Edward Jenner (1749-1823), British physician and naturalist inoculating his son. Jenner is famed for developing a vaccine for the often fatal viral infection, smallpox. He investigated folk tales about the immunity of cowpox victims to smallpox. In 1796 he used a thorn to inoculate a healthy boy with fluid from a cowpox blister on a dairy maid's finger. Six weeks later he inoculated the boy with smallpox, and the boy did not develop the disease. The immunising process was named vaccination after the cowpox virus (vaccinia), and was made compulsory in Britain in 1853. Smallpox was declared extinct outside laboratories in 1980. Image taken from Heroes of Britain in Peace and War, circa 1897.