_terrae incognitae_, and doubted whether they had yet been laid down in
the modern charts of London. For all this, however, I paid a heavy price
in distant years, when the human face tyrannised over my dreams, and the
perplexities of my steps in London came back and haunted my sleep, with
the feeling of perplexities, moral and intellectual, that brought
confusion to the reason, or anguish and remorse to the conscience.

Thus I have shown that opium does not of necessity produce inactivity or
torpor, but that, on the contrary, it often led me into markets and
theatres. Yet, in candour, I will admit that markets and theatres are
not the appropriate haunts of the opium-eater when in the divinest state
incident to his enjoyment. In that state, crowds become an oppression to
him; music even, too sensual and gross. He naturally seeks solitude and
silence, as indispensable conditions of those trances, or profoundest
reveries, which are the crown and consummation of what opium can do for
human nature. I, whose disease it was to meditate too much and to
observe too little, and who upon my first entrance at college was nearly
falling into a deep melancholy, from brooding too much on the sufferings
which I had witnessed in London, was sufficiently aware of the tendencies
of my own thoughts to do all I could to counteract them. I was, indeed,
like a person who, according to the old legend, had entered the cave of
Trophonius; and the remedies I sought were to force myself into society,
and to keep my understanding in continual activity upon matters of
science. But for these remedies I should certainly have become
hypochondriacally melancholy. In after years, however, when my
cheerfulness was more fully re-established, I yielded to my natural
inclination for a solitary life. And at that time I often fell into
these reveries upon taking opium; and more than once it has happened to
me, on a summer night, when I have been at an open window, in a room from
which I could overlook the sea at a mile below me, and could command a