56 METHODS OF CULTIVATION OF BACTERIA 



FIG. 14. Another method of inoculating 

 solid tubes. 



To inoculate, say, one ordinary upright gelatin tube from 

 another, the two tubes are held in an inverted position between 

 the forefinger and thumb of the left hand with their mouths 

 towards the person holding them ; the plugs are twisted round 



once or twice, to make 

 sure they are not adher- 

 ing to the glass. The 

 short, straight platinum 

 wire is then heated to 

 redness from point to 

 insertion, and 2 to 3 

 inches of the glass rod 

 are also passed two or 

 three times through the 

 Bunsen flame. It is 

 held between the right 

 fore and middle fingers, 

 with the needle project- 

 ing backwards, i.e., away 

 from the right palm. 

 Remove plug from cul- 



ture tube with right forefinger and thumb, and continue to 

 hold it between the same fingers by the part which projected 

 beyond the mouth of the tube. Now touch the culture with the 

 platinum needle, and, withdrawing it, replace plug. In the 

 same way remove plug from tube to be inoculated, and plunge 

 platinum wire down the centre of the gelatin 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. 

 A variation in detail, of this 

 method is to hold the plug 

 of the tube next the thumb 

 between the fore and middle 

 fingers, and the plug of the 

 other between the middle and 

 ring fingers, then to make the 

 inoculation (Fig. 14). If a 

 tube contain a liquid medium, 

 it must be held in a sloping 

 position between the same 



fingers, as above. For a stroke culture 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 



FIG. 15. Rack for platinum needles. 



