Methylation of polysaccharides has proved invaluable for the elucidation of the type of linkage which occur between the different sugar residues. The methylation of cellulose of glucomannan triacetate of degraded alginic acid of an amylopectin- type glucan (liquid ammonia), and of the following partially methylated polysaccarides, cherry gum, an arabinogalactan, and a mannan are described in detail. Although particular examples are cited, the experimental procedure has, in some instances, been altered as a result of more recent experience.