It affects the brain of a cow. Its origins are believed to be from cattle feed which contained lamb's infected intestines. It has been noticed in Europe more than a decade ago. These glands secrete tears which keep the eyes moist and free from dust. Tears come from our eyes when the eyes are irritated with dust.
Tears come out also a reflex action to human emotions.
Q. Mercury is a poisonous liquid. So doctors prefer to keep the thermometer on the fore head. Thermometers are made up of hard glass casings inside which the mercury is kept. There is no data to show that working before a computer for more than 7 hours is harmful to the eyes. Depending on each person, the contrast of the screen has to be adjusted to give minimum strain on the eyes.