Acid Hydrolysates of Casein to Replace Peptone in the Preparation of Bacteriological Media

Abstract

The traditional use of “peptone” for the preparation of culture media for the growth of pathogenic bacteria often presents certain obvious disadvantages. On the one hand, its presence seriously interferes with the isolation in pure form of the various products of bacterial growth,—toxins, specific carbohydrates, etc. Again, the preparation of toxoids for prophylactic use from a medium which contains peptone is not without risk, for there are instances on record of severe reactions even to the minute amounts injected when it is employed as a diluent in the Schick test. An additional drawback lies in the variation between lots of peptone, even of the same brand, which is inevitable and due to the methods of production. It appears that too often these commercial products have been considered as chemical entities, the word “peptone” being used to imply a conception almost, if not quite as definite as “salt” or “glucose.”