Stonehouse, age 12, of St. Catharines, Ontario, Canada, for his question:

Is it true that the body is 98 per cent water?

The average 12 year old boy tips the scales at about 100 pounds    and water makes up between 65 and 70 pounds of his total weight. This is quite a bit less than 98 per cent, but even so, the amount is amazing. After all, one’s body seems to be such a firm and solid possession    especially tough items such as bones. True, blood and tears appear to be watery liquids. But tears are rare and the body has only five quarts of liquid blood. However, the bulk of its moisture is in the secret cells  ¬and careful analysis reveals water even in the solid bones.

If the body were 98 per cent water, then only 2 per cent of its contents would be solid materials. In this case, it would be about as mushy as a jellyfish. Scientists estimate its actual water content to be between 65 per cent and 70 per cent of the total poundage. This means that somewhat more than one third of the body’s weight is solid material. However, biologists assure us that, without water, these solid ingredients would be as useless as a piles of dust. Quantities of streaming water are needed to transform these basic ingredients into living biological miracles.

These miniature rivers, of course, are trillions of living cells, working together in elaborate systems to keep all the body’s operations in balance. Water is necessary to carry on the complex electrochemical activities of every cell. Hence, water is the major component of cytoplasm, the jellified substance of cell tissue. Cells assigned to special duties involving electrical impulses contain more than the average quota    and brain cells are very watery. Bones are built from calcium and other sturdy materials. But microscopic analysis reveals that they are delicate openwork structures.. And chemical analysis reveals that 35 per cent to 50 per cent of the bony human skeleton is actually composed of water.

All this cellular moisture is used to create an enormous variety of precisely balanced chemical solutions. It suspends microscopic particles and keeps them mobile and available for cellular activity. The water in the body also provides the major transportation circuits that link all its systems together. The pale, liquid lymph seeps through the cell tissue, bearing essential nutrients and carrying away waste materials. The.blood is a stream of water crowded with an assortment of special cells,