Immunization against Smallpox before Jenner
Long before he introduced inoculation with cowpox, smallpox was prevented by inoculation with smallpox itself. The procedure was risky, but its spread in the 18th century set the stage for Jenner
Checks on Population Growth: 1750-1850
In this period the population of Europe nearly doubled, but without certain checks it would have grown even more. There is much evidence that the checks were the widespread practice of celibacy and infanticide
The Black Death
The plague that killed a quarter of the people of Europe in the years 1348–1350 is still studied to shed light on human behavior under conditions of universal catastrophe