In 1885 a country doctor in Pennsylvania heard a 16-year-old pneumonia patient say, “Doctor, if you don’t give me something to breathe, I’m going to stop.”
The doctor, George E. Holtzapple, who was also a chemist, as a hobby, decided that what the patient needed was oxygen, so he went and got some chlorate of potassium and black oxide of manganese, and “conducted the gas to the bottom of a bucket filled with water beside the patient’s bed.”
In short, it worked. One of the patients later saved by this technique was George’s sister Mary.
She remarked, “My brother always was a clever boy.”
I found this Rick Bromer story in Old News, a fantastic publication for those interested in history.