Abstract: On the mercuration of pyridine by means of mercuric acetate in the presence of watert, it was difficult to isolate the product, β-pyridylmercuric acetate. Heating of the reaction mixture with acetic acid caused the pyridylmercuric compound to decompose into mercurous acetate, which was also formed on similar treatment of phenylmercuric acetate. Mercurous acetate yas prepared by the double decomposition of mercurous nitrate with acetic acid-sodium acetate.