st difficulty in controlling my excitement. Unknown to
herself, Annie had provided us with an important piece of evidence. How
she would have gaped if she had realized that her "coarse kitchen salt"
was strychnine, one of the most deadly poisons known to mankind. I
marvelled at Poirot's calm. His self-control was astonishing. I awaited
his next question with impatience, but it disappointed me.

"When you went into Mrs. Inglethorp's room, was the door leading into
Miss Cynthia's room bolted?"

"Oh! Yes, sir; it always was. It had never been opened."

"And the door into Mr. Inglethorp's room? Did you notice if that was
bolted too?"

Annie hesitated.

"I couldn't rightly say, sir; it was shut but I couldn't say whether it
was bolted or not."

"When you finally left the room, did Mrs. Inglethorp bolt the door after
you?"

"No, sir, not then, but I expect she did later. She usually did lock it
at night. The door into the passage, that is."

"Did you notice any candle grease on the floor when you did the room
yesterday?"

"Candle grease? Oh, no, sir. Mrs. Inglethorp didn't have a candle, only
a reading-lamp."

"Then, if there had been a large patch of candle grease on the floor,
you think you would have been sure to have seen it?"

"Yes, sir, and I would have taken it out with a piece of blotting-paper
and a hot iron."

Then Poirot repeated the question he had put to Dorcas:

"Did your mistress ever have a green dress?"

"No, sir."

"Nor a mantle, nor a cape, nor a--how do you call it?--a sports coat?"

"Not green, sir."

"Nor anyone else in the house?"

Annie reflected.

"No, sir."

"You are sure of that?"

"Quite sure."

"Bien! That is all I want to know. Thank you very much."

With a nervous giggle, Annie took herself creakingly out of the room. My
pent-up excitement burst forth.

"Poirot," I cried, "I congratulate you! This is a great discovery."

"What is a great discovery?"

"Why, that it was the coco and not the coffee that was poisoned. That
explains everything! Of course it did not take effect until the early
morning, since the coco was only drunk in the middle of the night."

"So you think that the coco--mark well what I say, Hastings, the
coco--contained strychnine?"

"Of course! That salt on the tray, what else could it have been?"

"It might have been salt," replied Poirot placidly.

I shrugged my shoulders. If he was going to take the matter that way,
it was no good argu