SSOCIATED PROLIFERATION of the various hematologic elements in the marrow, although recognized for some time,2 has recently been the subject of renewed interest.3’8 A close relationship between myelofibrosis and he leukoerythroblastic conditions was demonstrated by Vaughan and HarrisonT in 1939. They suggested that an unknown stimulus acting on the primitive mesenchymal reticulum cell may be re...

The quantitative relationship between red cell volume, erythropoietin level, and erythropoiesis was evaluated in 43 human beings. Results in normal man were compared with studies in patients with anemia from bone marrow failure and with polycythemia vera. The maximum erythropoietin excretion after bleeding normal men was similar to the basal levels found in patients with chronic anemia of simil...