Abstract

In these experiments 10 and 100 mgm. per cent of sodium paranitrobenzoate had a temporary bacteriostatic effect on a strain of Streptococcus viridans, whereas with 200 and 400 mgm. per cent this effect was absent or slight. With increase of bacterial multiplication, measurable amounts of amino compound detectable by diazotization were present in the cultures. This amino compound was formed in larger amounts with the higher concentrations of paranitrobenzoate and with the larger inocula of bacteria.

The bacteriostatic action of the paranitrobenzoate was prevented by the addition of small amounts, 0.05 mgm. per cent, of sodium para-aminobenzoate to cultures.

Para-aminobenzoate alone had no demonstrable effect on the growth activity of this strain of Streptococcus viridans.