In 1922, Schultz1 described four patients with gangrenous throat lesions and marked leukopenia due to a decrease or absence of granular cells from the peripheral blood. The patients were all women of middle age, all died, and at autopsy very few myeloid cells were found in the bone marrow. Schultz designated the condition, agranulocytosis, and considered it a definite clinical entity. Since this first report, many similar cases have been reported, largely from Germany and America. Numerous names other than agranulocytosis, such as, agranulocytic angina, malignant neutropenia, idiopathic neutropenia, pernicious leukopenia, granulocytopenia, and granulopenia have been suggested to indicate the syndrome described by Schultz. The word, granulopenia, best describes the condition since it is primarily a decrease in the granular cells of the blood. Idiopathic granulopenia refers to granulopenia occurring without apparent cause. The subject has been in a confused state but increasing study suggests that leukopenia and necrotic lesions represent a symptom complex and not a clinical entity. It is now known that every degree of severity of both clinical symptoms and blood findings may be encountered. What Schultz observed was a high degree of bone marrow involvement which often occurs in much milder form as a result of the same etiologic agent or agents. It is now also evident that changes observed in the peripheral blood only reflect bone marrow disease, so no correct picture of the condition is possible without correlating the pathology of the bone marrow with the clinical and laboratory findings. This has been well. . .