ven especial attention to this subject, after quoting the
preceding remark of Dr. Clark, adds: "We believe this is the opinion of
all medical men who have studied the constitution of man, and its
relation to outward objects."

A distinguished surgeon[14] of Leeds, England, goes somewhat further in
praising pure air than most of his contemporaries. "Be it remembered,"
says he, "that man subsists more upon air than upon his food and
drink." There is some novelty in this remark, I admit: but is it not
truthful? Men have been known to live _three weeks_ without eating. But
exclude the atmospheric air from the lungs for the space of _three
minutes_, and death generally ensues. We thus see that life will
continue with abstinence from food three thousand times as long as it is
safe to protract an atmospheric fast.

[14] Dr. Thackrah, author of a most valuable work on the "Effects of
Employments on the Health and Longevity of Mankind."

Let us take another view of the subject. Men usually eat _three times_
in twenty-four hours. This is all that is necessary to, or compatible
with, the enjoyment of uninterrupted good health. But we involuntarily
breathe nearly _thirty thousand times_ in the same length of time. We
need, then, fresh supplies of pure air ten thousand times as often as it
is necessary to partake of meals. Is it not apparent, then, that _man
subsists more upon_ AIR _than upon his_ FOOD _and_ DRINK?

The atmosphere which we so frequently inhale, and upon which our
well-being so much depends, surrounds the earth to the height of about
forty-five miles. The surface of the earth contains about two hundred
millions of square miles, and it is estimated that there dwell upon it
eight hundred millions of inhabitants. This gives to each individual
about eleven cubic miles of air. But the air is breathed by the inferior
animals as well as by man. It is also rendered impure by combustion. If
by both of these causes ten times as much air is consumed as by man,
there is still left one cubic mile of uncontaminated atmospheric air to
every human being dwelling upon the surface of the earth. This would
allow him to live more than twice the age allotted to man, without
breathing any portion of the atmosphere a second time. And still, as if
to avoid the possibility of evil to man on this account, the beneficent
Creator has wisely so ordered, that while we do not interfere with the
laws of Nature, there is not even the poss