A monochromator was modified to measure the emissivity, ε(λ), of living tissue in the infrared region between 1 and 14 μm. The infrared radiation from the tissue was compared with blackbody radiation and in this way ε(λ) has been determined for white skin, black skin, burnt skin and pericardium.

A compensating skin thermometer was constructed to measure the temperature of the surface of the tissue. The temperature difference before and after contact between a gold ring and the surface was made as small as possible (0.05 K). A reference radiator with the same spectral radiance (experimentally determined) mas used in compensating for the environment.

It appeared that ε(λ) for skin is independent of the wavelength and equal to 0.98+-0.01. These results contradict those of Elam, Goodwin and Lloyd Williams, but are in good agreement with those of Hardy and Watmough and Oliver.

In addition there was no difference between ε(λ) for normal skin and burnt skin. Epicardium values were found to lie between 0.83 (fresh heart) and 0.90 (after 7 h and after 9 d).