The pre-coder Night Nurse has quite a cynical subtext that questions not only medical ethics but the 'good-time' moral apathy of big city life.
Medical and other ethics are discussed quite seriously in the first half in the banter between Barbara Stanwyck's Lora and the bootlegger when she patches him up and doesn't report the gun-shot wound. In the second half Lora is the only one with principles strong enough to fight for the kid's in her care. Even Joan Blondell's nurse Maloney who shares the care of the kids is prepared to let things ride, as is Lora's doctor mentor, until pushed to become involved by Lora's insistence that something must be done. The dipsomaniac mother is not only a lush but morally bankrupt, and has quite a few gowned women and tuxedo-ed men cavorting with her in her nightly bacchanals.
With the bootlegger's help the kid's are saved, but with disturbing irony, Lora is at the end happy to hook up with him despite her earlier insistence that he give up his 'career', and despite having a pretty good idea of the chauffeur's fate. Indeed, we find out about the meting out of this rough justice in a final comic scene where the bootlegger steers his car one-armed - the other arm is wrapped around Lorna - while Lorna shifts gear. Twice she jumps the car in reverse and hits the car behind played as slapstick. But her moral backsliding is not so funny.
Director William Wellman has hoodwinked us into laughing at an irreverent amoral conspiracy.
Great cinema and an unflinching critique of the zeitgeist.