A chambermaid was shrieking over a woman who was lying lethargic on the floor.

I looked more closely.

It was Dora Sears.

For the moment I could not imagine what had happened. Had the events of the past few days worked on her mind and driven her into temporary insanity? Or had the blackmailing gang of automobile thieves, failing in extorting money by their original plan, seized her?

Kennedy bent over and tried to lift her up. As he did so, the gold bracelet, unclasped, clattered to the floor.

He picked it up and for a moment looked at it. It was hollow, but in that part of it where it unclasped could be seen a minute hypodermic needle and traces of a liquid.

“A poison bracelet,” he muttered to himself, “one in which enough of a virulent poison could be hidden so that in an emergency death could cheat the law.”

“But this Dr. Hopf,” exclaimed Reginald, who stood behind us looking from the insensible girl to the bracelet and slowly comprehending what it all meant, “she alone knows where and who he is!”

We looked at Kennedy. What was to be done? Was the criminal higher up to escape because one of his tools had been cornered and had taken the easiest way to get out?

Kennedy had taken down the receiver of the wall telephone in the room. A moment later he was calling insistently for his laboratory. One of the students in another part of the building answered. Quickly he described the apparatus for vividiffusion and how to handle it without rupturing any of the delicate tubes.