100 



CLINICAL BACTERIOLOGY. 



hydrogen gas into the upper portion of the bell. Perfect 

 closure is effected with the aid of liquid paraffin. The dis- 

 placed air escapes at the 

 bottom through a second 

 rubber tube, which is re- 

 moved after the apparatus 

 has been completely rilled. 

 Beneath the glass bell a 

 vessel containing an alka- 

 line solution of pyrogallic 

 acid is placed for further 

 security. A disadvantage 

 of Botkin's apparatus con- 

 sists in the fact that the 

 plates are but incompletely 

 protected against contami- 

 nation by the air. 



Novy's apparatus is to 

 be warmly recommended, 

 both for plate-cultures as 

 well as for test-tube cul- 

 tures. This consists of a 

 high glass jar upon the 



edges of which an air-tight helmet-like cover is placed. 

 The latter is provided above with a revolving, doubly 

 perforated glass stopper, through which the hydrogen gas 



Fig. 31. Botkin's apparatus for making 

 anaerobic plate-cultures. 



Fig. 32. Novy's jars for anaerobic cultures. 



is introduced and the air is at the same time expelled. At 

 the close of the operation the stopper is simpxy rotated, and 



