after all?

To a general in the battlefield, human life is a factor which, if properly
used, can destroy the enemy. To an engineer human life is an equivalent to
energy, or a capacity to do work, mental or muscular, and the moment
something is found to be a source of energy and to have the capacity of
doing work, the first thing to do, from the engineer's point of view, is
to analyse the generator with a view to discovering how best to conserve
it, to improve it, and bring it to the level of maximum productivity.
Human beings are very complicated energy-producing batteries differing
widely in quality and magnitude of productive power. Experience has shown
that these batteries are, first of all, chemical batteries producing a
mysterious energy. If these batteries are not supplied periodically with a
more or less constant quantity of some chemical elements called food and
air, the batteries will cease to function--they will die. In the
examination of the structure of these batteries we find that the chemical
base is very much accentuated all through the structure. This chemical
generator is divided into branches each of which has a very different role
which it must perform in harmony with all the others. The mechanical parts
of the structure are built in conformity to the rules of mechanics and are
automatically furnished with lubrication and with chemical supplies for
automatically renewing worn-out parts. The chemical processes not only
deposit particles of mass for the structure of the generator but produce
some very powerful unknown kinds of energies or vibrations which make all
the chemical parts function; we find also a mysterious apparatus with a
complex of wires which we call brain glands, and nerves; and, finally,
these human batteries have the remarkable capacity of reproduction.

These functions are familiar to everybody. From the knowledge of other
physical, mechanical and chemical phenomena of nature, we must come to the
conclusion, that this human battery is the most perfect example of a
complex engine; it has all the peculiarities of a chemical battery
combined with a generator of a peculiar energy called life; above all, it
has mental or spiritual capacities; it is thus equipped with both mental
and mechanical means for producing work. The parts and functions of this
marvelous engine have been the subject of a vast amount of research in
various special branches of science. A very noteworthy fact is that b