The surface structure of mouse peritoneal cells—a study with the scanning electron microscope

SUMMARY Normal and stimulated peritoneal cells have been examined with the Stereo‐scan scanning electron microscope. Normal lymphocytes were identified by their small size; some had numerous small stubby or pointed processes on their surfaces. Macrophages were larger and had ridge‐like processes. Many of the stimulated cells showed no significant deviation from normal. Others, all macrophages, showed a marked deviation from the normal spherical shape. Ridge‐like processes were more prominent on their surfaces, and large flange‐like processes and a few finger‐like processes were seen. This suggests that on stimulation peritoneal cells become more deformable and therefore irregular in shape, and that their surfaces become rougher.