The Life that tied too tight escapes — Escaped Mind

A slave escaped will be retaken with a shot, but there is no way to catch an escaped mind. "Spectres of the rein" hints at slavery.

The Life that tied too tight escapes 1
Will ever after run
With a prudential look behind
And spectres of the Rein-
The Horse that scents the living Grass 5
And sees the Pastures smile
Will be retaken with a shot
If he is caught at all-
(F.1555/J.1535)
[1] Life:: the life of a slave, hinted by rein, retaken, shot, and caught.
[2] Will ever, run:: an escape let one's will run forever.
[4] spectres of Rein:: terrors of slavery.
[5] Horse:: one who works like a horse.
[6] Pastures:: leisure and nutritious places.
[7] retaken, shot:: the freedom of mind can be retaken only after death.
[8] caught at all:: no way to catch an escaped mind.

Should the hunters who have no dogs, start a slave from his hiding place, and the slave not stop at the hunter's call, he will shoot at him, as soon as he would at a deer. Some masters advertise so much for a runaway slave, dead or alive. ─ American Slavery As It Is (1839)