"How ridiculous! He's going out of the gate. Isn't he coming back to-day?"

"I don't know. I've given up trying to guess what he'll do next."

"Is he quite mad, Mr. Hastings?"

"I honestly don't know. Sometimes, I feel sure he is as mad as a hatter; and then, just as he is at his maddest, I find there is method in his madness."

"I see."

In spite of her laugh, Mary was looking thoughtful this morning. She seemed grave, almost sad.

It occurred to me that it would be a good opportunity to tackle her on the subject of Cynthia. I began rather tactfully, I thought, but I had not gone far before she stopped me authoritatively.

"You are an excellent advocate, I have no doubt, Mr. Hastings, but in this case your talents are quite thrown away. Cynthia will run no risk of encountering any unkindness from me."

I began to stammer feebly that I hoped she hadn't thought- But again she stopped me, and her words were so unexpected that they quite drove Cynthia, and her troubles, out of my mind.

"Mr. Hastings," she said, "do you think I and my husband are happy together?"

I was considerably taken aback, and murmured something about it's not being my business to think anything of the sort.

"Well," she said quietly, "whether it is your business or not, I will tell you that we are *NOT happy."

I said nothing, for I saw that she had not finished.

She began slowly, walking up and down the room, her head a little bent, and that slim, supple figure of hers swaying gently as she walked. She stopped suddenly, and looked up at me.

"You don't know anything about me, do you?" she asked. "Where I come from, who I was before I married John- anything, in fact? Well, I will tell you. I will make a father confessor of you. You are kind, I think-yes, I am sure you are kind."

Somehow, I was not quite as elated as I might have been. I remembered that Cynthia had begun her confidences in much the same way. Besides, a father confessor should be elderly, it is not at all the role for a young man.

"My father was English," said Mrs. Cavendish, "but my mother was a Russian."

"Ah," I said, "now I understand-"

"Understand what?"

"A hint of something foreign-different-that there has always been about you."

"My mother was very beautiful, I believe. I don't know, because I never saw her. She died when I was quite a little child. I believe there was some tragedy connected with her death-she took an overdose of some sleeping draught by mistake. However that may be, my father was broken-hearted. Shortly afterwards, he went into the Consular Service. Everywhere he went, I went with him. When I was twenty-three, I had been nearly all over the world. It was a splendid life-I loved it."

There was a smile on her face, and her head was thrown back. She seemed living in the memory of those old glad days.

"Then my father died. He left me very badly off. I had to go and live with some old aunts in Yorkshire." She shuddered. "You will understand me when I say that it was a deadly life for a girl brought up as I had been. The narrowness, the deadly monotony of it, almost drove me mad." She paused a minute, and added in a different tone: "And then I met John Cavendish."

"Yes?"

"You can imagine that, from my aunts' point of view, it was a very good match for me. But I can honestly say it was not this fact which weighed with me. No, he was simply a way of escape from the insufferable monotony of my life."

I said nothing, and after a moment, she went on:

"Don't misunderstand me. I was quite honest with him. I told him, what was true, that I liked him very much, that I hoped to come to like him more, but that I was not in any way what the world calls 'in love' with him. He declared that that satisfied him, and so-we were married."

She waited a long time, a little frown had gathered on her forehead. She seemed to be looking back earnestly into those past days.

"I think-I am sure-he cared for me at first. But I suppose we were not well matched. Almost at once, we drifted apart. He-it is not a pleasing thing for my pride, but it is the truth-tired of me very soon." I must have made some murmur of dissent, for she went on quickly: "Oh, yes, he did! Not that it matters now-now that we've come to the parting of the ways."

"What do you mean?"

She answered quietly:

"I mean that I am not going to remain at Styles."

"You and John are not going to live here?"

"John may live here, but I shall not."

"You are going to leave him?"

"Yes."

"But why?"

She paused a long time, and said at last:

"Perhaps-because I want to be-free!"

And, as she spoke, I had a sudden vision of broad spaces, virgin tracts of forests, untrodden lands-and a realization of what freedom would mean to such a nature as Mary Cavendish. I seemed to see her for a moment as she was, a proud wild creature, as untamed by civilization as some shy bird of the hills. A little cry broke from her lips:

"You don't know, you don't know, how this hateful place has been prison to me!"

"I understand," I said, "but-but don't do anything rash."

"Oh, rash!" Her voice mocked at my prudence.

Then suddenly I said a thing I could have bitten out my tongue for:

"You know that Dr. Bauerstein has been arrested?"

An instant coldness passed like a mask over her face, blotting out all expression.

"John was so kind as to break that to me this morning."

"Well, what do you think?" I asked feebly.

"Of what?"

"Of the arrest?"

"What should I think? Apparently he is a German spy; so the gardener had told John."

Her face and voice were absolutely cold and expressionless. Did she care, or did she not?

She moved away a step or two, and fingered one of the flower vases.

"These are quite dead. I must do them again. Would you mind moving-thank you, Mr. Hastings." And she walked quietly past me out of the window, with a cool little nod of dismissal.

No, surely she could not care for Bauerstein. No woman could act her part with that icy unconcern.

Poirot did not make his appearance the following morning, and there was no sign of the Scotland Yard men.

But, at lunch-time, there arrived a new piece of evidence- or rather lack of evidence. We had vainly tried to trace the fourth letter, which Mrs. Inglethorp had written on the evening preceding her death. Our efforts having been in vain, we had abandoned the matter, hoping that it might turn up of itself one day. And this is just what did happen, in the shape of a communication, which arrived by the second post from a firm of French music publishers, acknowledging Mrs. Inglethorp's cheque, and regretting they had been unable to trace a certain series of Russian folksongs. So the last hope of solving the mystery, by means of Mrs. Inglethorp's correspondence on the fatal evening, had to be abandoned.

Just before tea, I strolled down to tell Poirot of the new disappointment, but found, to my annoyance, that he was once more out.

"Gone to London again?"

"Oh, no, monsieur, he has but taken the train to Tadminster. 'To see a young lady's dispensary,' he said."

"Silly ass!" I ejaculated. "I told him Wednesday was the one day she wasn't there! Well, tell him to look us up to-morrow morning, will you?"

"Certainly, monsieur."

But, on the following day, no sign of Poirot. I was getting angry. He was really treating us in the most cavalier fashion.

After lunch, Lawrence drew me aside, and asked if I was going down to see him.

"No, I don't think I shall. He can come up here if he wants to see us."

"Oh!" Lawrence looked indeterminate. Something unusually nervous and excited in his manner roused my curiosity.

"What is it?" I asked. "I could go if there's anything special."

"It's nothing much, but-well, if you are going, will you tell him-" he dropped his voice to a whisper-"I think I've found the extra coffee-cup!"

I had almost forgotten that enigmatical message of Poirot's, but now my curiosity was aroused afresh.

Lawrence would say no more, so I decided that I would descend from my high horse, and once more seek out Poirot at Leastways Cottage.

This time I was received with a smile. Monsieur Poirot was within. Would I mount? I mounted accordingly.

Poirot was sitting by the table, his head buried in his hands. He sprang up at my entrance.

"What is it?" I asked solicitously. "You are not ill, I trust?"

"No, no, not ill. But I decide an affair of great moment."

"Whether to catch the criminal or not?" I asked facetiously.

But, to my great surprise, Poirot nodded gravely.

" 'To speak or not to speak,' as your so great Shakespeare says, 'that is the question.' "

I did not trouble to correct the quotation.

"You are not serious, Poirot?"

"I am of the most serious. For the most serious of all things hangs in the balance."

"And that is?"

"A woman's happiness, mon ami," he said gravely.

I did not quite know what to say.

"The moment has come," said Poirot thoughtfully, "and I do not know what to do. For, see you, it is a big stake for which I play. No one but I, Hercule Poirot, would attempt it!" And he tapped himself proudly on the breast.

After pausing a few minutes respectfully, so as not to spoil his effect, I gave him Lawrence's message.

"Aha!" he cried. "So he has found the extra coffee-cup. That is good. He has more intelligence than would appear, this long-faced Monsieur Lawrence of yours!"

I did not myself think very highly of Lawrence's intelligence; but I forebore to contradict Poirot, and gently took him to task for forgetting my instructions as to which were Cynthia's days off.

"It is true. I have the head of a sieve. However, the other young lady was most kind. She was sorry for my disappointment, and showed me everything in the kindest way."

"Oh, well, that's all right, then, and you must go to tea with Cynthia another day."

I told him about the letter.

"I am sorry for that," he said. "I always had hopes of that letter. But no, it was not to be. This affair must all be unravelled from within." He tapped his forehead. "These little grey cells. It is 'up to them'-as you say over here." Then, suddenly, he asked: "Are you a judge of finger-marks, my friend?"