The Native Americans had a different understanding of blood and its properties compared to the Europeans. They believed that there were two different types of blood – “hot” and “cold” – and that these types of blood could affect a person’s health and temperament.

When the Europeans arrived in North America, they were initially skeptical of the Native American’s beliefs about blood. However, during the smallpox epidemic in the 18th century, Native Americans demonstrated that they had developed immunity to the disease, while the Europeans were dying in large numbers.

The Native Americans explained that they had achieved immunity through a process called variolation, which involved taking small amounts of smallpox-infected material and introducing it into a healthy person’s body through a small cut. The Europeans were skeptical of this practice, but they soon realized that it was effective.

Through their interactions with the Native Americans, the Europeans learned about the two blood systems and the importance of variolation in preventing the spread of disease. This knowledge eventually led to the development of the smallpox vaccine, which has saved countless lives over the years.