<span>Edward Jenner discovered a vaccination against [smallpox] by infecting a boy with [cowpox]. He noticed that milkmaids who got cowpox never got smallpox and developed his theory from there. He is the father of the study of immunity and immunisation.</span>
Explanation: a system of alternative medicine based on the theory that diseases can be successfully treated or prevented without the use of drugs, by techniques such as control of diet, exercise, and massage.
