“Roberts is the man to ask about that. My own idea is that he was worried about the patient for some time before I gave the injection. He asked for camphor, remember. Naturally, you’ll think, I want to stress that point. Well, inspector, so I do. I suppose the serum injection is the dangerous corner as far as I’m concerned. Still, I did not prepare the syringe and I could hardly palm it and produce another from behind my left ear. Could I? What? Ha ha ha!”

“Let’s have a look at it,” said Alleyn imperturbably, “and we’ll see.”

Thoms went to one of the shelves and returned with a syringe at the sight of which the inspector gave a little shout of horror.

“Good God, Mr. Thoms, are you a horse-coper? You don’t mean to tell me you jabbed that horror into the poor man? It’s the size of a fire extinguisher!”

Thoms stared at him and then roared with laughter. “He didn’t feel it. Oh, yes, we plugged it into him. Well, now, I could hardly produce a thing like that by sleight of hand, could I?”

“Heavens, no! Put it away, do; it makes me feel quite sick. A disgusting, an indecent, a revolting implement.”

Thoms made a playful pass at the inspector, who seized the syringe and bore it away. He examined it, uttering little noises of disgust.

“This is the type used for the other two injections,” explained Thoms, who had been peering into the array of instruments. He showed Alleyn a hypodermic syringe of the sort familiar to the layman.

“Sufficiently alarming, hut not so preposterous. This would be the kind of thing Dr. Roberts handled?”

“Yes—or rather, no. Roberts didn’t give the camphor injection. The nurse gave it.”

“Oh, yes. Is that usual?”

“It’s quite in order. Generally speaking, that injection is given by the anæsthetist, but there’s nothing in his asking the nurse to give it.”

“This needle’s a delicate-looking thing. I suppose you never carry a syringe about ready for use?”

“Lord, no! In the theatre, of course, they are laid out all complete.”

“Would you mind filling this one for me?”

He gave Thoms a small syringe. The surgeon poured some water into a measuring-glass, inserted the needle and pulled back the piston.

“There you are. If a tablet’s used, the usual procedure is to squirt the syringe half full into the glass, dissolve the tablet, and then draw it up again.”

“The whole business only takes a few seconds?”

“Well—the tablet has to dissolve. In the case of the serum and the camphor the stuff was there ready.”

“Yes, I’ve got that. May I see the bottle the serum is kept in?”