In Alex Ayers book THE WIT AND WISDOM OF MARK TWAIN he quotes from Freud's work entitled JOKES AND THEIR RELATION TO THE UNCONSCIOUS (translated by J. Strachey. W.W. Norton, 1963.) Evidently Freud felt that anger was a frequent theme in Twain's humor and he illustrated his point with the story Twain told of the cow falling through the subterranean dwelling. Barb