The Relation of the Growth of Certain Micro-organisms to the Composition of the Medium

THIS investigation had as its main object the study of the influence of the ill-defined growth-promoting factor known as bios on the development of uni- cellular organisms in artificial media. In the early stages it became apparent that no appreciable progress could be achieved until the other essential requirements had been more clearly defined. In particular, this referred to their needs for inorganic salts and the most suitable sources of carbon compounds from which they could derive the necessary energy for their metabolic processes.