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,
Edward Jenner of nestling birds in general." Jenner's nephew assisted in the study. He was born on 30 June 1737. Jenner's understanding of the cuckoo's behaviour was not entirely believed until the artist Jemima Blackburn, a keen observer of bird life, saw a blind nestling pushing out a host's egg. Her description and illustration of this were enough to convince Charles Darwin to revise a later edition of "On the Origin of Species". Jenner married Catherine Kingscote (died 1815 from tuberculosis) in March 1788. He might have met her while he and other fellows were experimenting with balloons. Jenner's trial balloon descended