Isolated gastric mucosal cells will be examined for their content and localization of carbonic anhydrase by biochemical and histochemical means. Antibody to purified carbonic anhydrase will be raised and immunolabeling techniques will be used to localize the site of enzyme activity at both the light and hopefully at the electron microscope level. Further studies on isolated cells will be aimed at getting culture lines of gastric epithelial cells by destroying fibroblasts and finding a favorable medium for the stomach cells. An effort will be made to study normal gastric mucosa by rapid freezing and freeze substitution fixation. This will be aimed at ellucidating the structure of mucous and parietal cells not altered by initial chemical fixation.