Substantively, "the subject of judicial notice . . . belongs where the general topic of legal or judicial reasoning belongs, - to that part of the law which defines among other things, the nature and limitations of the judicial function - it is, indeed, woven into the very texture of this function." Functionally, the subject of judicial notice is that portion of procedural law relating to "Proof'' wherein the ordinary rules of evidence are inapplicable. That is to say, certain propositions, "facta probanda," of a party's case will be taken for true by the tribunal without proof. These are generally matters of such notoriety that the production of evidence in their support is entirely unnecessary. In Anglo-American jurisprudence this principle is unequivocally extended to the lex fori, for the court must be credited with a knowledge of the law governing its action, or at least deemed to possess the most competent knowledge of where to search for it. To this extent, then, it is fairly obvious that the law of judicial notice is founded on reason, policy, and convenience.