DISINFECTANTS 



487 



9. Take up 0.5 c.c. of B. coli emulsion in sterile 

 pipette graduated in tenths of a cubic centimetre and 

 stand by. 



10. As soon as the bell rings lift the pipette from 

 tube A with the left hand and from the charged pipette 

 held in the right hand deliver o.i c.c. of B. coli emulsion 

 into the i : 100 solution. Then replace the pipette and 

 washer. 



FIG. 219. Test-tube rack. 



IT. Raise the tube with the left hand and shake it to 

 mix germ and germicide, whilst returning the delivery 

 pipette in the right hand. 



12. Repeat the process with tubes B, C, D and E; 

 then drop the infected delivery pipette in the lysol jar. 

 The inoculation of the five tubes can be carried out 

 very expeditiously, but a period of 10 seconds must 

 be allowed for each tube. 



13. When the bell rings at 2j minutes blow through 

 the pipette in tube A (this agitates the germ + germicide 

 mixture and ensures the collection of a fair sample) ; 

 allow the mixture to enter the pipette, and as the 

 column of fluid extends well above the terminal 

 graduation, the right forefinger adjusted over the 

 butt-end of the pipette before it is lifted will retain 



