Although less than a quarter of a century has elapsed since the malady known as erythremia, polycythemia rubra vera or Vasquez-Osler disease attained prominence as a medical entity, it can no longer be regarded as an extremely rare condition. The larger clinics of this country can now furnish the case histories of a considerable number of patients for whom the diagnosis has been clearly established. The unfavorable prognosis and course of the disease place a premium on accurate information that may become the basis of progress in the understanding of this baffling condition. Very early, the assumption of splenic tuberculosis as the foremost etiologic factor was negated, and grounds were uncovered for believing that erythremia is due to a primary hyperplasia of the erythroblastic bone marrow.
The increased activity of bone marrow is reflected in the peripheral blood, as Minot and Buckman 1 of Harvard have pointed out in an