Sol Horwitz, the father of Moe, Shemp, and Curly, appears as a street onlooker in the scene near the end where the Stooges crash their gurney into the car; he's the stocky man with mustache and glasses, wearing a fedora. He's also in the courtroom audience in Disorder in the Court (1936), a spectator in Grips, Grunts and Groans (1937), a pedestrian in False Alarms (1936), and a man in the crowd in Half Shot Shooters (1936). Solomon and his wife Jenny were in town visiting their famous sons, and Sol was given these small parts when he visited the boys on the set. Moe later said that his dad was "kind of a ham" and enjoyed being in the films.
A production still shows June Gittelson, Eva Murray and Elaine Waters as the wives. However, the roles were recast: Gittelson remained, but Murray and Waters were replaced by Blanche Payson and Ione Leslie.
When the Stooges are "broadcasting" on the hospital PA system, the say that Brighto comes in six delicious flavors. This is a reference to the Jack Benny radio program, which was sponsored by Jello. The shows often incorporated clever methods to include the "six delicious flavors".
The set for "Los Arms Hospital" is the same one used by the Stooges in the earlier Men in Black (1934).
The boys have an "Tattoo Intermittent" alarm clock from the New Haven Clock Company. Obviously an alarm clock has little to no relation to skin ink. In this case, "tattoo" is used in the military sense of a bugle or drum call to soldiers.