4 GENERAL MICROBIOLOGY 



4. Rinse with alcohol. (Alcohol may be used repeatedly.) 



5. Drain. 



Fermentation Tubes. 1. Rinse with tap water. 



2. Fill with cleaning solution and heat fifteen minutes 

 in steam or allow to stand over night if more convenient. 



3. Wash thoroughly in tap water, using a test-tube 

 brush if necessary. 



4. Rinse in distilled water and drain. 

 Cover-glasses and Slides. 1. Immerse the cover-glasses 



or slides, one by one in a 10% solution of sodium hydrate 

 (NaOH) for thirty minutes only. This strength of NaOH 

 will etch the glassware if left longer. 



2. Wash separately in tap water, handling with ordinary 

 forceps.* 



3. Put, one at a time, in cleaning solution, and leave 

 over night as convenient. 



4. Wash separately in water. 



5. Immerse in clean alcohol (95%). 



6. Wipe with a clean physician's cloth. 



7. Store in clean Esmarch and deep culture dishes 

 respectively, to keep free from dust. 



Other Glassware. Some modification of these methods 

 will be adaptable to nearly all glassware. 



Note 1. Glassware containing liquefiable solid media is best 

 cleaned by heating and pouring out the material while in liquid 

 condition, then treating as above. (Solid media when liquefied by 

 heat should never be thrown in the sink, as it will solidify when 

 cold and clog up the traps and drains.) 



Note 2. Flasks, test tubes, Petri dishes, etc., containing 

 cultures, must be heated one hour in flowing steam before cleaning. 



Cultures containing spores should be autoclaved previous to 

 cleaning. 



Note 3. If cultures or media have become dry, add water 

 before heating. 



Especial care must be used in cleaning glassware in which mer- 

 curic chloride or any other disinfectant has been used. 



* Always handle cover-glasses and slides with forceps. 



