CERTAIN PHASES OF NITROGENOUS METABOLISM IN BACTERIAL CULTURES'

The classification of bacteria has been studied from different viewpoints since the researches of Pasteur. With the exception of the three great groups of bacteria, the form of the cell is not a very satisfactory means of differentiation. There is left, then, one method of study that is applicable and that method is the study of the metabolism of the bacteria. The determination of the ability of the bacteria to ferment various carbohydrates has been studied extensively. The study of the nitrogenous metabo-lism has, however, been confined for the greater part to the identi-fication of such compounds as indol or the determination of the ability of the bacteria to grow in certain nitrogenous media. The paucity of such data is the result of the complication of the subject with an unusual number of factors and, furthermore, of the fact that precise chemical methods have been wanting to give quantitative results. LITERATURE Hirschler (1886) was probably the first to observe that the presence of carbohydrate inhibited the production of such nitrog-enous decomposition products as indol, phenol and the cresols. Smith (1897) and.Peckham (1897) independently came to the conclusion that the production of acid in the medium containing carbohydrate inhibited the formation of indol. This early wor