STUTZENBERGER, F. J. (University of Houston, Houston, Tex.), AND E. 0. BENNETT. Sensitivity of mixed populations of Staphylococcus aureus and Escherichia coli to mercurials. Appl. Microbiol. 13:570-574.1965.-Staphylococcus aureus was found to have a higher resistance to merbromin and mercuric chloride in the presence of Escherichia coli. The protective effect of the gram-negative organism on S. aureus was due to the production of extracellular glutathione and hydrogen sulfide and to an unequal distribution of the inhibitor between the two species. S. aureus did not significantly influence the resistance of E. coli to mercurials.