In explaining the erythrocyte sedimentation reaction the majority of investigators have limited themselves to the study of the physicochemical changes that occur in the plasma and have paid little attention to the erythrocytes. The few attempts made to study the latter have been on citrated or oxalated blood. These anticoagulants, however, as will be shown later, so alter the quantitative relationship between the plasma and the cells as to render their use unsuitable for the study of the erythrocytes. The use of hirudin offers the best available means of keeping the blood in fluid condition without otherwise changing its composition. Its recent use by Gram and Norgaard1 for the determination of standards of hemoglobin, cell count and cell volume for healthy persons suggested its employment in studying the same factors in conjunction with the sedimentation reaction.
Specimens of blood were obtained before breakfast from ten healthy adults (physicians and