After the Civil War, both advertising and "toilet soap" (i.e., soap for the body) became more prevalent in the United States, says Katherine Ashenburg, author of The Dirt on Clean: An Unsanitized History. "Americans turned out to be much more gullible and susceptible to these things than Europeans," Ashenburg tells BuzzFeed Life.
Then, in the 1920s and '30s, more women entered the workforce and more Americans left their farms to work closely together in factories, leading to another major cultural focus on cleanliness and bathing. This time, it came from business books like Dale Carnegie's How to Win Friends and Influence People and was mainly about success and attractiveness.
"Germ theory didn't matter half as much as promises of beauty," Ashenburg says.