The numerical determination of the relationship between the sanitary conditions in which people live, and the risks to health and life this may involve is a relatively new method of understanding infectious disease. It came to be known as “sanitary statistics” in the early nineteenth century, when this kind of investigation reached the climax of its social importance. But its roots go back to the late seventeenth century, when England was again visited by the plague, shattering a country that had hardly recovered from two decades of civil unrest. The two basic motives of sanitary statistics, which later made it so potent a reformist tool, were already present then in a first outline, namely the attempt to rationalize the frightful phenomenon of the epidemic and the conviction that its causes were somehow bound up with the social organization of urban life. As long as people had seen in the great epidemics God's punishing hand, the flagellants' reaction made sense. Man could only bow to Him; the arm of flesh might at most seek to avoid His punishment by punishing itself in advance. But when in 1854 the Presbytery of Edinburgh suggested to the Home Secretary, Lord Palmerston, to call for a national fast against cholera, they received the cold reply that “the weal or woe of mankind
depends on the observance or neglect of those laws” which sanitary statistics had recently discovered. Divine reference was replaced by statistical reference, and the correlations thus revealed pointed to action by the “arm of flesh”.