Multiplication of Bacteria and the Influence of Temperature and some other conditions thereon

Abstract

The species of organisms used were B. coli, B. typhosus and B. enteritidis Gaertner. With these organisms:(1) When a fresh broth culture is made with a small inoculation there is a period during which there is no increase in the number of bacteria present.(2) When this period is over the bacteria commence to divide regularly; this is shown by the fact that the logarithms of the numbers plotted against time are found to fall on a straight line. This regular growth persists until (or nearly until) a maximum has been reached, after which the numbers remain more or less constant and then slowly decline.The time necessary for a complete division to take place (generation time) was determined for various temperatures between 20°C. and 42°C.(3) The effect of temperatures between 20° and 35.3°C. upon the rate of multiplication is in accordance with the Arrhenius-Van 't Hoff law; above this temperature the effect diminishes.