But there was no great difficulty in the first stage of my adventure.  Upper Swandam Lane is a vile alley lurking behind the high wharves which line the north side of the river to the east of London Bridge.  Between a slop-shop and a gin-shop, approached by a steep flight of steps leading down to a black gap like the mouth of a cave, I found the den of which I was in search.  Ordering my cab to wait, I passed down the steps, worn hollow in the centre by the ceaseless tread of drunken feet; and by the light of a flickering oil-lamp above the door I found the latch and made my way into a long, low room, thick and heavy with the brown opium smoke, and terraced with wooden berths, like the forecastle of an emigrant ship.

Through the gloom one could dimly catch a glimpse of bodies lying in strange fantastic poses, bowed shoulders, bent knees, heads thrown back, and chins pointing upward, with here and there a dark, lack-lustre eye turned upon the newcomer.  Out of the black shadows there glimmered little red circles of light, now bright, now faint, as the burning poison waxed or waned in the bowls of the metal pipes.  The most lay silent, but some muttered to themselves, and others talked together in a strange, low, monotonous voice, their conversation coming in gushes, and then suddenly tailing off into silence, each mumbling out his own thoughts and paying little heed to the words of his neighbour.  At the farther end was a small brazier of burning charcoal, beside which on a three-legged wooden stool there sat a tall, thin old man, with his jaw resting upon his two fists, and his elbows upon his knees, staring into the fire.

As I entered, a sallow Malay attendant had hurried up with a pipe for me and a supply of the drug, beckoning me to an empty berth.

“Thank you.  I have not come to stay,” said I.  “There is a friend of mine here, Mr. Isa Whitney, and I wish to speak with him.”

There was a movement and an exclamation from my right, and peering through the gloom, I saw Whitney, pale, haggard, and unkempt, staring out at me.

“My God!  It’s Watson,” said he.  He was in a pitiable state of reaction, with every nerve in a twitter.  “I say, Watson, what o’clock is it?”

“Nearly eleven.”

“Of what day?”

“Of Friday, June 19th.”

“Good heavens!  I thought it was Wednesday.  It is Wednesday.  What d’you want to frighten a chap for?” He sank his face onto his arms and began to sob in a high treble key.

“I tell you that it is Friday, man.  Your wife has been waiting this two days for you.  You should be ashamed of yourself!”

“So I am.  But you’ve got mixed, Watson, for I have only been here a few hours, three pipes, four pipes—­I forget how many.  But I’ll go home with you.  I wouldn’t frighten Kate—­poor little Kate.  Give me your hand!  Have you a cab?”

“Yes, I have one waiting.”

“Then I shall go in it.  But I must owe something.  Find what I owe, Watson.  I am all off colour.  I can do nothing for myself.”