The institution of slavery, under the stimulus given to it by the invention of the cotton gin by Eli Whitney, and the consequent development of the cotton-growing industry--aided, curiously enough, in a certain sense, by the prohibition of the African slave trade, giving rise to the slave-rearing business in Virginia and Maryland--has all along been exhibiting a steady, sturdy, and rapid growth. By the alliance, accidentally as it were, resulting from the prohibition of the slave trade, between the Southern and the Northern slaveholding States, a robustness and consistency were given to the whole slaveholding interest which possibly it might never have had under a different policy. If the foreign importation of slaves had continued, that species of population would gradually have overrun the cotton-raising border of States--would have overrun them to an extent threatening the safety of the institution there by its own plethora--while from the southern line of North Carolina and Tennessee northward, where this extra-profitable industry could not readily be extended, the temptation to the importation of slaves would have been slight, no market existing for the home increase. The hold of the institution would have been constantly weakened there in the affections of the white population; and, in those States, there is a seeming probability that white labor and free labor would have taken the place of the present system, as it did in the States farther north. This would have deprived the Southern belt of cotton-raising and negro-holding States of that sympathy which, under existing circumstances, they have steadily had from their more northern sisters, and favored an early extinction of the system. However this might have been, as things are and have been actually, it is certain that at no period has the growth of the slaveholding institution exhibited any weakness or defect of vitality. Like an infant giant, it has steadily waxed stronger and stronger, and more and more arrogant and aggressive.