, and
checked by the labor required to separate the seeds from the cotton.
Whitney's invention increased the efficiency of this labor hundreds of
times, and it became evident at once that the South enjoyed a practical
monopoly of the production of cotton. The effect on the slavery policy
of the South was immediate and unhappy. Since 1865, it has been found
that the cotton monopoly of the South is even more complete under a
free than under a slave labor system, but mere theory could never have
convinced the Southern people that such would be the case. Their whole
prosperity hinged on one product; they began its cultivation under slave
labor; and the belief that labor and prosperity were equally dependent
on the enslavement of the laboring race very soon made the dominant race
active defenders of slavery. From that time the system in the South was
one of slowly but steadily increasing rigor, until, just before
1860, its last development took the form of legal enactments for the
re-enslavement of free negroes, in default of their leaving the State
in which they resided. Parallel with this increase of rigor, there was a
steady change in the character of the system. It tended very steadily to
lose its original patriarchal character, and take the aspect of a purely
commercial speculation. After 1850, the commercial aspect began to be
the rule in the black belt of the Gulf States. The plantation knew only
the overseer; so many slaves died to so many bales of cotton; and the
slave population began to lose all human connection with the dominant
race.

The acquisition of Louisiana in 1803 more than doubled the area of the
United States, and far more than doubled the area of the slave system.
Slavery had been introduced into Louisiana, as usual, by custom, and had
then been sanctioned by Spanish and French law. It is true that Congress
did not forbid slavery in the new territory of Louisiana; but Congress
did even worse than this; under the guise of forbidding the importation
of slaves into Louisiana, by the act of March 26, 1804, organizing
the territory, the phrase "except by a citizen of the United States,
removing into said territory for actual settlement, and being at the
time of such removal bona fide owner of such slave or slaves," impliedly
legitimated the domestic slave trade to Louisiana, and legalized slavery
wherever population should extend between the Mississippi and the
Rocky Mountains. The Congress of 1803-05, whic