140 



BACTERIOLOGY. 



ing point at the extremity which projects into the tube 

 e, and is provided a short distance above this point with 

 a capillary opening, g, in one of its sides. 



When ready for use the cylinder e is filled with mer- 

 cury up to about the level shown in the figure. It is 

 then allowed to stand, or is suspended, in the bath the 



FIG. si. 



Mercurial thermo-regulator. 



temperature of which it is to regulate. The rubber 

 tubing coming from the gas-supply is attached to the 

 outer end of the glass tube a, and the tube going to the 

 burner is slipped over the branch tube b. The gas is 

 turned on and the burner lighted and placed under the 



