Anyone can see it who will simply read Grimm’s Fairy Tales or the fine collections of Mr. Andrew Lang. For the pleasure of pedantry I will call it the Doctrine of Conditional Joy. Touchstone talked of much virtue in an “if”; according to elfin ethics all virtue is in an “if.” The note of the fairy utterance always is, “You may live in a palace of gold and sapphire, if you do not say the word ‘cow’ ”; or “You may live happily with the King’s daughter, if you do not show her an onion.” The vision always hangs upon a veto. All the dizzy and colossal things conceded depend upon one small thing withheld. All the wild and whirling things that are let loose depend upon one thing that is forbidden. Mr. W. B. Yeats, in his exquisite and piercing elfin poetry, describes the elves as lawless; they plunge in innocent anarchy on the unbridled horses of the air⁠—