The constitutional basis of the authority of the Board of Review lies in its character as an administrative body having the duty of reconsidering or reviewing the assessments of the commissioner but not exercising any part of the judicial power of the Commonwealth: British Imperial Oil Co. Ltd. v. Federal Commissioner of Taxation [1] , affirmed sub nom. Shell Co. of Australia Ltd. v. Federal Commissioner of Taxation [2] . The appeal, therefore, given to the commissioner or taxpayer by s. 196, must be a proceeding in the original jurisdiction of the High Court. Although called an appeal it is a proceeding which, for the first time, brings into the Court a question between the Crown represented by the commissioner and the subject called upon to pay tax, that is to say a matter arising under a law of the Commonwealth under s. 76 (ii.) of the Constitution. Section 15 of the Judiciary Act 1903-1950 provides that the jurisdiction of the High Court may, subject to the provisions of this Act, be exercised by one or more justices sitting in open Court. By s. 20 of the Judiciary Act the appellate jurisdiction is, for the most part, to be exercised by the Full Court. But, except in applications under s. 74 of the Constitution, which must under s. 22 of the Judiciary Act be determined by a Full Court, it is generally true that the original jurisdiction of the High Court is exercisable by a single judge. It may, of course, be exercised by the Full Court either as a result of a reference under s. 18 of the Judiciary Act or as a result of an orginal proceeding coming before it by some other form of procedure. But prima facie it is exercised by a single judge. When s. 196 (3) speaks of the High Court, it is difficult to understand why it should not mean the High Court properly constituted in any manner for exercising the original jurisdiction. The Judiciary Act always speaks of the High Court independently of the manner in which it is constituted and uses the Full Court to mean the Full Court of the High Court. There appears to us to be no ground for construing the High Court as meaning the Full Court of the High Court. Whether an appeal from the Board of Review is heard by the Full Court must depend upon the manner in which the Court itself decides to exercise the jurisdiction. Under Order LIa., r. 13 of the High Court Rules the appeal is to be heard subject to s. 18 of the Judiciary Act before a single justice by way of an original hearing. This rule appears to us to be quite valid. When s. 196 (3) provides that the decision shall be final and conclusive, it appears to us to mean that there shall be no further appeals. If the question before the single judge merits the consideration of the Full Court, it is open for either party to request him to refer it to the Full Court and, unless he considers the matter to be one of fact or otherwise to be unsuitable for the consideration of the Full Court, doubtless he would make an order under s. 18 of the Judiciary Act. This has been a frequent practice. The suggestion that until the appellate power of the High Court is also exhausted, sub-s. (3) does not apply would, in effect, deprive it of any practical application. It would make it mean no more than that an appeal should not lie to the Privy Council except as of grace.