Coverslip holders for cuvette based fluorescence measurement, models CCH-1 and CCH-2 hold an 11 by 22 mm coverslip with cultured cells attached at the proper position in a standard 12.5 mm cuvette for fluorescence measurements. Adequate space is provided at the base of the cuvette for a magnetic stir bar. CCH-2 provides tubing for perifusion of cells during experiments. Both models allow the introduction of reagents by a microsyringe aperture.