“I’m walking up St. James’ Street,” he said slowly. “Now I’ve come to the club and I’m going past the smoking-room—windows—one—two—three—four. Now I’m at the steps. I turn in and begin going up them. One—two—three—four—five—six, then a broad step; six—seven—eight—nine, another broad step; nine—ten—eleven. Eleven—I’m inside. Good morning, Rogers. Fine day again.” With a little start he opened his eyes and came back again to his present surroundings. He turned to Bill with a smile. “Eleven,” he said. “Count them the next time you’re there. Eleven and now I hope I shall forget it again.”

Bill was distinctly interested.

“That’s rather hot,” he said. “Expound.”

“Well, I can’t explain it, whether it’s something in the actual eye, or something in the brain, or what, but I have got rather an uncanny habit of recording things unconsciously. You know that game where you look at a tray full of small objects for three minutes, and then turn away and try to make a list of them. It means a devil of a lot of concentration for the ordinary person, if he wants to get his list complete, but in some odd way I manage to do it without concentration at all. I mean that my eyes seem to do it without the brain consciously taking any part. I could look at the tray, for instance, and talk to you about golf at the same time, and still get my list right.”

“I should think that’s rather a useful gift for an amateur detective. You ought to have gone into the profession before.”

“Well, it is rather useful. It’s rather surprising, you know, to a stranger. Let’s surprise Cayley with it, shall we?”

“How?”

“Well, let’s ask him—” Antony stopped and looked at Bill comically, “let’s ask him what he’s going to do with the key of the office.”

For a moment Bill did not understand.

“Key of the office?” he said vaguely. “You don’t mean—Tony! What do you mean? Good God! do you mean that Cayley—But what about Mark?”