at least comparable to the uniformity of substitution which can be obtained with monochloroacetic acid as the etherifying agent and is definitely better than the result obtained with sodium monochloroacetate frequently viscosities which are markedly higher than about 100 000 mpa s measured in a 1 8 strength aqueous solution according to hoeppler can be observed and as a rule these high viscosities do not substantially decrease even in aqueous salt solutions the etherifying agent can be stored and handled safely without difficulty i e it is neither particularly sensitive to cold fp u2266 25 u00b0 c nor particularly readily evaporated bp u2267 130 u00b0 c and in addition it is less caustic and aggressive than the free acid the addition metering into the reaction mixture is without problems since a local drop of the ph value to the acid range which is possible if monochloroacetic acid is added cannot occur in this case shifting of the ph value into the acid range is undesirable since on the one hand it results in a decomposition of the polymer chain of the cellulose molecules and is thus one of the causes for a reduction of viscosity and on the other hand it destroys the alkali cellulose formed as compared with a reaction procedure which comprises initially mixing the cellulose with the etherifying agent and subsequently alkalizing an improved substitution yield per mole of etherifying agent employed is obtained and fewer by products of the reaction for example glycolic acid sodium glycolate are formed which must be removed from the mixture organic solvent water by a complicated treatment after carrying out the reaction in the examples which follow parts.