“I am lonely to-night without Mark. That’s funny, isn’t it?” CHAPTER XXII. Mr. Beverley Moves On “Good Lord!” said Bill, as he put down the letter. “I thought you’d say that,” murmured Antony. “Tony, do you mean to say that you knew all this?” “I guessed some of it. I didn’t quite know all of it, of course.” “Good Lord!” said Bill again, and returned to the letter. In a moment he was looking up again. “What did you write to him? Was that last night? After I’d gone into Stanton?” “Yes.” “What did you say? That you’d discovered that Mark was Robert?” “Yes. At least I said that this morning I should probably telegraph to Mr. Cartwright of Wimpole Street, and ask him to—” Bill burst in eagerly on the top of the sentence. “Yes, now what was all that about? You were so damn Sherlocky yesterday all of a sudden. We’d been doing the thing together all the time, and you’d been telling me everything, and then suddenly you become very mysterious and private and talk enigmatically—is that the word?—about dentists and swimming and the ‘Plough and Horses,’ and—well, what was it all about? You simply vanished out of sight; I didn’t know what on earth we were talking about.” Antony laughed and apologized. “Sorry, Bill. I felt like that suddenly. Just for the last half-hour; just to end up with. I’ll tell you everything now. Not that there’s anything to tell, really. It seems so easy when you know it—so obvious. About Mr. Cartwright of Wimpole Street. Of course he was just to identify the body.” “But whatever made you think of a dentist for that?” “Who could do it better? Could _you_ have done it? How could you? You’d never gone bathing with Mark; you’d never seen him stripped. He didn’t swim. Could his doctor do it? Not unless he’d had some particular operation, and perhaps not then. But his dentist could—at any time, always—if he had been to his dentist fairly often. Hence Mr. Cartwright of Wimpole Street.” Bill nodded thoughtfully and went back again to the letter. “I see. And you told Cayley that you were telegraphing to Cartwright to identify the body?” “Yes. And then of course it was all up for him. Once we knew that Robert was Mark we knew everything.” “How _did_ you know?” Antony got up from the breakfast table and began to fill his pipe.