Chain scission, and mild-oxidation of the type that leads to the formation of alkali-sensitive groups without scission, can be viewed as the results of two different chemical processes that may occur either simultaneously or sequentially during the degradation of cellulose. Measurement of these two products of the envisioned chemical steps yielded two important observations. First: the fact that the ratio of chain scission to hot-1%-alkali-soluble matter te constant both in thermal and in photochemical deterioration suggests that the two processes scission and oxidation without scission-take place independently of one another during the early stages of deterioration in which the principal reactions occur in the amorphous regions of the cellulose. Second: it is observed that the ratio of scissions to mild oxidation is greater in the case of thermal aging in contrast to photochemical aging induced by near ultraviolet and visible radiation. If the two processes indeed occur independently, determination of the ratio of linkages broken to hot-alkali-soluble matter formed should provide information regarding the relative kinetic rates of scission and oxidation under primarily thermal or photochemical circumstances. (Abstractor's note: Corrections: R. L. Feller reports 2 misprints in this paper: 1) p. 61-Scheme II should read: Cellulose ^k₁ oxycellulose-Chain Scisson. 2) p. 64, column 2-equation should read: log eta_rel -1 = log(eta) + K(eta) C i.e. -1 is not an exponential as printed).