"I am an Immortal," said the Russian, in deep tones. "You will be immortal to-morrow."

"I quite understand that I will probably catch the Blue Disease," said Sir Robert, suavely. "At present there are cases reported all over London, and we are at a loss to know what to do."

"You can do nothing," I said.

"We had thought of forming isolation camps." He stared at us thoughtfully. There was a slightly puzzled look in his face. It was the first time I had noticed it. It must have been due to Sarakoff's profound calm. "How did you gentlemen find the germ?" he asked suddenly.

Sarakoff reflected.

"It would take perhaps a week to explain."

Sir Robert smiled slightly.

"I'm afraid I am too busy," he murmured.

"You are wasting your time," muttered Alberan in his ear. "Arrest them."

The Home Secretary took no notice.