“You come here on business, sir?” he said.  “I am at a loss to know what that business can possibly he.”

The unconcealed curiosity, with which he looked hard in my face while he spoke, convinced me that I had passed unnoticed by him at the Opera.  He had seen Pesca first, and from that moment till he left the theatre he had evidently seen nothing else.  My name would necessarily suggest to him that I had not come into his house with other than a hostile purpose towards himself, but he appeared to be utterly ignorant thus far of the real nature of my errand.

“I am fortunate in finding you here to-night,” I said.  “You seem to be on the point of taking a journey?”

“Is your business connected with my journey?”

“In some degree.”

“In what degree?  Do you know where I am going to?”

“No.  I only know why you are leaving London.”

He slipped by me with the quickness of thought, locked the door, and put the key in his pocket.

“You and I, Mr. Hartright, are excellently well acquainted with one another by reputation,” he said.  “Did it, by any chance, occur to you when you came to this house that I was not the sort of man you could trifle with?”

“It did occur to me,” I replied.  “And I have not come to trifle with you.  I am here on a matter of life and death, and if that door which you have locked was open at this moment, nothing you could say or do would induce me to pass through it.”

I walked farther into the room, and stood opposite to him on the rug before the fireplace.  He drew a chair in front of the door, and sat down on it, with his left arm resting on the table.  The cage with the white mice was close to him, and the little creatures scampered out of their sleeping-place as his heavy arm shook the table, and peered at him through the gaps in the smartly painted wires.

“On a matter of life and death,” he repeated to himself.  “Those words are more serious, perhaps, than you think.  What do you mean?”

“What I say.”

The perspiration broke out thickly on his broad forehead.  His left hand stole over the edge of the table.  There was a drawer in it, with a lock, and the key was in the lock.  His finger and thumb closed over the key, but did not turn it.

“So you know why I am leaving London?” he went on.  “Tell me the reason, if you please.”  He turned the key, and unlocked the drawer as he spoke.

“I can do better than that,” I replied.  “I can show you the reason, if you like.”

“How can you show it?”

“You have got your coat off,” I said.  “Roll up the shirt-sleeve on your left arm, and you will see it there.”

The same livid leaden change passed over his face which I had seen pass over it at the theatre.  The deadly glitter in his eyes shone steady and straight into mine.  He said nothing.  But his left hand slowly opened the table-drawer, and softly slipped into it.  The harsh grating noise of something heavy that he was moving unseen to me sounded for a moment, then ceased.  The silence that followed was so intense that the faint ticking nibble of the white mice at their wires was distinctly audible where I stood.