Migration patterns of the hemolysis curves of SS RBCs from the light, reticulocyte-rich fraction during Ca²⁺-induced dehydration. Patterns shown are representative of 4 experiments with blood from 3 donors. Control (•) curve shows the distribution of osmotic fragilities in this RBC fraction before Ca²⁺ permeabilization. Time intervals for the other 3 curves are the sampling times after A23187 addition. Note the marked heterogeneity of osmotic fragilities and dehydration responses characteristic of this SS cell fraction.