My meditations were interrupted by the advent of a smart parlourmaid.

Yes, Mrs Folliott was at home. I was ushered into a big drawing-room, and looked round me curiously as I waited for the mistress of the house. A large bare room, some good bits of old china, and some beautiful etchings, shabby covers and curtains. A lady's room in every sense of the term.

I turned from the inspection of a Bartolozzi on the wall as Mrs Folliott came into the room. She was a tall woman, with untidy brown hair, and a very winning smile.

I was slightly nervous when I rang the bell at Marby Grange the following afternoon. I wondered very much what Poirot expected to find out. He had entrusted the job to me. Why? Was it because, as in the case of questioning Major Blunt, he wished to remain in the background? The wish, intelligible in the first case, seemed to me quite meaningless here.

"Dr Sheppard," she said hesitatingly.

"That is my name," I replied. "I must apologize for calling upon you like this, but I wanted some information about a parlourmaid previously employed by you, Ursula Bourne."

"Oh, yes, of course. I -- I remember perfectly."

"Anything about her?"

"Yes, where she comes from, who her people are -- that sort of thing?"

With the utterance of the name the smile vanished from her face, and all the cordiality froze out of her manner. She looked uncomfortable and ill at ease.

Mrs Folliott's face wore more than ever its frozen look.

"Ursula Bourne?" she said hesitatingly.

"I'm afraid I don't remember." There was a spark of anger now underlying her nervousness. She flung up her head in a gesture that was vaguely familiar.

"Can you tell me anything about her?" I asked.

"And you were satisfied with her whilst she was with you? How long was she with you, by the way?"

"She left you just over a year ago, I understand?"

"Yes. Yes, she did. That is quite right."

"Who was she with before she came to you?"

"I don't know at all."

"Oh! a year or two -- I can't remember exactly how long. She -- she is very capable. I'm sure you will find her quite satisfactory. I didn't know she was leaving Fernly. I hadn't the least idea of it."

"Yes," I said. "Perhaps you don't remember the name?"

"Not at all," I said, with an air of surprise and a tinge of apology in my manner. "I had no idea you would mind answering them. I am very sorry."

Her anger left her and she became confused again.

"Is it really necessary to ask all these questions?"

But it was also clear the she had no intention of telling me ^ything further. Whatever the mystery centring round Ursula Bourne might be, I was not going to learn it through Mrs Folliott.

"Oh! I don't mind answering them. I assure you I don't. Why should I? It -- it just seemed a little odd, you know. That's all. A little odd."

One advantage of being a medical practitioner is that you can usually tell when people are lying to you. I should have know from Mrs Folliott's manner, if from nothing else, that she did mind answering my questions -- minded intensely. She was thoroughly uncomfortable and upset, and there was plainly some mystery in the background. I judged her to be a woman quite unused to deception of any kind, and consequently rendered acutely uneasy when forced to practise u- A child could have seen through her.

I went to see a couple of patients and arrived home about six o'clock. Caroline was sitting beside the wreck of tea things. She had that look of suppressed exultation on her face which I know only too well. It is a sure sign with her of either the getting or the giving of information. I wondered which it had been.

Ill Defeated, I apologized once more for disturbing her, took my hat and departed.

"I've had a very interesting afternoon," began Caroline, as I dropped into my own particular easy-chair and stretched out my feet to the inviting blaze in the fireplace.

"Have you?" I said. "Miss Gannett drop in to tea?"

I thought a good many things of it, but I was careful not to say them to Caroline.

Miss Gannett is one of the chief of our newsmongers.

"Guess again," said Caroline, with intense complacency.

I guessed several times, working slowly through all the members of Caroline's Intelligence Corps. My sister received each guess with a triumphant shake of the head. In the end she volunteered the information herself.

"M. Poirot!" she said. "Now, what do you think of that?"

"He told me a lot about himself and his cases. You know that Prince Paul of Mauretania -- the one who's just married a dancer?"

"What did he talk about?" I asked.

"Why did he come?" I asked.

"To see me, of course. He said that, knowing my brother so well, he hoped he might be permitted to make the acquaintance of his charming sister -- your charming sister, I've got mixed up -- but you know what I mean."

"Yes?"

"Did he give him an emerald tie pin the size of a plover's egg?" I inquired sarcastically.

"He didn't mention it. Why?"

"I saw a most intriguing paragraph about her in Society Snippets the other day, hinting that she was really a Russian Grand Duchess -- one of the Czar's daughters who managed to escape from the Bolsheviks. Well, it seems that M. Poirot solved a baffling murder mystery that threatened to involve them both. Prince Paul was beside himself with gratitude."

"Nothing," I said. "I thought it was always done. It is in detective fiction anyway. The super-detective always has his rooms littered with rubies and pearls and emeralds from grateful Royal clients."

"He was not at liberty to speak," said Caroline importantly.

"It's very interesting to hear about these things from the inside," said my sister complacently.

It would be -- to Caroline. I could not but admire the ingenuity of M. Hercule Poirot, who had selected unerringly the case of all others that would most appeal to an elderly lady living in a small village.

"Did he tell you if the dancer was really a Grand Duchess?" I inquired.

"Don't be coarse, James. I don't know where you get these vulgar expressions from."

Caroline pushed her spectacles up and looked at me.

"And after all this," I remarked, "I suppose you were ready to eat out of his hand?"

"You seem very grumpy, James. It must be your liver. A blue pill, I think, tonight."

"Probably from my only link with the outside world -- my patients. Unfortunately, my practice does not lie amongst Royal princes and interesting Russian emigres."

I wondered how far Poirot had strained the truth in talking to Caroline -- probably not at all. He had conveyed his innuendoes by means of his eyebrows and his shoulders.

To see me in my own home, you would never imagine that I was a doctor of medicine. Caroline does the home prescribing both for herself and me.

Caroline was exactly like a cat that is full to overflowing with rich cream. She was positively purring.

"He would say so," I remarked bitterly. "Modesty is certainly not his middle name."

"Damn my liver," I said irritably. "Did you talk about the murder at all?"

"Well, naturally, James. What else is there to talk about locally? I was able to set M. Poirot straight upon several points. He was very grateful to me. He said I had the makings of a born detective in me -- and a wonderful Psychological insight into human nature."

"He talked a lot about the little grey cells of the brain, and of their functions. His own, he says, are of the first quality."

"I wish you wouldn't be so horribly American, James. He thought it very important that Ralph should be found as soon as possible, and induced to come forward and give an account of himself. He says that his disappearance will produce a very unfortunate impression at the inquest."

"Might get the girl into trouble," said Caroline sapiently. "But if M. Poirot gets hold of her, and puts it to her as her duty, she'll come forward of her own accord and clear Ralph."

"Caroline," I said sharply, "did you tell M. Poirot what you overheard in the wood that day?"

"I did," said Caroline complacently.

"If he's got a perfect alibi," I retorted, "why doesn't he come forward and say so?"

"Not at all," said Caroline, quite unruffled. "I was surprised you hadn't told him."

"You realize what you're doing, I hope," I jerked out. "You're putting a halter round Ralph Paton's neck as surely as you're sitting in that chair."

"So am I. That's why I say you're talking nonsense. I don't believe Ralph did it, and so the truth can't hurt him, and we ought to give M. Poirot all the help we can. Why, think, very likely Ralph was out with that identical girl on the night of the murder, and if so, he's got a perfect alibi."

"I took very good care not to," I said. "I'm fond of that boy."

"I agreed with him," said Caroline importantly. "And I was able to tell him the way people were talking already about it."

"And what did you say to that?"

I got up and began to walk about.

"Did Poirot ask you any more questions?" I inquired.

"Do you mean to say you were able to tell him that?" I demanded.

"Why not?" asked my sister triumphantly. "I can see the path up to the surgery door perfectly from this window. And I've got an excellent memory, James. Much better than yours, let me tell you."

Caroline is really amazing.

"I'm sure you have," I murmured mechanically.

"Only about the patients you had that morning."

"There was old Mrs Bennett, and that boy from the farm with the bad finger. Dolly Grice to have a needle out of her finger; that American steward off the liner. Let me see -- that's four. Yes, and old George Evans with c his ulcer. And lastly " She paused significantly.

I dropped into my chair again.

"Yes, your surgery patients. How many and who they were."

"The patients?" I demanded, unbelievingly.

My sister went on, checking the names on her fingers.

"You seem to have invented a romantic fairy story of your Own," I said. "You read too many trashy novels, Caroline. I've always told you so."

"But depend upon it, that was what he was trying to get at -- M. Poirot, I mean. There's something fishy about that woman, and he knows it."

"Precisely the remark Mrs Ackroyd made to me yesterday," I said. "That there was something fishy about Miss Russell."

"Another what?"

"Miss Russell!"

"What?" I asked.

"Well?"

"Bad knee," said Caroline. "Fiddlesticks! No more bad ^ee than you and I. She was after something else."

Caroline had to admit that she didn't know.

Caroline brought out her climax triumphantly. She hissed it in the most approved style -- aided by the fortunate number of s's at her disposal.

"I don't know what you mean," I said, quite untruthfully. "Why shouldn't Miss Russell consult me about h: r bad knee?"

"Ah!" said Caroline darkly, "Mrs Ackroyd! There's another!"

She sat back in her chair and looked at me meaningly, and when Caroline looks at you meaningly, it is impossible to miss it.

Caroline refused to explain her remarks. She merely nodded her head several times, rolling up her knitting, and went upstairs to don the high mauve silk blouse and the gold locket which she calls dressing for dinner.

I stayed there staring into the fire and thinking over Caroline's words. Had Poirot really come to gain information about Miss Russell, or was it only Caroline's tortuous mind that interpreted everything according to her own ideas?

There had certainly been nothing in Miss Russell's manner that morning to arouse suspicion. At least I remembered her persistent conversation on the subject of drug-taking -- and from that she had led the conversation to poisons and poisoning. But there was nothing in that. Ackroyd had not been poisoned. Still, it was odd…

I put some coal on the fire and went upstairs obediently.

It is well at any price to have peace in the home.

I heard Caroline's voice, rather acid in tone, calling from the top of the stairs. "James, you will be late for dinner."