The effect of the accessory substances of plant tissue upon growth of bacteria

Abstract

The study of the properties of blood upon which depends the ability of the so-called hemoglobinophilic bacilli to grow in this medium, has shown that these properties are related to at least two factors which can be separately studied. Further studies have shown that both of these factors are present in plant tissue, (potato and banana), and that sterile unheated vegetable tissue can replace blood in the cultivation of B. influenzce. These observations have now been extended; yellow and white turnip, carrot, beet, parsnip, and sweet potato, when added to fluid media have been found to possess the same growth stimulating action as white potato.

It has been found that these vegetable tissues not only permit the cultivation of the so-called hemoglobinophilic organisms, but that they also greatly favor the growth of other entirely unrelated organisms. For instance, in the case of pneumococcus, not only is there a marked acceleration of growth, but a seeding too minute to initiate growth in plain broth alone, will amply suffice to induce abundant multiplication in the same medium to which small pieces of sterile, unheated vegetable have been added. Moreover in the plant tissue medium the zone of hydrogen-ion concentration within which growth can be initiated is considerably extended beyond the acid and alkaline limits of the optimal range in ordinary bouillon. In addition certain other bacteria, which ordinarily fail to grow in the presence of free oxygen, multiply in a medium containing fresh plant tissue even though no precautions are taken to are taken to exclude air. It is evident, therefore, that the presence in media of certain substances contained in fresh plant tissue not only supplies the necessary factors for growth of the hemoglobinophilic bacilli, but furnishes the requisite requirements for the cultivation of other bacteria which multiply only under certain restricted conditions.