Abstract
1. Studies of the volume distributions of normal human, canine, and chicken erythrocytes through the use of a Model B Coulter electronic particle counter and plotter of 400 channel analyzer have confirmed that the instrument provides a true reflection of cell volume, independent of the conductivity of the medium, independent of the shape of the erythrocyte, independent of the buffers, and independent of the anticoagulants employed.
2. The non-Gaussian distribution pattern of normal human cells has been confirmed, but no evidence has been found for a distinct bimodal distribution pattern in cells which have been freshly collected, pipetted, and examined.
3. Swelling of human erythrocytes in 0.5 per cent NaCl alters the volume distribution pattern to that of a normal distribution, and the distribution pattern of hemoglobin-free ghosts in 1 per cent NaCl is more nearly symmetric than that of normal intact red cells in 1 per cent NaCl.
4. The Gaussian distribution of erythrocyte volumes in 0.5 per cent NaCl suggests a normal distribution pattern for both the critical volume and ionic content of red cells.
5. The asymmetry of red cell volume distribution at the tonicity of plasma appears related to higher intracellular osmotic activity in the smaller cells, based on the anomalous osmotic coefficient of hemoglobin. It is suggested, therefore, that skewing of the curve is related to asymmetry of the distribution pattern at the lower end of the volume spectrum, rather than the upper end.
