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
Mozart and smallpox reached European countries. Inoculation was not the same as the vaccination which later succeeded in eradicating the disease; rather, an inoculated person was treated with live smallpox virus, taken from pustules of the mildest variety of smallpox that could be found. Inoculation offered immunity to smallpox, but the procedure carried a definite risk that the inoculated person could die from smallpox as a result. Thus, many parents felt that they would rather do nothing, risking future smallpox arriving at random, rather than carry out a deliberate act that might well kill their children immediately. As Mozart biographer Ruth Halliwell points