Laboratory Outline for General Bacteriology 



16. Do take small amounts of bacteria for inoculation. Only a few 

 bacteria are necessary. 



17. Do keep bacterial cultures out of the sunlight, j 



Liquid Media 



18. Do keep cultures upright enough so that plugs will not become 

 wet. 



19. Same as 1 to 13 inclusive for agar slants. 



20. Do keep fermentation tubes so no air enters inner tube. 



21. Do sterilize loop after touching it to litmus paper in testing 

 for reaction before putting it back into the tube for another 

 loopful. 



22. Do handle incubated cultures gently before taking the ob- 

 servations. This is particularly important with nutrient broth 

 as the appearance may be greatly changed by jarring. 



23. Do use uninoculated tubes of media for comparison in making 

 observations and tests. 



Plate Cultures 



24. Do lift covers only high enough to insert the pipette or needle 

 when adding inoculation material. 



25. Do have medium at right temperature when pouring agar 

 about 40 C., and gelatin between 25 C. and 40 C. 



26. Do remove cotton plugs from tubes or flasks without touching 

 lips of tubes or flasks and burn off any adhering cotton that 

 would interfere with pouring. 



27. Do lift cover when pouring just high enough so tube or flask 

 will not scrape on edges of dish. 



28. Do mix medium well with inoculation so bacteria will be evenly 

 distributed. 



29. Do keep medium from getting on edges of plate when pouring 

 or mixing as this glues them together and frequently leads 

 to breakage and contamination. 



30. Do pour plates where air is quiet. 



31. Do keep plates closed while looking to see if medium has 

 hardened. 



32. Do place plates near center of table to harden as edges of table 

 are not level. 



33. Do always carry gelatin plates level and right side up. 



34. Do keep agar plates inverted after hardening and while in- 

 cubating. (Continued on Page 26) 



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