Hairy cell leukemia (HCL) 1  Is a type of blood cancer that begins in the bone marrow. 2  Is a rare type of leukemia in adults.  Hairy cell leukemia gets its name from the short, thin projections that look like hair on its cells.
In 1799 Humphrey Davy discovered anesthetic properties of nitrous oxide (N20)---also known as laughing gas.. He had recently joined Thomas Beddoesâ Pneumatic Institution (established 1798) for treatment of disease by inhalation.
Doctor using a sphygmomanometer to measure a patientâs blood pressure.Â© AVAVA/Shutterstock.com. The first clinically applicable sphygmomanometer was invented in 1881 by Austrian physician Karl Samuel Ritter von Basch. Von Basch introduced the aneroid manometer, which uses a round dial that provides a pressure reading. The pressure is indicated by a needle, which is deflected by air from an inflation device (e.g., a diaphragm or Bourdon tube).