Evidence is presented which indicates that a pectin-cellulose compoun d does not exist in native cotton fibers and that the pectic substance is present as the insoluble salt of polyvalent ions. Replacement of these ions by sodium or a mmonium renders the pectic substance soluble.Cotton freed of pectic substance with alkali showed no significant change in tensile strength or in viscosity, whereas treatment of the fibers with acids, which removed only a small proportion of the pectic substance, produced an appreciable lowering of these two properties.When dewaxed fibers were dispersed in euprammonium hydroxide solutions, it was found that a small portion remained insoluble. Analysis of the material showed it to consist practically entirely of pectic substance. A consideration of these results led to the conclusion that pectic substance does not contribute to the viscosity of cuprammonium dispersions of cotton. D eterminations of the viscosities of cuprammonium solutions to which had bcen added pectic material from different sources substantiated this conclusion.