I am arresting you on the charge of not being the celebrated anarchist, Professor de Worms.' This charge, if it was criminal at all, was certainly the lighter of the two, and I went along with the man, doubtful, but not greatly dismayed.

I was shown into a number of rooms, and eventually into the presence of a police officer, who explained that a serious campaign had been opened against the centres of anarchy, and that this, my successful masquerade, might be of considerable value to the public safety.

He offered me a good salary and this little blue card.

Though our conversation was short, he struck me as a man of very massive common sense and humour; but I cannot tell you much about him personally, because--" Syme laid down his knife and fork.
"I know," he said, "because you talked to him in a dark room." Professor de Worms nodded and drained his glass..