. Soon, to avoid confusion, smallpox inoculation continued to be referred to as "variolation" (from variola = smallpox) and cowpox inoculation was referred to as "vaccination" (from Jenner's use of "variolae vaccinae" = smallpox of the cow). Then, in 1891 Louis Pasteur proposed that the terms vaccine and vaccination should be extended to include the new protective procedures being developed