Time-lapse videotape recordings of polymorphonuclear leukocytes (PMNs) from clot preparations were used to quantify the locomotive behavior of individual PMNs from normal subjects. Tracings derived from the videotapes allow one to quantify multiple parameters of the locomotive behavior of PMNs--direction, distance, rate, and angle of turn. The results obtained are reproducible from subject-to-subject and from preparation-to-preparation. The method allows the investigator to record the locomotive behavior of 100 cells simultaneously within a 5- min period and analyze the recording as time permits. We utilized this technique to compare the locomotive behavior of slow and fast PMNs (arbitrarily defined as cells that move less than or equal to 7.0 micrometer/min and greater than 7.0 micrometer/min mean rate of locomotion, respectively). The studies show that slow and fast PMNs, thus defined, differ not only in mean rate of locomotion but also in their rate of locomotion during periods of active locomotion, in the number of periods of inactivity/PMN/5 min (slow = 1.65 +/- 0.31; fast = 0.36 +/- 0.12), and in their turning behavior as measured by angle of turn (slow = 92 degrees +/- 39 degrees; fast = 39 degrees +/- 35 degrees). These results show that human PMNs from clot preparations are remarkably heterogeneous in their locomotive behavior, and the results suggest this heterogeneity is due to endogenous differences within cells.