l
salts--therefore it is not necessary to know about them. They further
argue that their grandfathers never heard of calories and they got along
all right. That grandfather argument always enrages my mortal mind.

[Sidenote: _A Unit of Measure_]

Now you know that a calorie is a unit of measuring heat and food. It is
not heat, not food; simply a unit of measure. And as food is of supreme
importance, certainly a knowledge of how it should be measured is also
of supreme importance.

[Sidenote: _Yes, They Are Kosher_]

You should know and also use the word calorie as frequently, or more
frequently, than you use the words foot, yard, quart, gallon, and so
forth, as measures of length and of liquids. Hereafter you are going to
eat calories of food. Instead of saying one slice of bread, or a piece
of pie, you will say 100 Calories of bread, 350 Calories of pie.

The following is the way the calorie is determined:

An apparatus known as the bomb calorimeter has two chambers, the inner,
which contains the dry food to be burned, say a definite amount of
sugar, and an outer, which is filled with water. The food is ignited
with an electric connection and burned. This heat is transferred to the
water. When one pound of water is raised 4 degrees Fahrenheit, the
amount of heat used is arbitrarily chosen as the unit of heat, and is
called the Calorie.

Food burned (oxydized) in the body has been proved to give off
approximately the same amount of heat or energy as when burned in the
calorimeter.

[Sidenote: _Approximate Measures_]

1 oz. Fat = 275 C.
--about 255 in the body.

1 oz. Protein (dry) = 120 C.
--about 113 in the body.

1 oz. Carbohydrates (dry) = 120 C.
--about 113 in the body.

(ROSE.)

Can you see now why fats are valuable? Why they make fat more than any
other food? They give off more than two and one-fourth times as much
heat, or energy, as the other foods.

[Sidenote: _See Next Chapter for Definitions_]

Notice that protein and carbohydrates have the same food value as to
heat or energy, each 113 Calories to the dry ounce. However, they are
not interchangeable; that is, carbohydrates will not take the place of
protein for protein is absolutely necessary to build and repair tissue,
and carbohydrates cannot do that. But fats and carbohydrates are
interchangeable as fu