When the two partners are courteous to each other but not too yielding, when they are sympathetic but not too much alike in their characteristics and qualifications, when each of them supplements the weaker points of the other, then collaboration ought to result in plays of more variety of invention, and of more ingenuity of construction than is likely to be possessed by the average play due to a single mind. This much must be admitted; and it is the final justification for collaboration. But altho these partnerships in play-making spread abroad a knowledge of the principles of the art, and altho they raise the probable value of the average play, it must be admitted also, and with equal frankness, that the possibilities of collaboration are sharply limited. No single one of the mightiest masterpieces of dramatic literature, ancient and modern, is to be credited to collaboration; and the only possible exception to this sweeping statement would be urged by the critics who hold that the 'Gendre de M. Poirier' of Augier and Sandeau is the masterpiece of French comedy in the nineteenth century. Those who have climbed to the loftiest height of dramatic art have always done so alone, sustained by enthusiasm and supported by imagination. In spite of the greater "richness of purview, consideration, and invention" that collaboration undoubtedly bestows, the man of surpassing genius, the great master of the drama, Sophocles or Shakspere or Molière, works best alone. It is true that he may now and again take to himself an ally, as Shakspere condescended to the assistance of Fletcher in 'Henry VIII,' and as Molière invoked the aid of Corneille in 'Psyché,' but it is true also that these plays, written in collaboration by Shakspere and by Molière, are not the plays which establish and confirm their fame. Indeed, these plays are not even among the more important pieces of Shakspere and Molière, and the reputation of the authors would be no lower if these plays had never come into existence. It is by the comedies and tragedies which Shakspere wrote alone that the Elizabethan stage is made glorious, and not by the dramatic romances that go under the joint names of Beaumont and Fletcher. It is by the lyrical melodramas of which Victor Hugo was sole author that we recall the Romanticist revolt in the French theater in 1830, and immediately thereafter, and not by the perfervidly passionate pieces that the elder Dumas put together in partnership with a group of now-forgotten auxiliaries. It is by the comedies that Augier and the younger Dumas wrote, each of them expressing himself in his own fashion, that the drama of France is illumined a score or more years later, and not by the comedies in the composition of which Scribe had the aid of an army of allies.