The oxidase reaction is considered specific for the myeloid series of cells (polymorphonuclears, myelocytes and myeloblasts) and its performance is briefly summarized as follows: A normal blood smear is fixed in formaldehyd vapor and then flooded with a mixture of alphanaphthol (1 per cent.) and dimethylparaphenylenediamin (1 per cent.) for a few minutes. On examination the smear will show the presence of blue granules in the polymorphonuclear cells and no granules in the lymphocytes. The blue granules are supposed to be due to the synthesis of indophenol blue from the oxidation of alphanaphthol and dimethylparaphenylenediamin, the condensation of the molecules being effected by an oxidizing ferment or oxidase, which is present in the premature and mature bone marrow cells.
During the course of an investigation of the classification of the leukocytes in normal and abnormal blood I have had occasion to perform the oxidase reaction for the demonstration of the