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 cocoa?”

“Oh, là là! That miserable cocoa!” 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 fâchez pas! Allow me to interest myself in my coffee-cups, and I will respect your cocoa. 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 mantelpiece, 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.

“Bien!” he said at last. “It is evident! I had an idea—but clearly I was mistaken. Yes, altogether I was mistaken. Yet it is strange. But no matter!”

And, with a characteristic shrug, he dismissed whatever it was that was worrying him from his mind. I could have told him from the beginning that this obsession of his over the coffee was bound to end in a blind alley, but I restrained my tongue. After all, though he was old, Poirot had been a great man in his day.

“Breakfast is ready,” said John Cavendish, coming in from the hall. “You will breakfast with us, Monsieur Poirot?”

Poirot acquiesced. I observed John. Already he was almost restored to his normal self. The shock of the events of the last night had upset him temporarily, but his equable poise soon swung back to the normal. He was a man of very little imagination, in sharp contrast with his brother, who had, perhaps, too much.

Ever since the early hours of the morning, John had been hard at work, sending telegrams—one of the first had gone to Evelyn Howard—writing notices for the papers, and generally occupying himself with the melancholy duties that a death entails.

“May I ask how things are proceeding?” he said. “Do your investigations point to my mother having died a natural death—or—or must we prepare ourselves for the worst?”

“I think, Mr. Cavendish,” said Poirot gravely, “that you would do well not to buoy yourself up with any false hopes. Can you tell me the views of the other members of the family?”

“My brother Lawrence is convinced that we are making a fuss over nothing. He says that everything points to its being a simple case of heart failure.”

“He does, does he? That is very interesting—very interesting,” murmured Poirot softly. “And Mrs. Cavendish?”

A faint cloud passed over John’s face.

“I have not the least idea what my wife’s views on the subject are.”

The answer brought a momentary stiffness in its train. John broke the rather awkward silence by saying with a slight effort:

“I told you, didn’t I, that Mr. Inglethorp has returned?”

Poirot bent his head.

“It’s an awkward position for all of us. Of course one has to treat him as usual—but, hang it all, one’s gorge does rise at sitting down to eat with a possible murderer!”

Poirot nodded sympathetically.

“I quite understand. It is a very difficult situation for you, Mr. Cavendish. I would like to ask you one question. Mr. Inglethorp’s reason for not returning last night was, I believe, that he had forgotten the latch-key. Is not that so?”

“Yes.”

“I suppose you are quite sure that the latch-key was forgotten—that he did not take it after all?”

“I have no idea. I never thought of looking. We always keep it in the hall drawer. I’ll go and see if it’s there now.”

Poirot held up his hand with a faint smile.

“No, no, Mr. Cavendish, it is too late now. I am certain that you would find it. If Mr. Inglethorp did take it, he has had ample time to replace it by now.”

“But do you think——”

“I think nothing. If anyone had chanced to look this morning before his return, and seen it there, it would have been a valuable point in his favour. That is all.”

John looked perplexed.

“Do not worry,” said Poirot smoothly. “I assure you that you need not let it trouble you. Since you are so kind, let us go and have some breakfast.”

Everyone was assembled in the dining-room. Under the circumstances, we were naturally not a cheerful party. The reaction after a shock is always trying, and I think we were all suffering from it. Decorum and good breeding naturally enjoined that our demeanour should be much as usual, yet I could not help wondering if this self-control were really a matter of great difficulty. There were no red eyes, no signs of secretly indulged grief. I felt that I was right in my opinion that Dorcas was the person most affected by the personal side of the tragedy.

I pass over Alfred Inglethorp, who acted the bereaved widower in a manner that I felt to be disgusting in its hypocrisy. Did he know that we suspected him, I wondered. Surely he could not be unaware of the fact, conceal it as we would. Did he feel some secret stirring of fear, or was he confident that his crime would go unpunished? Surely the suspicion in the atmosphere must warn him that he was already a marked man.

But did everyone suspect him? What about Mrs. Cavendish? I watched her as she sat at the head of the table, graceful, composed, enigmatic. In her soft grey frock, with white ruffles at the wrists falling over her slender hands, she looked very beautiful. When she chose, however, her face could be sphinx-like in its inscrutability. She was very silent, hardly opening her lips, and yet in some queer way I felt that the great strength of her personality was dominating us all.

And little Cynthia? Did she suspect? She looked very tired and ill, I thought. The heaviness and languor of her manner were very marked. I asked her if she were feeling ill, and she answered frankly:

“Yes, I’ve got the most beastly headache.”

“Have another cup of coffee, mademoiselle?” said Poirot solicitously. “It will revive you. It is unparalleled for the mal de tête.” He jumped up and took her cup.

“No sugar,” said Cynthia, watching him, as he picked up the sugar-tongs.