©Wellcome Library, London

Pavlov considered that his vagotomised dogs functioned ‘with complete success' despite the fact that they could ‘no longer eat by themselves and digest their food adequately'. In addition, their health could be maintained ‘only on condition of a life artificially simplified, with a bland and tranquil regime' perpetually controlled by the experimenters. Until the 20th century, the reality of artificially controlled human life did not exist but as it became possible, the concept of ‘quality of life' emerged. Quality of life considered existence in terms of its value to an individual. Many people came to believe that existence for its own sake was, in fact, dehumanising.

Photograph, 1904.