A woman goes to the dentist for a toothache and is given gas. On her way home on the subway she can't stop laughing, and every other passenger catches the laughter from her.
Overview：A woman goes to the dentist for a toothache and is given gas. On her way home on the subway she can't stop laughing, and every other passenger catches the laughter from her.
![Laughing Gas (1907) Edison [incomplete]](https://i.ytimg.com/vi/0YCqkam_MX4/hqdefault.jpg)
