Clinical Fahrenheit thermometer, European, 1870-1901

Clinical thermometers only measure a limited temperature range. This makes them different from ordinary thermometers. There is also a small constriction above the bulb to prevent the mercury dropping back after the temperature has been taken. The typical, small modern pocket type was devised by Sir Clifford Allbutt (1836-1925) in 1867. This European example dates from the late 1800s. It comes in a small plastic carrying case with a screw top lid.