Grantley had deliberately torn up the equivalent of two hundred and fifty thousand dollars—a fortune in itself—and sent the fragments to his greatest enemy as a challenge of some sort.

But why?

The surgeon’s act promised to prove itself one of the most difficult puzzles of a case that had, all along, been full of unusual problems.

Both Grantley and the tragically obstinate millionaire himself had scored most heavily against the detectives when they had argued that the promised reward was so tempting that it made double-dealing out of the question. And yet, Grantley had now spurned that reward in the most contemptuous manner, after he had apparently brought pressure to bear on Baldwin in order to obtain the check two days before.

At this point Nick’s thoughts took a new turn.

How was the note to the millionaire’s secretary to be explained, he asked himself.

He still felt sure that Baldwin had written it, but if so, it was obvious that it had not been written since the operation on the financier’s head.

If Doctor Vanderpool were not greatly mistaken, the millionaire was not in a condition to know his own name, much less to write and sign a note without a tremor or a single false stroke.

Had the second operation been performed in the last two or three days? Apparently not, for Vanderpool was authority for the statement that the marks of it were several days old.

Nick had the note with him, and he examined it anew. It stood every test, as before, but there was one fact about it which, the detective had previously noted, became significant: It was not dated.