Mildly acid sodium chlorite solutions were allowed to act on white birch and black spruce sawdust at room temperature for various times; the insoluble fraction and the soluble nondialyzable fraction were isolated and weighed. If chlorite acts selectively on lignin the sum of these two fractions in time approaches true holocellulose. Chlorine and methoxyl determinations and examination of the ultraviolet absorption spectra showed that this was only approximately true. A small amount of carbohydrates was probably lost, and evidence was found for the existence of a chlorite-resistant lignin fragment in the soluble nondialyzable fraction.