The Spherical Form of the Mammalian Erythrocyte Iv. Disk-sphere Transformations between Surfaces Covered with Monolayers

THE most suggestive observation which we have regarding the remarkable disksphere transformation which occurs when mammalian red cells in saline are enclosed between slide and coverslip is that the velocity and extent of the shape change depends on the distance between the surfaces, and upon whether or not both surfaces are wetted by the suspension medium (Ponder, 1929). Thus the transformation occurs rapidly and completely between two glass surfaces 50 /i apart, but slowly and incompletely between two glass surfaces 1 mm. apart, and paraffining of both surfaces, or the substitution of surfaces unwetted by saline, prevents the shape change completely. That the transformation is due to electrostatic charges on the surfaces, pressure, or diffusion of alkali from the glass, has been disproved experimentally (Ponder, 1929, 1936), and the only suggestion which still .remains is that the surfaces have an orienting effect, of an obscure nature, on a "liquidcrystal" structure in the red-cell envelope. Since the extent to which the opposing surfaces are wetted by the suspension medium is of such importance, we have carried out experiments in which the glass surfaces were covered with hydrophilic and with hydrophobic surface layers. It is with these, and with certain unexpected results which have been obtained, that this paper is concerned.