“The thread which you merely deduce from a nail in the skirting board!” I interrupted. “Why, that nail may have been there for years!”
“No. The varnish was quite fresh.”
“Well, I still think there might be all sorts of explanations of it.”
“Give me one.”
At the moment I could not think of anything sufficiently plausible. Poirot took advantage of my silence to sweep on with his discourse.
“Yes, a restricted circle. That thread could only have been stretched across the top of the stairs after everyone had gone to bed. Therefore we have only the occupants of the house to consider. That is to say, the guilt lies between seven people. Dr. Tanios. Mrs. Tanios. Theresa Arundell. Charles Arundell. Miss Lawson. Ellen. Cook.”
“Surely you can leave the servants out of it.”
“They received legacies, mon cher. And there might have been other reasons—spite—a quarrel—dishonesty—one cannot be certain.”
“It seems to me very unlikely.”
“Unlikely, I agree. But one must take all possibilities into consideration.”
“In that case, you must allow for eight people, not seven.”
“How so?”
I felt I was about to score a point.
“You must include Miss Arundell herself. How do you know she may not have stretched that thread across the stairs in order to trip up some other members of the house party?”
Poirot shrugged his shoulders.
“It is a bêtise you say there, my friend. If Miss Arundell laid a trap, she would be careful not to fall into it herself. It was she who fell down the stairs, remember.”
I retired crestfallen.
Poirot went on in a thoughtful voice:
“The sequence of events is quite clear—the fall—the letter to me—the visit of the lawyer—but there is one doubtful point. Did Miss Arundell deliberately hold back the letter to me, hesitating to post it? Or did she, once having written it, assume it was posted?”
“That we can’t possibly tell,” I said. “No. We can only guess. Personally, I fancy that she assumed it had been posted. She must have been surprised at getting no reply….”
My thoughts had been busy in another direction.
“Do you think this spiritualistic nonsense counted at all?” I asked. “I mean, do you think, in spite of Miss Peabody’s ridiculing of the suggestion, that a command was given at one of these séances that she should alter her will and leave her money to the Lawson woman?”
Poirot shook his head doubtfully.
“That does not seem to fit in with the general impression I have formed of Miss Arundell’s character.”
“The Tripp women say that Miss Lawson was completely taken aback when the will was read,” I said thoughtfully.
“That is what she told them, yes,” agreed Poirot.
“But you don’t believe it?”
“Mon ami—you know my suspicious nature! I believe nothing that anyone says unless it can be confirmed or corroborated.”
“That’s right, old boy,” I said affectionately. “A thoroughly nice, trustful nature.”
“‘He says,’ ‘she says,’ ‘they say’—Bah! what does that mean? Nothing at all. It may be absolute truth. It may be useful falsehood. Me, I deal only with facts.”