The massive belief in the curative power of science for all ills is what I find so alluring in the early 20th century posters. They're engaging to me because there's an inherent optimism in many of them!

There was reason to be optimistic!

I know it's the way they talked and thought back then, but so much emphasis on Men of Science, with emphasis on Manliness in those ads. "Men who think", etc. Pretty jarring for recent times.