14 LABORATORY BACTERIOLOGY 



EXERCISE V 



INOCULATING TUBES OF BOUILLON, AGAR, AND 

 GELATIN 



19. Work for this exercise. See that the media made in 

 former exercises have been properly sterilized. Inoculate one 

 tube of bouillon, two (one inclined, the other not) of agar, and 

 one of gelatin from a culture of Bacillus coli communis, which 

 will be furnished. 



Wipe the slides. Transfer the cover glasses from the clean- 

 ing mixture to water and then to alcohol. Seal the agar slant 

 and gelatin tubes. 



Read the chapters in one or more text-books on inoculating 

 media or making tube cultures. 



20. Inoculating bouillon. In making this culture, carefully 

 remove the plug from the tube of bouillon by first twisting it 

 around to detach any adhesions and then by pulling it straight 

 out. Pass the open end of the tilted tube quickly through the 

 gas flame. The plug, which has meantime been carefully held, 

 is partially replaced and the tube returned to its stand. Treat 

 the tube containing the culture (which has been furnished) in 

 the same manner. Then place the two tubes side by side 

 between the thumb and forefinger of the left hand, palm facing 

 upward, and grasp them about the middle of the upper half 

 (see Fig. 38, p. 108, Crookshank). Sterilize the platinum 

 loop by passing it through the gas flame, care being taken that 

 the handle is also flamed for a distance of at least 15 cm. 

 Then carefully remove the plugs from the tubes and hold them 

 between the fingers in such a manner that the tube ends, pro- 

 jecting outward, will not touch anything during the inoculation 

 process. Insert the wire loop carefully into the culture and 

 transfer a loopful of the culture to the tube of bouillon and 

 gently rinse it from the loop. The loop is then withdrawn, the 



