from Pharsalia (V. 219-224)

...and as she was carried back to the common day
out of the sacred radiance she saw destiny in,
a darkness came between. The Healer threw
Stygian Lethe in her guts
so he could grab his secrets. Then the truth
left her breast, and the futures returned to the tripods.
--She fell, to be barely revived.

(my tr; 1983)

Now by degrees the fire aetherial fail'd,
And the dull human sense again prevail'd;
While Phoebus, sudden, in a marky shade,
Hid the past vision from the mortal maid.
Thick clouds of dark oblivion rose between,
And snatch away at once the wondrous scene;
Stretch'd on the ground the fainting princess lies,
While to the Tripod, back, th' informing spirit flies.

--Marcus Annaeus Lucanus (tr Rowe 1718)