56 METHODS OF CULTIVATION OF BACTERIA. 



backwards, i.e. away from the right palm. Remove plug 

 from culture with right forefinger and thumb, and continue 



to hold it between 

 the same fingers. 

 Now touch the cul- 

 ture with the pla- 

 tinum needle, and, 

 withdrawing it, re- 

 place plug. In the 

 same way remove 

 plug from tube to 

 be inoculated, and 

 plunge platinum 

 wire down the 

 centre of the gela- 



FIG. 15. Another method of inoculating tine to Within half 



an inch of the 



bottom. It must on no account touch the glass above the 

 medium. The wire is then immediately sterilised. The 

 sub-culture is labelled, and in a bacteriological laboratory 

 a label should never be licked. If one or other tube 

 contain a liquid medium, it must be held bottom down- 

 wards between the same fingers. When a stroke culture 

 is made the same manipulations are gone through. Here 

 the platinum loop is used, and a little of the culture 

 is smeared in a line along 

 the surface of the medium 

 from below upwards. In 

 inoculating tubes, it is 

 always well, on removing 

 the plugs to make sure 

 that no strands of cotton 

 fibre are adhering to the 

 inside of the necks. As 



,, i , i i i FIG. 16. Rack for platinum needles. 



these might be touched 



with the charged needle and the plug thus be contaminated, 

 they must be removed by heating the inoculating needle 

 red-hot and scorching them off with it. When the platinum 



