Abstract
From data on the surface area and electrical mobilities of mammalian red blood cells in M/15 phosphate buffer at pH 7.4, it has been possible, with the help of the Gouy and von Smoluchowski theories, to calculate the net surface charge per cell as well as the charge per unit area. It was found that a single mammalian red cell has a net surface charge ranging from four to fifteen million electrons, depending on the species. No clear relationship between zoological classification and surface charge is apparent. It is suggested that a mechanism exists which is capable of keeping the surface density of net charge constant when comparatively large changes in surface area occur in the anemias.