and Sinful Practice of Inoculation", the English theologian Reverend Edmund Massey argued that diseases are sent by God to punish sin and that any attempt to prevent smallpox via inoculation is a "diabolical operation". It was customary at the time for popular preachers to publish sermons, which reached a wide audience. This was the case with Massey, whose sermon reached North America, where there was early religious opposition, particularly by John Williams. A greater source of opposition there was William Douglass, a medical graduate of Edinburgh University and a Fellow of the Royal Society, who had settled in Boston. Smallpox vaccination After Edward Jenner introduced the smallpox vaccine in 1798, variolation declined and was banned in some countries. As with variolation, there was some religious opposition to vaccination, although this was balanced to some extent by support from clergymen, such as Reverend Robert Ferryman, a friend of Jenner's, and Rowland Hill, who not only preached in its favour but also performed vaccination themselves. There was also opposition from some variolators who saw the loss of a lucrative monopoly. William Rowley published illustrations of deformities allegedly produced by vaccination, lampooned in James Gillray's famous caricature depicted on this page, and Benjamin Moseley likened cowpox to syphilis, starting a controversy that would last into the 20th century. There was legitimate concern from supporters of vaccination about its safety and efficacy, but this was overshadowed by general condemnation, particularly when legislation started to introduce compulsory vaccination. The reason for this was that vaccination was introduced before laboratory methods were developed to control its production and account for its failures. Vaccine was maintained initially through arm-to-arm transfer and later through production on the skin of animals, and bacteriological sterility was impossible. Further, identification methods for potential pathogens were not available until the late 19th to early 20th century. Diseases later shown to be caused by contaminated vaccine included erysipelas, tuberculosis, tetanus, and syphilis. This last, though rareestimated at 750 cases in 100 million vaccinationsattracted particular attention. Much later, Charles Creighton, a leading medical opponent of vaccination, claimed that the vaccine itself was a cause of syphilis and devoted a book to the subject. As cases of smallpox started to occur in those who had been vaccinated earlier, supporters of vaccination pointed out that these were usually very mild and occurred years after the vaccination. In turn, opponents of vaccination pointed out that this contradicted