“Oh—well, because he wanted to be sure of the dosage, I suppose.”

“And then?”

“I went into the theatre.”

“Where you joined Phillips?”

“Yes. He’d just put the hyoscine tablet into the water, I think.”

“Did you notice the little bottle—how many tablets were left? I simply want to check up, you understand.”

“Of course. Well, it’s a tube; you can’t see the number of tablets unless you peer into it, and then you can only guess, but, of course, there would be nineteen, because it was a new lot.”

“How do you know that, Mr. Thoms?”

“Well, as a matter of fact, I saw he had two tubes and said something about it, and he said one of them was empty, so he’d opened another.”

“What happened to the empty one?”

“Eh? Search me. Chucked it away, I suppose. I say—er— look here, what is your name?”

“Alleyn.”

“Oh. Well, look here, Alleyn, you’re not attaching any importance to the second tube, are you? Because you jolly well needn’t. It’s all perfectly simple. Phillips uses a hypodermic case which holds two of these little phials. He’d obviously used the last tablet on a previous case without realising it was the last. Very easy thing to do.”

“I see that. All this business is merely by way of checking up.”

“Yes, but—”

“For my own sake I’ve got to account for every movement of the game, Mr. Thoms. It’s all frightfully muddling and I’ve got to try to learn it like a lesson. Do you remember anything that was said just then?”

“Well, I—well, I chaffed him about the two tubes—said he was doing Sir Derek proud, and then I—I remarked that he used a lot of water.”

“Did this seem to upset him at all?”

“Oh, Lord—no. I mean, Sir John always stands a bit on his dignity. I mean, he rather shut me up. He hasn’t got what I call a sense of humour.”

“Really? Did you go out together?”

“Yes. I went into the anteroom and Sir John into the anæsthetic-room to give the injection. I went first.”

“Sure, Mr. Thoms?”

“Oh, yes,” said Thoms, opening his eyes very wide. “Why?”

“I only want to get the order of events. Now let’s look at the theatre, shall we?”

Once again Thoms butted the swing-doors with his compact little stern, and this time Inspector Alleyn followed him through.

The theatre was scrupulously, monstrously immaculate— a place of tiles and chromium and white enamel. Thoms turned on a switch and for a moment an enormous high-powered cluster of lights poured down its truncated conical glare on the blank surface of the table. The theatre instantly became alive and expectant. He snapped it off and in its stead an insignificant wall bracket came to life over a side table on rubber castors.