Abstract
In formalin-fixed or glutaraldehyde-fixed frozen sections of mouse jejunum acid phosphatase activity is localized electron histochemically to a group of cytoplasmic bodies. These bodies are structurally heterogeneous, sometimes with internal membranous components. The common position for these structures is below the terminal web. Following oil-feeding the number of enzyme-carrying granules is decreased. Enzyme activity occasionally surrounds lipid droplets.