FIGURE 3.

The chemotactic velocity V_C as a function of time t elapsed in a movie to test for convergence of V_C as described in the text. The solid line shows an experiment where V_C converged to 7.1 μm s⁻¹, and the dotted line corresponds to a run where V_C did not converge. The latter case was discarded from further analysis. The cumulative trajectory time for the two cases was 907 and 494 s, respectively. A recording time of 9.4 s was typically sufficient to ensure convergence, and only 2 out of 28 experiments failed to converge.