"True enough, sir. There's no city in the world so full of mystery as London. We're a strange lot, sir. I read in a book once that every house contains a skeleton. The human mind, sir," said Constable Applebee, philosophically, "the human mind is a box, and no one but the man who owns that mind knows what is shut up in it."

It was a pregnant opening for discussion, but Dick did not pursue it. He returned to the subject that was engrossing his thoughts.

"Samuel Boyd kept a clerk,----"

"And I pity the poor devil," interjected the constable.

"So do I. The name of his last clerk is Abel Death. You've noticed him, I dare say."

"Oh, yes, I've noticed him. A weedy sort of chap--looks as it he had all the cares of the world on his shoulders. I didn't know his name, though. Abel Death! If it was mine, I'd change it."

"Have you seen him lately?"

"Let me think, now. It was Friday night when I saw him last. I noticed him particularly, because he staggered a bit, walked zig-zag like, as if he'd had a glass too much. That was what I thought at first, but I altered my opinion when I caught sight of his face. It wasn't so much like a man who'd been drinking, but like one who was fairly demented. Any special reason for asking about him, sir?"

"No special reason," replied Dick, not feeling himself justified in revealing what had passed in the police station, "You would call Mr. Death a respectable person, I suppose?"

"When there's nothing against a man," said Constable Applebee, "you're bound in common fairness to call him respectable. From the little I know of him I should say, poor, but respectable. If we come to that, there's plenty of poor devils in the same boat."