The Influence of Inorganic Salts on the Multiplication of Gonococcus

Abstract

A study was made of the growth-supporting properties of solid media containing 1% glucose, 2% agar, 25% tryptic digest of dialyzed egg-white (content of ions under consideration determined). and varying concentrations of certain inorganic salts. Na and K were interchangeable and non-toxic at high concentration. Ca and Mg were unessential, but inhibited growth at concentrations greater than 30 millimols per liter. Citrate and oxalate nullified the toxic action of Ca but not of Mg. Growth occurred at pH 6.0-8.2, with optimum at 7.0-7.6. Unless media were well-buffered either with bicarbonate or phosphate, growth did not occur. Chloride was replaceable by nitrate or sulphate without impairing growth. Below osmolar salt concentrations of 150 and above 550 millimols per liter, growth was inhibited.