ThcJ(xirnal of zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQ JANUARY 1988 Volume 36, zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Histochemistry and Cytochemistry