The Influence of Aeration and of Sodium Chloride upon the Growth Curve of Bacteria in Various Media

Abstract

In the course of studies on bacterial metabolism conducted in the Department of Public Health of Yale University, it became necessary to establish certain standard bacterial growth curves, so that periods could be selected which would represent with accuracy the lag phase, the phase of logarithmic increase and the maximum stationary phase (Buchanan (1918); Buchanan and Fulmer (1928)) or phase of peak stability (Winslow (1928)). Four different media were to be employed in the metabolism studies and the influence of these four media constituted the first phase of the research. Secondly, the metabolism observations were to be made in a medium constantly aerated with air freed from ammonia and carbon dioxide; the influence of this aeration must therefore be determined. Finally, the effect of stimulating and toxic salt concentrations upon metabolic products was an essential part of the problem; and the influence of these salt concentrations upon the growth curve must be accurately known. The determination of growth curves for these various conditions threw such light on certain phenomena related to the life cycle of bacterial populations and the effect upon this cycle of a