who went right up to her table and bent over her.
'Was there such a person? Yes, there were two people. The two stewards. Either of them could go up to Madame Giselle, lean toward her, and nobody would notice anything unusual.
'Was there anyone else?
'Well, there was Mr Clancy. He was the only person in the car who had passed immediately by Madame Giselle's seat – and I remember that it was he who had first drawn attention to the blowpipe-and-thorn theory.'
Mr Clancy sprang to his feet.
'I protest!' he cried. 'I protest! This is an outrage!'
'Sit down,' said Poirot. 'I have not finished yet. I have to show you all the steps by which I arrived at my conclusion.
'I had now three persons as possible suspects. Mitchell, Davis and Mr Clancy. None of them at first sight appeared like murderers, but there was much investigation to be done.
'I next turned my mind to the possibilities of the wasp. It was suggestive, that wasp. To begin with, no one had noticed it until about the time coffee was served. That in itself was rather curious. I constructed a certain theory of the crime. The murderer presented to the world two separate solutions of the tragedy. On the first or simplest, Madame Giselle was stung by a wasp and had succumbed to heart failure. The success of that solution depended on whether or not the murderer was in a position to retrieve the thorn. Japp and I agreed that that could be done easily enough – so long as no suspicion of foul play had arisen. There was the particular coloring of the silk which I had no doubt was deliberately substituted for the original cerise so as to simulate the appearance of a wasp.
'Our murderer, then, approaches the victim's table, inserts the thorn and releases the wasp! The poison is so powerful that death would occurr almost immediately. If Giselle cried out, it would probably not be heard, owing to the noise of the plane. If it was just noticed, well, there was a wasp buzzing about to explain the cry. The poor woman had been stung.
'That, as I say, was Plan No. 1. But supposing that, as actually happened, the poisoned thorn was discovered before the murderer could retrieve it. In that case, the fat is in the fire. The theory of natural death is impossible. Instead of getting rid of the blowpipe through the window, it is put in a place where it is bound to be discovered when the plane is searched. And at once it will be assumed that the blowpipe was the instrument of the crime. The proper atmosphere of distance will be created, and when the blowpipe is traced it will focus suspicion in a definite and prearranged direction.
'I had now my theory of the crime, and I had three suspects, with a barely possible fourth – M. Jean Dupont who had outlined the Death-by-a-wasp-sting theory, and who was sitting on the gangway so near Giselle that he might just possibly have moved from his seat without being noticed. On the other hand, I did not really think he would have dared to take such a risk.
'I concentrated on the problem of the wasp. If the murderer had brought the wasp onto the plane and released it at the psychological moment, he must have had something in the nature of a small box in which to keep it.
'Hence my interest in the contents of the passengers pockets and hand luggage.
'And here I came up against a totally unexpected development. I found what I was looking for – but, as it seemed to me, on the wrong person. There was an empty small-sized Bryant May's match box in Mr Norman Gale's pocket. But by everybody's evidence, Mr Gale had never passed down the gangway of the car. He had only visited the wash-room compartment and returned to his own seat.
'Nevertheless, although it seems impossible, there was a method by which Mr Gale could have committed the crime – as the contents of his attache case showed.'
'My attache case?' said Norman Gale. He looked amused and puzzled. 'Why, I don't even remember now what was in it.'
Poirot smiled at him amiably.
'Wait a little minute. I will come to that. I am telling you my first ideas.
'To proceed, I had four persons who could have done the crime – from the point of view of possibility. The two stewards, Clancy and Gale.
'I now looked at the case from the opposite angle – that of motive; if a motive were to coincide with a possibility – well, I had my murderer! But alas, I could find nothing of the kind. My friend Japp has accused me of liking to make things difficult. On the contrary, I approached this question of motive with all the simplicity in the world. To whose benefit would it be if Madame Giselle were removed? Clearly, to her unknown daughter's benefit, since that unknown daughter would inherit a fortune. There were also certain persons who were in Madame Giselle's power – or shall we say, who might be in Giselle's power for aught we knew? That, then, was a task of elimination. Of the passengers in the plane I could only be certain of one who was undoubtedly mixed up with Giselle. That one was Lady Horbury.
'In Lady Horbury's case the motive was clear. She had visited Giselle at her house in Paris the night before. She was desperate and she had a friend, a young actor, who might easily have impersonated the American who bought the blowpipe, and might also have bribed the clerk in Universal Air Lines to insure that Giselle traveled by the twelve o'clock service.
'I had, as it were, a problem in two halves. I did not see how it was possible for Lady Horbury to commit the crime. And I could not see for what motive the stewards, Mr Clancy or Mr Gale should want to commit it.
'Always, in the back of my mind, I considered the problem of Giselle's unknown daughter and heiress. Were any of my four suspects married, and if so, could one of the wives be this Anne Morisot? If her father was English, the girl might have been brought up in England. Mitchell's wife I soon dismissed – she was of good old Dorset country stock. Davis was courting a girl whose father and mother were alive. Mr Clancy was not married. Mr Gale was obviously head over ears in love with Miss Jane Grey.
'I may say that I investigated the antecedents of Miss Grey very carefully, having learned from her in casual conversation that she had been brought up in an orphanage near Dublin. But I soon satisfied myself that Miss Grey was not Madame Giselle's daughter.
'I made out a table of results. The stewards had neither gained nor lost by Madame Giselle's death, except that Mitchell was obviously suffering from shock. Mr Clancy was planning a book on the subject by which he hoped to make money Mr Gale was fast losing his practice. Nothing very helpful there.
'And yet, at that time I was convinced that Mr Gale was the murderer – there was the empty match box, the contents of his attache case. Apparently he lost, not gained, by the death of Giselle. But those appearances might be false appearances.
'I determined to cultivate his acquaintance. It is my experience that no one, in the course of conversation, can fail to give themselves away sooner or later. Everyone has an irresistible urge to talk about themselves.
'I tried to gain Mr Gale's confidence. I pretended to confide in him, and I even enlisted his help. I persuaded him to aid me in the fake blackmailing of Lady Horbury. And it was then that he made his first mistake.
'I had suggested a slight disguise. He arrived to play his part with a ridiculous and impossible outfit! The whole thing was a farce. No one, I felt sure, could play a part as badly as he was proposing to play one. What, then, was the reason for this? Because his knowledge of his own guilt made him chary of showing himself to be a good actor. When, however, I had adjusted his ridiculous make-up, his artistic skill showed itself. He played his part perfectly and Lady Horbury did not recognize him. I was convinced then that he could have disguised himself as an American in Paris and could also have played the necessary part in the 'Prometheus.'
'By this time I was getting seriously worried about Mademoiselle Jane. Either she was in this business with him, or else she was entirely innocent; and in the latter case she was a victim. She might wake up one day to find herself married to a murderer.
'With the object of preventing a precipitate marriage, I took Mademoiselle Jane to Paris as my secretary.
'It was whilst we were there that the missing heiress appeared to claim her fortune. I was haunted by a resemblance that I could not place. I did place it in the end, but too late.
'At first, the discovery that she had actually been in the plane and had lied about it seemed to overthrow all my theories. Here, overwhelmingly, was the guilty person.
'But if she were guilty, she had an accomplice – the man who bought the blowpipe and bribed Jules
