|
|
Bacteria have flourished on the earth for over three billion years. They were the first life forms on the planet.
In most cases, kidneys can recover from almost complete loss of function, such as in acute kidney (renal) failure.
In the ancient and medieval periods, dysentery killed about ? of all babies before they reach 12 months of age. The disease was transferred through contaminated drinking water, because there was no way to adequately dispose of sewage, which contaminated the water.
There are 20 feet of blood vessels in each square inch of human skin.
A cataract is a clouding of the eyes' natural lens. As we age, some clouding of the lens may occur. The first sign of a cataract is usually blurry vision. Although glasses and other visual aids may at first help a person with cataracts, surgery may become inevitable. Cataract surgery is very successful in restoring vision, and it is the most frequently performed surgery in the United States.