Difficult choices as death nears. As the changes described in this article develop in the final days or hours of a progressive terminal illness, difficult choices may arise. There may be questions about whether to provide food and fluids, receive blood transfusions, or treat infections.
The use of mercury in thermometers dates back hundreds of years. It was widely used because it reliably expands and contracts with changes in temperatures. It is highly poisonous, however, and can enter the body through the respiratory or digestive tracts, or directly through the skin.
They include the thermal expansion of solids or liquids with temperature, and the change in pressure of a gas on heating or cooling. Radiation-type thermometers measure the infrared energy emitted by an object, allowing measurement of temperature without contact. Most metals are good conductors of heat and they are solids at room temperature. Mercury is the only one in liquid state at room temperature, and has high coefficient of expansion. Hence, the slightest change in temperature is notable when it's used in a thermometer. This is the reason behind mercury being used in thermometer. Some of the principles of the thermometer were known to Greek philosophers of two thousand years ago.