The area and volume of single human erythrocytes during gradual osmotic swelling to hemolysis

Abstract

A double-chambered slide was designed for the microscope which would enable continuous viewing of cells hanging on edge in a Ringer solution which was gradually being reduced in osmotic pressure. This was achieved by putting a dialysis membrane between the cell chamber and a chamber containing distilled water. Photographs were taken at 1-min intervals of single cells on edge (revealing the biconcave profile) until the cells hemolyzed, usually within 30 min. The area and volume of revolution of each cell were calculated from measurements on photographic enlargements. No significant change in area occurs during the swelling series although the red cell changes gradually from biconcave to spherical and remains spherical for approximately 7 min before hemolyzing. This stability is best explained by a leakage of potassium ion from the cell prior to hemolysis (which has been reported by Seeman to be approximately 20%).