reached by walking have value.’1 In a similar spirit, the writer Henry David Thoreau observed that the moment my legs begin to move, my thoughts begin to flow, as if I had given vent to the stream at the lower end and consequently new fountains flowed into it at the upper. A thousand rills which have their rise in the sources of thought burst forth and fertilize my brain . . . Only while we are in action is the circulation perfect. The writing which consists with habitual sitting is mechanical, wooden, dull to read.
