34 



BACTERIOLOGY. 



the line of junction of the cylinder and cone. The 

 cone terminates in a projecting tube provided with 

 an adjustable ventilator. The apparatus is fixed 

 on three supports united to one another below. 

 One of them is utilised for adjusting the height of 

 the heating apparatus. Situated above this leg is the 

 heat regulating apparatus (Fig. 17), attached to a 

 circular, lipped aperture in the outer wall of the in- 

 cubator. To the lip is 

 fixed with six screws the 

 corresponding lip of a 

 brass box, with a tightly 

 stretched diaphragm of 

 india-rubber intervening. 

 Thus the diaphragm 

 FIG. 17. SCHLOSING'S MEMBRANE separates the cavity of 



REGULATOR. . . r . 



the box from the water 



in the interspace of the incubator. The cap of 

 the box, which screws on, is bored in the centre 

 for the screw- pipe, by which the gas is supplied. 

 Another pipe entering the box from below is 

 connected with the gas burners. Around the end 

 of the screw-pipe a collar loosely fits, and is pressed 

 against the diaphragm by means of a spiral wire 

 spring. Close to the mouth of the screw-pipe 

 a small opening exists, so that the gas supply to 

 the burners is not entirely cut off even when the 

 diaphragm completely occludes the mouth of the 

 screw-pipe. 



To work the apparatus the tube and plug must be 



