She is a Hindu--I believe, a former nautch-girl, daughter of a nautch-girl. She pa.s.ses by the name of Mrs. Anthony, but really her name is Kalia Da.s.s. Every one in Calcutta knew her."

Kennedy quietly drew his card-case from his pocket and handed a card to Mrs. Rogers.

"I should like to talk to you about her some time," he said, in a careful whisper. "If anything happens--don't hesitate to call on me."

Before Mrs. Rogers could recover from her surprise Kennedy had said good-by and we were on our way to the laboratory.

"That's a curious situation," I observed. "Can you make it out? How does Shirley fit into this thing?"

Craig hesitated a moment, as though debating whether to say anything, even to me, about his suspicions.

"Suppose," he said, slowly, "that Shirley was a secret agent of the British government, charged with the mission of finding out whether Mrs. Rogers was contributing--unknowingly, perhaps--to hatching another Indian mutiny? Would that suggest anything to you?"

"And the nautch-girl whom he had known in Calcutta followed him, hoping to worm from him the secrets which he--"

"Not too fast," he cautioned. "Let us merely suppose that Shirley was a spy. If I am not mistaken, we shall see something happen soon, as a result of what I said to Mrs. Rogers."

Excited now by the possibilities opened up by his conjecture regarding Shirley, which I knew must have amounted to a certainty in his mind, I watched him impatiently, as he calmly set to work cleaning up the remainder of the laboratory investigation in the affair.

It was scarcely half an hour later that a car drove up furiously to our door and Mrs. Rogers burst in, terribly agitated.

"You remember," she cried, breathlessly, "you said that a jequirity bean was sent to Captain Shirley?"

"Yes," encouraged Kennedy.

"Well, after you left, I was thinking about it. That Kalia Da.s.s used to wear a necklace of them, but she didn't have it on to-day. I began thinking about it. While she was talking to the swami I went over. I've noticed how careful she always is of her hand-bag. So I managed to catch my hand in the loop about her wrist. It dropped on the floor. We both made a dive for it, but I got it. I managed, also, to open the catch and, when I picked it up to hand to her, with an apology, what should roll out but a score of prayer-beans! Some papers dropped out, too. She almost tore them from my hands; in fact, one of them did tear.

After it was over I had this sc.r.a.p, a corner torn off one of them."

Kennedy took the sc.r.a.p which she handed to him and studied it carefully, while we looked over his shoulder. On it was a queer alphabetical table. Across the first line were the letters singly, each followed by a dash. Then, in squares underneath, were pairs of letters--AA, BA, CA, DA, and so on, while, vertically, the column on the left read: AA, AB, AC, AD, and so on.

"Thank you, Mrs. Rogers," Craig said, rising. "This is very important."

She seemed reluctant to go, but, as there was no excuse for staying longer, she finally left. Kennedy immediately set to work studying the sc.r.a.p of paper and the cipher message he had copied, while I stifled my impatience as best I could.

I could do nothing but reflect on the possibility of what a jealous woman might do. Mrs. Rogers had given us one example. Did the same explanation shed any light on the mystery of the nautch-girl and the jequirity bean sent to Shirley? There was no doubt now that Shirley had known her in Calcutta--intimately, also. Perhaps the necklace had some significance. At least, he must have remembered it, as his agitation over the single bean and the word "Gadhr" seemed to indicate. If she had sent it to him, was it as a threat? To all appearance, he had not known that she was in New York, much less that she was at the same hotel and on the same floor. Why had she followed him? Had she misinterpreted his attentions to Mrs. Rogers?

Longing to ask Kennedy the myriad questions that flashed through my mind, I turned to him as he scowled at the sc.r.a.p of paper and the cipher before him.

Presently he glanced up at me, still scowling.

"It's no use, Walter," he said; "I can't make it out without the key--at least, it will take so long to discover the key that it may be useless."

Just then the telephone-bell rang and he sprang to it eagerly. As I listened I gathered that it was another hurried call from Grady.

"Something has happened to Mrs. Anthony!" cried Craig, as he hooked up the receiver and seized his hat.

A second time we posted to the Prince Edward Charles, spurred by the mystery that surrounded the case. No one met us in the lobby this time, and we rode up directly in the elevator to Mrs. Anthony's room.

As we came down the hall and Grady met us at the door, he did not need to tell us that something was wrong. One experience like that with Shirley had put the hotel people on guard, and the house physician was already there, administering stimulants to Mrs. Anthony, who was lying on the bed.

"It's just like the other case," whispered Grady. "There are the same scratches on her face and hands."

The doctor glanced about at us. By the look on his face, I read that it was a losing fight. Kennedy bent down. The floor about the door was covered with little glittering slivers of gla.s.s. On Mrs. Anthony's face was the same drawn look as on Shirley's.

Was it a suicide? Had we been getting too close on her trail, or had Mrs. Anthony been attacked? Had some one been using her, and now was afraid of her and sought to get her out of the way for safety?

What was the secret locked in her silent lips? The woman was plainly dying. Would she carry the secret with her, after all?

Kennedy quickly drew from his pocket the vial which I had seen him place there in the laboratory early in the day. From the doctor's case he selected a hypodermic and coolly injected a generous dose of the stuff into her arm.

"What is it?" asked the doctor, as we all watched her face anxiously.

"The ant.i.toxin to abrin," he replied. "I developed some of it at the same time that I was studying the poison. If an animal that is immune to a toxin is bled and the serum collected, the ant.i.toxin in it may be injected into a healthy animal and render it immune. Ricin and abrin are vegetable protein toxins of enormous potency and exert a narcotic action. Guinea-pigs fed on them in proper doses attain such a degree of immunity that, in a short time, they can tolerate four hundred times the fatal dose. The serum also can be used to neutralize the toxin in another animal, to a certain extent."

We crowded about Kennedy and the doctor, our eyes riveted on the drawn face before us. Would the ant.i.toxin work?

Meanwhile, Kennedy moved over to the writing-table which he had examined on our first visit to the room. Covered up in the writing-pad was still the paper which he had copied. Only, Mrs. Anthony had added much more to it. He looked at it desperately. What good would it do if, after hours, his cleverness might solve the cipher--too late?

Mrs. Anthony seemed to be struggling bravely. Once I thought she was almost conscious. Glazed though her eyes looked, she saw Kennedy vaguely, with the paper in his hand. Her lips moved. Kennedy bent down, though whether he heard or read her lip movements I do not know.

"Her pocket-book!" he exclaimed.

We found it crushed under her coat which she had taken off when she entered. Craig opened it and drew forth a crumpled sheet of paper from which a corner had been torn. It exactly fitted the sc.r.a.p that Mrs.

Rogers had given us. There, contained within twenty-seven horizontal and twenty-seven vertical lines, making in all six hundred and seventy-six squares, was every possible combination of two letters of the alphabet.

Kennedy looked up, still in desperation. It did him no good. He could have completed the table himself.

"In--the--lining." Her lips managed to frame the words.

Kennedy literally tore the bag apart. There was nothing but a plain white blank card. With a superhuman effort she moved her lips again.

"Smelling-salts," she seemed to say.

I looked about. On the dressing-table stood a little dark-green bottle.

I pulled the ground-gla.s.s stopper from it and a most pungent odor of carbonate of ammonia filled the room. Quickly I held it under her nose, but she shook her head weakly.

Kennedy seemed to understand. He s.n.a.t.c.hed the bottle from me and held the card directly over its mouth. As the fumes of the ammonia poured out, I saw faintly on the card the letters HR.

We turned to Mrs. Anthony. The effort had used up her strength. She had lapsed again into unconsciousness as Craig bent over her.

"Will she live?" lasted.

"I think so," he replied, adding a hasty word to the doctor.

"What's that? Look!" I exclaimed, pointing to the card from which the letters HR had already faded as mysteriously as they had appeared, leaving the card blank again.

"It is the key!" he cried, excitedly. "Written in sympathetic ink. At last we have it all."

On the queer alphabetical table which the two pieces of paper made, he now wrote quickly the alphabet again, horizontally across the top, starting with H, and vertically down the side, starting with R, thus: