The average body of a human being contains about three pounds of calcium. Most of this is found in the bones. Calcium is an essential part of the structure of the bone.

We might, in fact, compare the structure of a bone to reinforced concrete. The bone has certain fibers called collagen fibers which are like the flexible iron wires often embedded in concrete. Calcium forms the bed in which these bone fibers are fixed.

The calcium content of our bones changes as we grow older. During the first year, a chilies bones have little calcium and great flexibility. A child can perform ah kinds of contortions without breaking any bones. By the time a man is eighty, his bones may be 80 per cent calcium and break easily.

One of the reasons young children are urged to drink a great deal of milk is that milk is the ideal calcium containing food, and, of course, young bodies need plenty of calcium for their bones. One quart of cow’s milk contains almost two grams of calcium. Cheese, buttermilk, and yogurt also supply great quantities of calcium.

In those parts of the country where calcium is hard to obtain, people have trouble with their teeth and often suffer from bone fractures. A frequent cause of calcium deficiency is the practice of making hard water soft by removing the calcium from it.

Hard water interferes with the lathering of soap. The calcium in hard water combines with acids and salts in the soap and produces compounds which don’t dissolve.

The practice of removing calcium from hard water also has a bad effect on the foods cooked in the water. If the water has a low calcium content, foods cooked in it actually lose part of their own calcium to the water. But foods will gain in calcium content when cooked in hard water with a high calcium content.