The prohibition of the foreign slave trade by the States and the Federal Government is the first thing to be considered in connection with the development of the internal slave trade. Although before 1808 all the States had passed laws to prohibit the introduction of slaves from without the United States, yet each State had the power to reopen the trade at will. South Carolina, perhaps, thinking it might be for the interest of the State, opened the foreign trade in 1803.[59] During the four years following so many slaves were imported that the market in the United States became overstocked and many of the negroes were sent to the West Indies for sale.[60] Had the States retained the power to import, it is not probable that the domestic trade would ever have assumed any great importance. It is not likely that the people of the South and West would have paid high prices for the negroes from the border States when they could have been had from abroad for so much less. The great profits, too, which induced men to carry on the domestic trade would have been wanting. Assuming this, then, the consequent low price of slaves in the border slave States, added to the disinclination of many in these States to make merchandise of the negro, might have led, as the negroes increased and became a burden upon their masters, to gradual emancipation. In 1807, however, when Congress exercised its constitutional right and prohibited the importation of slaves from without the United States after January 1, 1808, the right of the individual States to import slaves from foreign countries was lost. It is interesting to note that only a few years before the passage of the Federal non-importation-slave act the vast territory of Louisiana had been purchased from France. The acquisition of this territory had a wonderful influence upon the development and continuance of the internal slave trade. Of much less influence, and we might even say, of comparative insignificance, was the Florida cession of 1819. In a very short time this fertile region of the Louisiana purchase began to attract great numbers of immigrants who, it seems, often brought their slaves with them. But there were many who still had to be supplied.[61] To meet this demand' recourse was had, principally, to the exhausted plantations of Virginia and Maryland.[62] Tobacco, which had been a great agricultural staple in these States, had worn out the land. The price of tobacco, too, from about 1818 was very low and continued so until about 1840.[63] At the same time new States such as Kentucky, Tennessee, Missouri, the Carolinas and Georgia, had become great tobacco States. Such quantities came to be raised as to make the culture very unprofitable in Virginia and Maryland.[64] The condition with respect to this section could be no better illustrated than by a quotation from a speech of Thomas Marshall in the Virginia House of Delegates, January 20, 1832: