54 MICRO-ORGANISMS AND DISEASE [CHAP, 



altogether out of the tube and cotton-wool plug, and push 

 this latter down with the forceps into its former position. 

 Immediately after this proceed to inoculate the new culture- 

 tube by doing exactly the same as before — viz., draw up 

 slightly with .the forceps the top part of its cotton-wool plug, 

 push through the remainder of this plug the pointed end of 

 the capillary pipette, i.e. the one containing the droplet of 

 the material to be sown, and push it into the material at the 

 bottom of the test-tube or flask. A trace of the sowing 

 material flows out by itself, or, if a large quantity is required, 

 it is carefully blown from the pipette, but, of course, not 

 so that the tube is emptied by the blowing. If the sowing 

 is to be carried out on the surface of solid material, the 

 seed is deposited on the surface ; if in the depth, the end of 

 the pipette is pushed down into the depth of the material 

 and the seed there deposited. The pipette is then altogether 

 withdrawn and the plug replaced as before. The new tube 

 is then placed in a beaker on a cushion of cotton-wool, and 

 exposed to the required temperature in the incubator. 



The simple and now universally adopted method, par- 

 ticularly in a place kept ordinarily clean, is this : the culture- 

 tube or flask is held slantingly, the plug is withdrawn with 

 forceps, and with a sterile platinum needle or loop a trace of 

 the old culture is transferred to culture-medium in a new 

 tube or flask, also kept slantingly, and of which the plug has 

 also been withdrawn. After the transference, both the old 

 culture and new subculture are plugged, both plugs before 

 insertion having been passed through the flame. If the 

 new subculture is made on solid medium, the inoculation is 

 made either as stab-culture — i.e., by dipping the end of the 

 sterile platinum needle into the old culture material, then 

 stabbing (piercing) about the central part the new solid 

 medium ; streak-culture, by drawing the charged needle or 



