A Method for the Permanent Staining of Reticulated Red Cells

In the clinical study of pathologic conditions of the blood and bone marrow, the recognition of immature forms of red cells is often of great importance. In specimens fixed and stained by the ordinary methods, the chief evidence of immaturity are the presence of nucleated, polychromatophilic and probably stippled red cells. With the possible exception of the nucleated erythrocyte, however, none of these forms has been generally studied with a view to obtaining a quantitative index of the variation in bone marrow activity. This is undoubtedly due to the fact that they are rarely found in normal blood, and that even in conditions in which a stimulation of the bone marrow may be assumed they may be present in very small numbers. In this connection considerable interest has been manifested in recent years in the so-called "reticulated cells," in which a fine or coarse network, or a fine granulation arranged