"It's astounding!" declared M. de Maufil. "We have already examined nearly two hundred persons and found nothing."

"That may be," replied Juve, "but we may discover the culprit by the two hundred and first hand held out to us."

"There is one thing you forget, M. Juve."

"What is that?"

"If the culprit gets wind of our method of investigation, if he has any notion that you are inspecting the hands of all those who desire to leave the hospital, he won't be such a ninny as to come and submit to your inspection."

Juve nodded approval of the comment.

"You are right; but I have taken means to obviate that difficulty."

Since he had begun his inquiry on the spot, from the very moment when the revolver shots had rung out, the great detective was growing more and more sure that the arrest of the mysterious offender would be a matter of considerable time. The buildings of the establishment were extensive, and it was easy for a man to move about them without attracting attention. They offered really strange facilities for hiding.

"Mr. Director," said Juve, "I fancy we have inspected pretty well all the persons who leave LÂriboisiÈre as a rule, at this time?"

"That is so."

"Then we must now change our plan. Let us leave a nurse here to detain those who come to ask for passes, and begin a search of the hospital ourselves. I shall post my officers in line, each man keeping in sight the one behind and the one before him. At the foot of every staircase I shall leave a sentry. Then, beginning at the outer wall of the building we will drive everyone on the ground floor toward the other end. If we don't round up our man there, we will proceed to the floor above."

"A good idea," replied M. de Maufil. "We shall catch him in a trap."

When Doctor Chaleck found that the inspector watching the exit leading to the main door in the Rue Ambroise ParÉ refused him leave to pass out of the hospital without the sanction of the great detective, he had perforce to retrace his steps. Skirting the bushes in the courtyard he took his way toward the medical wards, turning his back on the directoral offices, where he might have encountered our friend Juve. He had taken off his white uniform and was dressed in his street clothes. He halted at the entrance to the long glazed gallery which extends to the operating rooms of the surgical department. Turning suddenly, he saw in the distance and coming his way Inspector Juve, accompanied by the director. He noticed at the same time the cordon of officers preparing to sweep the hospital from end to end. Mechanically, and as if bent on putting a certain distance between him and the new-comers, he turned into the glazed gallery, and reached the far end of it. He was about to go into the surgical ward when a nurse stopped him.

"Doctor, you can't go in just now; Professor Hugard is operating and has given express orders that no one is to be admitted."

Chaleck turned up the gallery again, but abruptly swung round again as he caught sight of Juve and the director just entering the gallery, driving before them half a dozen patients and orderlies. Chaleck joined this little group, which had pulled up at the end of the gallery and was making laughing comments on the rigid inspection to which Juve was just about to subject them.

"Now's the time to show clean hands," joked a non-resident, "eh, Miss Victorine?" he added, smiling at a buxom nurse whom the chances of duty had blockaded in the corridor.

"Depend upon it," growled one of the accountants of the administrative department, shrugging his shoulders, "they are making a great fuss over nothing. After all, no one is hurt. Just one more pistol shot; in this neighbourhood we have ceased to count them."

An old man, who had his hand bandaged, suggested: "Perhaps they'll be wanting to arrest me since the culprit is wounded in the fingers, they say."

Dignified and calm, Juve did his best to restore liberty to each of the persons brought together. They had only to show their two hands held up in front of the face, the fingers apart. M. de Maufil, at a sign from Juve, immediately bade the attendant hand the person in question a card bearing his name and description. Armed with this "Sesame" he could come and go unimpeded all over the hospital.

Pointing to a large door at the extreme end of the corridor, Juve asked:

"What exit is that?"

The other smiled. "You want to see everything, don't you?"

The director, opening the heavy door, made room for Juve, who entered a very narrow passage, damp and quite dark. The passage, a short one, opened on a vast apartment, much like a cellar, lighted by air-holes in the ceiling and intensely cold. A noise of running water from open taps broke with its monotonous splash the silence of this place, solely furnished with a huge slab of wood running from one end to the other. Upon the slab dim and lengthy white shapes were outstretched, and when his eyes grew accustomed to the twilight, Juve recognised the vague outline of these weird bundles. They were corpses swathed in shrouds. The heads and shoulders alone were visible, and on the brows of the dead trickled icy water, dispensed sparingly but regularly by duck-billed taps that overhung the inclined plane.

The director explained: "This is the amphitheatre where we keep the bodies for post-mortems. Do you want to stay any longer?"

"There is no access to the room except by the door we came in at?"

"None."

"In that case," rejoined Juve, "and as there is no furniture here for a person to hide in, let us look elsewhere. It's a rather gruesome place."

"You're not used to the sight, that's all," replied the director, as he led the way back to his office.

Juve looked at his watch. "Well, I must leave you now and make a report to M. Havard. I'm afraid the murderer has slipped through our fingers."

"But you'll come back?"

"Of course."

"What am I to do meanwhile?"

"Nothing, unless you care to go over the hospital again."

"And the passes? Are they to be in force still? We have no one in the place but the staff."

"That is essential," replied Juve. "I must know with certainty who comes in and goes out. However, anyone known to your doorkeeper who wishes to leave need only sign in a register."