Jenner (1749-1823), an English doctor and pupil of John Hunter, introduced fluid from a cowpox sore through a person's skin, in order to inoculate them against smallpox, a similar but more dangerous disease. He called his method 'vaccination' from 'vacca', the Latin word for cow. Although his discovery predated any scientific explanation, his research, published as 'Inquiry into the Cause and Effects of Variolae Vaccinae [cowpox]' in 1798, showed that using fluid from a human with cowpox was safer than variolation; inoculating non-infected people with fluid from pustules of smallpox. The 1853 Vaccination Act heralded an era of compulsory vaccination against smallpox.
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