A brief history of the clinical thermometer

Of the many tools and instruments regarded as essential to the clinical examination, none has had such widespread application as the clinical thermometer. In the time of Hippocrates, only the hand was used to detect the heat or cold of the human body, although fever and chills were known as signs of morbid processes. In Alexandrine medicine, the pulse was observed as an index of disease, superseding the crude assessment of temperature. In the Middle Ages, the four humours were assigned the qualities of hot, cold, dry and moist, and thus fever again acquired importance. Galileo in 1592 devised a crude temperature‐measuring instrument, but it had no scale and therefore no numerical readings; further, it was affected by atmospheric pressure. A large step forward was achieved by Santorio (Sanctorio Sanctorius) who invented a mouth thermometer. Santorio …