An apparatus for time‐lapse cinemicrography of living animal cells
in vitrois described. It has an increased information capacity in comparison with conventional types of equipment in that successful combination of the highest possible spatial resolution with phase contrast microscopy and an improved temporal resolution provided by flash light illumination has been achieved. The interval between exposures of 1/200 s approximately can be reduced to 1/4 s using a negative phase‐contrast objective of NA 1·3. Negative phase‐contrast also appeared to be the best technique for imaging of tiny cell surface structures. Thus the new apparatus is suitable for the study of the patterns of cell surface motility in vitro.