"Why not have told me the truth?" he countered. "In a place like this, all Ralph Paton's doings were bound to be known. If your sister had not happened to pass through the wood that day somebody else would have done so."

"And a great deal of valuable information," he added quietly.

He shook his head.

He inquired politely after my sister, whom he declared to be a most interesting woman.

He laughed and twinkled.

"You got all the local gossip anyway," I remarked. "True, and untrue."

"I always like to employ the expert," he remarked obscurely, but he refused to explain the remark.

"I'm afraid you've been giving her a swelled head," I said drily. "What about Sunday afternoon?"

Poirot greeted me hospitably. He had placed a bottle of Irish whiskey (which I detest) on a small table, with a soda water siphon and a glass. He himself was engaged in brewing hot chocolate. It was a favourite beverage of his, I discovered later.

"Such as --"

I think she would have liked to have accompanied me.

That evening, at Poirot's request, I went over to his house after dinner. Caroline saw me depart with visible reluctance.

I explained to the best of my ability.

"The last?" I hazarded.

He swelled his chest out importantly, looking so ridiculous, that I found it difficult not to burst out laughing. Then he took a small sip of his chocolate, and carefully wiped his moustache.

Again he twinkled. "Only one of them, doctor. Only one of them."

"Eh? What do you say -- fishy?"

"I find Miss Russell a study of the most interesting," he said evasively.

"And they say that, do they?"

"Do you agree with my sister and Mrs Ackroyd that there is something fishy about her?" I asked.

"Didn't my sister convey as much to you yesterday afternoon?"

"C'est possible."

"For no reason whatever," I declared.

"Les femmes," generalized Poirot. "They are marvellous! They invent haphazard -- and by miracle they are right. Not that it is that, really. Women observe subconsciously a thousand little details, without knowing that they are doing so. Their subconscious mind adds these little things together -- and they call the result intuition. Me, I am very skilled in psychology. I know these things."

"I suppose they would," I said grumpily. "What about this interest of yours in my patients?"

Poirot smiled at me indulgently.

"But necessary -- I assure you, necessary. Now first -- Dr Sheppard leaves the house at ten minutes to nine. How do I know that?"

"So I give you, then, a little lecture. The first thing is to get a clear history of what happened that evening -- always bearing in mind that the person who speaks may be lying."

"You have been what I have seen. Should not our ideas be the same?"

"You wish that?"

"I'm afraid you're laughing at me," I said stiffly. "Of course, I've no experience of matters of this kind."

"You put it very well," I said.

He put down his cup.

"You are like the little child who wants to know the way the engine works. You wish to see the affair, not as the family doctor sees it, but with the eye of a detective who knows and cares for no one -- to whom they are all strangers and all equally liable to suspicion."

"Because I told you so."

"I do."

"I wish you'd tell me," I burst out, "what you really think of it all?"

I raised my eyebrows. "Rather a suspicious attitude."

"I told you so," I began again, but Poirot interrupted me with a gesture of impatience.

"But you might not be speaking the truth -- or the watch you went by might be wrong. But Parker also says that you left the house at ten minutes to nine. So we accept that statement and pass on. At nine o'clock you run into a man -- and here we come to what we will call the Romance of the Mysterious Stranger -- just outside the Park gates. How do I know that that is so?"

"Ah! but it is that you are a little stupid tonight, my friend. You know that it is so -- but how am I to know? Eh bien, I am able to tell you that the Mysterious Stranger was not a hallucination on your part, because the maid of a Miss Gannett met him a few minutes before you did, and of her too he inquired the way to Fernly Park. We accept his presence, therefore, and we can be fairly sure of two things about him -- that he was a stranger to the neighbourhood, and that whatever his object in going to Fernly, there was no great secrecy about it, since he twice asked the way there."

"Yes," I said, "I see that."

"Precisement. There is also this, which, you will remember, I picked up in the summer-house."

"Yes, I think he had," I said, after a minute or two, during which I cast my mind back; "but a very slight one."

"Now I have made it my business to find out more about this man. He had a drink at the Three Boars, I learn, and the barmaid there says that he spoke with an American accent and mentioned having just come over from the States. Did it strike you that he had an American accent?"

"Diamorphine hydrochloride," I murmured mechanically.

"Yes, heroin, "snow." Drug-takers carry it like this, and sniff it up the nose."

Poirot, who had been watching my face, nodded.

"This method of taking the drug is very common on the other side. Another proof, if we wanted one, that the man came from Canada or the States."

"What first attracted your attention to that summerhouse?" I asked curiously.

He held out to me the little quill. I looked at it curiously. Then a memory of something I had read stirred in me.

"My friend the inspector took it for granted that anyone using that path did so as a short cut to the house, but as soon as I saw the summer-house, I realized that the same path would be taken by anyone using the summer-house as a rendezvous. Now it seems fairly certain that the stranger came neither to the front nor to the back door. Then did someone from the house go out and meet him? If so, what could be a more convenient place than that little summerhouse? I searched it with the hope that I might find some clue inside. I found two, the scrap of cambric and the quill."

"And the scrap of cambric?" I asked curiously. "What about that?"

Poirot raised his eyebrows. "You do not use your little grey cells," he remarked drily. "The scrap of starched cambric should be obvious."

"Exactly the question," said Poirot. "You will remember that Mrs Ackroyd and her daughter came over from Canada to live here?"

"Not very obvious to me." I changed the subject. "Anyway," I said, "this man went to the summer-house to meet somebody. Who was that somebody?"

"Perhaps. Now another point. What did you think of the parlourmaid's story?"

"To begin with, one must look at the thing logically --"

"Is that what you meant today when you accused them of hiding the truth?"

"To me it grows clearer. But tell me now your own ideas and theories." I drew a piece of paper from my pocket.

"I just scribbled down a few suggestions," I said apologetically.

"But excellent -- you have method. Let us hear them." I read out in a somewhat embarrassed voice.

"The story of her dismissal. Does it take half an hour to dismiss a servant? Was the story of those important papers a likely one? And remember, though she says she was in her bedroom from nine-thirty until ten o'clock, there is no one to confirm her statement."

"You bewilder me," I said.

"Point No. 2. -- At some time during the evening Ralph Paton must have come in through the window, as evidenced by the prints of his shoes.

"What story?"

"Point No. 1. -- Mr Ackroyd was heard talking to someone at half-past nine.

"Just what my poor Hastings used to say," interrupted Poirot, "but alas! he never did so."

"It is a theory that," admitted Poirot. "Decidedly you have tells of a kind. But it leaves a good deal unaccounted for."

"Point No. 3. -- Mr Ackroyd was nervous that evening, and would only have admitted someone he knew.

"Point No. 4. -- The person with Mr Ackroyd at nine-thirty was asking for money. We know Ralph Paton was in a scrape.

"And who was the murderer?" inquired Poirot.

"The American stranger. He may have been in league with Parker, and possibly in Parker we have the man who blackmailed Mrs Ferrars. If so, Parker may have heard enough to realize the game was up, have told his accomplice s0, and the latter did the crime with the dagger which Parker gave him."

"These four points go to show that the person with Mr Ackroyd at nine-thirty was Ralph Paton. But we know that Mr Ackroyd was alive at a quarter to ten, therefore it was not Ralph who killed him. Ralph left the window open. Afterwards the murderer came in that way."

"Such as --"

"The telephone call, the pushed-out chair --"

"Do you really think that latter important?" I interrupted.

"What?"

"Why was Blunt so certain in his own mind that it was Raymond with Mr Ackroyd at nine-thirty?"

"Perhaps not," admitted my friend. "It may have been pulled out by accident, and Raymond or Blunt may have shoved it into place unconsciously under the stress of emotion. Then there is the missing forty pounds."

"Given by Ackroyd to Ralph," I suggested. "He may have reconsidered his first refusal."

"That's rather more difficult," I said slowly. "I shall have to speak as a medical man. Ralph's nerves must have gone phut! If he suddenly found out that his uncle had been murdered within a few minutes of his leaving him -- after, perhaps, a rather stormy interview -- well, he might get the wind up and clear right out. Men have been known to do that -- act guiltily when they're perfectly innocent."

"He explained that," I said.

"That still leaves one thing unexplained."

"You think so? I will not press the point. Tell me, instead, what were Ralph Paton's reasons for disappearing?"

"Yes, that is true," said Poirot. "But we must not lose sight of one thing."

"I know what you're going to say," I remarked: "motive. Ralph Paton inherits a great fortune by his uncle's death."

"That is one motive," agreed Poirot.

"One?"

"Mais oui. Do you realize that there are three separate motives staring us in the face. Somebody certainly stole the blue envelope and its contents. That is one motive. Blackmail! Ralph Paton may have been the man who blackmailed Mrs Ferrars. Remember, as far as Hammond knew, Ralph Paton had not applied to his uncle for help of late. That looks as though he were being supplied with money elsewhere. Then there is the fact that he was in some -- how do you say -- scrape? -- which he feared might get to his uncle's ears. And finally there is the one you have just mentioned."

"Does it?" said Poirot. "That is where we disagree, you and I. Three motives -- it is almost too much. I am inclined to believe that, after all, Ralph Paton is innocent."

"Dear me," I said, rather taken aback. "The case does seem black against him."