We set off in early September, hacking and heaving our bags through the entangled bank of Waverley Station. The rectangular light of the Edinburgh-Glasgow train door beckons us through the buzz of flesh and bone.  PLEASE TAKE CARE, WHEN ALIGHTING FROM THIS TRAIN. I bustle past a small boy, a frail couple, and a beef-tub with a red mohawk, who by far gives me the biggest appraisal. Darwinism in...