Once when we were lying just below Whampo, the captain took
nearly every officer and nearly the whole ship's crew on a
punitive expedition up the Canton river. They were away
about a week. I was left behind, dangerously ill with fever
and ague. In his absence, Sir Thomas had had me put into his
cabin, where I lay quite alone day and night, seeing hardly
anyone save the surgeon and the captain's steward, who was
himself a shadow, pretty nigh. Never shall I forget my
mental sufferings at night. In vain may one attempt to
describe what one then goes through; only the victims know
what that is. My ghost - the ghost of the Whampo Reach - the
ghost of those sultry and miasmal nights, had no shape, no
vaporous form; it was nothing but a presence, a vague
amorphous dread. It may have floated with the swollen and
putrid corpses which hourly came bobbing down the stream, but
it never appeared; for there was nothing to appear. Still it
might appear. I expected every instant through the night to
see it in some inconceivable form. I expected it to touch
me. It neither stalked upon the deck, nor hovered in the
dark, nor moved, nor rested anywhere. And yet it was there
about me, - where, I knew not. On every side I was
threatened. I feared it most behind the head of my cot,
because I could not see it if it were so.

This, it will be said, is the description of a nightmare.
Exactly so. My agony of fright was a nightmare; but a
nightmare when every sense was strained with wakefulness,
when all the powers of imagination were concentrated to
paralyse my shattered reason.