Abstract
Fragments of mouse gut mucosa were frozen-dried and embedded in prepolymerized methacrylate. Serial sections were examined in the light and electron microscope after staining with Gomori's method for alkaline phosphatase. The tissue showed high enzyme activity. In the electron microscope deposits of calcium phosphate were seen in the brush border and the Golgi area of epithelial cells, and in large and small apical granules.