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.
As shown in the picture of the aneroid barometer, this instrument relies on a sealed, flexible unit which contains air at a fixed volume. As the atmospheric air pressure changes, this membrane expands and contracts, altering the position of a needle on the barometer. Mercury barometers use an evacuated tube, and Mercury rises or falls within this tube as the atmospheric pressure changes, pushing the Mercury higher or lower in the tube.