assumed that they possess power to draw an adverse inference from the failure or refusal of a party to produce such evidence."; the use of presumptions (Brewer, Holler and Co. case, Ralston, Vene¬zuelan Arbitrations of 1903, 584, presumption of "regularity and validity of all acts of public officials"; Frioraich and Co., ibid., pp.31, 42, regularity of official acts; Black and Stratton case, Moore, International Arbitrations, p.3138; and generally, Ralston, Law and Procedure of International Tribunals, pp. 223- 224, and Sandifer, op.cit., p.198); the doctrine of judicial notice (Island of Palmas, Scott, Plague Court Reports, 2nd, p. 92, at 96, holding the text of the Treaty of Utrecht to be "of pub¬lic notoriety"; and generally, Sandifer, op.cit., p.100, for exceptions to the doctrine. Witenberg, op.cit., p.31, points out that the law of a particular state must be proved as any other fact. The practice of the Permanent Court of International Justice supports this view: Anzilotti, J., in the Danzig Decrees, Judgments of the Permanent Court, Series A, No. 21, p.124; Hudson J., in the Societe Commerciale case, ibid., Series A/3, No. 78, p. 184, and idem., The Permanent Court of International Justice, p. 623); and rules relating to the burden of proof (I Wigmore, Evidence, p. 152; Sandifer, op.cit., pp. 91-92, 97; but compare Feller, Tne Mexican Claims Commissions, p. 26l, note 22). A diluted variation of the "best evidence" rule is applied by in¬ternational tribunals to the weight of evidence presented rather than to its admissibility. Says Sandifer: "Secondary evidence will not necessarily be ex¬cluded because better evidence is held to be available, but less weight, or in some cases no weight at all, may be attached to it. The rule is generally broadly stated as a requirement that the best available evidence be pro¬duced, without reducing it to specific technical require¬ments as to particular types of evidence *** The liber¬ality of tribunals in the admission of evidence has no doubt been a contributing factor to their frequent insistence on the production of the best evidence of which the circumstances of the case permit." 6. Not infrequently the justification for admitting material which would not constitute evidence by familiar standards is found in the express terms of the protocol or compromis. Thus in the Venezuelan arbitrations of 1903, it was provided that the claims should be decided upon such evidence or information only as should be furnished by or on behalf of the respective governments, and that the Commissions should consider all written documents or statements on behalf of the respective governments (Ralston,