The group of diseases commonly included under the terms Hodgkin's disease, lymphosarcoma, leukemia, mycosis fungoides and others even less sharply defined, is still so obscure as to etiology and interrelationship that any attempt at classification must, of necessity, be incomplete and unsatisfactory. Although the "Handbuch der Haut-und Geschlechtskrankheiten" still aims to maintain these diseases as entities, there has been a growing tendency in this country to regard them as varied clinical manifestations of the same disease,1 and as comparable to such known specific diseases as syphilis, tuberculosis and leprosy in their varied clinical manifestations. Mallory,2 and later Keim,3 suggested the term lymphoblastoma for the entire group. Our experience also harmonizes with and accentuates the conception that the diseases that make up the group are genetically closely related. In a considerable number of the cases at the Mayo Clinic manifestly belonging to this group,