Addition of polyethylene glycol (PEG) (final concn. 10%) to the culture medium of B. subtilis H, consisting of 0.5% glucose, 1% peptone, 0.5% meat extract, 0.2% yeast extract, and 0.2% NaCl at pH 7.2, with 0.15[image] phosphate buffer added for maintaining pH, did not change the rate of cell division after the lag period, but subsequent amylase formation was markedly accelerated. Added inorganic P increased amylase production, regardless of PEG addition, though inorganic P alone had no effect on cell division. Old cells may be exclusively responsible for yielding amylase. In a soy medium PEG caused a long-lasting acceleration of amylase formation with increasing PEG concentrations. Neither metabolism of PEG nor change in oxidation of added glucose was demonstrated. The addition of 5-10% sucrose reduced amylase production, presumably due in part, to acidifying, but 15% sucrose slightly accelerated enzyme yield.