A duration of a hundred years provides a certain stability. The century mark offers a point of rest, wherein we can pause, look back on past accomplishments, evaluate them, and look forward to the future. We may make a comparison, perhaps, with climbing a mountain and coming to a clearing. Here we can stop for a moment of retrospection and feel pleased that we have overcome so many difficulties. At the same time, on looking back, we see where we might have missed the best path and, moreover, the shape of the terrain that led us astray. We can also look upward toward an ever receding summit that we know we will never reach.
The historian, dealing with the past, describes the way that the past has brought us to where we are now. And for the historian, a century is like a cleared space part way up the mountain—a
King LS. I. The British Background for American Medicine. JAMA. 1982;248(2):217-220. doi:10.1001/jama.1982.03330020061032