The drug sulfapyridine depicted in this film was one of the first antibiotics. Discovered by the British firm May & Baker in 1937, it was first sold in 1939. Its powdered form was often applied directly to wounds during WWII.
The poison that was mixed into the antibiotic, according to the chemical formula on the tin's label, is disodium hydrogen arsenate - a form of arsenic.
Milburn Stone, seen here as Fredericks, would later play a pivotal role in one of television's longest-running hits: He was "Doc" in Gunsmoke.
The bad guys drive a 1939 Buick Sedan. The Buick has the extremely rarely-seen optional Twin Sidemounts (spare tires in the front fenders.) This was the last year Buick offered twin sidemounts.
The last of three "Crime Does Not Pay" shorts in which Charles D. Brown is cast as a supposedly-actual law enforcement official.