“As regards the actual solution,” said Phillips, “I used a tablet of a hundredth of a grain. This I dissolved in twenty-five minims of distilled water. There was a stock solution of hyoscine in the theatre which I did not use.”

“Less reliable or something?”

“It’s no doubt perfectly reliable, but hyoscine is a drug that should be used with extreme care. By preparing it myself I am sure of the correct dosage. In most theatres nowadays it’s put out in ampoules. I shall see,” added Phillips grimly, “that this procedure is followed here in future.”

“In this instance you went through the customary routine?”

“I did.”

“Were you alone when you prepared the syringe?”

“There may have been a nurse in the theatre—I don’t remember.” He paused and then added: “Thoms came in just as I finished.”

“Did he go out with you?”

“I really don’t know. I rather think he returned to the anteroom a few moments later. I left him in the theatre. I went to the anæsthetic-room and gave the injection.”

“Of course, you have no doubt in your own mind about the dosage?”

“I know quite well what you are thinking, Inspector Alleyn. It is a perfectly reasonable suspicion. I am absolutely assured that I dissolved one tablet and one tablet only. I filled the syringe with distilled water, squirted it into a measuring-glass, shook one tablet into my hand, saw that it was a single tablet, and dropped it into the glass.”

Phillips leant back, looked steadily into Alleyn’s eyes, and thrust his hands into his pockets. “I am prepared to swear to that,” he said.

“It’s perfectly clear, sir,” said Alleyn, “and although I had to consider the possibility of a mistake, I realise that even if you had dropped two tablets into the water it would have only meant a dosage of a fiftieth of a grain. Probably the entire contents of the tube would not be a quarter of a grain—the amount estimated.”

For the first time Phillips hesitated. “They are packed in tubes of twenty,” he said at last, “so an entire tube would contain a fifth of a grain of hyoscine.” He felt in his coat pocket and produced a hypodermic case which he handed to Alleyn.

“The actual tube is still in there. I have since used one tablet.”

Alleyn opened the case and took out a glass tube completely covered by its paper label. He pulled out the tiny cork and looked in.

“May I?” he asked, and shook out the contents into his hand. There were eighteen tablets.

“That settles it,” he said cheerfully. “Do you mind if I take these for analysis? Purely a matter of routine, as one says in crime fiction.”

“Do,” said Phillips, looking rather bored.

Alleyn took an envelope from his pocket, put the tablets back into the tube, the tube into the envelope, and the envelope into his pocket.