"Have I not told you that that is the essence of X's technique? There will be nothing connecting X with the death. That is certain."

"The connection will be hidden, you mean?"

"It will be so well hidden that neither you nor I will find it."

"But surely by studying X's past - "

"I tell you, no. Certainly not in the time. Murder may happen any moment, you comprehend?"

"To someone in this house?"

"To someone in this house."

"And you really do not know who, or how?"

"Ah, if I did, I should not be urging you to find out for me!"

"You simply base your assumption on the presence of X?" I sounded a little doubtful. Poirot, whose self-control had lessened as his limbs were perforce immobile, fairly howled at me.

"Ah, ma foi, how many times am I to go over all this? If a lot of war correspondents arrive suddenly in a certain spot of Europe, it means what? It means war! If doctors come from all over the world to a certain city - it shows what? That there is to be a medical conference. Where you see a vulture hovering, there will be a carcass. If you see beaters walking up a moor, there will be a shoot. If you see a man stop suddenly, tear off his coat and plunge into the sea, it means tha.t there, there will be a rescue from drowning.

"If you see ladies of middle age and respectable appearance peering through a hedge, you may deduce that there is there an impropriety of some kind! And finally, if you smell a succulent smell and observe several people all walking along a corridor in the same direction, you may safely assume that a meal is about to be served!"

I considered these analogies for a minute or two, then I said, taking the first one:

"All the same, one war correspondent does not make a war!

"Certainly not. And one swallow does not make a summer. But one murderer, Hastings, does make a murder."

That, of course, was undeniable. But it still occurred to me, as it did not seem to have occurred to Poirot, that even a murderer has his off times. X might be at Styles simply for a holiday with no lethal intent. Poirot was so worked up, however, that I dared not propound this suggestion. I merely said that the whole thing seemed to me hopeless. We must wait -

"And see," finished Poirot. "Like your Mr. Asquith in last war. That, mon cher, is just what we must not do. I do not say, mark you, that we shall succeed, for as I have told you before, when a killer has determined to fall, it is not easy to circumvent him. But we can at least try. Figure to yourself, Hastings, that you have here the bridge problem in the paper. You can see all the cards. What you are asked to do is 'Forecast the result of the deal'"