Considerations of oxygen-hemoglobin equilibrium in the physiological state.

A formulation is presented, which applies to the oxygen-hemoglobin equilibrium under physiological conditions. This formulation fits with excellent accuracy the experimental data obtained by various authors in man and in several animal species. The marked difference in the comportment of intracellular and dilute hemoglobin is emphasized. It is indicated that Adair's four compounds hypothesis does not apply in its simplest form to intracellular hemoglobin, unless different values for different O2 partial pressures are given to the association ‘coefficients’ and in particular to that of the fourth hemoglobin compound.