66 



PRACTICAL BACTERIOLOGY 



Before using the hydrogen apparatus test the hydrogen, and make 

 sure it is free from oxygen, as follows : 



Fill an ordinary test-tube with water, close the mouth with the 

 thumb, invert it, and place its mouth under water ; remove the thumb, 

 and the water will be kept in by atmospheric pressure. Conduct the 

 hydrogen into the test-tube by means of a piece of rubber tubing, 

 when the water in the tube will be replaced by gas. Hold a flame 

 near the mouth of the test-tube, and if no explosion occurs the 

 hydrogen is safe to use. 



FIG. 15. 



FIG. 16. 



Kitasato's Bottle for Anaerobic Cultures. 



Botkin's Apparatus for Anaerobic Plate Cultures. 



CXXIV. Kitasato devised a special flat bottle for the making 

 of anaerobic cultures (see Fig. 15). Kitasato and Wiel also suggest 

 the addition of 



Formic acid, . . 0*3 to 0'5 per cent. 



Glucose, . . . 1-5 to 2 



or blue litmus tincture in 5 per cent, per volume to the culture 

 medium in addition to an atmosphere free from oxygen. 



CXXV. Botkin has devised a special apparatus for anaerobic 

 plate cultures see Zeitschriftfilr Hygiene, 1890, 385 (see Fig. 16). 



CXXVI. BUCHNER'S METHOD. 



The bacteria are developed in an atmosphere robbed of its oxygen 

 by pyrogallic acid. Either oblique, roll, or stab cultures are made in 

 a test-tube which is placed inside a larger tube, having a brass support 

 for the bottom of the smaller tube to fit into (see Fig. 18, p. 67). 

 1 gramme of pyrogallic acid and 10 c.c. of T Vth normal caustic 



