Culture Media for Drosophila. I. Changes in Hydrogen Ion Concentration of the Medium

Abstract

In this paper it is shown that the hydrogen-ion concentration of the medium increases with the age of the culture until a point of buffered equilibrium is reached, in cultures of Drosophila melanogaster, on both banana and a synthetic medium. The total acid per gram of medium increases throughout the life of the culture as long as relatively large numbers of flies are present. The biological relations suggest that the synthetic medium here described is better suited to practical fly husbandry than is the standard banana medium, and demonstrate that the presence of fresh banana, or any other fruit, is in no wise biologically essential as a constituent of the food medium in the culture of Drosophila as far as concerns the processes of reproduction.