The other smiled appreciatively.

"Brrr," observed Poirot.

Poirot nodded. He looked round him.

Poirot examined the window carefully.

Followed by Dr. Constantine, Poirot made his way to the next coach and the compartment occupied by the murdered man. The conductor came and unlocked the door for them with his key.

The two men passed inside. Poirot turned inquiringly to his companion.

"How much has been disarranged in this compartment?"

He examined the frame of the window carefully. Taking a small case from his pocket he blew a little powder over it.

"I did not like to close it," he said.

"Nothing has been touched. I was careful not to move the body in making my examination."

"You are right," he announced. "Nobody left the carriage this way. Possibly the open window was intended to suggest the fact, but, if so, the snow has defeated the murderer's object."

The first thing that struck the senses was the intense cold. The window was pushed down as far as it would go and the blind was drawn up.

"No fingerprints at all," he said. "That means it has been wiped. Well, if there had been fingerprints it would have told us very little. They would have been those of M. Ratchett or his valet or the conductor. Criminals do not make mistakes of that kind nowadays.

He suited the action to the word and then turned his attention for the first time to the motionless figure lying in the bunk.

"And that being so," he added cheerfully, "we might as well shut the window. Positively it is the cold storage in here!"

"I had to see the nature of the wounds, you see," explained the doctor.

Poirot nodded. He bent over the body. Finally he straightened himself with a slight grimace.

Ratchett lay on his back. His pyjama jacket, stained with rusty patches, had been unbuttoned and thrown back.

"It is not pretty," he said. "Someone must have stood there and stabbed him again and again. How many wounds are there exactly?"

"I make it twelve. One or two are so slight as to be practically scratches. On the other hand, at least three would be capable of causing death."

"Something strikes you as odd, does it not?" he asked gently. "Speak, my friend. There is something here that puzzles you?"

Something in the doctor's tone caught Poirot's attention. He looked at him sharply. The little Greek was standing staring down at the body with a puzzled frown.

"And that?"

"Well, just one thing."

Poirot raised his hand.

"You are right," acknowledged the other.

"It would seem so," said Poirot thoughtfully. "Unless our murderer figured to himself that he had not accomplished his job properly and came back to make quite sure; but that is manifestly absurd! Anything else?"

"Which suggests?"

"That the man was already dead -- some little time dead -- when they were delivered. But that is surely absurd."

"You see this wound here -- under the right arm -- near the right shoulder. Take this pencil of mine. Could you deliver such a blow?"

"You see, these two wounds -- here and here,"-- he pointed. "They are deep, each cut must have severed blood vessels -- and yet -- the edges do not gape. They have not bled as one would have expected."

"Précisément," he said. "I see. With the right hand it is exceedingly difficult -- almost impossible. One would have to strike backhanded, as it were. But if the blow were struck with the left hand --"

"What is it?"

"Exactly, M. Poirot. That blow was almost certainly struck with the left hand."

"So that our murderer is left-handed? No, it is more difficult than that, is it not?"

"As you say, M. Poirot. Some of these other blows are just as obviously right-handed."

"Two people. We are back at two people again," murmured the detective. He asked abruptly: "Was the electric light on?"

He examined the switch of the top light and also the roll back bed-head light. The former was turned off. The latter was closed.

"The switches will tell us," said Poirot.

"It is difficult to say. You see it is turned off by the conductor every morning about ten o'clock."

"Eh bien," he said thoughtfully. "We have here a hypothesis of the First and Second Murderer, as the great Shakespeare would put it. The First Murderer stabbed his victim and left the compartment, turning off the light. The Second Murderer came in in the dark, did not see that his or her work had been done and stabbed at least twice at a dead body. Que pensez vous de ça?"

The other's eyes twinkled.

"Magnificent," said the little doctor with enthusiasm.

"You think so? I am glad. It sounded to me a little like the nonsense."

"I think I can say yes. Some of these blows, as I have already said, point to a weakness -- a lack of strength or a lack of determination. They are feeble glancing blows. But this one here -- and this one --" Again he pointed. "Great strength was needed for those blows. They have penetrated the muscle."

"That is just what I am asking myself. Have we here a coincidence or what? Are there any other inconsistencies, such as would point to two people being concerned?"

Poirot was silent a moment or two.

"Most certainly."

"A young, vigorous, athletic woman might have struck them, especially if she were in the grip of a strong emotion, but it is in my opinion highly unlikely."

"What other explanation can there be?"

"They were, in your opinion, delivered by a man?"

"They could not have been delivered by a woman?"

The other said anxiously. "You understand my point?"

"Perfectly," said Poirot. "The matter begins to clear itself up wonderfully! The murderer was a man of great strength, he was feeble, it was a woman, it was a right-handed person, it was a left-handed person -- Ah! c'est rigolo, tout ça!"

They looked round them. Ratchett's day clothing was hanging from the hooks on the wall. On the small table formed by the lid of the washing basin were various objects -- false teeth in a glass of water; another glass, empty; a bottle of mineral water, a large flask and an ashtray containing the butt of a cigar and some charred fragments of paper; also two burnt matches.

Poirot nodded. He picked up the two matches and scrutinized them carefully.

The doctor picked up the empty glass and sniffed it.

He spoke with sudden anger. "And the victim -- what does he do in all this? Does he cry out? Does he struggle? Does he defend himself?"

"Yes."

"Those two matches are of a different shape," said Poirot. "One is flatter than the other. You see?"

He slipped his hand under the pillow and drew out the automatic pistol which Ratchett had shown him the day before.

"Drugged?"

"Here is the explanation of the victim's inertia," he said quietly.

"You have a clue then?" demanded the little doctor eagerly.

"Fully loaded, you see," he said.

"The rounder one is a match struck by Mr. Ratchett," he said. "Let us see if he had also the flatter kind."

"Is it not?" said Poirot.

"It is the kind you get on a train," said the doctor, "in paper covers."

With a little exclamation he bent and picked up something from the floor.

Poirot was feeling in the pockets of Ratchett's clothing. Presently he pulled out a box of matches. He compared them carefully.

It was a small square of cambric, very dainty.

"What a stroke of luck for us!" exclaimed the doctor.

Poirot's eyes were darting about the compartment. They were bright and sharp like a bird's. One felt that nothing could escape their scrutiny.

"Our friend the chef de train was right. There is a woman concerned in this."

"And most conveniently she leaves her handkerchief behind!" said Poirot. "Exactly as it happens in the books and on the films -- and to make things even easier for us it is marked with an initial."

But a further search showed no other matches.

Something in his tone surprised the doctor. But before he could ask for elucidation, Poirot had made another dive on to the floor.

From the breast pocket he brought out a gold watch. The case was dented savagely, and the hands pointed to a quarter past one.

This time he held out on the palm of his hand -- a pipe cleaner.

"I overlooked this," he said. "I unbuttoned the jacket and threw it straight back."

"Ah!" The doctor had been delicately exploring the pyjama pockets of the dead man.

"It is perhaps the property of M. Ratchett?" suggested the doctor.

"There was no sign of any weapon. The murderer must have taken it away with him."

"I wonder why," mused Poirot.

"Oh! decidedly. And again dropped most conveniently. A masculine clue this time, you note! One cannot complain of having no clues in this case. There are clues here in abundance. By the way, what have you done with the weapon?"

"Then it is a clue."

"You see?" cried Constantine eagerly. "This gives us the hour of the crime. It agrees with my calculations. Between midnight and two in the morning is what I said, and probably about one o'clock, though it is difficult to be exact in these matters. Eh bien, here is confirmation. A quarter past one. That was the hour of the crime."

"There was no pipe in any of his pockets, and no tobacco or tobacco pouch."

"I do not understand myself," said Poirot. "I understand nothing at all, and, as you perceive, it worries me."

"It is possible, yes. It is certainly possible."

Dr. Constantine was at a loss to know what to make of this singular remark. In any case, Poirot gave him no time for questions. Opening the door into the corridor, he called for the conductor.

He sighed and bent over the little table, examining the charred fragment of paper. He murmured to himself. "What I need at this moment is an old-fashioned woman's hatbox."

The doctor looked at him curiously. "You will pardon me, M. Poirot, but I do not quite understand you."

The man arrived at a run.

"Yes, Monsieur."

Poirot considered.

"Then bring me -- let me see -- yes, the Swedish lady's and that of the lady's maid. Those two are the only hope. You will tell them it is a customs regulation -- something -- anything that occurs to you."

"They all have hatboxes, yes?"

The conductor counted on his fingers.

"One, two, three -- six, Monsieur. The old American lady, a Swedish lady, the young English lady, the Countess Andrenyi and Madame la Princess Dragomiroff and her maid."

"How many women are there in this coach?"

The conductor departed. He returned with the two hatboxes. Poirot opened that of the lady's maid and tossed it aside. Then he opened the Swedish lady's and uttered an exclamation of satisfaction. Removing the hats carefully, he disclosed round humps of wire netting.

"Then be quick."

"Ah, here is what we need. About fifteen years ago hatboxes were made like this. You skewered through the hat with a hatpin on to this hump of wire netting."

"See you, my dear doctor, me, I am not one to rely upon the expert procedure. It is the psychology I seek, not the fingerprint or the cigarette ash. But in this case I would welcome a little scientific assistance. This compartment is full of clues, but can I be sure that those clues are really what they seem to be?"

As he spoke he was skilfully removing two of the attachments. Then he repacked the hatbox and told the conductor to return them both where they belonged.

"That will be all right Monsieur. Neither lady is in her compartment at the moment."

When the door was shut once more he turned to his companion.

"I do not quite understand you, M. Poirot."

"Well, to give you an example -- we find a woman's handkerchief. Did a woman drop it? Or did a man, committing the crime, say to himself 'I will make this look like a woman's crime. I will stab my enemy an unnecessary number of times, making some of the blows feeble and ineffective, and I will drop this handkerchief where no one can miss it.' That is one possibility. Then there is another. Did a woman kill him and did she deliberately drop a pipe cleaner to make it look like a man's work? Or are we seriously to suppose that two people -- a man and a woman -- were separately concerned, and that each was so careless as to drop a clue to their identity? It is a little too much of a coincidence, that!"

"Ah! I'm coming to that. As I say, these clues, the watch stopped at a quarter past one, the handkerchief, the pipe cleaner, they may be genuine, or they may be fake. As to that I cannot yet tell. But there is one clue here which I believe -- though again I may be wrong -- has not been faked. I mean this flat match, M. le docteur. I believe that that match was used by the murderer, not by M. Ratchett. It was used to burn an incriminating paper of some kind. Possibly a note. If so, there was something in that note, some mistake, some error, that left a possible clue to the assailant. I am going to endeavour to resurrect what that something was."

"But where does the hatbox come in?" asked the doctor, still puzzled.

He went out of the compartment and returned a few moments later with a small spirit stove and a pair of curling tongs.

"I use them for the moustaches," he said, referring to the latter.

The doctor watched him with great interest. He flattened out the two humps of wire, and with great care wriggled the charred scrap of paper on to one of them. He clapped the other on top of it and then, holding both pieces together with the tongs, held the whole thing over the flame of the spirit lamp.

It was a very tiny scrap. Only three words and a part of another showed.

Poirot's eyes were shining. He laid down the tongs carefully.

"It is a very makeshift affair, this," he said over his shoulder. "Let us hope that it will answer its purpose."

"-- member little Daisy Armstrong."

The doctor watched the proceedings attentively. The metal began to glow. Suddenly he saw faint indications of letters. Words formed themselves slowly -- words of fire.

"It tells you something?" asked the doctor.

"Ah!" Poirot gave a sharp exclamation.

"What was his name?"

"Yes," he said. "I know the dead man's real name. I know why he had to leave America."

"Cassetti."

"Cassetti." Constantine knitted his brows. "It brings back to me something. Some years ago. I cannot remember… It was a case in America, was it not?"

Further than that Poirot was not disposed to be communicative. He looked round him as he went on:

"We will go into all that presently. Let us first make sure that we have seen all there is to be seen here."

"There is one thing that I do not understand," said Dr. Constantine. "If the murderer did not escape through the window, and if this communicating door was bolted on the other side, and if the door into the corridor was not only locked on the inside but chained, how then did the murderer leave the compartment?"

"Yes," said Poirot. "A case in America."

Quickly and deftly he went once more through the pockets of the dead man's clothes but found nothing there of interest. He tried the communicating door which led through to the next compartment, but it was bolted on the other side.

"That is what the audience says when a person bound hand and foot is shut into a cabinet -- and disappears."

"You mean --"

He locked the communicating door on their side. "In case," he said, "the excellent Mrs. Hubbard should take it into her head to acquire first-hand details of the crime to write to her daughter."

He looked round once more.

"I mean," explained Poirot, "that if the murderer intended us to believe that he had escaped by way of the window he would naturally make it appear that the other two exits were impossible. Like the 'disappearing person' in the cabinet -- it is a trick. It is our business to find out how the trick is done."

"There is nothing more to do here, I think. Let us rejoin M. Bouc."