"Wait a moment," said Dr. Cooper from within. "I will strike a light."

This accomplished, he opened the door, which, as we glided in, Rivers quickly closed and locked. Dr. Cooper had retreated from the door, and stood, holding the candle above his head. With an exclamation of alarm he let the candle slip from his hand, and we were in darkness.

"What a clumsy fellow you are!" exclaimed Rivers in a jocose tone. "Light it again, Mr. Emery. I have got Dr. Cooper quite safe."

And I saw, when I had picked up the candle and lighted it, Dr. Cooper standing quite still, with his arms pinned to his sides from behind by Rivers. I placed the candle out of the doctor's reach, and Rivers released him.

Dr. Cooper was in his nightshirt, and presented anything but a pleasant picture. Rivers, on the contrary, had an airy lightness about him which was new to me. His eyes shone, and he rubbed his hands together, as if he were taking part in a peculiarly agreeable function. On a table by the bedside were a glass and a bottle of whisky, half empty. Rivers put the bottle to his nose.

"Scotch," he said. "I always drink Scotch myself."

"Who are you?" Dr. Cooper managed to say. "What do you want?"

"All in good time, doctor," replied Rivers. "It's no good commencing in the middle of the game. You haven't the pleasure of my acquaintance yet, but you know this gentleman."

"I have seen him once before," said Dr. Cooper, with a troubled glance at me.

"And I am positive you must have enjoyed his society. He proves that he enjoyed yours by his anxiety to renew the intimacy. He is a private gentleman, I am a private detective, and we have come a long way to see you. But you will catch cold standing there with only your shirt on. Will you get into your clothes or into bed before we have our chat. You would like to dress? You shall. Softly, softly. I will hand you your clothes, taking the precaution to empty your pockets first."