A chara, – I am a retired neurosurgical anaesthetist. Twenty years ago our unit did its best for a much-loved fellow triathlete whose head hit the road. The helmet that would probably have saved his life was at home. None of his many friends has got on a bike unprotected since, and several of us have had cause to be grateful. Broken wrists and collarbones are long healed and forgotten, but a brain is a fragile computer in a thin box, and you only have one. – Is mise,