they have only
one parent the same, and the other different) shall never succeed as
heir to the estate of his half brother, but it shall rather escheat to
the king, or other superior lord. Now this is a positive law, fixed
and established by custom, which custom is evidenced by judicial
decisions; and therefore can never be departed from by any modern
judge without a breach of his oath and the law. For herein there is
nothing repugnant to natural justice; though the reason of it, drawn
from the feodal law, may not be quite obvious to every body. And
therefore, on account of a supposed hardship upon the half brother, a
modern judge might wish it had been otherwise settled; yet it is not
in his power to alter it. But if any court were now to determine, that
an elder brother of the half blood might enter upon and seise any
lands that were purchased by his younger brother, no subsequent judges
would scruple to declare that such prior determination was unjust, was
unreasonable, and therefore was _not law_. So that _the law_, and the
_opinion of the judge_ are not always convertible terms, or one and
the same thing; since it sometimes may happen that the judge may
_mistake_ the law. Upon the whole however, we may take it as a general
rule, "that the decisions of courts of justice are the evidence of
what is common law:" in the same manner as, in the civil law, what the
emperor had once determined was to serve for a guide for the
future[q].

[Footnote q: "_Si imperialis majestas causam cognitionaliter
examinaverit, et partibus cominus constitutis sententiam dixerit,
omnes omnino judices, qui sub nostro imperio sunt, sciant hanc esse
legem, non solum illi causae pro qua producta est, sed et in omnibus
similibus._" _C._ 1. 14. 12.]

THE decisions therefore of courts are held in the highest regard, and
are not only preserved as authentic records in the treasuries of the
several courts, but are handed out to public view in the numerous
volumes of _reports_ which furnish the lawyer's library. These reports
are histories of the several cases, with a short summary of the
proceedings, which are preserved at large in the record; the arguments
on both sides; and the reasons the court gave for their judgment;
taken down in short notes by persons present at the determination. And
these serve as indexes to, and also to explain, the records; which
always, in matters of consequence and nicety, the judges direct to be
searched. The report