Johnson smiled.

“I’m bewildered. I can’t understand why poor Mr. Maitland did this. But I had my first Frog warning to-day; I feel almost important,” he said.

From a worn pocket-case he extracted a sheet of paper. It contained only three words;

“You are next!”

and bore the familiar sign manual of the Frog.

“I don’t know what harm I have done to these people, but I presume that it is something fairly bad, for within ten minutes of getting this note, the porter brought me my afternoon tea. I took one sip and it tasted so bitter that I washed my mouth out with a disinfectant.”

“When was this?”

“Yesterday,” said Johnson. “This morning I had the analysis—I had the tea bottled and sent off at once to an analytical chemist. It contained enough hydrocyanic acid to kill a hundred people. The chemist cannot understand how I could have taken the sip I did without very serious consequences. I am going to put the matter in the hands of the police to-day.”

The front door opened, and Elk came in.

“What is the news?” asked the girl eagerly, rising to meet him.