



FIG. 34. SCHAFER'S WARM STAGE. 



Another form in which warm water or steam can 

 be used for heating, and by the employment of 



u 



(H 



a 



FIG. 35. STRICKER'S WARM STAGE. 



icea water also used for observing the effects of 

 cold, is shown in Fig. 35. It consists of a hollow rect- 

 angular box, with a central opening (C) permitting 



