CHAPTER VI

THE LABORATORY

At twelve o’clock, Lavenne, slipping from the bed, felt in his pockets to make sure that the _crochet_, the tinder-box and steel and the three special candles which he had brought with him, short and thick like modern night-lights, were to hand. Then he opened his door.

The passage was in black darkness, yet he felt sure of finding his way. He had noted the length of the passage, the position of the doors, and the position of the staircase leading to the upper floor; he had counted the number of steps in the stairs, the form of the landing to which they led was mapped in his mind, and also the point in the landing from which opened the passage leading to the dining-room corridor and to the laboratory of Camus.

He closed the door of the bedroom carefully, and groping his way, passed down the passage to the stairs. The stairs creaked under his foot, some stairways seem to creak the louder the more softly they are trodden on. Lavenne knew this idiosyncrasy and went boldly, reached the landing, found the passage to the dining-room corridor, and in a moment more was spreading his fingers on the door of Camus’ private room in search of the key-hole.

Then, taking the _crochet_ from his pocket, he inserted it in the lock.

Lavenne possessed a vast fund of special knowledge without which, despite his genius and fertility of resource, he would have been lost a hundred times in the course of a year. Not only had he a quick mind to receive knowledge, he had also a memory to retain it. Again, that kindness and rectitude of spirit which made so many men his friends, opened for him a living library in the Hôtel de Sartines. For instance, he had learned much of the science of Cryptography from Fremin. Jondret, who would certainly have been hanged some day as a housebreaker, had not de Sartines recognized his genius and drawn him into the police, had taught him the science of picking locks, whilst Cabuchon, a little old man, who in the year 1767 had placed his dirty forefinger on the poisoner of M. Terell, the haberdasher of the Rue St. Honoré, had taught him many of the tricks of poisoners.

The art of poisoning, first studied in Europe seriously by the Italians, had been imported into France in the days of the infamous Catherine de Medicis. The Revolution put its heel definitely on the last remnants of this fine product of the Middle Ages, but in the time of the fifteenth Louis there were still a few practitioners of the business, as witness the case of M. Terell poisoned by a candle.

Cabuchon had disclosed many of the secrets of this horrible science to the eager Lavenne. He had not only given him considerable knowledge of the methods used by the practitioners of the Italian art, such as the poisoning of gloves and flowers, but he had also given his pupil an insight into the psychology of the poisoner who uses recondite means, showing clearly and by instance that these people develop a passion for the business, and are sometimes held under the sway and fascination of the demon who presides over it so firmly that they will poison their fellow men and women for the slightest reason, and sometimes for no perceptible reason at all.

It was this knowledge derived from Cabuchon that disclosed to Lavenne at one stroke the poisoner of Atalanta, and the intending poisoner of Madame Camus.

It was the knowledge derived from Jondret that was now guiding his dexterous hand in the use of the _crochet_. Feeling and exploring the wards, examining the construction of the lock, using the delicacy and gentleness of a surgeon who is probing a wound, he worked, till, assured of the mechanism, with a powerful and sudden turn of the wrist he forced the bolt back and the door was open.

He entered the room, shut the door, and proceeded to examine the lock. The bolt was a spring bolt, that is to say, that whilst it required a key to open, it required none to lock it again. He pressed the door to, and it closed with a click scarcely audible and speaking well for the perfection of the mechanism.

Then he struck a spark from the tinder and steel, and lit one of his candles. The lamp was standing on the table, but he would have nothing to do with it. It was necessary to be prepared for instant concealment should anyone arrive to interrupt him, and a lamp takes a perceptible time to extinguish. He placed the lighted candle on the table, and turned to the curtains hiding the window. They were of heavy corded silk, and there was space enough behind them for a man to hide if necessary. Sure of the fact, he turned again to the table. He scarcely glanced at the bottles and retorts upon it; hastily, yet thoroughly, he examined it for drawers or secret compartments, but the table was solid throughout, made of English oak, roughly constructed and showing no sign of the French cabinet-makers’ art.

Leaving the table, he examined the cabinets in the corners of the room. They held nothing but the bottles and retorts visible through their glass doors. He examined the walls for concealed cupboards and _caches_, auscultating them here and there, just as a physician sounds the chest of a patient nowadays. But the walls made no response, they were of solid stone behind the stucco. He turned his attention to the flooring, sounding the solid parquet here and there, and had reached to a spot halfway between the table and the window-curtains, when a hollow note gave answer to his knock, a deep, resonant note, showing that a fairly large area of floor space was involved. He was going on both knees to examine this space more carefully when a step sounded in the corridor outside, a key was put into the lock of the door; and Lavenne, who, at the first sound of the step had blown out the candle, placed it in his pocket and whipped behind the curtains veiling the window.

It was Camus. He entered, lamp in hand, closed the door, placed the lamp on the table, and from it lit the other lamp. The Count evidently required plenty of light this evening, either to assist his thoughts or his studies. Lavenne, behind the curtains, had a good view of the room, its occupant, the table, the walls leading to the door and the door itself.

Camus, turning from the table, began to pace the floor. He seemed plunged in deep thought as he walked up and down, his hands behind his back, his head bent, the light now striking his face, now his hands knotted together, delicate yet powerful hands, remarkable, had you examined them closely, for the size of the thumbs.

Could you imagine yourself in the room with a man-eating tiger, and nothing separating you in the way of barrier but a curtain, you would feel somewhat as Lavenne felt alone thus with Count Camus. Looking through the small space between the curtains, he noted for the first time fully the powerful build of the man.

Camus, unconscious that he was being watched, continued to pace the floor. Then, pausing before one of the corner cupboards, he took a key from his pocket, opened the cupboard and drew out a wooden stand, holding two narrow tubes shaped like test-tubes. The tubes were corked, and one was half-filled with a violet-coloured solution, the other with a crystal-clear white liquid.

Camus closed the cupboard door with his left hand, and carrying the tubes carefully placed them and the stand containing them on the table. Then going to another cupboard, he took from it an object which held the watcher behind the curtain fascinated as he gazed on it. It was a mask made of glass, with black ribbons attached at the edge, so that it could be tied securely to the head of the wearer, the ribbons passing above and below the ears.

“Ah ha!” said Lavenne to himself, “we are going to see something now.”

He watched whilst Camus, having placed the mask on the table, went to the cupboard and produced a glass slab, a rod of glass and a small brush of camel-hair, such as artists use for water-colour painting. Also, from the same cupboard, he produced a tiny bottle with a gold stopper; this bottle was not made of glass, but of metal.

Having arranged his materials on the table, the Count drew from his pocket an object which caused the watcher behind the curtain much searching of mind. The object was a dagger, or rather a sheath knife, small, of exquisite design, and with scabbard and pommel crusted with gems.

He drew the blade from the sheath, which he placed carefully on one side. The blade was of silver, double-edged and damascened, about an inch broad and four inches long.

He placed the blade by the sheath. Then he put on the mask, took the tube containing the violet liquor and poured a few drops on the glass slab, then, as swiftly as light, a few drops from the tube containing the crystal-clear liquid, stirring the two together with the point of the glass rod. He reached out his left hand for the small metal bottle, uncorked it, and poured a few drops on the slab.

Instantly a cloud of vapour rose up, the liquid on the slab seemed to boil; dipping the little brush in the seething fluid, he drew the dagger blade to him and began to paint the silver with swift strokes, reaching from the haft to the point.

He only painted one side of the blade, and when the business was completed, instead of returning the blade to the sheath, he laid it on the table as if to dry.

Then he rose from the chair and removed the mask from his face.

A faint sickly odour filled the room. Lavenne, who had a pretty intimate knowledge of most perfumes, pleasant or unpleasant, and who in the course of his duties in the old quarters of Paris had learned the art of possessing no nose, drew back slightly from this effluvium, the effect of which was mental rather than physical. It might have been likened to an essence distilled from an evil dream. But it did not seem to trouble Camus. He was now putting away the bottle and the tubes, the rod and the slab of glass. He returned the mask to the cabinet he had taken it from, and then, coming back to the table, he took up the dagger, examined it attentively and returned it to its sheath.

Going to the right-hand wall, he touched a spot about four feet from the ground; a tiny door, the existence of which Lavenne had failed to detect, flew open. He placed the dagger in the _cache_ thus disclosed, shut the door, extinguished one of the lamps on the table, and carrying the other in his hand, left the room.

Lavenne drew a deep breath.

The situation was saved. Relieved of that terrible presence, his mind could now work freely. Up to this, he had been unable to guess the meaning of Camus’ labours.

Why had Camus used this terrible fluid to poison the knife only on one side? Why had he used such immense precaution that the other side of the steel should remain untainted.

The answer came now in a flash. Cabuchon had told him of this old medieval trick, only Cabuchon had used the word knife, not dagger.

Camus would use his dagger in this way. Laughingly, at some festival or banquet, he would take out his beautiful dagger, and, cutting a pear or a peach or an apple in two, offer half to his companion, whoever he or she might be.

And the half offered to his companion would be poisoned, inasmuch as it would have come closely in contact with the poisoned side of the knife, whereas the half retained for himself would be innocuous.

And who could say to him, “Madame Camus died after eating that peach you offered her,” considering the fact that he had also eaten of it?