i8 LABORATORY GUIDE IN BACTERIOLOGY 



filtered rapidly by the use of suitable apparatus, as illus- 

 trated in Fig. lo. At the connection with the vacuum 

 pump a valve should be inserted — or a flask with a rub- 



FlG. lo 



Filtering Media by Means of Vacuum Pump 

 a. Liquid medium c. Reiiex flaslc 



6. Absorbent cotton /. Rubber stopper with two holes 



c. Rubber stopper g. Connection with aspirator 



d. Filtered medium 



ber cork with two holes may take its place — to prevent 

 the water from entering the flask. 



Whichever method is employed, the filter must always 

 first be soaked in hot water, or, better, kept in steam 

 until used. 



