Rise of Morden Health

Before the rise of modern medicine, disease was attributed to a variety of spiritual or mechanical forces. It was interpreted as a punishment by God for sinful behaviour or the result of an imbalance in body elements or ‘humours’. Many infectious diseases were ascribed to a life of vice or a weak moral character or believed to be due to ‘miasma’, that is, bad air arising out of dirt and decaying organic matter. The ancient Greeks rejected the notion that disease was a punishment for sin or the consequence of witchcraft and saw disease as being related to the natural environment or the way in which human populations lived and worked. However, they failed to recognize that many diseases were contagious. The idea that disease could be passed from person to person arose in the Middle Ages and coexisted with the belief that disease was linked to evil behaviour. For example, by the mid-nineteenth century there was good evidence that cholera could be transmitted by close personal contact with a cholera victim. The observation that outbreaks occurred at great distances from existing cases led to the idea that the disease could also be transmitted in the water supply. John Snow, a physician who investigated the London cholera epidemics of 1848–9 and 1853–4, provided convincing evidence that the disease was spread by water contaminated by the excretions of cholera victims. While this provided a means to control epidemics of the disease it was not for another 40 years that the organism causing cholera was identified. However, Snow’s work did illustrate the important principle that epidemics of disease could be controlled without knowing the biological mechanisms involved.