Measurement of diffusivity and metabolic rate of O2 and CO2 in respiring tissue.

The method described is apt to measure, at the same time, Krogh's diffusion constant and specific metabolic rates for O2 and CO2 in intact, respiring tissues. Due to metabolism tissue thickness for this method is limited to about 500 mum unless hyperbaric conditions are used. The results suggest that both KO2 and KCO2 are similar in alive and in dead tissue. Due to tissue inhomogeneity and to possible facilitation of O2 or CO2 transport our values of K have to be considered as effective mean values for the physiological range of PO2 and PCO2 in muscle at rest and at exercise.