Abstract
Leukocytes from severely bled rabbits were sedimented and introduced in diffusion chambers that were implanted intraperitoneally into donor animals during the same day. Erythroblasts were found in the Millipore chambers on the fourth day culture. They were present in large numbers from the seventh to eighth day when they comprised 47.5 per cent of the nucleated cells present. Concomitantly, the young classes of reticulocytes, never found in controls, were detected in the diffusion chambers of bled animals, after more than 4 days of culture. It was assumed that: (1) Some circulating leukocytes may develop into erythroblasts under the influence of endogenous erythropoietin. (2) Under the experimental conditions employed, bleeding promoted only erythropoiesis within the implanted diffusion chambers containing leukocytes. There was no evidence of granulopoiesis and thrombopoiesis.
