Criticism has not given sufficient weight to the fact that English dramatic writing laboured for centuries—­and still labours to some degree—­under a historic misfortune.  It has never wholly recovered from the euphuism—­to use the word in its widest sense—­of the late sixteenth century.  The influence of John Lyly and his tribe is still traceable, despite a hundred metamorphoses, in some of the plays of to-day and in many of the plays of yesterday.  From the very beginnings of English comedy, it was accepted as almost self-evident that “wit”—­a factitious, supererogatory sparkle—­was indispensable to all dialogue of a non-tragic order.  Language was a newly discovered and irresistibly fascinating playground for the fancy.  Conversation must be thick-strewn with verbal quibbles, similes, figures, and flourishes of every description, else it was unworthy to be spoken on the stage.  We all know how freely Shakespeare yielded to this convention, and so helped to establish it.  Sometimes, not always, his genius enabled him to render it delightful; but in most of the Elizabethans—­though it be heresy to say so—­it is an extremely tedious mannerism.  After the Restoration, when modern light talk came into being in the coffee-houses, the fashion of the day, no doubt, favoured a straining after wit; so that the playwrights were in some measure following nature—­that very small corner of nature which they called “the town”—­in accepting and making a law of the Elizabethan convention.  The leading characters of Restoration comedy, from Etherege to Vanbrugh, are consciously and almost professionally wits.  Simile and repartee are as indispensable a part of a gentleman’s social outfit as his wig or his rapier.  In Congreve the word “wit” is almost as common as the thing.  When Farquhar made some movement towards a return to nature, he was rewarded with Pope’s line, which clings like a burr to his memory—­

  “What pert, low dialogue has Farquhar writ.”

If eighteenth-century comedy, as a whole, is not brilliantly written, it is for lack of talent in the playwrights, not for lack of desire or intention.  Goldsmith, like Farquhar and Steele, vaguely realized the superiority of humour to wit; but he died too early to exercise much influence on his successors.  In Sheridan the convention of wit reasserted itself triumphantly, and the scene in which Lady Teazle, Mrs. Candour, and the rest of the scandalous college sit in a semicircle and cap malicious similes, came to be regarded as an unapproachable model of comedy dialogue.  The convention maintained itself firmly down to the days of Money and London Assurance, the dullness of the intervening period being due, not to any change of theory, but to sheer impotence of practice.  T.W.  Robertson, as above mentioned, attempted a return to nature, with occasional and very partial success; but wit, with a dash of fanciful sentiment, reasserted itself in James Albery; while in H.J.