“There it is? Then what’s the matter? What ails you?”
Wolfe caught up the envelope, and drew forth the sheets of paper it contained.
“What ails me?” he hissed. “Just take a look at this! Here’s that valuable confession!”
He spread out the sheets of paper, and Ditson gazed at them in surprise, for apparently there was not a line of writing upon them.
“Confession?” muttered Duncan. “What are you talking about? There’s nothing there.”
“There was once. Look here—look close. Here, you can see the faintest tracing of a word. There, you can see part of another word. There was writing on this paper once. Why, I can even see a bit of my own signature down in this corner, but it’s gone. It’s faded. It’s no good to any one now.”
Looking intently at the paper, Ditson was able to make out the faint tracing of a few detached words upon it.
Suddenly Duncan smote his clenched right fist into his left palm.
“Well, if that wasn’t a slick trick on the part of Lynch!” he cried. “He wrote his confession with sympathetic ink.”
“With what? Sympathetic ink?”