The Hæmoglobin Distribution on Surfaces of Erythrocytes

Abstract

FROM time to time the point is brought home that factors should be discarded only when exact calculation proves them to be negligible. A case in point is the recent paper by Dr. K. Burker (Pfluger's Archiv fur die gesamte Physiologie, vol. 195, p. 516). In this interesting paper it is shown that in mammals the weight of haemoglobin per square micron of surface of the erythrocytes is apparently a constant equal to 31.7 × 1014 gm. Dr. Burker has, however, assumed that the surface area of the cells is equivalent to twice the area of a circle having for its diameter the large diameter of the cell. The general opinion is that in mammals (the camel excepted) the shape of the cells is a bi-concave disc, having a circle for its horizontal projection, and a flat bi-concave ellipse for the vertical projection of which the minor axis is about one-third of the major axis (E. Ponder, Proc. Roy. Soc. 94B, p. 102). The surface area of such an erythrocyte would then be equal to that of an ellipsoid of revolution around the minor axis. It can be shown by the integral calculus that the area of such an ellipsoid (if the minor axis is equal to one-third the major) is 1.09 times as great as that of two circles with the major axis for diameter. Dr. Burker's constant is therefore equal to 31.7/1.09 or 29 × 1014 gm. haemoglobin per square micron of surface of erythrocyte instead of 31.7 × 1014 gm.