Previous in-estigations (Jacobs, Stewart and Butler, '43) l1ave shown tliat tannic acid (TA) in very low concentrations greatly reduces the chai*acteristic permeability of the erythrocyte to anions and at the same time has little o r no effect on the permeability to water and non-electrolytes. Further studies by Edelberg ( ' 3 2 ) on the adsorption of TA by the red cell niembraiie indicate tliat only a small fraction of the surface is normally permeable to ions. The interpretation of these findings in ternis of membrane structure requires information as to wliich chemical constituent or constituents of the membrane a r e involved in the changcs in ionic pel.- nieability.
Cliemical analyses of erythrocyte ghosts ( P a r p a r t and Dzie- rnian, '40; Erickson et al., '37) have indicated that they consist on the average of perhaps 60% protein, with the phospliolipids cephalin and lecithin together accounting for an additional 25% and cholesterol, neutral fats and other less well-known substances comprising the remainder.
This study formed part of a disscrtation presented t o the facnlty of the llrpartment of Physiology of the Unirersity of P m n s y h ania School of 3Iediciue in partial fulfillment of the requirements for the degree of Doctor of Philosophy.