2Do not mistake these multiple trends--the energy flows of metropolitan growth, the new taste for tea, the nascent, half-formed awareness of mass behavior--for mere historical background. The clash of microbe and man that played out on Broad Street for ten days in 1854 was itself partly a consequence of each of these trends, though the chains of cause and effect played out on different scales of experience, both temporal and spatial. You can tell the story of the Broad Street outbreak on the scale of a few human human lives, people drinking water from the a pump, getting sick and dying over a few weeks, but in telling the story that way, you limit its perspective, limits its ability to convey a fair account of what really happened. Once you get to the , the story has to widen and tighten at the same time: to the long of urban development, or the microscopic tight focus of bacterial life cycles, These are causes, too.