Marriott sat very still, staring silently at his arm as though the solution of the whole mystery lay there actually written upon the skin.

"What's the matter? I see nothing very strange about a scratch," said Greene, in an unconvincing sort of voice. "It was your cuff links probably. Last night in your excitement——"

But Marriott, white to the very lips, was trying to speak. The sweat stood in great beads on his forehead. At last he leaned forward close to his friend's face.

"Look," he said, in a low voice that shook a little. "Do you see that red mark? I mean underneath what you call the scratch?"

Greene admitted he saw something or other, and Marriott wiped the place clean with his handkerchief and told him to look again more closely.

"Yes, I see," returned the other, lifting his head after a moment's careful inspection. "It looks like an old scar."

"It is an old scar," whispered Marriott, his lips trembling. "Now it all comes back to me."

"All what?" Greene fidgeted on his chair. He tried to laugh, but without success. His friend seemed bordering on collapse.