In general the drama has certain limitations which must be taken into account before passing judgment upon a play. Three hours is the utmost duration for a play; it must 'get across' within that period, since an audience becomes wearied during the third hour. It appeals to two senses, hearing and sight, while other forms of literature appeal but to one. This is an advantage as far as it enables the dramatist to tell his story by scenery and action as well as by speech and incidental music. It is a handicap when the action or the scenery is faulty and distracts the attention of the audience from the dialogue. Descriptions of any length, the study or analysis of personality, all features of ordinary fiction which delay the action are impossible on the stage. Speech and action must be fitted together so as to carry the plot through without pause, revealing the story forcibly, clearly, and yet naturally, within the restricted time. These limitations have been handled in widely varying manners: three systems of presentation have been employed, the ancient, the medieval, and the modern, all of which are to be seen at the present day, thanks to the revival of Greek plays in the stadiums and amphitheaters of our colleges and likewise to the revival of the Elizabethan drama during the past ten years. The ancient or Greek drama was presented in a stone amphitheater against a background of marble, constructed in the form of a palace or temple; the semicircular space occupied by the orchestra seats in our theaters contained an altar in the center and was used by the actors as a part of the stage; the chorus in particular used this space for their stately dances and stood at one side during the progress of the action, commenting on the course of events in odes which they chanted. The lack of movable scenery, and other limitations, resulted in the restrictions known as =the three 'unities,'= of action, time, and place. No play, according to =the unity of action=, should introduce incidents that were not a part of the main action; the plot must be absolutely simple. Thus the story of Jessica and Lorenzo, in "The Merchant of Venice" would be barred by this convention, as it does not contribute to the development of the main story of Antonio and Shylock. The =unity of time= required that the action should not represent the occurrences of more than a day at the very outside, and the =unity of place= held the action to one spot. These latter conventions were to increase the impression of truth and actuality on the minds of the spectators, heightening the effect of complete naturalness and leaving their imaginations free to grasp the problems of the plot without the additional effort of supposing lapses of time and changes of scene to have occurred. The number of actors was small; usually two, or at most three, were permitted to take part at one time in a portion of the dialogue. These conventions produce a simplicity that was not bare and dull,