on of the cells.
While salt is a necessary food, in large amounts, as when the attempt is
made to use sea water as a beverage, it acts as a poison, suggesting
that a material may be both a food and a poison. When sodium chloride is
entirely withheld from an animal, death from salt starvation ensues.
Many foods contain naturally small amounts of sodium chloride.

4. Organic Matter.--That portion of a food material which is converted
into gaseous or volatile products during combustion is called the
organic matter. It is a mechanical mixture of compounds made up of
carbon, hydrogen, oxygen, nitrogen, and sulphur, and is composed of
various individual organic compounds, as cellulose, starch, sugar,
albumin, and fat. The amount in a food is determined by subtracting the
ash and water from 100. The organic matter varies widely in composition;
in some foods it is largely starch, as in potatoes and rice, while in
others, as forage crops consumed by animals, cellulose predominates. The
nature of the prevailing organic compound, as sugar or starch,
determines the nutritive value of a food. Each has a definite chemical
composition capable of being expressed by a formula. Considered
collectively, the organic compounds are termed organic matter. When
burned, the organic compounds are converted into gases, the carbon
uniting with the oxygen of the air to form carbon dioxide, hydrogen to
form water, sulphur to form sulphur dioxide, and the nitrogen to form
oxides of nitrogen and ammonia.

5. Classification of Organic Compounds.--All food materials are
composed of a large number of organic compounds. For purposes of study
these are divided into classes. The element nitrogen is taken as the
basis of the division. Compounds which contain this element are called
nitrogenous, while those from which it is absent are called
non-nitrogenous.[2] The nitrogenous organic compounds are composed of
the elements nitrogen, hydrogen, carbon, oxygen, and sulphur, while the
non-nitrogenous compounds are composed of carbon, hydrogen, and oxygen.
In vegetable foods the non-nitrogenous compounds predominate, there
being usually from six to twelve parts of non-nitrogenous to every one
part of nitrogenous, while in animal foods the nitrogenous compounds are
present in larger amount.

NON-NITROGENOUS COMPOUNDS

6. Occurrence.--The non-nitrogenous compounds of foods consist mainly
of cellulose, starch, sugar, and fat. For purposes of study, they are