14 LABORATORY BACTERIOLOGY 



EXERCISE V 



INOCULATING TUBES OF BOUILLON, AGAR, AND GELATIN 



18. Work for this Exercise. — Inoculate one tube of bouil- 

 lon, two (one inclined, the other not) of agar, and one of gelatin 

 from a culture oi Bacillus coli communis, which will be furnished. 



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

 ing mixture to water and alcohol and wipe them. Place them 

 in a Petri dish and heat them as directed in paragraph 3 e. 



Read the chapters in one or more of the text-books on inocu- 

 lating media or making tube cultures. 



19. 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 pull 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 The loop is then withdrawn, the 

 plugs replaced in their respective tubes, and the loop flamed 

 and put aside. Label the freshly inoculated tube with the 

 name of the organism, source, and date. Stand it in a tray or 



