No abstract

1. Red cells from different layers of centrifuged cells vary in composition. Cells obtained from the upper layer, which is relatively richer in reticulocytes, contain more water, sodium, potassium, chloride and phosphorus than the remaining cells. 2. The direct method of analysis of red blood cells using a constricted type centrifuge tube to separate the entire red cells sample from buffy layer cells and from plasma avoids the errors in direct analysis caused by different cell population in upper and lower layers of centrifuged cells and the cumulative errors inherent in indirect analysis. 3. Using the direct method and a constricted type centrifuge tube, the means and standard deviations of the water and mineral content of the erythrocytes and plasma of 11 normal males and 11 normal females were determined. Males were found to have a higher sodium content of red cells and plasma. 4. The sum of the molal concentrations of sodium, potassium, chloride and phosphorus in red cells is not always equal to the sum of the molal concentrations of these minerals in the plasma.