Some of these States became free while others remained slave; but between the people of the two sections there was continuous communication.

Slaveholders came into free States to liberate their slaves.

Non-slaveholders came to get rid of the competition of slave labor, and free negroes came to avoid reenslavement.

Slaves fled thither on their way to liberty.

It was not a matter of choice; it was an unavoidable condition which compelled the people of the border States to give continuous attention to the institution of slavery.
The modern anti-slavery movement had its origin in this great middle section, and from the same source it derived its chief support.