“They use the pure hydro-chloride of strychnine very little—only occasionally for pills. It is the official solution, Liq. Strychnine Hydro-clor. that is used in most medicines. That is why the finger-marks have remained undisturbed since then.”
“How did you manage to take this photograph?”
“I dropped my hat from the balcony,” explained Poirot simply. “Visitors were not permitted below at that hour, so, in spite of my many apologies, Mademoiselle Cynthia’s colleague had to go down and fetch it for me.”
“Then you knew what you were going to find?”
“No, not at all. I merely realized that it was possible, from your story, for Monsieur Lawrence to go to the poison cupboard. The possibility had to be confirmed, or eliminated.”
“Poirot,” I said, “your gaiety does not deceive me. This is a very important discovery.”
“I do not know,” said Poirot. “But one thing does strike me. No doubt it has struck you too.”
“What is that?”
“Why, that there is altogether too much strychnine about this case. This is the third time we run up against it. There was strychnine in Mrs. Inglethorp’s tonic. There is the strychnine sold across the counter at Styles St. Mary by Mace. Now we have more strychnine, handled by one of the household. It is confusing; and, as you know, I do not like confusion.”
Before I could reply, one of the other Belgians opened the door and stuck his head in.