Identification and Counting of Granulocytes by Peroxidase Reaction

The present investigation concerns a staining method based on peroxidase activity which can be used for the specific staining of granulocytes both in the counting chamber and in smears. The reagent employed at pH 7.0 contained low concentrations of hydrogen peroxide as substrate, benzidine as chromogenic hydrogen donator and 2,4-dichlorphenol as catalase inhibitor. The only positively reacting cells, granulocytes, stained brown. The other cells failed to stain.

The observations made support the view that the peroxidase reaction of eosinophils differs slightly from that of neutrophils.

Nearly exactly two-thirds of the bone marrow cells of adult male rats of the Sprague-Dawley strain belonged to the myeloid cell series.