Examines the role of serum albumin in blood chemistry with respect to the binding of hydrogen, chloride, and calcium. Serum albumin is considered as a mathematical entity. Emphasis is on the interpretation of binding data using the Linderstrom-Lang theory, which treats the molecule as a charged sphere. The mathematical procedure is based on the calculation of a chemical equilibrium by minimization of the Gibbs' free energy function under the conditions of the experiment. It is found that, although in each of the cases studied the charged-sphere theory can be stretched to fit the laboratory data, the consequent Debye-Huckel parameter bears little relation to the predicted values. Indications are that a much improved theory must be developed. Adequate explanation will probably have to begin with determination of the exact geometry of the molecule and the consequent molecular interactions. 55 pp. Refs.