The Ministry of Finance Directive (72) Tai-Tsai-Shui-Tze No. 31229 (February 24, 1983) issued to its subordinate financial and tax agencies states: "The recordation of a mortgage has an absolute effect under Article 758 of the Civil Code and Article 43 of the Land Act. Where a creditor who loans money to a debtor against the furnishing of real property as a security perfects the recordation of a mortgage with a land administration office, with the agreed interest expressly stipulated therein, the tax collection office may, based on the information recorded at the land office, assess the creditor*s income from such interest accruable in the year before deletion of the recordation of the mortgage and levy tax thereon as a Category 4 income under Article 14, Paragraph 1, of the Income Tax Act. This is because a loan arrangement between individuals is not comparable with that between companies or firms in that the unavailability of account books to show the receipt or payment of interest thereon makes it impossible to assess such income by the rule of income and disbursement realization, and thus it is only natural that the income from such interest is deemed to have been periodically received as it is stipulated in the documents recorded. If the party alleges that he has received no interest, he must bear the burden of proof to support his allegation, and the evidence produced must be concrete and acceptable under the ordinary rule of thumb (erfahrungsmäβig). A documentary proof executed by an individual as the debtor will be inadmissible." Inasmuch as this directive, albeit not totally satisfactory and appropriate, constitutes merely an instruction to tax collection offices with respect to the method of identifying the fact to support the cause of taxation rather than prohibiting the party concerned from producing rebuttal evidence, and is not binding upon the court, which, when hearing a case, has in any event the duty to consider the contents of all arguments and the results of investigation of evidence and to judge whether the fact is true, it can not be said to be an encroachment upon the right of the people or in conflict with Articles 15 and 19 of the Constitution.