Abstract
The disadvantages of ordinary Loeffler''s blood serum are discussed. A modification is suggested which contains glycerol and cystine to promote growth and metabolism of Corynebacterium diphtheriae, K2HPO4 and proteose-peptone for their buffering action, Na2S to enhance granule-formation, and hog or human serum. This medium supports luxuriant growth of the organism in the presence of Staphylococcus aureus.