"And afterwards?" asked Poirot.

"I got a place as a clerk. Of course there was good money to be got just then. And I didn't do so badly after the war. Of course, a smaller salary . . . . And—I didn't seem to get on. I was always being passed over for promotion. I wasn't going ahead enough. It grew very difficult—really very difficult . . . . Especially when the slump came. To tell you the truth, I'd got hardly enough to keep body and soul together (and you've got to look presentable as a clerk) when I got the offer of this stocking job. A salary and commission!"

Poirot said gently: "But you are aware, are you not, that the firm who you say employed you deny the fact?"

Mr. Cust got excited again. "That's because they're in the conspiracy—they must be in the conspiracy.''

He went on: "I've got written evidence, written evidence. I've got their letters to me, giving me instructions as to what places to go and a list of people to call on."

"Not written evidence exactly—typewritten evidence."

"It's the same thing. Naturally a big firm of wholesale manufacturers typewrite their letters."

"Don't you know, Mr. Cust, that a typewriter can be identified? All those letters were typed by one particular machine."

"What of it?"

"And that machine was your own—the one found in your room."

"It was sent me by the firm at the beginning of my job."

"Yes, but these letters were received afterwards. So it looks, does it not, as though you typed them yourself and posted them to yourself?"

"No, no! It's all part of the plot against me!"

He added suddenly: "Besides, their letters would be written on the same kind of machine."

"The same kind, but not the same actual machine."

Mr. Cust repeated obstinately: "It's a plot!"

"And the A.B.C.'s that were found in the cupboard?"

"I know nothing about them. I thought they were all stockings."

"Why did you tick off the name of Mrs. Ascher in that first list of people in Andover?"

"Because I decided to start with her. One must begin somewhere."

"Yes, that is true. One must begin somewhere."

"I don't mean that!" said Mr. Cust. "I don't mean what you mean!"

"But you know what I meant?"

Mr. Cust said nothing. He was trembling. "I didn't do it!" he said. "I'm perfectly innocent! It's all a mistake. Why, look at that second crime—that Bexhill one. I was playing dominoes at Eastbourne. You've got to admit that!"

His voice was triumphant.

"Yes," said Poirot. His voice was meditative—silky. "But it's so easy, isn't it, to make a mistake of one day? And if you're an obstinate, positive man, like Mr. Strange, you'll never consider the possibility of hawing been mistaken. What you've said you'll stick to. He's that kind of man. And the hotel register—it's very easy to put down the wrong date when you're signing it—probably no one will notice it at the time."

"I was playing dominoes that evening!"

"You play dominoes very well, I believe."

Mr. Cust was a little flurried by this. "I—I—well, I believe I do."

"It is a very absorbing game, is it not, with a lot of skill in it?"

"Oh, there's a lot of play in it—a lot of play! We used to play a lot in the city, in the lunch hour. You'd be surprised the way total strangers come together over a game of dominoes."

He chuckled. "I remember one man—I've never forgotten him because of something he told me—we just got talking over a cup of coffee, and we started dominoes. Well, I felt after twenty minutes that I'd known that man all his life."

"What was it that he told you?" asked Poirot.

Mr. Cust's face clouded over. "It gave me a turn—a nasty turn. Talking of your fate being written in your hand, he was. And he showed me his hand and the lines that showed he'd have two near escapes of being drowned—and he had had two near escapes. And then he looked at mine and he told me some amazing things. Said I was going to be one of the most celebrated men in England before I died. Said the whole country would be talking about me. But he said—he said—"

Mr. Cust broke down—faltered . . . .

"Yes?"

Poirot's gaze held a quiet magnetism. Mr. Cust looked at him, looked away, then back again like a fascinated rabbit.

"He said—he said—that it looked as though I might die a violent death—and he laughed and said: 'Almost looks as though you might die on the scaffold,' and then he laughed and said that was only his joke . . . ."

He was silent suddenly. His eyes left Poirot's face—they ran from side to side . . . .

"My head—I suffer very badly with my head . . . the headaches are something cruel sometimes. And then there are times when I don't know—when I don't know—"

He broke down.

Poirot leant forward. He spoke very quietly but with great assurance.

"But you do know, don't you," he said, "that you committed the murders?''

Mr. Cust looked up. His glance was quite simple and direct. All resistance had left him. He looked strangely at peace.

"Yes," he said. "I know."

"But—I'm right, am I not?—you don't know why you did them?"

Mr. Cust shook his head.

"No," he said. "I don't."

We were sitting in a state of tense attention to listen to Poirot's final explanation of the case.

"All along," he said, "I have been worried over the why of this case. Hastings said to me the other day that the case was ended. I replied to him that the case was the man. The mystery was not the mystery of the murders, but the mystery of A.B.C.. Why did he find it necessary to commit these murders? Why did he select me as his adversary?"

"It is no answer to say that the man was mentally unhinged. To say a man does mad things because he is mad is merely unintelligent and stupid. A madman is as logical and reasoned in his action as a sane man—given his peculiar biased point of view. For example, if a man insists on going out and squatting about in nothing but a loincloth his conduct seems eccentric in the extreme. But once you know that the man himself is firmly convinced that he is Mahatma Gandhi, then his conduct becomes perfectly reasonable and logical."

"What was necessary in this case was to imagine a mind so constituted that it was logical and reasonable to commit four or more murders and to announce them beforehand by letters written to Hercule Poirot."

"My friend, Hastings, will tell you that from the moment I received the first letter I was upset and disturbed. It seemed to me at once that there was something very wrong about the letter."

"You were quite right," said Franklin Clarke dryly.

"Yes. But there, at the very start, I made a grave error. I permitted my feeling—my very strong feeling about the letter to remain a mere impression. I treated it as though it had been an intuition. In a well-balanced, reasoning mind them is no such thing as an intuition—an inspired guess! You can guess, of course—and a guess is either right or wrong. If it is right you call it an intuition. If it is wrong you usually do not speak of it again. But what is often called an intuition is really impression based on logical deduction or experience. When an expert feels that there is something wrong about a picture or a piece of furniture or the signature on a cheque he is really basing that feeling on a host of small signs and details. He has no need to go into them minutely—his experience obviates that—the net result is the definite impression that something is wrong. But it is not a guess, it is an impression based on experience."