“Exactly.”
“Although the nurse, who was an older woman, was in the room?”
“Yes.”
“That does not look very good.”
“It doesn’t mean a thing, really. You don’t stand on ceremony at a picnic lunch.”
“Who cut the sandwiches?”
“Elinor Carlisle.”
“Was there anyone else in the house?”
“No one.”
Poirot shook his head.
“It is bad, that. And the girl had nothing but the tea and the sandwiches?”
“Nothing. Stomach contents tell us that.”
Poirot said:
“It is suggested that Elinor Carlisle hoped the girl’s death would be taken for food poisoning? How did she propose to explain the fact that only one member of the party was affected?”
Peter Lord said:
“It does happen that way sometimes. Also, there were two pots of paste—both much alike in appearance. The idea would be that one pot was all right and that by a coincidence all the bad paste was eaten by Mary.”
“An interesting study in the laws of probability,” said Poirot. “The mathematical chances against that happening would be high, I fancy. But another point, if food poisoning was to be suggested: Why not choose a different poison? The symptoms of morphine are not in the least like those of food poisoning. Atropine, surely, would have been a better choice!”
Peter Lord said slowly:
“Yes, that’s true. But there’s something more. That damned District Nurse swears she lost a tube of morphine!”
“When?”
“Oh, weeks earlier, the night old Mrs. Welman died. The nurse says she left her case in the hall and found a tube of morphine missing in the morning. All bunkum, I believe. Probably smashed it at home some time before and forgot about it.”
“She has only remembered it since the death of Mary Gerrard?”
Peter Lord said reluctantly:
“As a matter of fact, she did mention it at the time—to the nurse on duty.”
Hercule Poirot was looking at Peter Lord with some interest.
He said gently:
“I think, mon cher, there is something else—something that you have not yet told me.”
Peter Lord said:
“Oh, well, I suppose you’d better have it all. They’re applying for an exhumation order and going to dig up old Mrs. Welman.”