es, he did!"

"Impossible! We were all together the whole time."

Poirot shook his head.

"No, my friend, there was a moment when you were not all together. There
was a moment when you could not have been all together, or it would not
have been necessary to call to Monsieur Lawrence to come and join you on
the balcony."

"I'd forgotten that," I admitted. "But it was only for a moment."

"Long enough."

"Long enough for what?"

Poirot's smile became rather enigmatical.

"Long enough for a gentleman who had once studied medicine to gratify a
very natural interest and curiosity."

Our eyes met. Poirot's were pleasantly vague. He got up and hummed a
little tune. I watched him suspiciously.

"Poirot," I said, "what was in this particular little bottle?"

Poirot looked out of the window.

"Hydro-chloride of strychnine," he said, over his shoulder, continuing
to hum.

"Good heavens!" I said it quite quietly. I was not surprised. I had
expected that answer.

"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.

"There is a lady below, asking for Mr Hastings."

"A lady?"

I jumped