growing, apparently unchanged by time,
to all appearances immortal so long as they are periodically washed of
poison and nourished in a proper medium. If we could at intervals
thoroughly wash man free of his poisons and nourish him, there seems to
be no reason why he should not live indefinitely.

Section V--Hygiene and Civilization

In view of the vast extent of human misery from ill health, the question
naturally arises, How does it happen that the world is burdened with so
colossal a load? Is it no more than is biologically normal? Is it true
that in other organisms, animals and plants, ill health is the rule
rather than the exception? Are all races of men subject to the same
heavy load?

[Sidenote: Natural Adjustments Upset]

These questions have not yet received sufficient attention. The answer
seems to be that man is suffering from his own mistakes made
unconsciously and in ignorance. He has upset the equilibrium which
Nature had established among the various powers and activities of his
body, and between himself and the outside world. Man has done mischief
for his own body similar to what he has done for the natural resources
on which he lives. In Professor Shaler's epoch-making little book, "Man
and the Earth," he shows, for instance, that the little layer of soil
on the surface of the earth from which plants and animals derive their
nutriment was, before the advent of man, replenished quite as fast as it
was washed away, but that after man had put his plow into it and had
taken off the protective mat of vegetation, he unconsciously despoiled
the accumulation of ages. "In a plowed field, an hour's torrential rain
may wash off to the sea more than would pass off in a thousand years in
the slow process of erosion which the natural state of the earth
permits." He also shows that the constant croppings of the soil rob it
of nitrogen, phosphorus, and other elements faster than Nature restores
them. The problem of conservation is to reestablish the balance which
has been lost through the depredations of man, for instance, to lessen
soil-wash by terracing, and to restore to the soil the lost elements by
supplying nitrates and phosphates and by other methods of scientific
farming.

In the same way man has upset his pristine animal mode of living and
needs to find scientific ways to restore the equilibrium. Most of the
present-day problems of hygiene arise from introducing, uncompensated,
the effects of certain d