nd is for that and other reasons an
excellent hygienic practise.

[Sidenote: Mental State]

The mode of our breathing is closely related to our mental condition;
either influences the other. Agitation makes us catch our breath, and
sadness makes us sigh. Conversely, slow, even breathing calms mental
agitation. It is not without reason that, in the East, breathing
exercises are used as a means of cultivating mental poise and as an aid
to religious life.

CHAPTER II

FOOD

Section I--Quantity of Food

The body has often been compared to a blacksmith's forge, the lungs
being the bellows and food the coal. The comparison is a good one, for
food is actually burned in the body by the aid of the air we breathe.

[Sidenote: Calories]

All food is capable of being used as body-fuel and by far the greater
part of it is so used. Consequently, food is measured in fuel-units,
called calories. Many people eat too much, that is, too many calories;
some eat too little, that is, too few calories. In both cases the person
is usually unaware of the fact, because he makes the mistake of
measuring his food by its weight or bulk. Some foods are concentrated,
that is, contain many calories of food value in a given bulk; others are
bulky, that is, contain few calories in a given bulk. For instance,
olive oil is concentrated, and most vegetables are bulky. A third of an
ounce of olive oil contains 100 calories, which is as much as is
contained in a pound or more of tomatoes, lettuce, celery, cucumbers,
string beans, asparagus, or watermelon.

It will help to give a picture of food values if, before going further,
we note how much it takes of some of the common foods to make a given
amount of food value, say 100 calories. It is surprising in how many
cases the ordinary amount of food served at table happens to contain
about 100 calories. We find 100 calories in a small lamb chop (weighing
about an ounce); in a large egg (about 2 ounces); in a small side-dish
of baked beans (about 3 ounces); in 11/2 cubic inches of cheese (about an
ounce); in an ordinary side-dish of sweet corn (about 31/2 ounces); in one
large-sized potato (if baked, about 3 ounces; if boiled, about
4 ounces); in an ordinary thick slice of bread (about 11/2 ounces); in one
shredded wheat biscuit (about an ounce); in a very large dish of oatmeal
(about 6 ounces); in a small piece of sponge-cake (about an ounce); in a
third of an ordinary piece of pie (about 11