same case he
said, "that, unless the objection appeared to him to carry a strong
danger of perjury, and some apparent advantage might accrue to the
witness, he was always inclined to let it go to his credit, only _in
order to let in a proper light to the case, which would otherwise be
shut out_; and _in a doubtful case_, he said, it was generally his
custom _to admit the evidence_, and give such directions to the jury as
the nature of the case might require."[60]

It is a known rule of evidence, that an interest in the matter to be
supported by testimony disqualifies a witness; yet Lord Mansfield held,
"that _nice_ objections to a remote interest which could not be paid or
released, though they held in other cases, were not allowed to
disqualify a witness to a will, as parishioners might have [prove?] a
devise to the use of the poor of the parish forever." He went still
nearer, and his doctrine tends so fully to settle the principles of
departure from or adherence to rules of evidence, that your Committee
inserts part of the argument at large. "The disability of a witness from
interest is very different from a positive incapacity. If a deed must be
acknowledged before a judge or notary public, every other person is
under a positive incapacity to authenticate it; but objections of
interest are deductions from natural reason, and proceed upon a
presumption of too great a bias in the mind of the witness, and the
public utility of rejecting partial testimony. Presumptions stand no
longer than till the contrary is proved. The presumption of bias may be
taken off by showing the witness has a [as?] great or a greater
interest the other way, or that he has given it up. The presumption of
public utility may be answered by showing that it would be very
inconvenient, under the particular circumstances, not to receive such
testimony. Therefore, from the course of business, necessity, and other
reasons of expedience, _numberless exceptions_ are allowed to the
_general_ rule."[61]

These being the principles of the latter jurisprudence, the Judges have
suffered no positive rule of evidence to counteract those principles.
They have even suffered subscribing witnesses to a will which recites
the soundness of mind in the testator to be examined to prove his
insanity, and then the court received evidence to overturn that
testimony and to destroy the credit of those witnesses. They were five
in number, who attested to a will and codici