"No, it is not dangerous," said Sarakoff. He sat on the edge of the writing-table, swinging his legs and staring meditatively at the floor. "It is not dangerous, is it, Harden?"

I replied only with a jerky, impatient movement.

"What I mean," persisted the man, "is this—supposin' the police arrest me, when I go back to my job. 'Ave they a right? 'Ave people a right to give me the shove—to put me in a 'orspital? That crowd round me in the street—it confused me, like—as if I was a leper." He paused and looked up at Sarakoff enquiringly. "What's the cause of it?"

"A germ—a bacillus."

"Same as what gives consumption?"

Sarakoff nodded. "But this germ is harmless," he added.

"Then I ain't going to die?"

"No. That's just the point. You aren't going to die," said the Russian slowly. "That's what is so strange."

I jumped round from the window.

"How do you know?" I said fiercely. "There's no proof. It's all theory so far. The calculations may be wrong."