The voice answered, “I am down here amongst the roots of the oak-tree. Let me out! Let me out!” The scholar began to loosen the earth under the tree, and search among the roots, until at last he found a glass bottle in a little hollow. He lifted it up and held it against the light, and then saw a creature shaped like a frog, springing up and down in it. “Let me out! Let me out!” it cried anew, and the scholar thinking no evil, drew the cork out of the bottle. Immediately a spirit ascended from it, and began to grow, and grew so fast that in a very few moments he stood before the scholar, a terrible fellow as big as half the tree by which he was standing. “Knowest thou,” he cried in an awful voice, “what thy wages are for having let me out?”

“No,” replied the scholar fearlessly, “how should I know that?”

“Then I will tell thee,” cried the spirit; “I must strangle thee for it.”