The Smallpox Vaccine
On May 14, 1796, Edward Jenner inoculated an 8-year old boy named James Phipps with cowpox. The cowpox matter came from a milkmaid named Sarah Nelms. Phipps would lose his appetite and grow cold 9 days later, but took a positive turn the next day eventually recovering. Later on, in July 1796, Jenner inoculated Phipps once again, this time with matter from a smallpox lesion. Phipps did not develop smallpox in this subsequent inoculation, leading Jenner to conclude that Phipps was fully protected. For this experiment, Jenner is widely credited as the inventor of the modern vaccine, though inoculations had been done in a similar fashion before Jenner.