270 



PRACTICAL DAIRY BACTERIOLOGY 



again for 20 minutes. Set aside another 24 hours and steam 

 again. The bouillon is now sterile and can be kept indefinitely. 



FIG. 72 FILTERING CULTURE MEDIA THROUGH ABSORBENT COTTON 

 The upper funnel containing cheese cloth, the lower absorbent cotton 



If the bouillon or any part of it is to be made into agar or 

 gelatin as shown below, the neutralization and sterilization may 

 be omitted. 



*No. 5. Agar Culture Medium. 



a. To 500 c.c. bouillon prepared as in (3) add 1.5% of agar 



