At that moment my elbow rested on something hard in my pocket. Almost at the same moment an idea flashed into my brain. I tried to dispel it, but it wouldn’t go. I allowed my mind to dwell upon it, and quickly it obsessed me.
Why, I don’t know, but since the chemist had returned the little flask to me, after analysing its contents, I had carried it in my pocket constantly. It was there now. It was the flask that my elbow had pressed, recalling it to my mind.
“Twenty drops will send a strong man to sleep—for ever,” he had said.
The words came back to me now. If it needed twenty drops to kill a strong man, surely a small dose could with safety be administered to a wiry little old man who, though decrepit, seemed still to possess considerable vitality. But would it be quite safe? Did I dare risk it?
“A cup of tea will do just as well,” I said carelessly, tossing aside my cigarette. “No, don’t you move. I see you have everything ready, and there are cups up on the shelf. Let me make the tea. I like tea made in one way only.”
I felt quite guilty when he answered—
“You are very kind, sir; you are very kind; you are a gen’leman.”
It was easily and quickly done. I had my back to him. I poured the tea into the cups. Then I let about five drops of the fluid in the flask fall into a spoon. I put the spoon into his cup, and stirred his tea with it.
In a few moments I saw he was growing drowsy. His bony chin dropped several times on to his chest, though he tried to keep awake. He muttered some unintelligible words. In a few minutes he was asleep.
I took his pulse. Yes, it was still quite strong. I waited a moment or two. Then, slipping my hand into his jacket-pocket, I took out the bunch of keys noiselessly, turned out the gas-stove, and stepped quietly out of the room, closing the door behind me.