. . " modified natural substances, such as, for example, carboxymethylcellulose and other cellulose ethers, hydroxyethylcellulose and hydroxypropylcellulose and microcrystalline cellulose and the like,organic, completely synthetic compounds, such as, for example, polyacrylic and polymethacrylic compounds, vinyl polymers, polycarboxylic acids, polyethers, polyimines, polyamides, polyurethanes,inorganic" . . . . . .