A Useful Selective Bactericidal Property of Tergitol-7.

Starch tryptone agar containing 1 : 20,000 Tergitol-7 was successfully sterilized in the Arnold by one 30-minute heating period. Decreasing the concentration to 1 : 30,000 resulted in 4 per cent failures. A concentration of 1 : 20,000 in the cold killed spores of B. mycoides and an unidentified heat-resistant bacillus but failed to kill spores of B. subtilis. Concentrations of 1 : 30,000 permitted growth after sterilization of all species of Streptomyces which were tested, while concentrations of 1 : 20,000 permitted growth of all species but one. Concentrations of 1 : 20,000 did not inhibit the growth of selected species of Penicillium and Aspergillus or of Staph. aureus. Concentrations as high as 1 : 10,000 did not inhibit the growth of E. coli.