To be natural on the stage is most difficult, and yet a grain of nature is worth a bushel of artifice.  But you may say—­what is nature?  I quoted just now Shakespeare’s definition of the actor’s art.  After the exhortation to hold the mirror up to nature, he adds the pregnant warning:  “This overdone or come tardy off, though it make the unskilful laugh, cannot but make the judicious grieve, the censure of which one must in your allowance o’erweigh a whole theatre of others.”  Nature may be overdone by triviality in conditions that demand exaltation; for instance, Hamlet’s first address to the Ghost lifts his disposition to an altitude far beyond the ordinary reaches of our souls, and his manner of speech should be adapted to this sentiment.  But such exaltation of utterance is wholly out of place in the purely colloquial scene with the Gravedigger.  When Macbeth says, “Go, bid thy mistress, when my drink is ready, she strike upon the bell,” he would not use the tone of

    “Pity, like a naked new-born babe,
    Striding the blast, or Heaven’s cherubim, horsed
    Upon the sightless couriers of the air,
    Shall blow the horrid deed in every eye,
    That tears shall drown the wind.”

Like the practised orator, the actor rises and descends with his sentiment, and cannot always be in a fine phrenzy.  This variety is especially necessary in Shakespeare, whose work is essentially different from the classic drama, because it presents every mood of mind and form of speech, commonplace or exalted, as character and situation dictate:  whereas in such a play as Addison’s Cato, everybody is consistently eloquent about everything.

There are many causes for the growth of naturalism in dramatic art, and amongst them we should remember the improvement in the mechanism of the stage.  For instance, there has been a remarkable development in stage-lighting.  In old pictures you will observe the actors constantly standing in a line, because the oil-lamps of those days gave such an indifferent illumination that everybody tried to get into what was called the focus—­the “blaze of publicity” furnished by the “float” or footlights.  The importance of this is illustrated by an amusing story of Edmund Kean, who one night played Othello with more than his usual intensity.  An admirer who met him in the street next day was loud in his congratulations:  “I really thought you would have choked Iago, Mr. Kean—­you seemed so tremendously in earnest.”  “In earnest!” said the tragedian, “I should think so!  Hang the fellow, he was trying to keep me out of the focus.”