For a brief period of time in the 19th century, doctors used "mesmerism" for pain-free surgery.
In 1881, Prudential announced that insurance policies held by black adults would be worth one-third less than the same plans held by whites.
During the Korean War, North Korea suffered widespread epidemics of typhus and smallpox. The Communist party blamed U.S. germ warfare.
Decades after Charles Knowlton died, his book would be credited with the reversal of population growth in England and the popularization of contraception in the United States.