Robert Boyle, the renowned scientist, has been largely forgotten in the usual histories of medicine despite the fact that he was, according to Michael Hunter, “arguably the most influential figure in the emerging culture of late seventeenth century Britain” and the main patron of the Scientific Revolution in England (Figure 5.1). Boyle is of particular interest for us because, during his entire active life as a scientist, he was unhealthy. Until recently his poor health has been ignored, as has the diversity of his interests. He is emerging as an important, powerful, early medical scientist who was also a patient. He, more than most other figures during the Scientific Revolution, brought together the Cartesian rationalist picture of the body as a machine with the more experimental Paracelsian view of the chemical nature of the body. After Boyle, the scientific understanding of the mechanical patient became the objective of medical research.