“You are a model witness. I suppose this glass has also been cleaned? Yes. A hospital is a poor hunting ground for the likes of me. Now don’t worry too much about this. It may be quite beside the point. In any case it would have been criminal to withhold it. Consciousness of having done the right thing brings, I understand, solace to the troubled breast.”

“I can’t say it does to mine.”

“Nonsense. Now will you be very kind and get your scrap of paper for me? Bring Nurse Banks back with you, and don’t mention homicide. By the way, what did you think about her reception of the glad tidings—I gather she looked upon them as glad?”

“She’s an ass,” answered Nurse Graham unexpectedly, “but she’s no murderer.”

“What did she say exactly?”

“Oh, something out of the Bible about praising the Lord for He hath cast down our enemies.”

“Good lack!” apostrophised Alleyn. “What an old—I beg your pardon, nurse. Ask the lady to come here, will you? And if you hear me scream come in and rescue me. I’ve no desire to die at the feet of that marble goddess there—who is she, by the way—Anæsthesia?”

“I’ve no idea, inspector,” said Nurse Graham with a sudden broad smile. She went out briskly and returned in a few minutes to give him a small square of white paper such as chemists use in wrapping up prescriptions. Fragments of red sealing-wax remained on the margins and the creases suggested that it had contained a round box. Alleyn put it in his pocketbook.

“Nurse Banks is waiting,” remarked Nurse Graham.

“Loose her,” said Alleyn. “Good-bye, nurse.”

“Good-bye, inspector.”

Miss Banks made a somewhat truculent entrance. She refused a chair and stood uncomfortably erect, just inside the door. Alleyn remained politely on his feet.

“Perhaps Nurse Graham has told you of my business here?” he suggested.

“She said something about Scotland Yard,” sniffed Banks. “I didn’t know what she was talking about.”

“I am investigating the circumstances of Sir Derek O’Callaghan’s death.”

“I said all there was to say about it at that inquest.”

Alleyn decided that finesse was not indicated.

“You didn’t mention it was murder,” he remarked.

For a moment he thought she looked frightened. Then she said woodenly:

“It is?”

“Yes. What do you think of that?”

“How do you know?”

“The post-mortem revealed indications of at least a quarter of a grain of hyoscine.”

“A quarter of a grain!” exclaimed Banks. He was reminded of Phillips. Neither of these two had ejaculated “Hyoscine!” as one might have expected, but had exclaimed at the amount.

“Wouldn’t you have expected that to kill him?” he asked.

“Oh, yes. Mr. Thoms said—” She stopped short.

“What did Mr. Thoms say?”

“Heard him say before the op. that a quarter-grain would be a fatal dose.”

“How did the subject arise?”

“Don’t remember.”