1. The Musical Elements
Technically known as a girl-act, and booked by managers who wish a "flash"—a big effect—the one-act musical comedy naturally puts its best foot foremost as soon as the curtain rises. And, equally of course, it builds up its effects into a concluding best-foot.
The best-foot of a musical comedy is the ensemble number, in which all the characters—save the principals, sometimes—join in a rousing song. The ensemble is musical comedy, and one-act musical comedy is—let this exaggeration clinch the truth—the ensemble. [1]
[1] Of course, I am discussing the usual musical comedy—the flash of a bill—in pointing out so forcefully the value of the ensemble. There have been some fine one-act musical comedies in which the ensemble was not used at all. Indeed, the musical comedy in one act without any ensemble offers most promising possibilities.
Between the opening and the closing ensembles there is usually one other ensemble number, and sometimes two. And between these three or four ensembles there are usually one or two single numbers—solos by a man or a woman—and a duet, or a trio, or a quartet. These form the musical element of the one-act musical comedy.
2. Scenery and Costumes—The Picture-Elements
While the one-act musical comedy may be played in one set of scenery only, it very often happens that there are two or three different scenes. The act may open in One, as did Joe Hart's "If We Said What We Thought," and then go into Full Stage; or it may open in Full Stage, go into One for a little musical number, and then go back into a different full-stage scene for its finish. It may even be divided into three big scenes—each played in a different set—with two interesting numbers in One, if time permits, or the act be planned to make its appeal by spectacular effects.
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.