"Not if you were drugged, mademoiselle."
"Drugged?"
"_Mais, oui!_"
"You remember"--he addressed us collectively again--"that through allthe tumult and noise next door Mademoiselle Cynthia slept. That admittedof two possibilities. Either her sleep was feigned--which I did notbelieve--or her unconsciousness was indeed by artificial means.
"With this latter idea in my mind, I examined all the coffee-cupsmost carefully, remembering that it was Mrs. Cavendish who had broughtMademoiselle Cynthia her coffee the night before. I took a sample fromeach cup, and had them analysed--with no result. I had counted the cupscarefully, in the event of one having been removed. Six persons hadtaken coffee, and six cups were duly found. I had to confess myselfmistaken.
"Then I discovered that I had been guilty of a very grave oversight.Coffee had been brought in for seven persons, not six, for Dr.Bauerstein had been there that evening. This changed the face of thewhole affair, for there was now one cup missing. The servants noticednothing, since Annie, the housemaid, who took in the coffee, broughtin seven cups, not knowing that Mr. Inglethorp never drank it, whereasDorcas, who cleared them away the following morning, found six asusual--or strictly speaking she found five, the sixth being the onefound broken in Mrs. Inglethorp's room.
"I was confident that the missing cup was that of Mademoiselle Cynthia.I had an additional reason for that belief in the fact that all thecups found contained sugar, which Mademoiselle Cynthia never took inher coffee. My attention was attracted by the story of Annie aboutsome 'salt' on the tray of cocoa which she took every night to Mrs.Inglethorp's room. I accordingly secured a sample of that cocoa, andsent it to be analysed."
"But that had already been done by Dr. Bauerstein," said Lawrencequickly.
"Not exactly. The analyst was asked by him to report whether strychninewas, or was not, present. He did not have it tested, as I did, for anarcotic."
"For a narcotic?"
"Yes. Here is the analyst's report. Mrs. Cavendish administered asafe, but effectual, narcotic to both Mrs. Inglethorp and MademoiselleCynthia. And it is possible that she had a _mauvais quart d'heure_ inconsequence! Imagine her feelings when her mother-in-law is suddenlytaken ill and dies, and immediately after she hears the word 'Poison'!She has believed that the sleeping draught she administered wasperfectly harmless, but there is no doubt that for one terrible momentshe must have feared that Mrs. Inglethorp's death lay at her door. Sheis seized with panic, and under its influence she hurries downstairs,and quickly drops the coffee-cup and saucer used by Mademoiselle Cynthiainto a large brass vase, where it is discovered later by MonsieurLawrence. The remains of the cocoa she dare not touch. Too many eyesare upon her. Guess at her relief when strychnine is mentioned, and shediscovers that after all the tragedy is not her doing.
"We are now able to account for the symptoms of strychnine poisoningbeing so long in making their appearance. A narcotic taken withstrychnine will delay the action of the poison for some hours."
Poirot paused. Mary looked up at him, the colour slowly rising in herface.
"All you have said is quite true, Monsieur Poirot. It was the mostawful hour of my life. I shall never forget it. But you are wonderful. Iunderstand now----"
"What I meant when I told you that you could safely confess to PapaPoirot, eh? But you would not trust me."
"I see everything now," said Lawrence. "The drugged cocoa, taken on topof the poisoned coffee, amply accounts for the delay."
"Exactly. But was the coffee poisoned, or was it not? We come to alittle difficulty here, since Mrs. Inglethorp never drank it."
"What?" The cry of surprise was universal.
"No. You will remember my speaking of a stain on the carpet in Mrs.Inglethorp's room? There were some peculiar points about that stain. Itwas still damp, it exhaled a strong odour of coffee, and imbedded inthe nap of the carpet I found some little splinters of china. What hadhappened was plain to me, for not two minutes before I had placed mylittle case on the table near the window, and the table, tilting up, haddeposited it upon the floor on precisely the identical spot. In exactlythe same way, Mrs. Inglethorp had laid down her cup of coffee onreaching her room the night before, and the treacherous table had playedher the same trick.
"What happened next is mere guess work on my part, but I should say thatMrs. Inglethorp picked up the broken cup and placed it on the table bythe bed. Feeling in need of a stimulant of some kind, she heated upher cocoa, and drank it off then and there. Now we are faced with a newproblem. We know the cocoa contained no strychnine. The coffee was neverdrunk. Yet the strychnine must have been administered between sevenand nine o'clock that evening. What third medium was there--a medium sosuitable for disguising the taste of strychnine that it is extraordinaryno one has thought of it?" Poirot looked round the room, and thenanswered himself impressively. "Her medicine!"
"Do you mean that the murderer introduced the strychnine into hertonic?" I cried.
"There was no need to introduce it. It was already there--in themixture. The strychnine that killed Mrs. Inglethorp was the identicalstrychnine prescribed by Dr. Wilkins. To make that clear to you, Iwill read you an extract from a book on dispensing which I found in theDispensary of the Red Cross Hospital at Tadminster:
"'The following prescription has become famous in text books:
Strychninae Sulph. . . . . . gr.I Potass Bromide . . . . . . . 3vi Aqua ad. . . . . . . . . . . 3viii Fiat Mistura
This solution deposits in a few hours the greater part of the strychninesalt as an insoluble bromide in transparent crystals. A lady in Englandlost her life by taking a similar mixture: the precipitated strychninecollected at the bottom, and in taking the last dose she swallowednearly all of it!"
"Now there was, of course, no bromide in Dr. Wilkins' prescription, butyou will
remember that I mentioned an empty box of bromide powders.One or two of those powders introduced into the full bottle of medicinewould effectually precipitate the strychnine, as the book describes,and cause it to be taken in the last dose. You will learn later thatthe person who usually poured out Mrs. Inglethorp's medicine was alwaysextremely careful not to shake the bottle, but to leave the sediment atthe bottom of it undisturbed.
"Throughout the case, there have been evidences that the tragedy wasintended to take place on Monday evening. On that day, Mrs. Inglethorp'sbell wire was neatly cut, and on Monday evening Mademoiselle Cynthia wasspending the night with friends, so that Mrs. Inglethorp would havebeen quite alone in the right wing, completely shut off from help of anykind, and would have died, in all probability, before medical aid couldhave been summoned. But in her hurry to be in time for the villageentertainment Mrs. Inglethorp forgot to take her medicine, and the nextday she lunched away from home, so that the last--and fatal--dose wasactually taken twenty-four hours later than had been anticipated by themurderer; and it is owing to that delay that the final proof--the lastlink of the chain--is now in my hands."
Amid breathless excitement, he held out three thin strips of paper.
"A letter in the murderer's own hand-writing, mes amis! Had it been alittle clearer in its terms, it is possible that Mrs. Inglethorp, warnedin time, would have escaped. As it was, she realized her danger, but notthe manner of it."
In the deathly silence, Poirot pieced together the slips of paper and,clearing his throat, read:
_"'Dearest Evelyn:_
"_'You will be anxious at hearing nothing. It is all right--only it willbe to-night instead of last night. You understand. There's a goodtime coming once the old woman is dead and out of the way. No onecan possibly bring home the crime to me. That idea of yours about thebromides was a stroke of genius! But we must be very circumspect. Afalse step----'_
"Here, my friends, the letter breaks off. Doubtless the writer wasinterrupted; but there can be no question as to his identity. We allknow this hand-writing and----"
A howl that was almost a scream broke the silence.
"You devil! How did you get it?"
A chair was overturned. Poirot skipped nimbly aside. A quick movement onhis part, and his assailant fell with a crash.
"_Messieurs, mesdames_," said Poirot, with a flourish, "let me introduceyou to the murderer, Mr. Alfred Inglethorp!"