The catalytic effect of Mn(II), Co(II), and Cu(I) hydroxides on the oxidation of cellulose by hypochlorite has been examined, particularly the very early stages of the reaction where the primary process may be presumed to predominate. The rate of oxidation in the absence of any catalyst and in the presence of manganese and cobalt is greatest at pH 7.0, and in the presence of copper, the rate is greatest at pH 7.5. The catalytic activity of the three hydroxides is in the order Co Ü0 Cu Ü0 Mn. Copper numbers and acid contents of some of the oxycelluloses have been measured before and after treatment with chlorous acid. The results show that the faster the reaction the greater the ratio of aldehyde to other reducing groups in the product and that, with copper, initially formed aldehyde groups are more readily oxidized further by hypochlorite than with the other catalysts. -- CAL