In my absence Craig had set to work on a peculiar apparatus, as though he were distilling something from several of the other cigarette stubs.

I placed the cat in a basket and watched Craig until finally he seemed to be rewarded for his patient labors. It was well along toward morning when he obtained in a test-tube a few drops of a colorless, almost odorless liquid.

I watched him curiously as he picked the cat out of the basket and held it gently in his arms. With a dropper he sucked up a bit of the liquid from the test-tube. Then he let a small drop fall into the eye of the cat.

The cat blinked a moment and I bent over to observe it more closely. The cat's eye seemed to enlarge, even under the light, as if it were the proverbial cat's eye under a bed.

What did it mean? Was there such a thing as the drug of the evil eye?

"What have you found?" I queried.

"Something very much like the so-called 'weed of madness,' I think," he replied slowly.

"The weed of madness?" I repeated.

"Yes, something like that Mexican toloache and the Hindu datura which you must have heard about," he continued. "You know the jimson weed—the Jamestown weed? It grows almost everywhere in the world, but most thrivingly in the tropics. They are all related in some way, I believe. The jimson weed on the Pacific coast of the Andes has large white flowers which exhale a faint, repulsive odor. It is a harmless looking plant with its thick tangle of leaves, a coarse green growth, with trumpet-shaped flowers. But, to one who knows its properties, it is quite too dangerously convenient.

"I think those cigarettes have been doped," he went on positively. "It isn't toloache that was used. I think it must be some particularly virulent variety of the jimson weed. Perhaps it is in the preparation of the thing. The seeds of the stramonium, which is the same thing, contain a higher percentage of poison than the leaves and flowers. Perhaps they were used. I can't say."

He took a drop of the liquid he had isolated and added a drop of nitric acid. Then he evaporated it by gentle heat and it left a residue which was slightly yellow.

Next he took from the shelf over his table a bottle marked alcoholic solution, potassium hydrate, and let a drop fall on it. Instantly the residue became a beautiful purple, turning rapidly to violet, then to dark red and finally disappeared.

"Stramonium all right," he nodded with satisfaction. "That was known as Vitali's test. Yes, there was stramonium in those cigarettes—datura stramonium—perhaps a trace of hyocyamino. They are all, like atropine, mydriatic alkaloids, so-called from the effect on the eye. One one-hundred-thousandth of a grain will affect the cat's eye. You saw how it acted. It is more active than even atropine. Better yet, you remember how Don Luis's eyes looked."

"How about the SeÑora?" I put in.

"Oh," he answered quickly, "her pupils were normal enough. Didn't you notice that? This concentrated poison which has been used in Mendoza's cigarettes does not kill, at least not outright. It is worse. Slowly it accumulates in the system. It acts on the brain. Of all the dangers to be met with in superstitious countries, these mydriatic alkaloids are among the worst. They offer a chance for crimes of the most fiendish nature—worse than the gun or the stiletto, and with little fear of detection. It is the production of insanity!"

Horrible though the idea was I could not doubt it in the face of Craig's investigations and what I had already seen. In fact, it was necessary for me only to recall the peculiar sensations I myself had experienced after smoking merely a few puffs of one of Mendoza's cigarettes in order to be convinced of the possible effect of the insidious poison contained in the many that he smoked.

It was almost dawn before Craig and I left the laboratory after his discovery of the manner of the stramonium poisoning. I was thoroughly tired, though not so much so that my dreams were not haunted by a succession of baleful eyes peering at me from the darkness.

I slept late, but Kennedy was about early at the laboratory, verifying his experiments and checking over his results, carefully endeavoring to isolate any other of the closely related mydriatic alkaloids that might be contained in the noxious fumes of the poisoned tobacco. Though he was already convinced of what was going on, I knew that he considered it a matter of considerable medico-legal importance to be exact, for if the affair ever came to the stage of securing an indictment, the charge could be sustained only by specific proof.

Early in the forenoon Kennedy left me alone in the laboratory and made a trip downtown, where he visited a South American tobacco dealer and placed a rush order for a couple of hundred cigarettes, duplicating in shape and quality those which SeÑor Mendoza doza preferred, except, however, the deadly drug which was in those he was smoking.

I had some writing to do and was busily engaged at my typewriter when I suddenly became conscious of that feeling of being watched. Perhaps I had heard a footstep outside and did not remember it, but at any rate I had the feeling. I stopped tapping the keys suddenly and wheeled about in my chair just in time to catch a glimpse of a face dodging back from the window. I don't think that I would be prepared to swear just who it was, but there was just enough that was familiar about the fleeting glimpse of the eyes to make me feel uncomfortable.

I ran to the door, but it was too late. The intruder had disappeared. Still, the more I thought about it, the more determined I was to verify my suspicions, if possible. I put on my hat and walked over to the registrar's office. Sure enough, Alfonso de Moche was registered in the summer school as well as in the regular course. I was now fully convinced that it was he who had been watching us.

Not satisfied, I determined to make further inquiries about the young man. He had been at the University that morning, I learned from one of his professors, and that convinced me more than ever that he had employed at least a part of the time in spying on us. As I had expected, the professor told me that he was an excellent student, though very quiet and reserved. His mind seemed to run along the line of engineering and mining, especially, and I could not help drawing the conclusion that perhaps he, too, was infected by the furore for treasure hunting, in spite of his Indian ancestry.

Nothing further occurred, however, during the day to excite suspicion and Craig listened with interest, though without comment, when I related what had happened. He divided his time during the rest of the day between some experimental work of his own and fits of deep reverie in which he was evidently trying to piece together the broken strands of the strange story in which we were now concerned.

The package of cigarettes which he had ordered was delivered late in the afternoon. Kennedy had already wrapped up a small package of a powder and filled a small atomizer with some liquid. Stowing these things away in his pockets as best he could, with a little vial which he shoved into his waistcoat pocket, he announced that he was ready at last to take an early train to Atlantic Beach.

We dined that night, as Craig had requested, with the Mendozas and Lockwood up in the sitting-room of Don Luis's suite. It was a delightfully situated room, overlooking the boardwalk and the ocean, and the fresh wind that was wafted in from the water made it quite the equal of a roof garden.

Dinner had been ordered but not served, when Craig maneuvered to get a few minutes alone with Inez. Although I could not hear, I gathered that he was outlining at least a part of his plans to her and seeking her co-operation. She seemed to understand and approve, and I really believe that the dinner was the first in a long time that the distracted girl had really enjoyed.

While we were waiting for it, I suddenly became aware that she had contrived to leave Kennedy and myself alone in the sitting-room for a moment. It was evidently part of Craig's plan. Instantly he opened a large case in which Mendoza kept cigarettes and hastily substituted for those in it an equal number of the cigarettes which he had had made.

The dinner itself was more like a family party than a formal dinner, for Kennedy, when he wanted to do so, had a way of ingratiating himself and leading the conversation so that everyone was at his ease. Everything progressed smoothly until we came to the coffee. The SeÑorita poured, and as she raised the coffee pot Kennedy called our attention to a long line of colliers just on the edge of the horizon, slowly making their way up the coast.

I was sitting next to the SeÑorita, not particularly interested in colliers at that moment. From a fold in her dress I saw her hastily draw a little vial and pour a bit of yellowish, syrupy liquid into the cup which she was preparing for her father.

I could not help looking at her quickly. She saw me, then raised her finger to her lips with an explanatory glance at Kennedy, who was keeping the others interested in colliers. Instantly I recognized the little vial that Kennedy had shoved into his vest pocket.

More coffee and innumerable cigarettes followed. I did my best to aid in the conversation, but my real interest was centered in Don Luis himself, whom I could not help watching closely.

Was it a fact or was it merely imagination? He seemed quite different. The pupils of his eyes did not seem to be quite so dilated as they had been the night before. Even his heart action appeared to be more normal. I think the SeÑorita noticed it, too.

Dinner over and darkness cutting off the magnificent sweep of ocean view, Inez suggested that we go down to the concert, as had been their custom. It was the first time that Kennedy had not seemed to fall in with any of her suggestions, but I knew that that, too, must be part of his preconcerted plan.

"If you will pardon us," he excused, "Mr. Jameson and I have some friends over at Stillson Hall whom we have promised to run in to see. I think this would be a good opportunity. We'll rejoin you—in the alcove where we were last night, if possible."

No one objected. In fact I think Lockwood was rather glad to have a chance to talk to Inez, for Kennedy had monopolized a great deal of her attention.

We left them at the elevator, but instead of leaving the Inn Kennedy edged his way around into the shadow of a doorway where we could watch. Fortunately the SeÑorita managed to get the same settee in the corner which we had occupied the night before.

A moment later I caught a glimpse of a familiar face at the long window opening on the veranda. SeÑora de Moche and her son had drawn up chairs, just outside.

They had not seen us and, as far as we knew, had no reason to suspect that we were about. As we watched the two groups, I could not fail to note that the change in Don Luis was really marked. There was none of the wildness in his conversation, as there had been. Once he even met the keen eye of the SeÑora, but it did not seem to have the effect it had had on the previous occasion.

"What was it you had the SeÑorita drop into his coffee?" I asked Craig under my breath.

"You saw that?" he smiled. "It was pilocarpine, jaborandi, a plant found largely in Brazil, one of the antidotes for stramonium poisoning. It doesn't work with everyone. But it seems to have done so with Mendoza. Besides, the caffeine in the coffee probably aided the pilocarpine. Did you notice how it contracted his pupils almost back to normal again?"

Kennedy did not take his eyes off the two groups as he talked. "I've got at the case from a brand-new angle, I think," he added. "Unless I am mistaken, when the criminal sees Don Luis getting better, it will mean another attempt to substitute more cigarettes doped with that drug."

Satisfied so far with the play he was staging, Kennedy moved over to the hotel desk, and after a quiet conference with the head clerk, found out that the room next to the suite of the Mendozas was empty. The clerk gave him several keys and with a last look at the SeÑora and her son, to see whether they were getting restive, I followed Craig into the elevator and we rode up to the eighth floor again.

The halls were deserted now and we entered the room next to the Mendozas without being observed. It was a simple matter after that to open a rather heavy door that communicated between the two suites.

Instead of switching on the light, Kennedy first looked about carefully until he was assured that no one was there. Quickly he sprinkled on the floor from the hall door to the table on which the case of cigarettes lay some of the powder which I had seen him wrap up in the laboratory before we left. Then with the atomizer he sprayed over it something that had a pungent, familiar odor, walking backwards from the hall door as he did so.

"Don't you want more light?" I asked, starting to cross to a window to raise a shade to let the moonlight stream in.

"Don't walk on it, Walter," he whispered, pushing me back. "First I sprinkled some powdered iodine and then ammonia enough to moisten it. It evaporates quickly, leaving what I call my anti-burglar powder."

He had finished his work and now the evening wind was blowing away the slight fumes that had risen. For a few moments he left the door into the next room open to clear away the odor, then quietly closed it, but did not lock it.

In the darkness we settled ourselves now for a vigil that was to last we knew not how long. Neither of us spoke as we half crouched in the shadow of the next room, listening.

Slowly the time passed. Would anyone take advantage of the opportunity to tamper with that box of cigarettes on Mendoza's table? Who was it who had conceived and executed this devilish plot? What was the purpose back of it all?

Once or twice we heard the elevator door clang and waited expectantly, but nothing happened. I began to wonder whether if someone had a pass-key to the Mendoza suite we could hear them enter. The outside hall was thickly carpeted and deadened every footfall if one exercised only reasonable caution.

"Don't you think we might leave the door ajar a little?" I suggested anxiously.

"Sh!" was Kennedy's only comment in the negative.

I glanced now and then at my watch and was surprised to see how early it was. The minutes were surely leaden-footed.

In the darkness and silence I fell to reviewing the weird succession of events which had filled the past two days. I am not by nature superstitious, but in the darkness I could well imagine a staring succession of eyes, beginning with the dilated pupils of Don Luis and always ending with those remarkable piercing black eyes of the Indian woman with the melancholy-visaged son.

Suddenly I heard in the next room what sounded like a series of little explosions, as though someone were treading on match-heads.

"My burglar powder," muttered Craig in a hoarse whisper. "Every step, even those of a mouse running across, sets it off!"

He rose quickly and threw open the door into the Mendoza suite. I sprang through after him.

There, in the shadows, I saw a dark form, starting back in retreat. But it was too late.

In the dim light of the little explosions, I caught a glimpse of a face—the face of the person who had been craftily working on the superstition of Don Luis, now that his influence had got from the government the precious concession, working with the dread drug to drive him insane and thus capture both Mendoza's share of the fortune as well as his daughter, well knowing that suspicion would rest on the jealous Indian woman with the wonderful eyes whose brother had already been driven insane and whose son Inez Mendoza really loved better than himself—the soldier of fortune, Lockwood.