“I supposed you might be conducting some experiments, or perhaps writing a book which you wished to keep from the public for a time, and that possibly you might imagine that I was a reporter.”

“So! And THAT is all,” he returned, with evident relief. “No, my dear sir, I was the spy; it is the truth; and I was spying upon you. I confess my shame. I wish very much to know what you were like, what kind of a man you are. And so,” he concluded with an opening of the hands, palms upward, as if to show that nothing remained for concealment, “and so I have watched you.”

“Why?” I asked.

“The explanation is so simple: it was necessary.”

“Because of—of Mr. Saffren?” I said slowly, and with some trepidation.

“Precisely.” The professor exhaled a cloud of smoke. “Because I am sensitive for him, and because in a certain way I am—how should it be said?—perhaps it is near the truth to say, I am his guardian.”

“I see.”

“Forgive me,” he rejoined quickly, “but I am afraid you do not see. I am not his guardian by the law.”

“I had not supposed that you were,” I said.

“Why not?”