, and it may be
relied on by plea, answer, demurrer, _or at the trial or hearing_. As
a denial of jurisdiction over the subject-matter of a suit between
parties within the realm, over which and whom the court has power to
act, cannot be successful in an English court of general jurisdiction,
a motion like the present could not be sustained consistently with the
principles of its constitution. _But as this court is one of limited
and special original jurisdiction_, its action must be confined to the
particular cases, controversies, and parties, over which the
Constitution and laws have authorized it to act; any proceeding
without the limits prescribed is _coram non judice_, and its action a
nullity. And whether the want or excess of power is objected by a
party, or is apparent to the court, it must surcease its action or
proceed extra-judicially."

In the constructing of pleadings either in abatement or in bar, every
fact or position constituting a portion of the public law, or of known
or general history, is necessarily implied. Such fact or position need
not be specially averred and set forth; it is what the world at large
and every individual are presumed to know--nay, are bound to know and
to be governed by.

If, on the other hand, there exist facts or circumstances by which a
particular case would be withdrawn or exempted from the influence of
public law or necessary historical knowledge, such facts and
circumstances form an exception to the general principle, and these
must be specially set forth and _established_ by those who would avail
themselves of such exception.

Now, the following are truths which a knowledge of the history of the
world, and particularly of that of our own country, compels us to
know--that the African negro race never have been acknowledged as
belonging to the family of nations; that as amongst them there never
has been known or recognised by the inhabitants of other countries
anything partaking of the character of nationality, or civil or
political polity; that this race has been by all the nations of Europe
regarded as subjects of capture or purchase; as subjects of commerce
or traffic; and that the introduction of that race into every section
of this country was not as members of civil or political society, but
as slaves, as _property_ in the strictest sense of the term.

In the plea in abatement, the character or capacity of citizen on the
part of the plaintiff is denied; and the ca