Brown Stain formed on Wet Cellulose

Abstract

THE phenomenon of the ‘brown stain’ formation on wet cellulosic materials was reported¹ in 1934 and has since been studied by Turner² and his colleagues at Manchester, and by Appel³ and others in the United States, but does not even yet seem widely known. As the effect may be encountered in paper chromatography and with the Weisz⁴ ‘ring-oven’, it may save trouble to workers in those techniques if attention is directed to it. The effect can readily be seen by putting a strip of filter paper as a wick in distilled water. In a few hours a brown stain is found at the top of the wick, or of its wet portion. The immediate neighbourhood of the stain has a brilliant white fluorescence under ultra-violet light and is strongly dyed by methylene blue (0.1 per cent in water).