Other oxidising agents produce similar results; even by exposure to air and light, cellulose is slowly converted into these oxidised derivatives.[2] From their mode of formation, they have been termed oxycelluloses, and to distinguish them from a series of more highly oxidised derivatives, produced by the action of nitric acid upon cellulose, which they nevertheless resemble in many of their characteristics, the prefix α is employed. The following are the distinguishing features of the α oxycelluloses as represented by the more extreme of the above mentioned products. It reduces Fehling’s solution at the boiling temperature, and the cuprous oxide is deposited upon the fibre in a state of intimate union, producing the effect of an orange dye. It attracts the basic colouring matters from their solutions and is dyed to a full shade, the depth of colour being proportionate to the amount of oxidation to which the cellulose has been subjected. See also p. 43. Treated with a warm solution of phenylhydrazine salts in water, it is coloured a bright lemon-yellow. Its most remarkable property is its attraction for the vanadium compounds, which is so powerful that combination may be proved to take place when this element in the form of chloride is presented to the oxycellulose in an aqueous solution containing not more than 1 in 1,000,000,000,000 parts. [Footnote 2: Witz. Bull. Soc. Ind. Rouen, _X._ 416, and _XI._ 189.] The β oxycellulose resulting, as already indicated, from the action of dilute nitric acid upon cellulose, will be subsequently considered, under the head of the decompositions of cellulose, to which the reaction which we have been considering may be regarded as transitional. {12} _Decomposition of Cellulose._—_Acids._—Of the decomposition of cellulose by artificial means, i.e. by the action of reagents, the most important are those which disclose the relationship which it bears to the group of so-called carbo-hydrates. Cellulose is, indeed, a highly _elaborated_ carbo-hydrate, differing from dextrin and starch, not so much in its essential constitution as in the molecular arrangement which has been impressed upon it in and through the life of the plant. There are numerous observations in biological science which demonstrate the close connection, and in many cases the physiological equivalence of the members of this natural group, which includes the sugars, dextrin, starches, and cellulose. The following facts show the constitutional or chemical ties which underlie their interdependence.