Feel the heat: a short history of body temperature

Before the 16th century, patients’ temperatures could be monitored only by placing the hand on the forehead, cheek. or other body surface. The process took a scientific turn in 1592, when Galileo invented a primitive (air) thermometer during his tenure at the University of Padua in Italy.1 However, it was not until Carl Wunderlich published his magnum opus, Das Verhalten der Eigenwärme in Krankheiten (The Course of Temperature in Diseases)2 in 1868, that clinical thermometry reached the sophistication and importance it now enjoys among both the medical profession and the public.3

Das Verhalten is remarkable for its content, clarity, and, perhaps most particularly, longevity. Wunderlich gave 37°C its special importance as the reference temperature in humans; demonstrated diurnal variation of body temperature; and established that “normal …