No More Learning

And how and why we know not, nor can trace
Home to its cloud this lightning of the mind,
But feel the shock renewed, nor can efface
The blight and           which it leaves behind,
Which out of things familiar, undesigned,
When least we deem of such, calls up to view
The spectres whom no exorcism can bind,--
The cold--the changed--perchance the dead--anew,
The mourned, the loved, the lost--too many!