The Friday File: In 1851, scientists established body temperature at 98.6 degrees. After reexamining almost 700,000 temperature readings since 1840, researchers find body temperature has been steadily falling by 1/20 of a degree per birth decade. After accounting for measurement error and improved thermometry, the reason is reduced population-level inflammation; heat is a symptom of inflammation. Improving health, quicker illness detection and better interventions including antibiotics and steroids are why.