CULTIVATION OF ANAEROBIC BACTERIA. 



69 



Buchner's Method. The test tube containing the culture is 

 placed within a larger tube, the lower part of which contains 

 an alkaline solution of pyrogallic acid. 

 The tube is then closed with a rubber 

 stopper. (Fig. 41.) 



Botkin's Method. Petri dishes, un- 

 covered, are placed on a rack under a 

 large bell-jar, into which hydrogen gas 

 is conducted. Alkaline pyrogallic acid 

 is placed in the upper and lower dishes 

 to absorb what oxygen remains. 



Wright's Method. Applicable to 

 both fluid and solid media. After in- 

 oculating the test-tube, the plug, which 

 must be of absorbent cotton, is cut off 

 flush with the extremity of the tube 

 and pushed inward for a distance of 1 

 cm. It is then impregnated with 1 c.c. 

 of a watery solution of pyrogallic acid 

 and 1 c.c. of 5 per cent, sodium hydrate 

 solution. A tightly fitting rubber stop- 

 per is inserted, and the tube is then 

 ready for incubation. 



Park's Method. An Erlenmeyer 

 flask containing the medium to be used 

 is boiled in a water-bath from ten to 

 fifteen minutes to drive off dissolved 

 oxygen, quickly cooled, and inoculated. 

 Hot melted paraffine is then poured 

 into the flask, which forms a layer over 

 the medium and on congealing pro- 

 vides an air-tight seal which does not 

 adhere to the glass so closely as to pre- 

 vent the escape of any gases formed by the bacterial growth. 



Fir;. 42. Wright's method 

 for the cultivation of anae- 

 robes. 



