In our studies of the chronic rheumatic diseases we have resorted to various aids to facilitate the diagnosis and differentiation of chronic rheumatoid arthritis and osteo-arthritis. Because infection is considered the etiologic factor in some forms of these diseases, we have for some time sought diagnostic assistance from the study of the blood picture. The total white count and the conventional differential count are not sufficiently enlightening in chronic arthritis.1 In the study of acute infections, Schilling's modification2 of the Arneth count has received widespread approval. In many chronic infections, however, particularly in the chronic rheumatic diseases, the procedure still has to demonstrate its value. Schilling2 states that "in rheumatoid conditions only slight changes in the hemogram are found." No extensive hemogram studies, outside of a few sporadic case reports,3 have appeared in the literature of chronic arthritis until the recent study of Eaton.4 He