He went to his bookcase and took down several volumes, from which he read in a rapid, dry and didactic manner, rather as though Alleyn was a collection of students. This went on for some time. The servant brought in tea, and with an air of patient benevolence, poured it out himself. He placed Roberts’s cup on a table under his nose, waited until the doctor closed the book with which he was at the moment engaged, took it firmly from him and directed his attention to the tea. He then moved the table between the two men and left the room.

“Thank you,” said Roberts vaguely some time after he had gone.

Roberts, still delivering himself of his learning, completely forgot to drink his tea or to offer some to Alleyn, but occasionally stretched out a hand towards the toast. The time passed rapidly. Alleyn looked at his watch.

“Good Lord!” he exclaimed, “it’s half-past four. We’ll have to collect ourselves, I’m afraid.”

“Tch!” said Roberts crossly.

“I’ll call a taxi.”

“No, no. I’ll drive you there, inspector. Wait a moment.” He darted out into the hall and gave flurried orders to the little servant, who silently insinuated him into his coat and gave him his hat. Roberts shot back into the sitting-room and fetched his stethoscope.

“What about your anæsthetising apparatus?” ventured Alleyn.

“Eh?” asked Roberts, squinting round at him.

“Your anæsthetising apparatus.”

“D’you want that?”

“Please—if it’s not a great bore. Didn’t Sir John tell you?”

“I’ll get it,” said Roberts. He darted off across the little hall.

“Can I assist you, sir?” asked the servant.

“No, no. Bring out the car.”

He reappeared presently, wheeling the cruet-like apparatus with its enormous cylinders.

“You can’t carry that down the steps by yourself,” said Alleyn. “Let me help.”

“Thank you, thank you,” said Roberts. He bent down and examined the nuts that fastened the frame at the bottom. “Wouldn’t do for these nuts to come loose,” he said. “You take the top, will you? Gently. Ease it down the steps.”

With a good deal of bother they got the thing into Roberts’s car and drove off to Brook Street, the little doctor talking most of the time.

As they drew near the hospital, however, he grew quieter, seemed to get nervous, and kept catching Alleyn’s eye and hurriedly looking away again. After this had happened some three or four times Roberts laughed uncomfortably.

“I—I’m not looking forward to this experiment,” he said. “One gets moderately case-hardened in our profession, I suppose, but there’s something about this affair”—he blinked hard twice—“something profoundly disquieting. Perhaps it is the element of uncertainty.”

“But you have got a theory, Dr. Roberts?”

“I? No. No. I did hope it might be suicide. No—I’ve no specific theory.”

“Oh, well. If you won’t tell me, you won’t,” rejoined Alleyn.