The mutual effect of hydrogen ion concentration and osmotic pressure on the shape of the human erythrocyte as determined by light scattering and by electronic cell volume measurement.

The measurement of the fluctuations of the scattered light were the source of information on the flatness of erythrocytes. Data on cell volume, together with the measure of scattered light fluctuations, defined the cell shape. The measurements were repeated in a wide range of osmotic pressures and pH values in order to affect both the hemoglobin and cytoskeleton. Major volume changes were detected at low osmotic pressures and pH. The erythrocyte volume was determined by electronic volume measurement. The cell flatness is maximal at physiological conditions.