Mr. McDuffie then drew from the statistics of the foreign trade of the United States the fact that the sections cultivating cotton and rice, constituting less than {176} one-fifth of the Union, both in territory and population, produced thirty of the fifty-eight millions' worth of annual exports; and finally drew the conclusion from these premises that one-fifth of the people, the population of the planting sections, paid more than one-half of the duties on the imports of the country. [Sidenote: The danger in Mr. McDuffie's conclusions.] If this were true it was indeed a grievous burden. And if the people of the South, or that part of the South devoted to the production of these staples, believed it to be true, then would the reason for one great scruple against resistance to the execution of the tariff laws be removed, namely, the general belief theretofore prevailing, from the doctrine that the consumers of the imports ultimately pay the duties, that the burden of the duties fell nearly equally upon the different sections. So long as this belief was general the sense of oppression in any particular part or section of the country could not become very keen. Substitute for this old idea, however, the new doctrine advanced by Mr. McDuffie, and, under the existing distribution of the articles of export, there could not fail to be developed a most bitter sense of wrong and oppression on the part of the producers of the Southern staples. [Sidenote: The acceptance of Mr. McDuffie's doctrine at the South.] The Southerners, especially the South Carolinians, did embrace the new doctrine, apparently, at least, with all sincerity. It was utterly futile that Mr. Gorham and Mr. Everett pointed out to them the fact that they consumed only a comparatively small portion of the imports received in exchange for their exports, and sold the rest to the people of the other sections with the duties added on, thus shifting the duties upon the other sections. They clung to the new doctrine as if it were something for which they had long been seeking, and to which their {177} hearts were already too much attached to be drawn away by argument. [Sidenote: Growing belief in the incapacity of slave labor for manufacture.] It was in this speech, furthermore, that Mr. McDuffie abandoned his former view of the capacity of slave labor for manufacturing industry, and embraced and enounced the doctrine held before this by Colonel Hayne upon that subject, which was that slave labor could only be employed successfully in agriculture. This was, of course, another necessary element in the consolidation of the interests of the South against the tariff. [Sidenote: The Tariff pronounced unconstitutional.]