Peptone Solution 189 



producing bacterium (Bacillus coli) and placed in the ther- 

 mostat. Early next morning the infusion, covered with a 

 thin layer of froth, is boiled, filtered, peptone and salt added, 

 and the neutralization and sterilization carried on as usual. 



Other culture media employed for special purposes will be 

 mentioned as occasion arises. 



