The distribution of leukocytes in Boyden millipore filters after stimulation with casein was determined after 30 and 180 min by the use of a photographic method. After 30 min the distribution was characterized by a second degree curve with a falling slope and after 180 min by a linear curve with a rising slope. The results showed that with most of the modifications of the Boyden method in use at present, the choice of incubation time is crucial for the evaluation of counting results.
