“Uncle is out,” she informed us. “He went for a walk along the Drive.”

“And Mr. Arnesson, I suppose, has not yet returned from the university.”

“No; but he’ll be here for lunch. He has no classes Tuesday afternoons.”

“In the meantime, then, we’ll confer with Beedle and the admirable Pyne.—And I might suggest that it would do Mrs. Drukker no end of good if you’d pay her a visit.”

With a troubled smile and a little nod the girl passed out through the basement door.

Heath at once went in search of Beedle and Pyne and brought them to the drawing-room, where Vance questioned them about the preceding night. No information, however, was obtained from them. They had both gone to bed at ten o’clock. Their rooms were on the fourth floor at the side of the house; and they had not even heard Miss Dillard when she returned from the theatre. Vance asked them about noises on the range, and intimated that the screen-porch door of the Drukkers might have slammed shut at about midnight. But apparently both of them had been asleep at that hour. Finally they were dismissed with a warning not to mention to any one the questions that had just been asked them.

Five minutes later Professor Dillard came in. Though surprised to see us, he greeted us amiably.

“For once, Markham, you’ve chosen an hour for your visit when I am not absorbed in work.—More questions, I suppose. Well, come along to the library for the inquisition. It’ll be more comfortable there.” He led the way up-stairs, and when we were seated he insisted that we join him in a glass of port which he himself served from the sideboard.

“Drukker should be here,” he remarked. “He has a fondness for my ‘Ninety-six,’ though he’ll drink it only on rare occasions. I tell him he should take more port; but he imagines it’s bad for him, and points to my gout. But there’s no connection between gout and port—the notion is sheer superstition. Sound port is the most wholesome of wines. Gout is unknown in Oporto. A little physical stimulation of the right kind would be good for Drukker. . . . Poor fellow. His mind is like a furnace that’s burning his body up. A brilliant man, Markham. If he had sufficient bodily energy to keep pace with his brain, he’d be one of the world’s great physicists.”

“He tells me,” commented Vance, “that you twitted him on his inability to work out a modification of the quantum theory in regard to light-interference.”