l8 GLASS APPARATUS IN COMMON USE 



is bent in the bat's-wing flame, to an acute angle, and 

 the open extremity of the long arm sealed off in the 

 blowpipe flame. The open end of the short arm is 

 rounded off and then plugged with cotton- wool, and 

 the tube is ready for sterilisation. 



CLEANING OF GLASS APPARATUS. 



All glassware used in the bacteriological laboratory 

 must be thoroughly cleaned before use, and this rule 

 applies as forcibly to new as to old apparatus, although 

 the methods employed may vary slightly. 



To Clean New Test=tubes. 



1. Place the tubes in a bucket or other convenient 

 receptacle, fill with water and add a handful of " Sapon " 

 or other soap powder. See that the tubes are full and 

 submerged. 



2. Fix the bucket over a large Bunsen flame and boil 

 for thirty minutes or boil in the autoclave for a 

 similar period. 



3. Cleanse the interior of the tubes with the aid of 

 test-tube brushes, and rinse thoroughly in cold water. 



4. Invert the tubes and allow them to drain com- 

 pletely. 



5. Dry the tubes and polish the glass inside and out 

 with a soft cloth, such as selvyt. 



New flasks, plates, and capsules must be cleaned in 

 a similar manner. 



To Clean New Graduated Pipettes. 



1. Place the pipettes in a convenient receptacle, 

 filled with water to which soap powder has been added. 



2. Boil the water vigorously for twenty minutes over 

 a Bunsen flame. 



3. Rinse the pipettes in running water and drain. 



4. Run distilled water through the pipettes and 

 drain. 



