possible that Skeel witnessed the murder. That couldn't, by any stretch of the imagination, be your precious theory?"
"That's part of it, anyway."
"My dear Vance, you do astonish me!" Markham laughed outright. "Skeel, then, according to you, is innocent; but he keeps his knowledge to himself, invents an alibi, and doesn't even tattle when he's arrested. . . . It won't hold water."
"I know," sighed Vance. "It's a veritable sieve. And yet, the notion haunts me—it rides me like a hag—it eats into my vitals."
"Do you realize that this mad theory of yours presupposes that, when Spotswoode and Miss Odell returned from the theatre, there were two men hidden in the apartment—two men unknown to each other—namely Skeel and your hypothetical murderer?"
"Of course I realize it; and the thought of it is breaking down my reason."
"Furthermore, they must have entered the apartment separately, and hidden separately. . . . How, may I ask, did they get in? And how did they get out? And which one caused the girl to scream after Spotswoode had left? And what was the other one doing in the meantime? And if Skeel was a passive spectator, horrified and mute, how do you account for his breaking open the jewel-case and securing the ring?"
"Stop! Stop! Don't torture me so," Vance pleaded. "I know I'm insane. Been given to hallucinations since birth; but—Merciful Heaven!—I've never before had one as crazy as this."
"On that point at least, my dear Vance, we are
