The chemical synthesis of polysaccharides is an old problem, wh ich has been studied for several decades without noteworthy success. We have accomplished this synthesis in three different ways. The most comprehen sive in application is the synthesis from mono-or disaccharides in dimethyl sulphoxide as solvent, at room temperature and under H-ion catalysis. If the water formed in the equilibrium between mono- and polysaccharides is removed, polysaccharides of molecular weights up to about 30. 000 are obtained. These are still soluble in water. Substantially higher molecular weight...