THE CULTIVATION OF MICRO-ORGANISMS III 



portion of the material to be examined — pus, for example — and 

 introduce it with a sterilized platinum wire or loop into one of 

 the tubes. The plug of the test-tube is to be withdrawn, twisting 

 it slightly, taking it between the third and fourth fingers of the 

 left hand, with the part that projects into the tube pointing to- 

 ward the back of the hand. It must not be allowed to touch 

 any object while the inoculatiofi. is going on. Pass the neck of 

 the tube through the flame. If any of the cotton adheres to the 

 neck of the tube, pull the cotton away with sterilized forceps, 

 while the neck of the tube touches the flame, so that the threads 

 of cotton may be burned and not fly into the air of the room. 



Pig. 41.- — Method of inoculating culture media. 



The tube is held as nearly horizontal as possible, in the left hand 

 between the thumb and forefinger, resting upon the palm, and the 

 neck of the tube pointing upward and to the right. Mix the 

 material introduced thoroughly with the hquefied culture-medium, 

 taking care not to wet the plug. Now remove the plug again, 

 and, having sterilized the platinum wire, insert it into the liquefied 

 medium. Carry three loopfuls in succession from this tube, 

 which is No. i, into tube No. 2. When two tubes are being used 

 at the same time, they are placed side by side between the thumb 

 and forefinger of the left hand. The two plugs are held between 

 the second and third and the third and fourth fiingers of the left 

 hand, respectively. The wire may now be passed into the first 

 tube, which we wiU suppose to hold some material containing 

 bacteria, and a Uttle of this material may be removed on the tip 



