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More than 2,500 barbiturates have been synthesized. At the height of their popularity, about 50 were marketed for human use.
There are 20 feet of blood vessels in each square inch of human skin.
There used to be a metric calendar, as well as metric clocks. The metric calendar, or "French Republican Calendar" divided the year into 12 months, but each month was divided into three 10-day weeks. Each day had 10 decimal hours. Each hour had 100 decimal minutes. Due to lack of popularity, the metric clocks and calendars were ended in 1795, three years after they had been first marketed.
Blood in the urine can be a sign of a kidney stone, glomerulonephritis, or other kidney problems.
There are more sensory neurons in the tongue than in any other part of the body.
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