Hercule Poirot looked out of his window and saw Henrietta Savernake walking up the path to the front door. She was wearing the same green tweeds that she had worn on the day of the tragedy. There was a spaniel with her.

He hastened to the front door and opened it. She stood smiling at him.

"May I come in and see your house? I like looking at people's houses. I'm just taking the dog for a walk."

"But most certainly. How English it is to take the dog for a walk!"

"I know," said Henrietta. "I thought of that. Do you know that nice poem: 'The days passed slowly one by one. I fed the ducks, reproved my wife, played Handel's Largo on the fife. And took the dog a run.'"

Again she smiled-a brilliant, unsubstantial smile.

Poirot ushered her into his sitting room.

She looked round its neat and prim arrangement and nodded her head.

"Nice," she said, "two of everything.

How you would hate my studio."

"Why should I hate it?"

"Oh, a lot of clay sticking to things-and here and there just one thing that I happen to like and which would be ruined if there were two of them."

"But I can understand that. Mademoiselle.

You are an artist."

"Aren't you an artist too, M. Poirot?"

Poirot put his head on one side.

"It is a question, that. But, on the whole, I would say no. I have known crimes that were artistic-they were, you understand, supreme exercises of imagination-but the solving of them-no, it is not the creative power that is needed. What is required is a passion for the truth."

"A passion for the truth," said Henrietta meditatively. "Yes, I can see how dangerous that might make you. Would the truth satisfy you?"

He looked at her curiously.

"What do you mean. Miss Savernake?"

"I can understand that you would want to know. But would knowledge be enough?

Would you have to go a step further and translate knowledge into action?"

He was interested in her approach.

"You are suggesting that if I knew the truth about Dr. Christow's death-I might be satisfied to keep that knowledge to myself.

Do you know the truth about his death?"

Henrietta shrugged her shoulders.

"The obvious answer seems to be Gerda.

How cynical it is that a wife or a husband is always the first suspect."

"But you do not agree?"

"I always like to keep an open mind."

Poirot said quietly:

"Why did you come here. Miss Saver - nake?"

"I must admit that I haven't your passion for truth, M. Poirot. Taking the dog for a walk was such a nice English countryside excuse. But, of course, the Angkatells haven't got a dog-as you may have noticed the other day."

"The fact had not escaped me."

"So I borrowed the gardener's spaniel. I am not, you must understand, M. Poirot, very truthful."

Again that brilliant, brittle smile flashed out. He wondered why he should suddenly find it unendurably moving. He said quietly:

"No, but you have integrity."

"Why on earth do you say that?"

She was startled-almost, he thought, dismayed.

"Because I believe it to be true."

"Integrity," Henrietta repeated thoughtfully.

"I wonder what that word really means…"

She sat very still, staring down at the carpet, then she raised her head and looked at him steadily.

"Don't you want to know why I did come?"

"You find a difficulty, perhaps, in putting it into words."

"Yes, I think I do… The inquest, M.

Poirot, is tomorrow. One has to make up one's mind just how much-"

She broke off. Getting up, she wandered across to the mantel piece, displaced one or two of the ornaments and moved a vase of Michaelmas daisies from its position in the middle of a table, to the extreme corner of the mantelpiece. She stepped back, eyeing the arrangement with her head on one side.

"How do you like that, M. Poirot?"

"Not at all. Mademoiselle."

"I thought you wouldn't." She laughed, moved everything quickly and deftly back to their original positions. "Well, if one wants to say a thing one has to say it! You are, somehow, the sort of person one can talk to. Here goes. Is it necessary, do you think, that the police should know that I was John Christow's mistress?"

Her voice was quite dry and unemotional.

She was looking, not at him, but at the wall over his head. With one forefinger she was following the curve of the jar that held the purple flowers. He had an idea that in the touch of that finger was her emotional outlet.

Hercule Poirot said precisely and also without emotion:

"I see. You were lovers?"

"If you prefer to put it like that."

He looked at her curiously.

"It was not how you put it. Mademoiselle."

"No."

"Why not?"

Henrietta shrugged her shoulders. She came and sat down by him on the sofa. She said slowly:

"One likes to describe things as-as accurately as possible."

His interest in Henrietta Savernake grew stronger. He said:

"You had been Dr. Christow's mistress-for how long?"

"About six months."

"The police will have, I gather, no difficulty in discovering the fact?"

Henrietta considered.

"I imagine not. That is, if they are looking for something of that kind?"

"Oh, they will be looking, I can assure you of that."

"Yes, I rather thought they would." She paused, stretched out her fingers on her knee and looked at them, then gave him a swift friendly glance. "Well, M. Poirot, what does one do? Go to Inspector Grange and say-what does one say to a moustache like that?

It's such a domestic family moustache."

Poirot5 s hand crawled upwards to his own proudly borne adornment.

"Whereas mine. Mademoiselle?"

"Your moustache, M. Poirot, is an artistic triumph. It has no associations with anything but itself. It is, I am sure, unique."

"Absolutely."

"And it is probably the reason why I am talking to you as I am. Granted that the police have to know the truth about John and myself, will it necessarily have to be made public?"

"That depends," said Poirot. "If the police think it has no bearing on the case, they will be quite discreet. You-are very anxious on this point?"

Henrietta nodded. She stared down at her fingers for a moment or two, then suddenly lifted her head and spoke. Her voice was no longer dry and light.

"Why should things be made worse than they are for poor Gerda? She adored John and he's dead. She's lost him. Why should she have to bear an added burden?"

"It is for her that you mind?"

"Do you think that is hypocritical? I suppose you're thinking that if I cared at all about Gerda's peace of mind, I would never have become John's mistress. But you don't understand-it was not like that. I did not break up his married life. I was only one-of a procession."

"Ah, it was like that?"

She turned on him sharply:

H "No, no, no! Not what you are thinking.

That's what I mind most of all! The false idea that everybody will have of what John was like. That's why I'm here talking to you-because I've got a vague foggy hope that I can make you understand. Understand, I mean, the sort of person John was!

I can see so well what will happen-the headlines in the papers-A Doctor's Love Life-Gerda, myself, Veronica Cray. John wasn't like that-he wasn't, actually, a man who thought much about women. It wasn't women who mattered to him most, it was his work! It was in his work that his interest and his excitement-yes, and his sense of adventure really lay! If John had been taken unawares at any moment and asked to name the woman who was most in his mind, do you know who he would have said-Mrs.

Crabtree."

"Mrs. Crabtree?" Poirot was surprised.

"Who, then, is this Mrs. Crabtree?"

There was something between tears and laughter in Henrietta's voice as she went on.

"She's an old woman-ugly, dirty, wrinkled, quite indomitable. John thought the world of her. She's a patient in St. Christopher's Hospital. She's got Ridgeway's Disease.

That's a disease that's very rare but if you get it, you're bound to die-there just isn't any cure. But John was finding a cure -I can't explain technically-it was all very complicated-some question of hormone secretion.

He'd been making experiments and

Mrs. Crabtree was his prize patient-you see, she's got guts, she wants to live-and she was fond of John. She and he were fighting on the same side. Ridgeway's Disease and Mrs. Crabtree is what has been uppermost in John's mind for months-night and day-nothing else really counted. That's what being the kind of doctor John was really means-not all the Harley Street stuff and the rich fat women, that was only a sideline-it's the intense scientific curiosity and achievement. I-oh, I wish I could make you understand."

Her hands flew out in a curiously despairing gesture and Hercule Poirot thought how very lovely and sensitive those hands were.

He said:

"You seem to understand very well."

"Oh, yes, I understood. John used to come and talk, do you see? Not quite to me-partly I think to himself. He got things clear that way. Sometimes he was almost despairing-he couldn't see how to overcome the heightened toxicity-and then he'd get an idea for varying the treatment.

I can't explain to you what it was like-it was like, yes, a battle. You can't imagine the-the fury of it and the concentration-and yes, sometimes the agony. And sometimes the sheer tiredness…"

She was silent for a minute or two, her eyes dark with remembrance.

Poirot said curiously:

"You must have a certain technical knowledge yourself?"

She shook her head.

"Not really. Only enough to understand what John was talking about. I got books and read about it."

She was silent again, her face softened, her lips half parted. She was, he thought, remembering.

With a sigh, her mind came back to the present. She looked at him wistfully.

"If I could only make you see-"

"But you have. Mademoiselle."

"Really?"

"Yes. One recognizes authenticity when one hears it."