ABSTRACT
The most suggestive observation which we have regarding the remarkable disk-sphere 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 50μ. 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,2 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.
Dr Douglas Marsland tells us that he has subjected red cells to as much as 7000 lb. pressure in a bomb without the spherical form being assumed.
Waller’s observation that red cells do not become spherical between slides and cover-glasses which have been freshly cleaned with ether is possibly accounted for by the fact that washing with ether is very apt to leave a thin film of hydrophobic material on the glass, unless the ether is exceedingly pure.
If the number of cells which haemolyse from minute to minute, expressed as a percentage of the total, is plotted against time, excellent sigmoid curves result from these experiments. We have never observed anything which would support Kesten’s claim (Kesten, 1929) that the percentage haemolysis curve is concave to the time axis instead of sigmoid, when it is based on observations of the rate of lysis of individual erythrocytes.
