Read it through once

"It's perfectly true. Wilson detected it in his hand, by palmistry, and charged him with it, and cornered him up so close that he had to confess; but both twins begged us on their knees to keep the secret, and swore they would lead straight lives here; and it was all so pitiful that we gave our word of honor never to expose them while they kept that promise. You would have done it yourself, uncle."