|
|
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.
Pubic lice (crabs) are usually spread through sexual contact. You cannot catch them by using a public toilet.
Bacteria have flourished on the earth for over three billion years. They were the first life forms on the planet.
Human stomach acid is strong enough to dissolve small pieces of metal such as razor blades or staples.
Throughout history, plants containing cardiac steroids have been used as heart drugs and as poisons (e.g., in arrows used in combat), emetics, and diuretics.