124 BACTERIOLOGICAL LABORATORY TECHNIC 



position and the cotton plug is removed, and held by its outside 

 end between the fingers of the left hand, care being taken to pre- 

 vent the tubal part of the plug touching anything and being con- 

 taminated. The platinum loop is then slowly and carefully 

 introduced into the median, and stirred around so that the tube 

 walls are not touched. The needle is again sterilized and tube 

 number two is held in the palm of the left hand parallel to 

 the first one and its plug is removed also; then with a carefully 

 sterilized needle, three loops of the inoculated gelatine are re- 

 moved from number one and mixed with number two tube. 



FIG. 31. Method of inoculating culture media. (Williams.) ' 



The needle is then again carefully sterilized in the flame, the plug 

 of number one is carefully replaced and another tube, number 

 three, is held in the palm of the left hand and its plug is carefully 

 removed and held as the previous ones were. With the sterilized 

 loop three loopfuls of the gelatine from number two are carefully 

 introduced into number three and the needle is then sterilized 

 and p'ut aside. The petri dishes should now be laid on a cold level 

 slab, and the contents of the tubes run into the different dishes. 

 Tube number one is taken first; the lip of the tube is wiped with 

 the cotton plug and then held in the flame to destroy all bacteria 

 clinging to it. The lid of a petri dish is carefully and partially 

 lifted and the contents of the tube 'rapidly and evenly poured 

 over the bottom of the plate, and the lid quickly replaced. 



