“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 glass.  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 antitoxin 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 antitoxin 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 antitoxin 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.