An anonymous observer wrote that it "doesn't complain about the condition of the weather, seeks no 'social security' and never asks for a vacation.  It will work best when treated well, but will do its utmost to give good service when working conditions are unduly taxing its strength."  No, it isn't your dog--man's best friend--who sits by the gate and awaits your arrival with wagging tail.  It is your heart, located six inches below your collarbone slightly off-center on the left side of your body.