[Editorial: Discrepancies in granulocyte survival time (author's transl)]

Important discrepancies between the renewal rate of mature granulocytes measured by in vitro labelling with DF 32P and with sodium chromate 51Cr are observed. The possible explanations are reviewed: errors made in the drawing of the experimental curve of the radioactivity disappearance; labelling of long-living lymphocytes with chromium; elution of 32P; toxicity of DFP for the tagged cells. If the renewal-rate measured by using 51Cr is the real one, as it seems to be, currently accepted models of granulopoiesis will need reappraisal.