Effects of Three Kinds of Decoction on Histopathology of GastricMucosa, Gastric pH and the Content of Bile Acid in ExperimentalChronic Gastritis in Rats Effects of Three Kinds of Decoction on Serum Gastrin,Gastrin Cell Density and theContent of PGE2 of Gastric Antral Mucasa in Experimental Chronic Gastritis in Rats Mechanisms of muscovite on gastric mucosal protective effect