Rick Brummett, age 9, of Deer Park', Wash., for his question:

WHERE DO TEARS COME FROM?

Tears continually bathe the tough outer layer of the eyeball. The fluid is a secretion of the lachrymal glands and it helps to clear the eyes of foreign particles such as dust. Also, without tears the eyes would dry out which would result in blindness.

Two lachrymal glands, one over each eye, lie behind the eyelids. Their fluid enters through several small ducts in the underside of the lid. Each time the eyelid blinks, it sucks a little fluid from the glands.

After the tears pass across the eyeball, they flow out through two lachrymal ducts that open at the inner corner of each eye. Lachrymal fluid is mostly a salt solution that also helps fight bacteria and makes the eyes immune to infection.