the branch of the science to which it relates,
when men have dealt and made contracts on the faith of it, whether it
relates to the right of property itself, or to the evidence by which
that right may be substantiated, though it may appear to us "flatly
absurd and unjust," to overrule such a decision is an act of positive
injustice, as well as a violation of law, and an usurpation by one
branch of the government upon the powers of another. An example will
illustrate this position. In the case of Walton _v._ Shelley (1 Term
Rep. 296), in 1786, the King's Bench, Lord Mansfield, Chief Justice,
decided that a person is not a competent witness to impeach a security
which he has given, though he is not interested in the event of the
suit, on the trial of which he is offered. In Jordaine _v._ Lashbrooke
(7 Term Rep. 601), the same court, in 1798, under the presidency of Lord
Kenyon, rightly overruled that decision. Now it so happens that Walton
_v._ Shelley was recognized as authority and followed in Pennsylvania,
in 1792, in Stille _v._ Lynch (2 Dall. 194), before it had been
overruled in England: and though limited as it was understood to be in
Bent _v._ Baker (3 Term Rep. 34), to negotiable paper (Pleasants _v._
Pemberton, 2 Dall. 196), it has never been varied from since that time,
though it has frequently been admitted that Walton _v._ Shelley was
properly overruled. It ought not now to be overruled in Pennsylvania.
"After the decisions cited," says Judge Rogers, in Gest _v._ Espy (2
Watts, 268), "this cannot be considered an open question, nor do we
think ourselves at liberty now to examine the foundations of the rule."
Unfortunately our Supreme Court have not always put this sound and wise
limitation upon their own power. In the case of Post _v._ Avery (5 W. &
S. 509), they declared in regard to a rule of more than thirty years'
standing, and confirmed by numerous cases, that they had "vainly hoped
that the inconvenience of the rule would have attracted the attention of
the legislature, _who alone are competent to abolish it_;" but as
nothing was to be expected from that quarter, "they were driven by
stress of necessity" to overrule a case expressly decided on the
authority of the rule. (Hart _v._ Heilner, 3 Rawle, 407.) And two years
afterwards, after having made the remarkable declaration that the
legislature alone was competent to abolish the rule, they nevertheless
pronounced it "exploded altogether." (McClelland _v.