Hydrogen and oxygen combined form water, hence we find from the above
calculation that about three-fifths of the body is composed of water.
Carbon is a solid: diamonds are nearly pure carbon; "lead" of lead
pencils, anthracite coal and coke are impure forms of carbon. Carbon
combined with other elements in the body makes about one-fifth of the
whole weight. Carbon with oxygen will burn. In this way the carbon
taken into the body as food, when combined with the oxygen of the
inhaled air, yields heat to keep the body warm, and force--muscular
strength--for work. The carbonic acid (or carbon dioxide) is given out
through the lungs and skin. In the further study of carbonaceous
foods, their relation to the body as fuel will be more clearly
understood, as carbon is the most important fuel element. Phosphorus
is a solid. According to the table, about one pound six ounces would
be found in a body weighing 148 pounds. United with oxygen, phosphorus
forms what is known as phosphoric acid; this, with lime, makes
phosphate of lime, in which form it is found in the bones and teeth;
it is found also in the brain and nerves, flesh and blood. Hydrogen is
a gas, and like carbon unites with the oxygen of the inhaled air in
the body, thus serving as fuel. The water produced is given off in the
respiration through the lungs and as perspiration through the skin.[3]
Calcium is a metal. The table given allows three pounds of calcium;
united with oxygen, calcium forms lime. This with phosphoric acid
makes phosphate of lime, the basis of the bones and teeth, in which
nearly all the calcium of the body is found.

The elements which bear no direct relation to the force production of
the body, but which enter into tissue formation, are chlorine,
sulphur, iron, sodium, potassium, phosphorus, calcium and magnesium.
Bone tissue contains about 50 per cent. of lime phosphate, hence the
need of this substance in the food of a growing infant, in order that