STUDY AND IDENTIFICATION OF BACTERIA. 



The Method of Liborius. In this it is necessary to have a test- 

 tube containing about four inches of a one percent glucose agar. 

 Glucose acts as a reducing agent and furnishes energy. It is conven- 

 ient to add about one-tenth of one percent of sulphindigotate of soda ; 

 the loss of the blue color at the site of a colony enabling us to pick them 



out. The tube of agar should be boiled 

 just before using to expel remaining 

 oxygen from the tube. Now rapidly 

 bring down the temperature to about 

 42 C., by placing the tube in cold water, 

 and inoculate the material to be ex- 

 amined. A second or third tube may be 

 inoculated from the first, just as in ordi- 

 nary diluting methods for plate cultures. 

 Having inoculated the tubes, solidify 

 them as quickly as possible, using tap- 

 water or ice-water. The anaerobic 

 growth develvops in the depths of the 

 medium. Some pour a little sterile vaselin 

 or paraffin, or additional agar on the top 

 of the medium in the tube as a seal from 

 the air. Others have recommended the 

 inoculation of some aerobe, as B. prodi- 

 giosus, on the surface. This latter method 

 is not advisable. A deep stab culture is 

 often sufficient. 



The Method of Buchner. In this 

 method one gram each of pyrogallic acid 

 and caustic potash or soda for every 

 100 c.c. of space in the vessel containing 

 the culture is used to absorb the oxygen. 



It is convenient to drop in the pyrogallic acid; then put in place the 

 inoculated tubes or plates; then quickly pouring in the amount of 

 caustic soda, in a 10% aqueous solution, to immediately close the con- 

 taining vessel. A large test-tube in which a smaller one containing 

 the inoculated medium is placed, and which may be closed by a 



FIG. 20. Arrangement of 

 tubes for cultivation of anae- 

 robes by Buchner's method. 

 (Williams.) 



