If it happens that there be one which does not cultivate it, it is because, even to itself, such cultivation is not useful.

Analogy will show us, that under the influence of an unshackled trade, notwithstanding similar differences, wheat would be produced in every kingdom of Europe; and if any one were induced to abandon entirely the cultivation of it, this would only be, because it would _be her interest_ to employ otherwise her lands, her capital, and her labor.

And why does not the fertility of one department paralyze the agriculture of a neighboring and less favored one?
Because the phenomena of political economy have a suppleness, an elasticity, and, so to speak, _a self-leveling power_, which seems to escape the attention of the school of protectionists.

They accuse us of being theorists, but it is themselves who are theorists to a supreme degree, if being theoretic consists in building up systems upon the experience of a single fact, instead of profiting by the experience of a series of facts.

In the above example, it is the difference in the value of lands, which compensates for the difference in their fertility.