Having a kind of relationship to what we call arbitrarily the Metrical Tale is the Beast Fable in verse, in which animals and birds are endowed with reason and speech. The excuse for the Beast Fable is an ethical one, and the story, often humorous, is merely a vehicle for instruction,--a fact evident enough from the so-called moral appended to most Beast Fables. The best Beast Fables in English are those of John Gay. It is beyond the scope of this introduction to make any but a passing reference to the forms of versification which have been used in narrative poetry. In general, the range of metres is wide and varied, though a few common lines and stanzas occur with much frequency. Blank Verse, a favorite Epic measure used by Milton in _Paradise Lost_, has also been effective in the Metrical Romance (Arnold's _Sohrab and Rustum_) and the Metrical Tale (Wordsworth's _Michael_). It is peculiarly fitting to longer poems of a serious character. The Heroic Couplet, made up of two rimed iambic pentameters, was invented by Chaucer and tried in many of the _Canterbury Tales_. It has since become very common, being the measure of such widely different poems as Marlowe's _Hero and Leander_, Pope's _The Rape of the Lock_, and Keats's _Lamia_. Octosyllabic verse is frequently found,--sometimes in rimed couplets as in Scott's _Marmion_, less often unrimed as in Longfellow's _Hiawatha_. In the couplet form it is especially suited to war poetry where a rapid movement is desirable. The standard four-lined ballad stanza with rimed alternate lines has continued in popularity with the artificial ballad writers and has been used in such poems as Wordsworth's _Lucy Gray_ and Longfellow's _The Wreck of the Hesperus_. Most complicated of all the narrative stanzaic forms is the Spenserian stanza, devised by Spenser for his _Faerie Queene_ and imitated by Keats in _The Eve of St. Agnes_. It has a stateliness which makes it well adapted to dignified themes. In some few examples there is a metre wholly irregular and following the movement of the story, as in Tennyson's _The Revenge_ and Browning's _Hervé Riel_.