Loss in motility with polymer added into the medium of synchronized SB3860 swarmer cells. A. Fraction of motile cells plotted versus PEG 4000, PEG 35000, and PEO 400000 in weight percentage. B. The same data collapsed to a single line when re-plotted as a function of viscosity. The errors bars, some smaller than the symbols, represent the standard errors of the mean. The numbers of cells counted were 531 in PEG 4000, 5884 in PEG 35000, and 1191 in PEO 400000.