Art. 17, 19 SchKG; appealability of a cantonal supervisory instruction and standing of a debt enforcement office. A supervisory instruction addressed to debt enforcement offices, which merely directs precautionary administrative action and does not finally determine the legal validity of the underlying rights, is not a disposition subject to complaint. Debt enforcement officers are entitled to challenge supervisory measures only when their own personal and material interests are directly affected; absent such interest, the complaint is inadmissible. The Federal Tribunal will also deny entry where the measure is not definitively conclusive on the substantive question, but only anticipates possible registration pending judicial determination (consid. 1-2).