t Nature and how she works. After many years they knew much more and
were also far more comfortable than those people who continued to live
where Nature supplied everything.

There are now so many more people on the earth than there were long ago
that to furnish them all with food is a very great task. Besides, there
are now many people engaged in work other than farming, hunting, and
fishing. All such people have to be provided for by those whose business
it is to get food. People of the great cities are dependent upon those
in the country for all that they eat! We can picture to ourselves the
suffering that would follow if for only one week every one had to get
his own food.

We need many things that the first people thought nothing about, because
their manner of life was so much simpler than ours. Let us see now what
they are.

We live in tightly closed houses, and so have less trouble in keeping
warm and dry. But we do not always get the supply of fresh air that we
need. Many of us are sickly and weak because of this. Our ancestors
lived in the open air, which is always pure and fresh. A supply of pure
air, then, is one of the things that we must now provide for.

People once gave no thought to the purity of the water that they drank.
When there were few people, water did not easily become impure. One
could drink water wherever one found it and there was small risk of
harm. Now in many places there are so many thousands of people gathered
together that they have to take the greatest care about drinking water,
in order to keep in good health. To get pure water it is often necessary
to bring it many miles from mountainous regions where no one lives.

Clothing is another thing that concerns us very much. Our ancestors were
not troubled about their clothing. In the warm countries they went
almost naked. Where it was cold the skins of animals served very well.
Changes of fashion did not disturb them and cause them to throw away
warm covering. To supply ourselves now with clothing we call upon Nature
for many things. As she cannot, without our help, furnish what we need,
we have to keep a great number of flocks, for their wool and skins, and
cultivate vast fields of cotton and flax.

When Nature raised in her own way the berries, grains, and roots that
the first men ate, no thought was given to the soil in which these
things grew. In truth, it was not necessary to pay any attention to the
soil. Nature is very carefu