Studies on Bacterial Nutrition. v. the Effect of Plant Tissue upon the Growth of Anaerobic Bacilli

In the case of the pneumococcus, a seeding so minute as to cause in dextrose broth a period of bacterial lag extending over 18 hours will amply suffice to induce prompt growth in plain broth to which pieces of sterile unheated potato have been added. The presence of vegetable tissue causes other changes in the configuration of the growth curve. There is a prolongation of both the stationary phase and phase of decline of the pneumococcus culture. Moreover, in plant tissue medium the zone of pH within which growth can be initiated is extended beyond the acid and alkaline limits of the range in ordinary bouillon. A study of the behavior of other Gram-positive organisms shows that the growth of Streptococcus viridans and Streptococcus hcemolyticus is greatly accelerated in vegetable tissue media.