Metabolic and biochemical function is investigated in a single cell type. A technic provides a suspension of living parietal cells which permits investigation of chemical activities. The gastric fundus is removed from freshly sacrificed rabbits and the mucous manually stripped from submucosa and muscularis; the mucosa is minced, extracted with collagenase, strained, layered on a density gradient medium and centrifuged. Cellular identification is made on a histological and histochemical basis. After differential centrifugation an upper band containing mucous and debris and a lower band containing a variable amount of debris and a large number of distinct intact single cells are apparent. These cells exhibit characteristic staining reactions for parietal cells with hematoxylin and eosin and with neotetrasolium salts for succinic dehydrogenase. Preparations of freshly extracted parietal cells incubated in serum at 37[degree]C exhibit HC1 production.