The Biphasic Appearance of Labelled Lymphocytes in the Blood after Single Injections of H3‐Thymidine

Abstract
In earlier work Fichtelius (1951) demonstrated a biphasic appearance of labelled lymphocytes in the blood after a single injection of P32 as orthophosphate. The second activity increase was at that time explained in three alternative ways: re‐circulation, reutilization or delayed output.This biphasic appearance of labelled lymphocytes in the blood was confirmed in this new study in rabbits using H3‐thymidine. To‐day all three alternative explanations are still possible and more work is needed for a certain interpretation of the second activity peak observed.