156 



PATHOGENIC BACTERIA. 



hydrogen. In using Botkin's apparatus the uncovered 

 Petri dishes are placed one above the other in the rack c, 

 and covered with the bell-glass A. Liquid paraffin is 

 poured in the dish B until it is about half full. From a 



Kipp's apparatus hydrogen 

 gas enters the little rubber 

 tube <z, subsequently escap- 

 ing by the tube b. When 

 only pure hydrogen escapes 

 the rubber tubes a and b are 

 withdrawn, and the appa- 

 ratus remains filled with hy- 

 drogen. Lest a little oxygen 

 should remain, it is best to 

 have the dishes at the top 

 and bottom of the rack filled 

 with alkaline pyrogallic 

 acid. Tetanus can be cul- 

 tivated in this apparatus. 

 The jars recently intro- 



j j v XT *1 



duced bv Now are similar 



FlG. 38. Botkin's apparatus for male- 

 ing anaerobic cultures. 



in principle, depending 

 upon the replacement of the air by hydrogen. They are 



in; }Q. Novy's jars for anaerobic 



so constructed that when the stopper occupies a certain 

 relative position to the neck the gas can enter and exit, 



