Nef published his first work on the oxidation of sugars by Fehling's solution, or, more correctly, by a suspension of cupric hydroxide in an alkaline sugar solution, in Liebig's Annalen in 1907.~ The sugars studied were I-arabinose, d-glucose, d-mannose and d-fructose. Thereafter a series of investigations was undertaken by Nef, in part in collaboration with his students.3 The present work was undertaken in order to obtain more complete information with regard to the amounts of the oxidation products. Experimental proof of the production of certain acids, such as ribonic acid, was sought for. When I-arabinose was oxidized in alkaline solutions by air, E-erythronic, d-threonic, d-and I-glyceric, glycollic, formic and carbonic acids were produced. When oxidation was accomplished by cupric hydroxide, I-arabonic, I-glyceric, glycollic, oxalic, formic and carbonic acids were found among the oxidation products: 1-Ribonic acid was not found, although it was presumably produced, for d-lyxonic acid was found among the oxidation products of 1-xylose. Other products of oxidation of 1arabinose were obtained by Nef in former experiment^.^ When I-xylose was oxidized in alkaline solutions by air, I-threonic, d-erythronic, I-glyceric, glycollic, formic and carbonic acids were found to be present among the products. When oxidation was accomplished 1 The experimental work described in this paper was done by Dr. Nef during the two years previous to his death on August 13, 1915, with the assistance of Dr. Glattfeld and myself. I have undertaken to prepare the results of t h e work of this period for publication. Dr. Glattfeld has assisted in the preparation of this paper.-Oscar F. Hedenburg.
