"It isn't Strychnine, is it?"
"Where did you find this?" I asked Poirot, in lively curiosity.
"In the waste-paper basket. You recognise the handwriting?"
"Yes, it is Mrs. Inglethorp's. But what does it mean?"
Poirot shrugged his shoulders.
"I cannot say--but it is suggestive."
A wild idea flashed across me. Was it possible that Mrs. Inglethorp's mind was deranged? Had she some fantastic idea of demoniacal possession? And, if that were so, was it not also possible that she might have taken her own life?
I was about to expound these theories to Poirot, when his own words distracted me.
"Come," he said, "now to examine the coffee-cups!"
"My dear Poirot! What on earth is the good of that, now that we know about the coco?"
"Oh, la la! That miserable coco!" cried Poirot flippantly.
He laughed with apparent enjoyment, raising his arms to heaven in mock despair, in what I could not but consider the worst possible taste.
"And, anyway," I said, with increasing coldness, "as Mrs. Inglethorp took her coffee upstairs with her, I do not see what you expect to find, unless you consider it likely that we shall discover a packet of strychnine on the coffee tray!"
Poirot was sobered at once.
"Come, come, my friend," he said, slipping his arms through mine. "Ne vous fachez pas! Allow me to interest myself in my coffee-cups, and I will respect your coco. There! Is it a bargain?"
He was so quaintly humorous that I was forced to laugh; and we went together to the drawing-room, where the coffee-cups and tray remained undisturbed as we had left them.
Poirot made me recapitulate the scene of the night before, listening very carefully, and verifying the position of the various cups.
"So Mrs. Cavendish stood by the tray--and poured out. Yes. Then she came across to the window where you sat with Mademoiselle Cynthia. Yes. Here are the three cups. And the cup on the mantel-piece, half drunk, that would be Mr. Lawrence Cavendish's. And the one on the tray?"
"John Cavendish's. I saw him put it down there."
"Good. One, two, three, four, five--but where, then, is the cup of Mr. Inglethorp?"
"He does not take coffee."
"Then all are accounted for. One moment, my friend."
With infinite care, he took a drop or two from the grounds in each cup, sealing them up in separate test tubes, tasting each in turn as he did so. His physiognomy underwent a curious change. An expression gathered there that I can only describe as half puzzled, and half relieved.