Introduction
In the majority of patients with chronic hemolytic anemia either of acquired or congenital type, reticulocytosis and persistent increases in bilirubin globin are the prominent characteristics. However, hemoglobinemia and hemoglobinuria are rarely found in these patients even during their hemolytic crisis, when a considerable amount of blood is presumably destroyed, as indicated by the rapid fall of the hemoglobin level and hematocrit in a relatively short period. On the contrary, however, in patients with acute hemolytic anemia the earliest and most outstanding findings are marked hemoglobinemia and hemoglobinuria, which are, as a rule, followed by an only temporary increase in bilirubin globulin in the the plasma and reticulocytes in the peripheral blood.This discrepancy leads us to think that the cells of the reticuloendothelial system (perhaps the liver and the spleen of patients with chronic hemolytic anemia) may be capable of adapting to, or compensating for, the process of