Osmometric behavior of blood cells and of whole body cells

¹ Department of Physiology, Washington University School of Medicine, St. Louis, Missouri

When mannitol was added to heparinized dog blood the shrinkage of cell volume agreed with that predicted on the basis of perfect osmometer behavior, i.e., R = 1. After infusion of hypertonic mannitol in saline the ratio of observed to predicted cell hematocrit was somewhat less than that predicted on the basis that whole body cells are perfect osmometers, i.e., R for whole body cells was greater than 1. When allowance is made for the sodium calculated to have moved out of body cells the agreement between observed and predicted cell hematocrit becomes quite close.