A melodrama (melo-drama), it is worth remembering, was originally any sort of spoken word drama with background instrumental and vocal music off.
By 'off', I mean the music comes from no one visible in the drama in the role of a singer or musician, providing both the music and being part of the spoken word drama itself.
Instead the music source is either totally invisible (and in fact inaudible to the actors) or it comes in quietly, from a distant and almost invisible source -- one (barely) audible to the actors because while it is contained within the world of the drama it is not really a part of the main stage interaction.
(Exactly the way all non-musical film and television dramas are 'scored' since they began, in fact.)
If in the original melo-drama sometimes the heightened speech, at moments of very strong emotion, sounded a lot like a sort of stage talk-singing set against the background music (off), that effect was deliberate - the whole point of having the Background music on constant standby.
New York City during WWII was living at the very height of the Golden Age of Radio, a time well before TV or the Internet.
All of NYC's workplaces seemed to have someone with very dear relatives in the war zone, so it was natural that all those workplaces also had half hidden/barely audible cheap little table sets, tuned to a big station with great overseas news correspondents (and great music).
The moment a news flash came along, up went the volume and the whole workplace strained to hear the glad or grim news.
The rest of the time, those little radios functioned as a constant quiet backdrop to the wartime dramas of high tension and high emotion also going on in those workplaces ---- as well as overseas.
One can argue - indeed I do argue - that the intense drama going on in a little lab, office and ward at Columbia-Presbyterian's Floor G during the war had at least as big an impact on all ten billion of us since 1940 as anything FDR or Hitler ever did.
There the dying Dr Dawson's tiny team, pursuing his vision of "Natural penicillin for All ", fueled by Agape love and powered by 4Fs, Women and the Grace of God, defied their own bodies and their own Allied governments to deliver one of humanity's greatest ever boons.
Yes they all got very emotional --- for they were always dealing with life and death, on both the intimate personal level and the mass international level --- and yes they had quiet little clandestine table radios on in the background.
So, 'a hospital drama with radio music' that rather like the famous "Little Red Lighthouse", just down the hill from Floor G, proved a bright beacon of hope to a world in trouble.
And in its totally massive and unexpected success, well beyond even Dawson's wildest hopes, it proved a textbook example for our postwar era of the hope that the ethos of Emergent Modernity can bring to our troubled world....