The trial of John Cavendish for the murder of his stepmother took place two months later.

Of the intervening weeks I will say little, but my admiration and sympathy went out unfeignedly to Mary Cavendish.  She ranged herself passionately on her husband’s side, scorning the mere idea of his guilt, and fought for him tooth and nail.

I expressed my admiration to Poirot, and he nodded thoughtfully.

“Yes, she is of those women who show at their best in adversity.  It brings out all that is sweetest and truest in them.  Her pride and her jealousy have ­”

“Jealousy?” I queried.

“Yes.  Have you not realized that she is an unusually jealous woman?  As I was saying, her pride and jealousy have been laid aside.  She thinks of nothing but her husband, and the terrible fate that is hanging over him.”

He spoke very feelingly, and I looked at him earnestly, remembering that last afternoon, when he had been deliberating whether or not to speak.  With his tenderness for “a woman’s happiness,” I felt glad that the decision had been taken out of his hands.

“Even now,” I said, “I can hardly believe it.  You see, up to the very last minute, I thought it was Lawrence!”

Poirot grinned.

“I know you did.”

“But John!  My old friend John!”

“Every murderer is probably somebody’s old friend,” observed Poirot philosophically.  “You cannot mix up sentiment and reason.”

“I must say I think you might have given me a hint.”

“Perhaps, mon ami, I did not do so, just because he was your old friend.”

I was rather disconcerted by this, remembering how I had busily passed on to John what I believed to be Poirot’s views concerning Bauerstein.  He, by the way, had been acquitted of the charge brought against him.  Nevertheless, although he had been too clever for them this time, and the charge of espionage could not be brought home to him, his wings were pretty well clipped for the future.

I asked Poirot whether he thought John would be condemned.  To my intense surprise, he replied that, on the contrary, he was extremely likely to be acquitted.

“But, Poirot ­” I protested.

“Oh, my friend, have I not said to you all along that I have no proofs.  It is one thing to know that a man is guilty, it is quite another matter to prove him so.  And, in this case, there is terribly little evidence.  That is the whole trouble.  I, Hercule Poirot, know, but I lack the last link in my chain.  And unless I can find that missing link ­” He shook his head gravely.

“When did you first suspect John Cavendish?” I asked, after a minute or two.

“Did you not suspect him at all?”

“No, indeed.”

“Not after that fragment of conversation you overheard between Mrs. Cavendish and her mother-in-law, and her subsequent lack of frankness at the inquest?”

“No.”

“Did you not put two and two together, and reflect that if it was not Alfred Inglethorp who was quarrelling with his wife ­and you remember, he strenuously denied it at the inquest ­it must be either Lawrence or John.  Now, if it was Lawrence, Mary Cavendish’s conduct was just as inexplicable.  But if, on the other hand, it was John, the whole thing was explained quite naturally.”

“So,” I cried, a light breaking in upon me, “it was John who quarrelled with his mother that afternoon?”

“Exactly.”

“And you have known this all along?”

“Certainly.  Mrs. Cavendish’s behaviour could only be explained that way.”

“And yet you say he may be acquitted?”

Poirot shrugged his shoulders.

“Certainly I do.  At the police court proceedings, we shall hear the case for the prosecution, but in all probability his solicitors will advise him to reserve his defence.  That will be sprung upon us at the trial.  And ­ah, by the way, I have a word of caution to give you, my friend.  I must not appear in the case.”

“What?”

“No.  Officially, I have nothing to do with it.  Until I have found that last link in my chain, I must remain behind the scenes.  Mrs. Cavendish must think I am working for her husband, not against him.”

“I say, that’s playing it a bit low down,” I protested.

“Not at all.  We have to deal with a most clever and unscrupulous man, and we must use any means in our power ­otherwise he will slip through our fingers.  That is why I have been careful to remain in the background.  All the discoveries have been made by Japp, and Japp will take all the credit.  If I am called upon to give evidence at all” ­he smiled broadly ­“it will probably be as a witness for the defence.”

I could hardly believe my ears.

“It is quite en règle,” continued Poirot.  “Strangely enough, I can give evidence that will demolish one contention of the prosecution.”

“Which one?”

“The one that relates to the destruction of the will.  John Cavendish did not destroy that will.”

Poirot was a true prophet.  I will not go into the details of the police court proceedings, as it involves many tiresome repetitions.  I will merely state baldly that John Cavendish reserved his defence, and was duly committed for trial.

September found us all in London.  Mary took a house in Kensington, Poirot being included in the family party.

I myself had been given a job at the War Office, so was able to see them continually.

As the weeks went by, the state of Poirot’s nerves grew worse and worse.  That “last link” he talked about was still lacking.  Privately, I hoped it might remain so, for what happiness could there be for Mary, if John were not acquitted?

On September 15th John Cavendish appeared in the dock at the Old Bailey, charged with “The Wilful Murder of Emily Agnes Inglethorp,” and pleaded “Not Guilty.”

Sir Ernest Heavywether, the famous K. C., had been engaged to defend him.

Mr. Philips, K. C., opened the case for the Crown.

The murder, he said, was a most premeditated and cold-blooded one.  It was neither more nor less than the deliberate poisoning of a fond and trusting woman by the stepson to whom she had been more than a mother.  Ever since his boyhood, she had supported him.  He and his wife had lived at Styles Court in every luxury, surrounded by her care and attention.  She had been their kind and generous benefactress.

He proposed to call witnesses to show how the prisoner, a profligate and spendthrift, had been at the end of his financial tether, and had also been carrying on an intrigue with a certain Mrs. Raikes, a neighbouring farmer’s wife.  This having come to his stepmother’s ears, she taxed him with it on the afternoon before her death, and a quarrel ensued, part of which was overheard.  On the previous day, the prisoner had purchased strychnine at the village chemist’s shop, wearing a disguise by means of which he hoped to throw the onus of the crime upon another man ­to wit, Mrs. Inglethorp’s husband, of whom he had been bitterly jealous.  Luckily for Mr. Inglethorp, he had been able to produce an unimpeachable alibi.

On the afternoon of July 17th, continued Counsel, immediately after the quarrel with her son, Mrs. Inglethorp made a new will.  This will was found destroyed in the grate of her bedroom the following morning, but evidence had come to light which showed that it had been drawn up in favour of her husband.  Deceased had already made a will in his favour before her marriage, but ­and Mr. Philips wagged an expressive forefinger ­the prisoner was not aware of that.  What had induced the deceased to make a fresh will, with the old one still extant, he could not say.  She was an old lady, and might possibly have forgotten the former one; or ­this seemed to him more likely ­she may have had an idea that it was revoked by her marriage, as there had been some conversation on the subject.  Ladies were not always very well versed in legal knowledge.  She had, about a year before, executed a will in favour of the prisoner.  He would call evidence to show that it was the prisoner who ultimately handed his stepmother her coffee on the fatal night.  Later in the evening, he had sought admission to her room, on which occasion, no doubt, he found an opportunity of destroying the will which, as far as he knew, would render the one in his favour valid.

The prisoner had been arrested in consequence of the discovery, in his room, by Detective Inspector Japp ­a most brilliant officer ­of the identical phial of strychnine which had been sold at the village chemist’s to the supposed Mr. Inglethorp on the day before the murder.  It would be for the jury to decide whether or not these damning facts constituted an overwhelming proof of the prisoner’s guilt.

And, subtly implying that a jury which did not so decide, was quite unthinkable, Mr. Philips sat down and wiped his forehead.

The first witnesses for the prosecution were mostly those who had been called at the inquest, the medical evidence being again taken first.

Sir Ernest Heavywether, who was famous all over England for the unscrupulous manner in which he bullied witnesses, only asked two questions.

“I take it, Dr. Bauerstein, that strychnine, as a drug, acts quickly?”

“Yes.”

“And that you are unable to account for the delay in this case?”

“Yes.”

“Thank you.”

Mr. Mace identified the phial handed him by Counsel as that sold by him to “Mr. Inglethorp.”  Pressed, he admitted that he only knew Mr. Inglethorp by sight.  He had never spoken to him.  The witness was not cross-examined.

Alfred Inglethorp was called, and denied having purchased the poison.  He also denied having quarrelled with his wife.  Various witnesses testified to the accuracy of these statements.

The gardeners’ evidence, as to the witnessing of the will was taken, and then Dorcas was called.

Dorcas, faithful to her “young gentlemen,” denied strenuously that it could have been John’s voice she heard, and resolutely declared, in the teeth of everything, that it was Mr. Inglethorp who had been in the boudoir with her mistress.  A rather wistful smile passed across the face of the prisoner in the dock.  He knew only too well how useless her gallant defiance was, since it was not the object of the defence to deny this point.  Mrs. Cavendish, of course, could not be called upon to give evidence against her husband.

After various questions on other matters, Mr. Philips asked: 

“In the month of June last, do you remember a parcel arriving for Mr. Lawrence Cavendish from Parkson’s?”

Dorcas shook her head.

“I don’t remember, sir.  It may have done, but Mr. Lawrence was away from home part of June.”

“In the event of a parcel arriving for him whilst he was away, what would be done with it?”

“It would either be put in his room or sent on after him.”

“By you?”

“No, sir, I should leave it on the hall table.  It would be Miss Howard who would attend to anything like that.”

Evelyn Howard was called and, after being examined on other points, was questioned as to the parcel.

“Don’t remember.  Lots of parcels come.  Can’t remember one special one.”

“You do not know if it was sent after Mr. Lawrence Cavendish to Wales, or whether it was put in his room?”

“Don’t think it was sent after him.  Should have remembered it if it was.”

“Supposing a parcel arrived addressed to Mr. Lawrence Cavendish, and afterwards it disappeared, should you remark its absence?”

“No, don’t think so.  I should think some one had taken charge of it.”

“I believe, Miss Howard, that it was you who found this sheet of brown paper?” He held up the same dusty piece which Poirot and I had examined in the morning-room at Styles.

“Yes, I did.”

“How did you come to look for it?”

“The Belgian detective who was employed on the case asked me to search for it.”

“Where did you eventually discover it?”

“On the top of ­of ­a wardrobe.”

“On top of the prisoner’s wardrobe?”

“I ­I believe so.”

“Did you not find it yourself?”

“Yes.”

“Then you must know where you found it?”

“Yes, it was on the prisoner’s wardrobe.”

“That is better.”

An assistant from Parkson’s, Theatrical Costumiers, testified that on June 29th, they had supplied a black beard to Mr. L. Cavendish, as requested.  It was ordered by letter, and a postal order was enclosed.  No, they had not kept the letter.  All transactions were entered in their books.  They had sent the beard, as directed, to “L.  Cavendish, Esq., Styles Court.”

Sir Ernest Heavywether rose ponderously.

“Where was the letter written from?”

“From Styles Court.”

“The same address to which you sent the parcel?”

“Yes.”

“And the letter came from there?”

“Yes.”

Like a beast of prey, Heavywether fell upon him: 

“How do you know?”

“I ­I don’t understand.”

“How do you know that letter came from Styles?  Did you notice the postmark?”

“No ­but ­”

“Ah, you did not notice the postmark!  And yet you affirm so confidently that it came from Styles.  It might, in fact, have been any postmark?”

“Y ­es.”

“In fact, the letter, though written on stamped notepaper, might have been posted from anywhere?  From Wales, for instance?”

The witness admitted that such might be the case, and Sir Ernest signified that he was satisfied.

Elizabeth Wells, second housemaid at Styles, stated that after she had gone to bed she remembered that she had bolted the front door, instead of leaving it on the latch as Mr. Inglethorp had requested.  She had accordingly gone downstairs again to rectify her error.  Hearing a slight noise in the West wing, she had peeped along the passage, and had seen Mr. John Cavendish knocking at Mrs. Inglethorp’s door.

Sir Ernest Heavywether made short work of her, and under his unmerciful bullying she contradicted herself hopelessly, and Sir Ernest sat down again with a satisfied smile on his face.

With the evidence of Annie, as to the candle grease on the floor, and as to seeing the prisoner take the coffee into the boudoir, the proceedings were adjourned until the following day.

As we went home, Mary Cavendish spoke bitterly against the prosecuting counsel.

“That hateful man!  What a net he has drawn around my poor John!  How he twisted every little fact until he made it seem what it wasn’t!”

“Well,” I said consolingly, “it will be the other way about to-morrow.”

“Yes,” she said meditatively; then suddenly dropped her voice.  “Mr. Hastings, you do not think ­surely it could not have been Lawrence ­Oh, no, that could not be!”

But I myself was puzzled, and as soon as I was alone with Poirot I asked him what he thought Sir Ernest was driving at.

“Ah!” said Poirot appreciatively.  “He is a clever man, that Sir Ernest.”

“Do you think he believes Lawrence guilty?”

“I do not think he believes or cares anything!  No, what he is trying for is to create such confusion in the minds of the jury that they are divided in their opinion as to which brother did it.  He is endeavouring to make out that there is quite as much evidence against Lawrence as against John ­and I am not at all sure that he will not succeed.”

Detective-inspector Japp was the first witness called when the trial was reopened, and gave his evidence succinctly and briefly.  After relating the earlier events, he proceeded: 

“Acting on information received, Superintendent Summerhaye and myself searched the prisoner’s room, during his temporary absence from the house.  In his chest of drawers, hidden beneath some underclothing, we found:  first, a pair of gold-rimmed pince-nez similar to those worn by Mr. Inglethorp” ­these were exhibited ­“secondly, this phial.”

The phial was that already recognized by the chemist’s assistant, a tiny bottle of blue glass, containing a few grains of a white crystalline powder, and labelled:  “Strychnine Hydrochloride.  POISON.”

A fresh piece of evidence discovered by the detectives since the police court proceedings was a long, almost new piece of blotting-paper.  It had been found in Mrs. Inglethorp’s cheque book, and on being reversed at a mirror, showed clearly the words:  “. . . erything of which I die possessed I leave to my beloved husband Alfred Ing...”  This placed beyond question the fact that the destroyed will had been in favour of the deceased lady’s husband.  Japp then produced the charred fragment of paper recovered from the grate, and this, with the discovery of the beard in the attic, completed his evidence.

But Sir Ernest’s cross-examination was yet to come.

“What day was it when you searched the prisoner’s room?”

“Tuesday, the 24th of July.”

“Exactly a week after the tragedy?”

“Yes.”

“You found these two objects, you say, in the chest of drawers.  Was the drawer unlocked?”

“Yes.”

“Does it not strike you as unlikely that a man who had committed a crime should keep the evidence of it in an unlocked drawer for anyone to find?”

“He might have stowed them there in a hurry.”

“But you have just said it was a whole week since the crime.  He would have had ample time to remove them and destroy them.”

“Perhaps.”

“There is no perhaps about it.  Would he, or would he not have had plenty of time to remove and destroy them?”

“Yes.”

“Was the pile of underclothes under which the things were hidden heavy or light?”

“Heavyish.”

“In other words, it was winter underclothing.  Obviously, the prisoner would not be likely to go to that drawer?”

“Perhaps not.”

“Kindly answer my question.  Would the prisoner, in the hottest week of a hot summer, be likely to go to a drawer containing winter underclothing.  Yes, or no?”

“No.”

“In that case, is it not possible that the articles in question might have been put there by a third person, and that the prisoner was quite unaware of their presence?”

“I should not think it likely.”

“But it is possible?”

“Yes.”

“That is all.”

More evidence followed.  Evidence as to the financial difficulties in which the prisoner had found himself at the end of July.  Evidence as to his intrigue with Mrs. Raikes ­poor Mary, that must have been bitter hearing for a woman of her pride.  Evelyn Howard had been right in her facts, though her animosity against Alfred Inglethorp had caused her to jump to the conclusion that he was the person concerned.

Lawrence Cavendish was then put into the box.  In a low voice, in answer to Mr. Philips’ questions, he denied having ordered anything from Parkson’s in June.  In fact, on June 29th, he had been staying away, in Wales.

Instantly, Sir Ernest’s chin was shooting pugnaciously forward.

“You deny having ordered a black beard from Parkson’s on June 29th?”

“I do.”

“Ah!  In the event of anything happening to your brother, who will inherit Styles Court?”

The brutality of the question called a flush to Lawrence’s pale face.  The judge gave vent to a faint murmur of disapprobation, and the prisoner in the dock leant forward angrily.

Heavywether cared nothing for his client’s anger.

“Answer my question, if you please.”

“I suppose,” said Lawrence quietly, “that I should.”

“What do you mean by you ‘suppose’?  Your brother has no children.  You would inherit it, wouldn’t you?”

“Yes.”

“Ah, that’s better,” said Heavywether, with ferocious geniality.  “And you’d inherit a good slice of money too, wouldn’t you?”

“Really, Sir Ernest,” protested the judge, “these questions are not relevant.”

Sir Ernest bowed, and having shot his arrow proceeded.

“On Tuesday, the 17th July, you went, I believe, with another guest, to visit the dispensary at the Red Cross Hospital in Tadminster?”

“Yes.”

“Did you ­while you happened to be alone for a few seconds ­unlock the poison cupboard, and examine some of the bottles?”

“I ­I ­may have done so.”

“I put it to you that you did do so?”

“Yes.”

Sir Ernest fairly shot the next question at him.

“Did you examine one bottle in particular?”

“No, I do not think so.”

“Be careful, Mr. Cavendish.  I am referring to a little bottle of Hydro-chloride of Strychnine.”

Lawrence was turning a sickly greenish colour.

“N ­o ­I am sure I didn’t.”

“Then how do you account for the fact that you left the unmistakable impress of your finger-prints on it?”

The bullying manner was highly efficacious with a nervous disposition.

“I ­I suppose I must have taken up the bottle.”

“I suppose so too!  Did you abstract any of the contents of the bottle?”

“Certainly not.”

“Then why did you take it up?”

“I once studied to be a doctor.  Such things naturally interest me.”

“Ah!  So poisons ‘naturally interest’ you, do they?  Still, you waited to be alone before gratifying that ‘interest’ of yours?”

“That was pure chance.  If the others had been there, I should have done just the same.”

“Still, as it happens, the others were not there?”

“No, but ­”

“In fact, during the whole afternoon, you were only alone for a couple of minutes, and it happened ­I say, it happened ­to be during those two minutes that you displayed your ‘natural interest’ in Hydro-chloride of Strychnine?”

Lawrence stammered pitiably.

“I ­I ­”

With a satisfied and expressive countenance, Sir Ernest observed: 

“I have nothing more to ask you, Mr. Cavendish.”

This bit of cross-examination had caused great excitement in court.  The heads of the many fashionably attired women present were busily laid together, and their whispers became so loud that the judge angrily threatened to have the court cleared if there was not immediate silence.

There was little more evidence.  The hand-writing experts were called upon for their opinion of the signature of “Alfred Inglethorp” in the chemist’s poison register.  They all declared unanimously that it was certainly not his hand-writing, and gave it as their view that it might be that of the prisoner disguised.  Cross-examined, they admitted that it might be the prisoner’s hand-writing cleverly counterfeited.

Sir Ernest Heavywether’s speech in opening the case for the defence was not a long one, but it was backed by the full force of his emphatic manner.  Never, he said, in the course of his long experience, had he known a charge of murder rest on slighter evidence.  Not only was it entirely circumstantial, but the greater part of it was practically unproved.  Let them take the testimony they had heard and sift it impartially.  The strychnine had been found in a drawer in the prisoner’s room.  That drawer was an unlocked one, as he had pointed out, and he submitted that there was no evidence to prove that it was the prisoner who had concealed the poison there.  It was, in fact, a wicked and malicious attempt on the part of some third person to fix the crime on the prisoner.  The prosecution had been unable to produce a shred of evidence in support of their contention that it was the prisoner who ordered the black beard from Parkson’s.  The quarrel which had taken place between prisoner and his stepmother was freely admitted, but both it and his financial embarrassments had been grossly exaggerated.

His learned friend ­Sir Ernest nodded carelessly at Mr. Philips ­had stated that if the prisoner were an innocent man, he would have come forward at the inquest to explain that it was he, and not Mr. Inglethorp, who had been the participator in the quarrel.  He thought the facts had been misrepresented.  What had actually occurred was this.  The prisoner, returning to the house on Tuesday evening, had been authoritatively told that there had been a violent quarrel between Mr. and Mrs. Inglethorp.  No suspicion had entered the prisoner’s head that anyone could possibly have mistaken his voice for that of Mr. Inglethorp.  He naturally concluded that his stepmother had had two quarrels.

The prosecution averred that on Monday, July 16th, the prisoner had entered the chemist’s shop in the village, disguised as Mr. Inglethorp.  The prisoner, on the contrary, was at that time at a lonely spot called Marston’s Spinney, where he had been summoned by an anonymous note, couched in blackmailing terms, and threatening to reveal certain matters to his wife unless he complied with its demands.  The prisoner had, accordingly, gone to the appointed spot, and after waiting there vainly for half an hour had returned home.  Unfortunately, he had met with no one on the way there or back who could vouch for the truth of his story, but luckily he had kept the note, and it would be produced as evidence.

As for the statement relating to the destruction of the will, the prisoner had formerly practiced at the Bar, and was perfectly well aware that the will made in his favour a year before was automatically revoked by his stepmother’s remarriage.  He would call evidence to show who did destroy the will, and it was possible that that might open up quite a new view of the case.

Finally, he would point out to the jury that there was evidence against other people besides John Cavendish.  He would direct their attention to the fact that the evidence against Mr. Lawrence Cavendish was quite as strong, if not stronger than that against his brother.

He would now call the prisoner.

John acquitted himself well in the witness-box.  Under Sir Ernest’s skilful handling, he told his tale credibly and well.  The anonymous note received by him was produced, and handed to the jury to examine.  The readiness with which he admitted his financial difficulties, and the disagreement with his stepmother, lent value to his denials.

At the close of his examination, he paused, and said: 

“I should like to make one thing clear.  I utterly reject and disapprove of Sir Ernest Heavywether’s insinuations against my brother.  My brother, I am convinced, had no more to do with the crime than I have.”

Sir Ernest merely smiled, and noted with a sharp eye that John’s protest had produced a very favourable impression on the jury.

Then the cross-examination began.

“I understand you to say that it never entered your head that the witnesses at the inquest could possibly have mistaken your voice for that of Mr. Inglethorp.  Is not that very surprising?”

“No, I don’t think so.  I was told there had been a quarrel between my mother and Mr. Inglethorp, and it never occurred to me that such was not really the case.”

“Not when the servant Dorcas repeated certain fragments of the conversation ­fragments which you must have recognized?”

“I did not recognize them.”

“Your memory must be unusually short!”

“No, but we were both angry, and, I think, said more than we meant.  I paid very little attention to my mother’s actual words.”

Mr. Philips’ incredulous sniff was a triumph of forensic skill.  He passed on to the subject of the note.

“You have produced this note very opportunely.  Tell me, is there nothing familiar about the hand-writing of it?”

“Not that I know of.”

“Do you not think that it bears a marked resemblance to your own hand-writing ­carelessly disguised?”

“No, I do not think so.”

“I put it to you that it is your own hand-writing!”

“No.”

“I put it to you that, anxious to prove an alibi, you conceived the idea of a fictitious and rather incredible appointment, and wrote this note yourself in order to bear out your statement!”

“No.”

“Is it not a fact that, at the time you claim to have been waiting about at a solitary and unfrequented spot, you were really in the chemist’s shop in Styles St. Mary, where you purchased strychnine in the name of Alfred Inglethorp?”

“No, that is a lie.”

“I put it to you that, wearing a suit of Mr. Inglethorp’s clothes, with a black beard trimmed to resemble his, you were there ­and signed the register in his name!”

“That is absolutely untrue.”

“Then I will leave the remarkable similarity of hand-writing between the note, the register, and your own, to the consideration of the jury,” said Mr. Philips, and sat down with the air of a man who has done his duty, but who was nevertheless horrified by such deliberate perjury.

After this, as it was growing late, the case was adjourned till Monday.

Poirot, I noticed, was looking profoundly discouraged.  He had that little frown between the eyes that I knew so well.

“What is it, Poirot?” I inquired.

“Ah, mon ami, things are going badly, badly.”

In spite of myself, my heart gave a leap of relief.  Evidently there was a likelihood of John Cavendish being acquitted.

When we reached the house, my little friend waved aside Mary’s offer of tea.

“No, I thank you, madame.  I will mount to my room.”

I followed him.  Still frowning, he went across to the desk and took out a small pack of patience cards.  Then he drew up a chair to the table, and, to my utter amazement, began solemnly to build card houses!

My jaw dropped involuntarily, and he said at once: 

“No, mon ami, I am not in my second childhood!  I steady my nerves, that is all.  This employment requires precision of the fingers.  With precision of the fingers goes precision of the brain.  And never have I needed that more than now!”

“What is the trouble?” I asked.

With a great thump on the table, Poirot demolished his carefully built up edifice.

“It is this, mon ami!  That I can build card houses seven stories high, but I cannot” ­thump ­“find” ­thump ­“that last link of which I spoke to you.”

I could not quite tell what to say, so I held my peace, and he began slowly building up the cards again, speaking in jerks as he did so.

“It is done ­so!  By placing ­one card ­on another ­with mathematical ­precision!”

I watched the card house rising under his hands, story by story.  He never hesitated or faltered.  It was really almost like a conjuring trick.

“What a steady hand you’ve got,” I remarked.  “I believe I’ve only seen your hand shake once.”

“On an occasion when I was enraged, without doubt,” observed Poirot, with great placidity.

“Yes indeed!  You were in a towering rage.  Do you remember?  It was when you discovered that the lock of the despatch-case in Mrs. Inglethorp’s bedroom had been forced.  You stood by the mantel-piece, twiddling the things on it in your usual fashion, and your hand shook like a leaf!  I must say ­”

But I stopped suddenly.  For Poirot, uttering a hoarse and inarticulate cry, again annihilated his masterpiece of cards, and putting his hands over his eyes swayed backwards and forwards, apparently suffering the keenest agony.

“Good heavens, Poirot!” I cried.  “What is the matter?  Are you taken ill?”

“No, no,” he gasped.  “It is ­it is ­that I have an idea!”

“Oh!” I exclaimed, much relieved.  “One of your ’little ideas’?”

“Ah, ma foi, no!” replied Poirot frankly.  “This time it is an idea gigantic!  Stupendous!  And you ­you, my friend, have given it to me!”

Suddenly clasping me in his arms, he kissed me warmly on both cheeks, and before I had recovered from my surprise ran headlong from the room.

Mary Cavendish entered at that moment.

“What is the matter with Monsieur Poirot?  He rushed past me crying out:  ‘A garage!  For the love of Heaven, direct me to a garage, madame!’ And, before I could answer, he had dashed out into the street.”

I hurried to the window.  True enough, there he was, tearing down the street, hatless, and gesticulating as he went.  I turned to Mary with a gesture of despair.

“He’ll be stopped by a policeman in another minute.  There he goes, round the corner!”

Our eyes met, and we stared helplessly at one another.

“What can be the matter?”

I shook my head.

“I don’t know.  He was building card houses, when suddenly he said he had an idea, and rushed off as you saw.”

“Well,” said Mary, “I expect he will be back before dinner.”

But night fell, and Poirot had not returned.