You must have noticed that whenever somebody weeps, tears begin to fall from his eyes. When someone is very happy even then tears come to his eyes. Do you know why it happens? When we blink our eyes, many muscles come into play and the eyelids close and open just like stage curtains. The movement of the eyelids is so fast that it does not disturb our vision. The blinking of the eyes is an involuntary action that takes place every six seconds throughout our life. In each eye, there is a ‘tear gland‘ located at the outer corner. There are small tubes or ducts, which carry the tears to the upper eyelids, and from there they fall out of the eyes through other ducts. Every time we blink our eyes, some fluid comes out through the openings of the tear ducts. This keeps the eyes lubricated and prevents them from drying. When we weep, more fluid comes out through openings of the ducts in the form of tears. It is a reflex action that occurs without our control. Sometimes tears come out even when we laugh a great deal. That is because, when we laugh, the muscles squeeze the tear glands, due to which tears begin to flow out. Tears also come to our eyes when we cut onions because the onion gives off an irritating volatile substance. When it reaches our eyes, tears are produced to protect the eye from irritation. The tears ‘wash‘ the irritating substance away. The same thing happens in the case of smoke. Some sad news also produces tears by reflex action. This happens only when we do not have words to express our feelings.