An instant coldness pa.s.sed 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 a.s.s!" I e.j.a.c.u.l.a.t.ed. "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?"

"No," I said, rather surprised, "I know that there are no two finger-marks alike, but that's as far as my science goes."

"Exactly."

He unlocked a little drawer, and took out some photographs which he laid on the table.

"I have numbered them, 1, 2, 3. Will you describe them to me?"

I studied the proofs attentively.

"All greatly magnified, I see. No. 1, I should say, are a man's finger-prints; thumb and first finger. No. 2 are

a lady's; they are much smaller, and quite different in every way. No. 3".I paused for some time."there seem

to be a lot of confused finger-marks, but here, very distinctly, are No. 1's."

"Overlapping the others?"

"Yes."

"You recognize them beyond fail?"

"Oh, yes; they are identical."

Poirot nodded, and gently taking the photographs from me locked them up again.

"I suppose," I said, "that as usual, you are not going to explain?"

"On the contrary. No. 1 were the finger-prints of Monsieur Lawrence. No. 2 were those of Mademoiselle Cynthia. They are not important. I merely obtained them for comparison. No. 3 is a little more complicated."

"Yes?"

"It is, as you see, highly magnified. You may have noticed a sort of blur extending all across the picture. I will not describe to you the special apparatus, dusting powder, etc., which I used. It is a well-known process to the police, and by means of it you can obtain a photograph of the finger-prints of any object in a very short

s.p.a.ce of time. Well, my friend, you have seen the finger-marks.it remains to tell you the particular object on which they had been left."

"Go on.I am really excited."