ides; and
so capital goods come and go, but a stock of them abides, kept up by
perpetual replacement. We may trace the career of any single
instrument from a beginning to an end; but we may, on the other hand,
cease to look at any instruments that we single out and identify and
look rather at the procession of them; and if we do this, we look at a
body which never wastes away, though the things that compose it are,
separately considered, forever wasting.

There are many kinds of transient things which, by the same process of
renewal, constitute permanent entities. Composing a human body at this
moment are certain tissues that can be separately identified; and if
we watch any one of them, we shall see it going in a short time to
destruction. Yet the body lasts while life continues. Indeed, the
evidence of the life itself is the discarding and replacing of the
tissues. A living body is a durable thing, though the particular
tissues that at any one time compose it are not so. In a like way
drops of water make a river, and this is a permanent thing, however
rapidly its composition changes. The waterfall that drives the
machinery of a mill is permanent, though no particular particle of
water remains in it for more than a moment. Society is permanent,
though the men who compose it are short-lived. In an exactly similar
way a body of capital goods is maintained as a perpetual
instrumentality of production. _This is capital properly so called._
It is, as it were, a quasi-living body, perpetuated by the constant
replacement of the component parts, which are destroyed as its normal
activities go on.

_The Difference between Capital Goods and Capital Summarized._--The
distinction between capital goods, on the one hand, and capital, on
the other, is, then, like that between particular tissues and a living
body, or like that between particular particles of water in the river
and the river that flows forever. We can single out and watch certain
drops of the water as they flow from a spring, and we can trace them
through their brief careers, and say truly that the river is composed
of fickle and transient stuff; but we cannot say that the river is
transient. That is perpetuated by the renewing of the supply of water
as the original drops disappear. We can mentally watch a particular
man, as he enters the social force of workmen, labors for a time, and
drops out of the line, and can see that society is composed of
transient material