LABORATORY BACTERIOLOGY 



EXERCISE I 



CLEANING GLASSWARE 



1. It is necessary that the glassware employed should be 

 thoroughly cleaned before it is used. Several special methods 

 have been suggested for this purpose, but the one frequently 

 employed by chemists seems to be the most easily handled 

 and quite as efficient for general use as the more elaborate, 

 specialized processes. It consists in applying the chromic 

 acid cleaning mixture after washing the tubes and flasks with 

 water. Experience has taught that usually this method may 

 be abandoned, as a strong alkali is quite sufficient to clean 

 the ordinary glassware. It is sometimes necessary to employ 

 more special methods for cover glasses which are to be used 

 in staining bacteria where a mordant is required. Only one 

 of these special methods will be given here. 



2. Work for this exercise. Clean all the glassware, test 

 tubes, fermentation tubes, flasks, Petri dishes, and reagent 

 bottles assigned. 



If the next laboratory period occurs on the following day, 

 place the flasks and test tubes in the incubator to insure their 

 being dry before they are plugged. 



Put the slides and cover glasses in the cleaning mixture ; 

 they can be rinsed and wiped later. 



Read the laboratory maxims. 



3. Methods to be followed in cleaning the different appa- 

 ratus, (a) Test tubes. Wash the tubes carefully with a strong 

 alkali soap and water, using the test-tube brush. Rinse the 



