The world of 18th century chemistry was a bit of a cluster fuck in that it was not so much a science as much as just mixing together whatever chemicals one had lying around to see what happened. Many of these early discoveries often involved burning one’s eyebrows off, or worse. This was probably why in 1772 an English chemist named Joe Priestly was probably rather pleased at the result of his sticking iron filings in nitric acid. The resulting gas not only didn't burn his face off, it also made Joe feel giddy to the point that he started laughing uncontrollably like an idiot. Being a man of science, he of course repeated his experiment numerous times to verify his results, which he then wrote about in a paper which mostly went on about the gas' possible use as a medical painkiller for surgeries and the such, because even back then scientists who wrote about discoveries that got you high as shit got little to no respect. In the scientific literature the gas became known as nitrous oxide, but everyone else called it laughing gas.
For the next twenty years or so scientists continued to experiment with laughing gas based on the claim that it could "totally be used for medicine man". However, the only result of these experiments were some extremely giggly scientists. This eventually led to one enterprising young man, a laughing gas aficionado by the name of Humphrey Davy, inventing a large machine that could produce enough nitrous oxide for anyone to huff to their heart’s content. He was pretty much that guy you knew in college who built a bong out of an old vacuum hose and a pineapple. Being a man of science, Humphrey of course wrote about his machine’s possible use in medicine. However, he pretty much only used it when he invited over large numbers of friends for giggle parties. Humphrey later became one of England’s top scientists.
The art of getting high on laughing gas just kind of took off from there. What started as a way for Humphrey to convince girls that he was cool, soon blew up into the latest craze for the bored upper class. After all, why should they wile away their days worrying about big piles of money and poor people learning to read when instead they could spend all their time laughing for absolutely no reason whatsoever? Eventually, as always happens with such things, the middle class noticed the stupid thing the rich were doing, and rather than rolling their eyes at the frivolities of their so-called social betters, instead demanded to get in on the action. As a result, a whole industry was born, with countless laughing gas peddlers making their way across Europe and North America throughout the early 19th century. They were pretty much the ice cream men of their day, selling a hit of laughing gas for what amounted to a couple of bucks in today’s money. One of the more famous of these laughing gas peddlers was Samuel Colt, who later became rich and famous for inventing guns that made killing people much easier and more convenient, but that’s not important to this story. What is important is the fact that everyone getting high on laughing gas pretty much killed any interest in using it as any type of medicine.
Things continued this way until 1844, when an American dentist named Horace Wells noticed that some random guy high as shit on laughing gas didn't curse or shout when he banged the crap out of his leg on a bench. Dentistry back then mostly involved getting patients drunk off their ass or having a bunch of big guys holding them down, both of which often led to the dentist getting punched in the face. Not really liking a good sock to the mouth, Horace decided to try laughing gas on his patients, which lo and behold, worked like a charm. Believing himself to be on the cusp of greatness, Horace decided to show off his discovery at the nearby medical college. Unfortunately, it did not go well, probably because medical students are complete jackasses. Horace was jeered off the stage. As a result of the ridicule, his dental practice soon after collapsed, which eventually led to him losing his mind, throwing acid on two prostitutes, and slitting his own throat with a razor.
Somewhat deterred, it took another twenty years for any other dentists to try using nitrous oxide again. However, once the ball got rolling, within a decade it became common practice throughout both the dental and medical industries. In fact, nitrous oxide became so popular that for a time snake oil salesman pushed it as a cure all. Oh, but don’t you worry, even today people still use it to get high as shit.
Image: https://en.m.wikipedia.org/wiki/File:A_man_breathing_in_nitrous_oxide_(laughing_gas)_and_a_man_ex_Wellcome_L0023721.jpg