Knowledge of the metabolism of Pasteurella petsis remains fragmentary and indirect, despite the fact that plague has long been the subject of considerable research. Information concerning the nutritional requirements of P. pestis can be found in the reports of Rao, 1940b; Doudoroff, 1943; Hills and Spurr, 1952; Rockenmacher et al., 1952. Completely lacking are quantitative metabolic data on nonproliferating, resting cells. It is known that resting cells of P. pestis will oxidize a variety of organic compounds including carbohydrates, amino acids, and several metabolically important organic acids (Rao, 1940a). Doudoroff (1943) established that growing cultures metabolize glucose via pyruvate and that P. pestis will produce lactic, acetic, formic, and succinic acids, ethanol, C02, and small amounts of pyruvate anaerobically in complex media containing glucose.