Virology in order to immunize others. In 1717 Lady Mary Wortley Montagu observed the practice in Istanbul and attempted to popularize it in Britain, but encountered considerable resistance. In 1796 Edward Jenner developed a much safer method, using cowpox to successfully immunize a young boy against smallpox, and this practice was widely adopted. Vaccinations against other viral diseases followed, including the successful rabies vaccination by Louis Pasteur in 1886. The nature of viruses however was not clear to these researchers. In 1892, the Russian biologist Dmitry Ivanovsky used a Chamberland filter to try to isolate the bacteria that caused tobacco mosaic
1837 Great Plains smallpox epidemic experienced a major smallpox epidemic in 1780-81 which severely reduced their numbers down to less than a few thousand. Many other bands along the Missouri river suffered smallpox epidemics during 1801-02 and 1831. Sporadic efforts were made to promote vaccination among the Indigenous peoples since the turn of the nineteenth century. Later, the Indian Removal Act the U.S. Congress took its first step in 1832 to generate public support for vaccination of the Native Americans. But shortly after passage of this congressional act to extend vaccinations to Indians, Secretary Cass stated that no effort would be made "under any circumstances"