It was early the next morning, about half an hour after the time set for the release of the passengers, that our laboratory door was flung open and Collette Aux Cayes rushed in, wildly excited.

"What's the matter?" asked Kennedy anxiously.

"Someone has been trying to keep me on the boat," she panted. "And all the way over here a man has been following me."

Kennedy looked at her a minute calmly. We could understand why she might have been shadowed, though it must have been a bungling job of Burke's operative. But who could have wanted her kept on the boat?

"I don't know," she replied, in answer to Kennedy's question. "But somehow I was the only one not told that we could go. And when I did go, one of the Secret Service men stopped me."

"Are you sure it was a Secret Service man?"

"He said he was."

"Yes, but if he had been, he would not have done that, nor let you get away, if he had. Can't you imagine anyone who might want you detained longer?"

She looked at us, half frightened. "N—not unless it is that man—or the woman with him," she replied, clasping her hands.

"You mean Castine?"

"Yes," she replied, avoiding the use of his name. "Ever since you had the body removed, he has been in great fear. I have heard him ask fifty times, 'Where have they taken him?' and 'Is he to be embalmed?'"

"That's strange," remarked Kennedy. "Why that anxiety from him? I remember that it was he who wanted the body left alone. Is it for fear that we might discover something which might be covered up?"

Kennedy disappeared into the anteroom and I heard him making a great fuss as he regulated the various pieces of machinery that surrounded the little chamber.

Some minutes later, he emerged.

"Meet us here in an hour," he directed Collette, "with your guardian."

Quickly Craig telephoned for a tank of oxygen to be sent over to the laboratory, then got Burke on the wire and asked him to meet us down at the dock.

We arrived first and Craig hurried into the lumber-room, where fortunately he found everything undisturbed. He tore off the strip of paper from the drum and held it up. On it was a series of marks, which looked like dots and dashes, of a peculiar kind, along a sort of base line. Carefully he ran his eye over the strip. Then he shoved it into his pocket in great excitement.

"Hello," greeted Burke, as he came up puffing from the hurried trip over from the Customs House, where his office was. "What's doing now?"

"A great deal, I think," returned Kennedy. "Can you locate Castine and that woman and come up to the laboratory—right away?"

"I can put my finger on them in five minutes and be there in half an hour," he returned, not pausing to inquire further, for, like me, Burke had learned that Kennedy could not be hurried in any of his revelations.

Together, Craig and I returned to the laboratory to find that Collette Aux Cayes was already there with her guardian, as solicitous as ever for her comfort and breathing fire and slaughter against the miscreants who had tried to detain her, without his knowledge.

Some minutes later Castine and "Madame" Castine arrived. At sight of Collette she seemed both defiant and restless, as though sensing trouble, I thought. Few words were spoken now by anyone, as Burke and I completed the party.

"Will you be so kind as to step into the little anteroom with me?" invited Craig, holding open the door for us.

We entered and he followed; then, as he led the way, stopped before a little glass window in the compartment which I have described. Collette was next to me. I could feel the tenseness of her senses as she gazed through the window at the body on the shelf-like pallet inside.

"What is this thing?" asked Aux Cayes, as Collette drew back, and he caught her by the arm.

For the moment Kennedy said nothing, but opened a carefully sealed door and slid the pallet out, unhinging it, while I saw Castine trembling and actually turning ashen about the lips.

"This," Kennedy replied at length, "is what is known as a respiration calorimeter, which I have had constructed after the ideas of Professors Atwater and Benedict of Wesleyan, with some improvements of my own. It is used, as you may know, in studying food values, both by the government and by other investigators. A man could live in that room for ten or twelve days. My idea, however, was to make use of it for other things than that for which it was intended."

He took a few steps over to the complicated apparatus which had so mystified me, now at rest, as he turned a switch on opening the carefully sealed door.

"It is what is known as a closed circuit calorimeter," he went on. "For instance, through this tube air leaves the chamber. Here is a blower. At this point, the water in the air is absorbed by sulphuric acid. Next the carbon dioxide is absorbed by soda lime. Here a little oxygen is introduced to keep the composition normal and at this point the air is returned to the chamber."

He traced the circuit as he spoke, then paused and remarked, "Thus, you see, it is possible to measure the carbon dioxide and the other respiration products. As for heat, the walls are constructed so that the gain or loss of heat in the chamber is prevented. Heat cannot escape in any other way than that provided for carrying it off and measuring it. Any heat is collected by this stream of water which keeps the temperature constant and in that way we can measure any energy that is given off. The walls are of concentric shells of copper and zinc with two of wood, between which is 'dead air,' an effective heat insulator. In other words," he concluded, "it is like a huge thermos bottle."

It was all very weird and fascinating. But what he could have been doing with a dead body, I could not imagine. Was there some subtle, unknown poison which had hitherto baffled science, but which now he was about to reveal to us?

He seemed to be in no hurry to overcome the psychological effect his words had on his auditors, for as he picked up and glanced at a number of sheets of figures, he went on: "In the case of live persons, there is a food aperture here, a little window with air locks arranged for the passage of food and drink. That large window through which you looked admits light. There is also a telephone. Everything is arranged so that all that enters, no matter how minute, is weighed and measured. The same is true of all that leaves. Nothing is too small to take into account."

He shook the sheaf of papers before us. "Here I have some records which have been made by myself, and, in my absence, by one of my students. In them the most surprising thing that I have discovered is that in the body of Leon metabolism seems still to be going on."

I listened to him in utter amazement, wondering toward what his argument was tending.

"I got my first clew from an injection of fluoriscine," he resumed. "You know there are many people who have a horror of being buried alive. It is a favorite theme of the creepy-creep writers. As you know, the heart may stop beating, but that does not necessarily mean that the person is dead. There are on record innumerable cases where the use of stimulants has started again the beating of a heart that has stopped.

"Still, burial alive is hardly likely among civilized people, for the simple reason that the practice of embalming makes death practically certain. At once, when I heard that there had been objections to the embalming of this body, I began to wonder why they had been made.

"Then it occurred to me that one certain proof of death was the absolute cessation of circulation. You may not know, but scientists have devised this fluoriscine test to take advantage of that. I injected about ten grains. If there is any circulation, there should be an emerald green discoloration of the cornea of the eye. If not, the eye should remain perfectly white.

"I tried the test. The green eye-ball gave me a hint. Then I decided to make sure with a respiration calorimeter that would measure whatever heat, what breath, no matter how minute they were."

Collette gave a start as she began to realize vaguely what Craig was driving at.

"It was not the voodoo sign, Mademoiselle," he said, turning to her. "It was a sign, however, of something that suggested at once to me the connection of voodoo practices."

There was something so uncanny about it that my own heart almost skipped beating, while Burke, by my other side, muttered something which was not meant to be profane.

Collette was now trembling violently and I took her arm so that if she should faint she would not fall either on my side or on that of her guardian, who seemed himself on the verge of keeling over. Castine was mumbling. Only his wife seemed to retain her defiance.

"The skill of the voodoo priests in the concoction of strange draughts from the native herbs of Hayti is well known," Kennedy began again. "There are among them fast and slow poisons, poisons that will kill almost instantly and others that are guaged in strength to accumulate and resemble wasting away and slow death.

"I know that in all such communities today no one will admit that there is such a thing still as the human sacrifice, 'the lamb without horns.' But there is on record a case where a servant was supposed to have died. The master ordered the burial, and it took place. But the grave was robbed. Later the victim was resuscitated and sacrificed.

"Most uncanny of the poisons is that which will cause the victim to pass into an unconscious condition so profound that it may easily be mistaken for death. It is almost cataleptic. Such is the case here. My respiration calorimeter shows that from that body there are still coming the products of respiration, that there is still heat in it. It must have been that peculiar poison of the voodoo priests that was used."

Racing on now, not giving any of us a chance even to think of the weird thing, except to shudder instinctively, Kennedy drew from his pocket and slapped down on a table the photographic records that had been taken by his home-made wireless recording apparatus.

"From Mr. Burke," he said, as he did so, "I received the hint that many messages were being transmitted by wireless, secretly perhaps, from the Haytien. I wanted to read those messages that were being flashed so quietly and secretly through the air. How could it be done? I managed to install down at the dock an apparatus known as the capillary electrometer. By the use of this almost unimaginably delicate instrument I was able to drag down literally out of the air the secrets that seemed so well hidden from all except those for whom they were intended. Listen."

He took the roll of paper from the drum and ran his finger along it hastily, translating to himself the Morse code as he passed from one point to another.

"Here," cried Craig excitedly. "'Leon out of way for time safely. Revolution suppressed before Forsythe can make other arrangements. Conspiracy frustrated.' Just a moment. Here's another. 'Have engaged bridal suite at Hotel La Coste. Communicate with me there after tomorrow.'"

Still holding the wireless record, Kennedy swung about to Burke and myself. "Burke, stand over by the door," he shouted. "Walter—that tank of oxygen, please."

I dragged over the heavy tank which he had ordered as he adjusted a sort of pulmotor breathing apparatus over Leon. Then I dropped back to my place beside Collette, as the oxygen hissed out.

Castine was now on his knees, his aged arms outstretched.

"Before God, Mr. Kennedy—I didn't do it. I didn't give Leon the poison!"

Kennedy, however, engrossed in what he was doing, paid no attention to the appeal.

Suddenly I saw what might have been a faint tremor of an eyelid on the pallid body before us.

I felt Collette spring forward from my side.

"He lives! He lives!" she cried, falling on her knees before the still cataleptic form. "Guillaume!"

There was just a faint movement of the lips, as though as the man came back from another world he would have called, "Collette!"

"Seize that man—it is his name signed to the wireless messages!" shouted Kennedy, extending his accusing forefinger at Aux Cayes, who had plotted so devilishly to use his voodoo knowledge both to suppress the revolution and at the same time to win his beautiful ward for himself from her real lover.