Very often, as in Lasky’s “A Night on a Houseboat,” a big set-piece or a trick scene is used to give an effect of difference, although the entire act is played without dropping a curtain.

To sum up the idea behind the use of musical comedy scenery:  it is designed to present an effect of bigness—­to make the audience feel they are viewing a “production.”

The same thought is behind the continual costume changes which are an integral part of the one-act musical comedy effect.  For each ensemble number the girls’ costumes are changed.  If there are three ensembles there are three costumes, and four changes if there are four ensembles.  Needless to say, it sometimes keeps the girls hustling every minute the act is in progress, changing from one costume to another, and taking that one off to don a third or a fourth.

The result in spectacular effect is as though a scene were changed every time an ensemble number is sung.  Furthermore, the lights are so contrived as to add to this effect of difference, and the combination of different colors playing over different costumes, moving about in different sets, forms an ever-changing picture delightfully pleasing and big.

Now, as the musical comedy depends for its appeal upon musical volume, numbers of people, sometimes shifting scenery, a kaleidoscopic effect of pretty girls in ever changing costumes and dancing about to catchy music, it does not have to lean upon a fascinating plot or brilliant dialogue, in order to succeed.  But of course, as we shall see, a good story and funny dialogue make a good musical comedy better.

3.  The Element of Plot

If your memory and my recollection of numerous musical comedies of both the one-act and the longer production of the legitimate stage are to be trusted, a plot is something not vital to the success of a musical comedy.  Indeed, it is actually true that many a musical comedy has failed because the emphasis was placed on plot rather than on a skeleton of a story which showed the larger elements to the best advantage.  Therefore I present the plot element of the average one-act musical comedy thus: 

Whereas the opening and the finish of the playlet are two of its most difficult parts to write, in the musical comedy the beginning and the finish are ready-made to the writer’s hand.  However anxious he may be to introduce a novel twist of plot at the end, the writer is debarred from doing so, because he must finish with an ensemble number where the appeal is made by numbers of people, costumes, pretty girls and music.  At the beginning, however, the writer may be as unconventional as he pleases—­providing he does not take too long to bring on his first ensemble, and so disappoint his audience, who are waiting for the music and the girls.  Therefore the writer must be content to “tag on” his plot to an opening nearly always—­ if not always—­indicated, and to round his plot out into an almost invariably specified ending.