to the abolition of slavery. The effect of that institution was to give a very distinct industrial character to the laboring population of those States which unfitted them for all but a very limited number of occupations, but gave them a certain special fitness for these. Almost the entire industry of the country was consequently [pg 386] turned to the production of two or three crude commodities, in raising which the industry of slaves was found to be effective; and these were used, through an exchange with foreign countries, as the means of supplying the inhabitants with all other requisites.... In the main, however, it would seem that this cause [personal aptitudes] does not go for very much in international commerce.”266
In brief, then, international trade is but an extension of the principle of division of labor; and the gains to increased productiveness, arising from the latter, are exactly the same as those from the former.
§ 4. —Not in a Vent for exports, nor in the gains of Merchants.
According to the doctrine now stated, the only direct