24 BACTERIOLOGICAL DIAGNOSIS. 



hand, pointing the mouth of the tube slightly down- 

 wards (so that no dust shall drop into it) and to the 

 right. Tubes of solid media should always be held in 

 this position during inoculation ; tubes of liquid media 

 are held in a similar way, but of course their mouths 

 must point upwards. 



2. Put the projecting portion of the cotton-wool plug 

 of the test tube into the flame so as to singe it ; this is 

 to destroy any germs which may have been deposited 

 upon it from the atmosphere. 



3. Sterilise the points of the forceps by passing them 

 slowly through the flame and then use them to remove 

 the plug. Place this between the ring and little fingers 

 of the left hand and put the forceps down. 



4. Take the platinum needle in the right hand, heat 

 the whole of the wire to redness, and pass the lower 

 three or four inches of the glass rod slowly through the 

 flame. Remember that every portion of the needle 

 which goes inside the tube must be sterilised in the 

 flame. Allow the needle to cool ; you should have 

 found out how long this will take by a previous 

 experiment. 



5. Dip the tip of the needle into the pus ; pass it into 

 the tube until it reaches nearly to the bottom of the 

 tube (now uppermost) and allow to rest upon the 

 sloping surface of the medium ; now withdraw it gently, 

 allowing the tip of the wire to trail gently along the 

 whole length of the sloped surface. Do not touch the 

 medium with the glass shoulder of the needle. 



6. Sterilise the needle as before. This step must 

 never be forgotten. 



7. Take the cotton-wool plug in the forceps, put it in 

 the flame, and singe all parts of its surface. Then plug 

 the tube while the wool is still burning. Label it. 



