⁶³Ibid, p xvii. 44 amended statute. If anything, a reprint can make the incoherence more obvious. A mixture of statute and common law 85 Continual  amendment  is  a  particular  kind  of  impediment  to  accessing  the  law. Another is the impact of significant statutory incursion into the common law and the reverse phenomenon of common law incursion into, or gloss on, the statute. New Zealand evidence law is a mixture of case law and statute law. 86 In the preface to its report Evidence: Reform of the Law,⁶³ the Law Commission observed that— . ..  in its present form the law of evide nce is a patchwork of dispa rate elements  that have never  been  co-ordinated  and  whose  effect  is  frequently  disputed  by  experts.  Problems resulting  from  ancient  rules  of  the  judge-made  common  law,  themselves  often  neither precise nor readily accessible, have been met by ad hoc statutory reforms which have in turn presented difficulties of construction and of scope. 87 The  Commerce  Act  1986  is  an  example  of  a  statute  around  which  an  essential jurisprudence has quickly developed to spell out the Act’s under lying principles. That was always anticipated, but it means that to understand the statute one has to be familiar with a substantial body of case law in New Zealand, Australia, and the United States as well as the decisions of the Commerce Commission. The discretion contained in section 4 of the Family Protection Act 1956 cannot be understood without recourse to the cases decided under it and the way in which the concept of “moral duty” ha s been developed by the courts.