22 LABORATORY GUIDE IN BACTERIOLOGY 



are required they may rest with the plugged end on a 

 glass rod or rubber hose until the agar has solidified. 



For the purpose of filtering media heavy filter 

 paper (Schleicher and SchuU No. 598) of the best 

 quality only should be used. This is especially im- 

 portant when filtering agar or gelatin. After the filter 



Q 



Fig. 12 



has been folded and inserted into the funnel hot water 

 should be run through the filter, until it is soaked 

 and warm. 



Method of folding filters (Fig. 13).— a and b) Take 

 a square piece of filter paper twice as wide as the depth 

 of the funnel and fold to half the size so as to make 

 No. I cover No. 2. (Compare with Fig. 13.) 



