She looked at me a moment, then drew from a fold of her waist a yellow paper.  It was a telegram.  I took it and read: 

     Beware of Teresa de Leon, Hotel Pan-America.

      A friend.

“You know her?” I asked, folding the telegram, but not returning it.

Eulalie looked at me frankly and shook her head.  “I have no idea who she is.”

“Or of who sent the telegram?”

“None at all.”

“When did you receive it?”

“Only a few minutes ago.”

Here was another mystery.  Who had sent the anonymous telegram to Eulalie so soon after it had been evident that Kennedy had entered the case?  What was its purpose?

“I may keep this?” I asked, indicating the telegram.

“I was about to send it to Professor Kennedy,” she replied.  “Oh, I hope he will find something Won’t you go to him and tell him to hurry?”

I needed no urging, not only for her sake, but also because I did not wish to be seen or to have the receipt of the telegram by Kennedy known so soon.

In the hotel I stopped only long enough to see that Anitra was now hurrying toward the elevator, eager to get back to her brother and oblivious to every one around.  What had become of Page and the sinister watcher whom he had not seen I did not know, nor did I have time to find out.

A few moments later I rejoined Kennedy at the laboratory.  He was still immersed in work, and, scarcely stopping, nodded to me to tell what I had discovered.  He listened with interest until I came to the receipt of the anonymous telegram.

“Did you get it?” he asked, eagerly.

He almost seized it from my hands as I pulled it out of my pocket and studied it intently.

“Strange,” he muttered.  “Any of them might have sent it.”

“Have you discovered anything?” I asked, for I had been watching him, consumed by curiosity, as I told my story.  “Do you know yet how the thing was done?”

“I think I do,” he replied, abstractedly.

“How was it?” I prompted, for his mind was now on the telegram.

“A poison-gas pistol,” he resumed, coming back to the work he had just been doing.  “Instead of bullets, this pistol used cartridges charged with some deadly powder.  It might have been something like the anesthetic pistol devised by the police authorities in Paris some years ago when the motor bandits were operating.”

“But who could have used it?” I asked.

Kennedy did not answer directly.  Either he was not quite sure yet or did not feel that the time was ripe to hazard a theory.  “In this case,” he continued, after a moment’s thought, “I shouldn’t be surprised if even the wielder of the pistol probably wore a mask, doubly effective, for disguise and to protect the wielder from the fumes that were to overcome the victim.”

“You have no idea who it was?” I reiterated.