Figure 7. Examples of pH responses of related arginolytic and non-arginolytic bacteria (see Table) mixed in a 1:1 ratio and incubated with glucose at 4.2 mM and arginine at 3.3 mM. Total bacterial cell concentration was 8.3% (v/v). In all cases, the mixing of pure cultures of oral bacteria produced an intermediate result (from Wijeyeweera and Kleinberg, 1989b).