This paper compares procedures for qualitatively and quantitatively studying cellular responses to inflammatory substances. It was noted that estimates of total cells in the aspirated exudate suggested conclusions not obvious from data obtained from differential counts. These data suggest that the observed sequence of inflammatory cells is due not only to the initial migration of cells into the inflamed area, but to the rate of phagocytosis of the granulocytes by the macrophages. The inflammatory exudate of sensitized animals contained fewer neutrophils and greater numbers of eosinophils. Plasma cells and mononuclear cells with intense basophilic cytoplasm were frequently observed following the disappearance of eosinophils.