"Idun," Odin had said as he gave into her hands the rosy apples, "to guard these apples and keep them forever from all harm, is to do a greater service for Asgard than even Thor, with his mighty thunders, or Baldur, with his warm light, can do; for these are the apples of everlasting youth. Without them, what would Asgard be more than the cities of Midgard or of Jotunheim? What would the gods be more than the mortals of Midgard or the giants of Jotunheim? So guard them well, beautiful Idun, for to them you owe your beauty, even as we owe to them our never fading youth." One day, when all was quiet and peaceful and happy in the city of Asgard, Loke, feeling within him the stirring of his own evil heart, betook himself to Midgard in search of mischief. The peace and quiet of Asgard he could no longer endure. Then, too, it was to him a cruel delight to shoot his arrows into the lives of the helpless children of Midgard and make them sad. O, Loke was a cruel god! "Surely," Odin would sometimes say, as he looked upon him and thought of the wretchedness that yet would fall on Asgard through Loke's wicked deeds, "surely, Loke has the spirit of a Frost giant; and the Frost giants are bitter, bitter foes to Asgard." This day Loke longed for mischief. "I will go down to Midgard and find some happy heart to sadden," said he, his eyes shining with their wicked light. Down the rainbow bridge he hastened, and, with a light bound, sprang upon a bright tree in the beautiful land of Midgard. "Who are you?" cried he, seeing in the tree beside him a great, white bird. But the bird made no reply; he only winked, and blinked, and stared at Loke, and crooned, and pruned his feathers. "Do you not know a god speaks to you?" stormed Loke, growing angry even with a bird. Still no answer. "Was ever there such a stupid bird? Indeed, like the people of Midgard, you seem to have no wisdom," sneered Loke. And determined to vent his evil mood, he seized a branch and began to beat the bird. Then a strange thing happened. The bird, who all this time had seemed so stupid--too stupid even to fly away--now seized upon the bough and held it fast. Loke pulled and pulled with all his godlike strength. He could not move it; it was as if held in the grasp of a giant. "Stupid bird!" sneered Loke, when he found he could do the bird no harm. "I will not stay in the tree with such a stupid creature." A strange sound--almost like a laugh of triumph--squeezed itself out from the beak of the big bird. "Go, Loke, go at once. Go back to Asgard; or perhaps you would like to go with me to Jotunheim," spoke the bird at last. And as he spoke, he spread his wings, and arose high in the air. Alas, alas for Loke, as the bird rose, he rose too; nor could he free himself. He screamed, he fought, he begged, he strove with all his godlike arts to free himself, but all in vain.