Reduction and metamorphosis by homogenization and fragmentation are the persistent themes of the fourth book (l1. 453­6): O! would the Sons of Men once think their Eyes And Reason giv’n them but to study Flies ! See Nature in some partial narrow shape, And let the Author of the Whole escape: But these were the means by which, as Yeats tells us: Locke sank into a swoon; The Garden died; God took the spinning jenny Out of his side.