Spectral Reflectance of the Skin of Chester White Pigs in the Ranges 235–700 mµ and 0.707–2.6 µ

¹ From the Biophysics Department, Army Medical Research Laboratory, Fort Knox, Kentucky

The spectral reflectance of the intact skin of the Chester White pig was measured and compared with that of other experimental animals and of the human. From 235 to 1300 mµ the shape of the reflectance curves of the Chester White pig, rat, rabbit and human is similar. The carotene absorption band appears noticeably only on the human and faintly on the rabbit. Above 1.3 µ all reflectance curves, including the one of the hairless mouse, practically coincide. The low reflectance values above 1.8 µ, probably caused by Fresnel reflection, indicate high absorption independent of the thickness of the skin but do not yet permit identification of the absorber. Earlier results that showed spectral reflectance differences to be caused by differences in pigmentation, in skin blood content and in other skin components, and that manifested themselves only between 300 and 1200 mµ have been found valid also for the skin of the Chester White pig.