Cowpox children. In 1796, British medical practitioner Edward Jenner tested the theory that cowpox could protect someone from being infected by smallpox. Although cowpox originates on the udder of cows, Jenner took his sample from a milkmaid, Sarah Nelmes. Jenner extracted the pus of one of the lesions formed by cowpox on Nelmes to another individual who never had smallpox, James Phipps. He eventually developed a scab and fever that was manageable. Approximately six weeks later, Jenner then introduced an active sample of the smallpox virus into Phipps to test the theory. After being observed for an extended amount of time,
Sir William Jenner, 1st Baronet Sir William Jenner, 1st Baronet Sir William Jenner, 1st Baronet, GCB, QHP, FRCP, FRS (30 January 1815 – 11 December 1898) was a significant English physician primarily known for having discovered the distinction between typhus and typhoid. Jenner was born at Chatham on 30 January 1815, and educated at University College London. He became a Member of the Royal College of Surgeons of England (M.R.C.S.) in 1837, a Fellow of the Royal College of Physicians (F.R.C.P.) in 1852, and in 1844 took the London M.D. In 1847 he began at the London Fever Hospital investigations into cases of continued fever