Lick ratios (mean ± SE) for B6 and D2 mice to concentration series of QHCl (A), PROP (B), MgCl2 (C), and RUA (D). The dotted lines on each graph represent a ratio score of 1.0, which indicates a lick rate equal to that of water. Asterisks identify significant strain effects at particular concentrations, as indicated by planned comparisons (p < 0.01). Lick ratios for each strain generally decreased with increasing concentration; B6 made fewer licks than D2 mice to high concentrations of QHCl (A) and PROP (B), and to both low and concentrations of MgCl2 (C). D2 mice made fewer licks than B6 mice at almost all concentrations of RUA (D).