Gwen Ann Youngblood, aged 7, of Tulsa, Okla., for her question:

Why are our tears salty?

Did you know that your heart must float in a salty bath? This is also true of the lungs, liver and kidneys, In fact, this salty bath is necessary for all the organs and tissues Inside the skin.

The body provides this bath of salt for itself. Every inside cell is moist and damp with body fluids. The body uses the food you eat and the liquids you drink to make these special fluids. And they are special. The brews must be just right. Each mixture contains minerals and chemicals ‑ Just enough and not too much. And one of the most necessary chemicals is salt ‑ ordinary salt.

Sometimes these body fluids leak outside the skin. Then you can taste the salt in them for yourself. Blood, sweat and tears all have a salty taste. Lost salt must be replaced. On a hot day you perspire a. lot. The body must get more salt to make good the loss. Travelers in hot deserts carry salt tablets to make up the salt lost by perspiration. Normally we get our supply of salt as we season our food. A grown man has about one‑‑third of a pound of salt inside his body.

Tears, of course, are one of the body's fluids. They are formed in little glands under the upper eyelids. They have special work to do all the time ‑ not just on special occasions. The moist tear fluid provides a soothing bath for the sensitive eyes. Eyes must be kept moist all the time. And there must be salt in their bath water. The tears provide this proper fluid.

The eyelids work like little windshield wipers. They blink and blink, spreading just enough and not too much tear juice over the eyes. The used moisture funs down a tiny, tiny tube into the back of the nose. You can see the opening of this little tube at the nose end of your lower eyelid.

Now blink hard several times. You can feel an extra supply of tear juice flowing into your eyes. The muscles around your eyes have squeezed the tear glands, forcing out more juice. This also happens when you laugh a lot ‑ and also when you cry,

When tears flow freely they cannot drain away fast enough. Remember the tube that drains off the moisture is very, very small. It carries as much of the extra tear juice as it can down the back of your nose. You sniffle and your nose runs.

The extra tears slop all over the place. They run down your cheeks and off your chin. It's all very embarrassing. It is because the tear drain cannot handle this extra duty. Their real job is to keep the eyes bathed in a soothing flow of salty moisture.