ABSTRACT
Osmotic fragility curves for normal RBCs bathed with each of four different cations [Na[+],K[+],Ca[2] and Mg[2+] and five different anions [Lactate, H[2]PO[-4], Cl[-],HCo[-3] and HPO[--4] were constructed The curves for cations were typical "S" shaped. The divalent cations [Ca[+2] and Mg[+2]] produced more hemolysis than monovalent ones [Na[+] and K[+]] at each osmolal concentration of the curves. HCO[-3] has the least hemozytic effect while lactate the greatest. Divalent phosphate [HPO[--4] has less hemolytic effect than monovalent one H[2]PO[-4]] at high osmolal concentrations [150-300 mosm/L], The reverse effect occurs at lower osmosal concentrations [50-150 mosm/L], It is not only the total osmotic pressure [O.P] of the solution or the diameter of the ion but also the ion charge and the presence or absence of specific ion which determines the osmotic behaviour of the cell