Rule 301.        Presumptions in General in Civil Actions
           and Proceedings

In all civil actions and proceedings not otherwise provided for by Act of Congress or by these rules, a presumption imposes on the party against whom it is directed the burden of going forward with evidence to rebut or meet the presumption, but does not shift to such party the burden of proof in the sense of the risk of non-persuasion, which remains throughout the trial upon the party on whom it was originally cast.