Diffusion Coefficient of Oxyhæmoglobin

IN work described elsewhere 1 we showed how to understand the steady-state transport of oxygen through hæmoglobin solution by the application of Fick's law of mass transport. The oxygen flux was shown to depend not only on the pressure difference across the diffusion cell but also on the absolute partial pressures of oxygen at the cell boundaries. This behaviour is a direct consequence of the nonlinear relation between oxyhæmoglobin concentration and oxygen partial pressure. We pointed out, for example, that if the hæmoglobin is saturated with oxygen at both ends of the diffusion path it cannot contribute to the transport of oxygen and all the oxygen transport must therefore take place through the plasma.