copper and gold, iron and bronze have been used as metallic means of
exchange--that is, as money. So from the beginning of trade and
swapping article for article, it came to be common eventually to swap
an article for something called money and then use the money for the
purchase of other desirable articles. This made it possible for the
individual to carry about in a small compass the means of obtaining any
article in the market within the range of the purchasing power of his
money. Trade, transportation, and exchange not only had a vast deal to
do with economic progress but were of tremendous importance in social
development. They were powerful in diffusion, extension, and promotion
of culture.

_The Struggle for Existence Develops the Individual and the Race_.--The
remnants and relics of the arts and industries of man give us a fair
estimate of the process of man's mind and the accomplishment of his
physical labor. It is through the effort involved in the struggle for
existence that he has made his various steps forward. Truly the actual
life of primitive man tends to verify the adage that "necessity is the
mother of invention." It was this tremendous demand on him for the
means of existence that caused him to create the things that protected
and improved his life. It was the insistent struggle which forced him
to devise means of taking advantage of nature and thus led to invention
and discovery. Every new invention and every new discovery showed the
expansion of his mind, as well as gave him the means of material
improvement. It also added to his bodily vigor and added much to the
development of his physical powers. Upon this economic foundation has
been built a superstructure of intellectual power, of moral worth and
social improvement, for these in their highest phases of existence may
be traced back to the early beginnings of life, where man was put to
his utmost effort to supply the simplest of human wants.

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SUBJECTS FOR FURTHER STUDY

1. The change in social life caused by the cultivation of the soil.

2. The effect of the discovery and use of fire on civilization.

3. What was the social effect of the exchange of economic products?

4. What influence had systematic labor on individual development?

5. Show how the discovery and use of a new food advances civilization.

6. Compare primitive man's food supply with that of a modern city
dweller.

7. Trace a cup of coffee to