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When Gabriel Fahrenheit invented the first mercury thermometer, he called "zero degrees" the lowest temperature he was able to attain with a mixture of ice and salt. For the upper point of his scale, he used 96°, which he measured as normal human body temperature (we know it to be 98.6° today because of more accurate thermometers).
Blood is approximately twice as thick as water because of the cells and other components found in it.
About 100 new prescription or over-the-counter drugs come into the U.S. market every year.
Most childhood vaccines are 90–99% effective in preventing disease. Side effects are rarely serious.
Calcitonin is a naturally occurring hormone. In women who are at least 5 years beyond menopause, it slows bone loss and increases spinal bone density.