"What?"

"Surely, Hastings. As the keeper, his teeth were broken and discoloured, in Paris they were even and white, as the doctor they protruded slightly, and as Savaronoff they had unusually long canines. Nothing alters the face so completely as a different set of teeth.

You see where all this is leading us?" 

"Not exactly," I said cautiously.

"A man carries his profession written in his face, they say."

"He's a criminal," I cried.

"He is an adept in the art of making up."

"It's the same thing."

"Rather a sweeping statement, Hastings, and one which would hardly be appreciated by the theatrical world. Do you not see that the man is, or has been, at one time or another, an actor?"

"An actor?"

"But certainly. He has the whole technique at his finger-tips. Now there are two classes of actors, the one who sinks himself in his part, and the one who manages to impress his personality upon it. It is from the latter class that actor managers usually spring. They seize a part and mould it to their own personality. The former class is quite likely to spend its days doing Mr. Lloyd George at different music halls, or impersonating old men with beards in repertory plays. It is among that former class that we must look for our Number Four.

He is a supreme artist in the way he sinks himself in each part he plays."

I was growing interested.

"So you fancy you may be able to trace his identity through his connection with the stage?"

"Your reasoning is always brilliant, Hastings."

"It might have been better," I said coldly, "if the idea had come to you sooner. We have wasted a lot of time."

"You are in error, mon ami. No more time has been wasted than was unavoidable. For some months now my agents have been engaged on the task. Joseph Aarons is one of them. You remember him? They have compiled a list for me of men fulfilling the necessary qualifications-young men round about the age of thirty, of more or less nondescript appearance, and with a gift for playing character parts-men, moreover, who have definitely left the stage within the last three years."

"Well?" I said, deeply interested.

"The list was, necessarily, rather a long one. For some time now, we have been engaged on the task of elimination. And finally we have boiled the whole thing down to four names. Here they are, my friend."

He tossed me over a sheet of paper. I read its contents aloud.

"Ernest Luttrell. Son of a North Country parson.

Always had a kink of some kind in his moral makeup.

Was expelled from his public school. Went on the stage at the age of twenty-three. (There followed a list of parts he had played, with dates and places.) Addicted to drugs. Supposed to have gone to Australia four years ago. Cannot be traced after leaving England. Age 32, height 5 ft. 10 Vi in., clean-shaven, hair brown, nose straight, complexion fair, eyes gray.

"John St. Maur. Assumed name. Real name not known. Believed to be of cockney extraction. On stage since quite a child. Did music hall impersonations. Not been heard of for three years. Age, about 33, height 5 ft. 10 in., slim build, blue eyes, fair colouring.

"Austen Lee. Assumed name. Real name Austen Foly. Good family. Always had taste for acting and distinguished himself in that way at Oxford. Brilliant war record. Acted in- (The usual list followed. It included many Repertory plays.) An enthusiast on criminology.

Had bad nervous breakdown as the result of a motor accident three and a half years ago, and has not appeared on the stage since. No clue to his present whereabouts.

Age 35, height 5 ft. 9Vi in., complexion fair, eyes blue, hair brown.

"Claud Darrell. Supposed to be real name. Some mystery about his origin. Played at music halls, and also in Repertory plays. Seems to have had no intimate friends. Was in China in 1919. Returned by way of |»j America. Played a few parts in New York. Did not appear on the stage one night, and has never been heard of since. New York police say most mysterious disappearance.

Age about 33, hair brown, fair complexion, gray eyes. Height 5 ft. 10 Vi in.

"Most interesting," I said, as I laid down the paper.

"And so this is the result of the investigation of months? These four names. Which of them are you inclined to suspect?"

Poirot made an eloquent gesture.

"Mon ami, for the moment it is an open question. I would just point out to you that Claud Darrell has been in China and America-a fact not without significance, perhaps, but we must not allow ourselves to be unduly biased by that point. It may be a mere coincidence."

"And the next step?" I asked eagerly.

"Affairs are already in train. Every day cautiously worded advertisements will appear. Friends and relatives of one or the other will be asked to communicate with my solicitor at his office. Even to-day we might-Aha, the telephone! Probably it is, as usual, the wrong number, and they will regret to have troubled us, but it may be-yes, it may be-that something has arisen."

I crossed the room and picked up the receiver.

"Yes, yes. M. Poirot's rooms. Yes, Captain Hastings speaking. Oh, it's you, Mr. McNeil! (McNeil and Hodgson were Poirot's solicitors.) I'll tell him. Yes, we'll come round at once."

I replaced the receiver and turned to Poirot, my eyes dancing with excitement.

"I say, Poirot, there's a woman there. Friend of Claud Darrell's. Miss Flossie Monro. McNeil wants you to come round."

"At the instant!" cried Poirot, disappearing into his bedroom, and reappearing with a hat.

A taxi soon took us to our destination, and we were ushered into Mr. McNeil's private office. Sitting in the arm-chair facing the solicitor was a somewhat lurid looking lady no longer in her first youth. Her hair was of an impossible yellow, and was prolific in curls over each ear, her eyelids were heavily blackened, and she had by no means forgotten the rouge and the lip salve.

"Ah, here is M. Poirot.'" said Mr. McNeil. "M.

Poirot, this is Miss-er-Monro, who has very kindly called to give us some information."

"Ah, but that is most kind!" cried Poirot.

He came forward with great empressement, and shook the lady warmly by the hand.

"Mademoiselle blooms like a flower in this dry-asdust old office." he added, careless of the feelings of Mr. McNeil.

This outrageous flattery was not without effect. Miss Monro blushed and simpered.

"Oh, go on now, Mr. Poirot!" she exclaimed. "I know what you Frenchmen are like."

"Mademoiselle, we are not mute like Englishmen before beauty. Not that I am a Frenchman-1 am a Belgian, you see."

"I've been to Ostend myself," said Miss Monro.

The whole affair, as Poirot would have said, was marching splendidly.

"And so you can tell us something about Mr. Claud Darrell?" continued Poirot.

"I knew Mr. Darrell very well at one time," explained the lady. "And I saw your advertisement, being out of a shop for the moment, and my time being my own, I said to myself: There, they want to know about poor old Claudie- lawyers, too-maybe it's a fortune looking || for the rightful heir, I'd better go round at once."

Mr. McNeil rose.

"Well, Monsieur Poirot, shall I leave you for a little conversation with Miss Monro?"

"You are too amiable. But stay-a little idea presents itself to me. The hour of the dejeuner approaches. Mademoiselle will perhaps honour me by coming out to luncheon with me?"

Miss Monro's eyes glistened. It struck me that she was in exceedingly low water, and that the chance of a square meal was not to be despised.

A few minutes later saw us all in a taxi, bound for one of London's most expensive restaurants. Once arrived there, Poirot ordered a most delectable lunch, and then turned to his guest.

"And for wine, mademoiselle? What do you say to champagne?"